Functional Anatomy of the Cervical Spine: Difference between revisions

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<div class="editorbox"> '''Original Editor '''- [[User:Robin Tacchetti|Robin Tacchetti]] based on the course by [https://members.physio-pedia.com/course_tutor/daphne-xuan/ Daphne Xuan]<br>
'''Top Contributors''' - {{Special:Contributors/{{FULLPAGENAME}}}}</div>


== Introduction ==
== Introduction ==
The cervical spine supports and promotes movement of the head and neck. <ref>Frost BA, Camarero-Espinosa S, Foster EJ. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6356370/ Materials for the spine: anatomy, problems, and solutions]. Materials. 2019 Jan;12(2):253</ref> <ref name=":0">Kaiser JT, Lugo-Pico JG. [[Anatomy, Head and Neck, Cervical Vertebrae]]. 2019.</ref>The cervical spine is subjected to extrinsic factors such as repetitive movements, whole body vibrations and static load.<ref>Petersen JA, Brauer C, Thygesen LC, Flachs EM, Lund CB, Thomsen JF. [https://bmjopen.bmj.com/content/12/2/e053999 Prospective, population-based study of occupational movements and postures of the neck as risk factors for cervical disc herniation]. BMJ open. 2022 Feb 1;12(2):e053999.</ref>  
The cervical spine supports the weight of the head and enables head and neck movement.<ref>Frost BA, Camarero-Espinosa S, Foster EJ. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6356370/ Materials for the spine: anatomy, problems, and solutions]. Materials. 2019 Jan;12(2):253</ref> <ref name=":0">Kaiser JT, Reddy V, Lugo-Pico JG. Anatomy, Head and Neck: Cervical Vertebrae. [Updated 2022 Oct 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539734/</ref> Intervertebral discs maintain the spaces between the vertebrae. These discs act like shock absorbers throughout the spinal column to cushion the bones as the body moves. Ligaments hold the vertebrae in place, and tendons attach the muscles to the spinal column. The cervical spine is subjected to a range of extrinsic factors such as repetitive movements, whole-body vibrations and static load.<ref>Petersen JA, Brauer C, Thygesen LC, Flachs EM, Lund CB, Thomsen JF. [https://bmjopen.bmj.com/content/12/2/e053999 Prospective, population-based study of occupational movements and postures of the neck as risk factors for cervical disc herniation]. BMJ open. 2022 Feb 1;12(2):e053999.</ref>[[File:C-spine-picture.jpg|thumb|250x250px|Cervical spine]]
 
== Key Terms ==
== Key Terms ==
[[Cardinal Planes and Axes of Movement|Axes]]: lines around which an object rotates. The rotation axis is a line that passes through the centre of mass. There are three axes of rotation: ''sagittal'' passing from posterior to anterior, ''frontal'' passing from left to right, and ''vertical'' passing from inferior to superior. The rotation axes of the foot joints are perpendicular to the cardinal planes. Therefore, motion at these joints results in rotations within three planes. Example: supination involves inversion, internal rotation, and plantarflexion.
[[Cardinal Planes and Axes of Movement|Axes]]: lines around which an object rotates. The rotation axis is a line that passes through the centre of mass. There are three axes of rotation: ''sagittal'' passing from posterior to anterior, ''frontal'' passing from left to right, and ''vertical'' passing from inferior to superior. The rotation axes of the foot joints are perpendicular to the cardinal planes. Therefore, motion at these joints results in rotations within three planes. Example: supination involves inversion, internal rotation, and plantarflexion.


[[Bursitis|Bursae]]: reduce friction between the moving parts of the body joints. A bursa is a fluid-filled sac. There are four types of bursae: adventitious, subcutaneous, [[/www.physio-pedia.com/Synovial Fluid Analysis|synovial]], and sub-muscular.
[[Bursitis|Bursae]]: reduce friction between the moving parts of the body joints. A bursa is a fluid-filled sac. There are four types of bursae: adventitious, subcutaneous, [[Synovial Fluid Analysis|synovial]], and sub-muscular.


[[Capsular and Non-Capsular Patterns|Capsule]]: one of the characteristics of the synovial joints. It is a fibrous connective tissue which forms a band that seals the joint space, provides passive and active stability and may even form articular surfaces for the joint. The capsular pattern is "the proportional motion restriction in range of motion during passive exercises due to tightness of the joint capsule."
[[Capsular and Non-Capsular Patterns|Capsule]]: one of the characteristics of the synovial joints. It is a fibrous connective tissue which forms a band that seals the joint space, provides passive and active stability and may even form articular surfaces for the joint. The capsular pattern is "the proportional motion restriction in range of motion during passive exercises due to tightness of the joint capsule."


Closed pack position: the position with the most congruency of the joint surfaces. In this position, joint stability increases. For example, the closed pack position for the interphalangeal joints is a full extension.
Closed pack position: the position with the most congruency of the joint surfaces. In this position, joint stability increases. For example, the closed pack position for the interphalangeal joints is full extension.


Degrees of freedom: the direction of joint movement or rotation; there is a maximum of six degrees of freedom, including three translations and three rotations.
Degrees of freedom: the direction of joint movement or rotation; there is a maximum of six degrees of freedom, including three translations and three rotations.
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== Cervical Spine Structure ==
== Cervical Spine Structure ==


=== '''Cervical vertebrae''' ===
=== Cervical Vertebrae===
There are seven lumbar vertebrae, which are known as C1-C7.   Considering the small weight-bearing load of the cervical spine, large vertebral bodies are not required. In this section of the spine, vertebral size is not as important as flexibility and range of motion. Increased movement correlates to a heightened injury potential of the spinal cord and its associated neurovascular structures.<ref name=":0" />
There are seven cervical vertebrae, which are known as C1-C7. Their role is to support the head and neck and to promote head movement. The cervical spine is only exposed to small weight-bearing loads. Therefore, the cervical vertebral bodies do not need to be large and "an increased range of motion takes priority over vertebral size and rigidity".<ref name=":0" /> However, because of this increased range of motion at the cervical spine, there is a heightened injury risk for the spinal cord and the associated neurovascular structures.<ref name=":0" />
 
The cervical vertebral bodies (C3-C6) have unique characteristics:<ref name=":0" /><ref name=":1">Teach me anatomy The cervical Spine Available from:https://teachmeanatomy.info/neck/bones/cervical-spine/</ref>
 
* vertebral bodies are smaller compared to the rest of the spine
* vertebral foramen is triangular
* spinous process is bifid (i..e. it splits into two distally)
* there are openings in the transverse processes which allow passage for the vertebral artery, vein, and sympathetic nerves
 
The Atlas (C1), Axis (C2) and C7 have further distinguishing features:
 
<div class="row">
<div class="col-md-8 ">[[Atlas]] (C1)<br>
* has no vertebral body or spinous process
* instead, it has lateral masses for articulation with the occiput of the head and the second cervical vertebra (the Axis)
</div>
<div class="col-md-4">[[File:Cervical vertebra 1 close-up bottom (1).png|thumb|200x200px|Atlas - C1]]<br>
</div>
</div>
 
<div class="row">
<div class="col-md-8 ">[[Axis]] (C2)<br>
* has a bony projection from the anterior portion called the dens, or the odontoid process, which articulates with the atlas
* it is the primary weight-bearing bone of upper cervical region
</div>
<div class="col-md-4">[[File:Cervical vertebra 2 close-up bottom.png|thumb|200x200px|Axis - C2]]<br>
</div>
</div>
 
<div class="row">
<div class="col-md-8 ">C7<br>
* singular spinous process
* larger spinous process
* spinous process is not bifid
</div>
<div class="col-md-4">[[File:Cervical vertebrabifud.jpg|thumb|C3-C6]]<br>
</div>
</div>
<nowiki>**</nowiki>In supine, it may be difficult to palpate the spinous process of C3-C6 in individuals with normal cervical lordosis.
 
=== Intervertebral Discs (IVD) ===
The intervertebral discs make up 25% of the height of the entire spine. However, in the cervical region, they make up 40% of the height. This increased height relative to vertebral body height provides a mobility advantage.<ref name=":2">Learn muscles . Cervical spine joints. Available from: https://learnmuscles.com/blog/2017/08/01/cervical-spinal-joints/ (last accessed 29.1.2020)</ref>
 
The nucleus pulposus of the cervical discs is gelatinous in children and young people. However, it dries out by the age of 30 years and becomes a firm, fibrocartilaginous plate.<ref>Peng B, Bogduk N. [https://academic.oup.com/painmedicine/article/20/3/446/5232305?login=false Cervical discs as a source of neck pain. An analysis of the evidence.] Pain Medicine. 2019 Mar 1;20(3):446-55.</ref>[[File:Cervical Vertebra Unlabeled.jpg|thumb|Intervertebral disc]]
The following are characteristics of the cervical spine intervertebral discs:
 
* thicker anteriorly than posteriorly
* concave superior surface
* convex inferior surface
* movement limited by the uncinate process
* anteroposterior translation does occur
 
<nowiki>**</nowiki> Due to the location of the uncinate process, posterolateral disc herniations are less frequent.
=== Cervical Lordosis ===
Typically, the cervical spine has a lordotic curvature. A lordotic posture can resist large compressive loads. It also helps to decrease stress on vertebral end plates. Compressive loads are distributed differently in the cervical spine than in the thoracic and lumbar spine. In the cervical spine, the anterior column absorbs 36% of the load, and the posterior facet (zygapophyseal) joints absorb 64%.<ref>Guo GM, Li J, Diao QX, Zhu TH, Song ZX, Guo YY, Gao YZ. [https://josr-online.biomedcentral.com/articles/10.1186/s13018-018-0854-6 Cervical lordosis in asymptomatic individuals: a meta-analysis. J]ournal of orthopaedic surgery and research. 2018 Dec;13(1):1-7.</ref>
== Kinematics and Joints of the Cervical Spine ==
[[File:Cervical spine exercises.png|thumb|Range of Motion in Cervical Spine]]
The cervical spine is the most mobile part of the vertebral column. 
 
'''Flexion''' range of motion is usually around 40 degrees, and extension is around 50 degrees. The largest contributors to flexion/extension are:   
 
* C4/C5 and C5/C6 in sitting
* C6/C7 in supine
 
C7/T1 contributes the least to flexion/extension.   
 
'''Lateral flexion''' range of motion is normally close to 30 degrees. C3/C4 and C6/C7 allow for the most movement in this plane of motion. 


Cervical '''rotation''' range of motion is usually close to 70 degrees. Flexibility in this plane is mainly achieved through the C1/C2 segment.<ref>Lindenmann S, Tsagkaris C, Farshad M, Widmer J. [https://link.springer.com/article/10.1007/s10439-022-03088-8 Kinematics of the Cervical Spine Under Healthy and Degenerative Conditions: A Systematic Review]. Annals of Biomedical Engineering. 2022 Dec 10:1-29.</ref>
{| class="wikitable"
{| class="wikitable"
|+'''Cervical Spine Vertebral Bodies'''
|+'''Joints of the Cervical Spine'''<ref name=":2" /><ref>RSNA Joints of Luschka Available from: https://pubs.rsna.org/doi/10.1148/66.2.181 (last accessed 28.1.2020)</ref>
! '''C spine'''
!Joint
!              '''C3-C6'''
!Location/Articulations
!             '''Atlas'''
!Function
!                 '''Axis'''
!Orientation/Composition
!           '''C7'''
|-
|-
|<small>Features</small>
|'''Intervertebral Disc Joint'''
|
|
* <small>triangular vertebral foramen</small>
* <small>Between the vertebral bodies</small>
* <small>bifed spinous process</small>
* <small>transverse foramina (space for nerves and vasculature</small>
|
|
* <small>no spinous process</small>
*<small>Bear weight</small>
* <small>no vertebral body</small>
* <small>Facilitate motion</small>
* <small>Absorb shock</small>
|
|
* <small>odontoid process (dens) extending superiorly from anterior portion of the vertebra</small>
|
* <small>singular spinous process</small>
* <small>larger spinous process</small>
|-
|-
|<small>Articulations</small>
|<small>'''Facet (Zygapophyseal) Joints'''</small>
|<small>.</small>
|
|
# <small>occiput via superior and inferior facets</small>
* <small>Formed by articulations between the superior and inferior articular processes of adjacent vertebrae</small>
# <small>axis through lateral masses</small>
|
|
* <small>anterior arch of the atlas</small>
*<small>Guide motion at the segmental level</small>
* <small>Determine the direction of motion</small>
|
|
|}
* <small>Upper cervical spine =  horizontal</small>
 
* <small>Lower cervical spine = more vertical</small>
 
<ref name=":1">Teach me anatomy The cervical Spine Available from:https://teachmeanatomy.info/neck/bones/cervical-spine/</ref><ref name=":0" />
{| class="wikitable"
|+'''Joints of  Cervical Spine'''
!'''Joints'''
!'''Disc Joint'''
!'''Facet Joint or Zygapophyseal joints'''
!'''Uncovertebral'''
!'''Atlanto-axial'''
!'''Atlanto-occipital'''
|-
|-
|<small>Location/articulations</small>
|<small>'''Uncovertebral Joint'''</small>
|
* <small>between vertebral bodies</small>
|
|
* <small>formed by articulations of superior and inferior articular processes from adjacent vertebrae</small>
*<small>Between the five lower cervical vertebral bodies</small>
* <small>Anteromedially to the nerve root</small>
* <small>Posteromedially to the vertebral artery</small>
|
|
* <small>between 5 lower cervical vertebral bodies</small>
* <small>Control movement</small>
* <small>anteromedially to nerve root</small>
* <small>Limit lateral flexion</small>
* <small>posteromedially to vertebral artery</small>
|
|
* <small>between atlas an axis</small>
* <small>2 lateral: interior facetws of lateral masses of C1 and superior facets of C2</small>
* <small>1 medial: between dens C2 and articular facet C1</small>
|
* <small>between spine and cranium</small>
* <small>between superior facets of lateral masses of the atlas and the occipital condyles</small>
|-
|-
|<small>Functions</small>
|<small>'''Atlanto-Axial Joint'''</small>
|
|
# <small>bear weight</small>
* <small>Between the atlas and axis</small>
# <small>facilitate motion</small>
* <small>Two lateral: interior facets of the lateral masses of C1 and superior facets of C2</small>
# <small>absorb shock</small>
* <small>One medial: between the dens of C2 and the articular facet of C1</small>
|
|
# <small>guide motion at the segmental level</small>
* <small>Cervical rotation (60% of cervical rotation occurs at this joint)</small>
# <small>determine direction of motion</small>
|
|
# <small>control movement</small>
* <small>Lateral: plane-type synovial joint</small>
# <small>limit lateral flexion</small>
* <small>Medial: pivot-type synovial joint</small>
|
# <small>allow cervical rotation</small>
|
# <small>flexion and extension of the head on the neck</small>
# <small>lateral flexion</small>
|-
|-
|<small>Orientation/Composition</small>
|<small>'''Atlanto-Occipital Joint'''</small>
|
|
* <small>Between the spine and cranium</small>
* <small>Between the superior facets of the lateral masses of the atlas and the occipital condyles</small>
|
|
# <small>upper c-spine- horizontal</small>
* <small>Flexion and extension of the head on the neck</small>
# <small>lower-more vertical</small>
* <small>Lateral flexion</small>
|
|
|
* <small>median: pivot-type synovial joint</small>
* <small>Condyloid-type synovial joint</small>
* <small>lateral: plane -type synovial joint</small>
|
* <small>condyloid-type synovial joint</small>
|}
|}
<ref name=":2">Learn muscles . Cervical spine joints. Available from: https://learnmuscles.com/blog/2017/08/01/cervical-spinal-joints/ (last accessed 29.1.2020)</ref><ref>RSNA Joints of Luschka Available from: https://pubs.rsna.org/doi/10.1148/66.2.181 (last accessed 28.1.2020)</ref>


== Intervertebral Disc (IVD) ==
== Spinal Ligaments ==
In general, intervertebral discs involve 25% of the height of the entire spine.  In the cervical region, the discs compromise 40% of the height.  This increased height compared to vertebral body height gives the advantage of greater range of motion potential. <ref name=":2" />Disks are thicker anteriorly than posteriorly to enable the lordotic curvature of the cervical spine. The nucleus pulposus of cervical discs dries out by the age of 30 to a firm, fibrocartilaginous plate.<ref>Peng B, Bogduk N. [https://academic.oup.com/painmedicine/article/20/3/446/5232305?login=false Cervical discs as a source of neck pain. An analysis of the evidence.] Pain Medicine. 2019 Mar 1;20(3):446-55.</ref>
Ligaments present throughout the entire vertebral column:
* Coronal plane
** concave superior surface 
** convex inferior surface to conform to adjacent vertebral bodies
** movement limited by uncinate process
** anteroposterior translation does occur
<nowiki>**</nowiki> Due to location of uncinate process, posterolateral disk herniations are less frequent
 
* Cartilaginous endplate
** composed of hyaline cartilage
** located adjacent to the subchondral bone.
** serves as a barrier to nucleus pulposus pressure on the vertebral body
*** limiting protrusion
 
''<br />''
=== ''Cervical Lordosis'' ===
''Lordosis = the natural curve for the lumbar spine. This curve defines lumbar spine alignment in the saggital plane. However, the pelvis is "the cornerstone of spinal sagittal alignment". The curve of the sacrum determines the lumbar curve.''
 
''.''
 
== ''Bones, Articulations and Kinematics of the Lumbar Spine'' ==
=== ''Bones and Articulations'' ===
=== ''Kinematics'' ===
''The lumbar spine is considered a three-joint complex or an articular triad. The zygapophyseal (facet) joints and intervertebral disc joint are part of a "spinal motion segment". The various parts of the spinal motion segment work together to allow spinal motion and to protect the spine from excessive movements.''


''The spinal motion segment has the following characteristics:''
# Anterior longitudinal ligament: anterior surface of the vertebral bodies; limits extension of the spine
# Posterior longitudinal ligament: posterior surface of the vertebral bodies; limits flexion of the spine
# Ligamentum flavum: connects the laminae of each vertebrae; series of short ligaments
# Intertransverse ligament: a series of short ligaments that connect the laminae of each vertebrae; preserves upright posture and prevents hyperflexion of the spine<ref name=":3" />


* ''The intervertebral disc joint transmits mostly vertical compressive loads''
* ''The facet joints guide and stabilise the motion segment''
* ''In an erect standing position and erect sitting posture, spine load is also transmitted through the facet joints''
'''normal flexion range of about 40 degrees. Note that because all of these muscles are paired, they ha'''
'''Here we can see it overlaid with the goniometer showing a normal extension range of around 50 degree'''
'''Here we can see it overlaid with the goniometer showing a normal lateral flexion range of around 30 degrees. N'''
{| class="wikitable"
{| class="wikitable"
|+
|+'''Ligaments Unique to the Cervical Spine'''
!''Joint''
!'''<small>Ligament</small>'''
!''Type of joint''
!'''<small>Origin</small>'''
!''Plane of movement''
!'''<small>Insertion</small>'''
!''Motion''
!'''<small>Role/Function</small>'''
!''Kinematics''
!''Closed pack position''
!''Open pack position''
|-
|-
|[[Intervertebral disc|''Intervertebral disc joint'']]
|<small>'''Nuchal ligament'''</small>
|''Cartilaginous joint, symphysis''
|<small>Occiput</small>
|''A single joint: structurally fused but allows very limited, multidirectional movements''
|<small>Tips of the spinous process from C1-C7</small>
''All lumbar intervertebral disc joints and zygapophyseal joints combin''
|<small>Limits hyperflexion</small>
|''Full extensexion:60 degrees''
''Extension 25 degrees''
 
''Lateral flexion 20-30 degrees''
 
''Rotation 1-5 degrees''
|''Full extension''
|''Halfway between flexion and extension''
|}
 
== Spinal Ligaments ==
{| class="wikitable"
|+'''Ligaments found throughout spinal column'''
!'''Key ligaments'''
!'''Origin'''
!'''Insertion'''
!'''Action/role'''
!'''Key palpation points'''
|-
|-
|[[Anterior longitudinal ligament|<small>Anterior longitudinal ligament</small>]]
|<small>'''Transverse ligament'''</small>
|<small>The anterior portion of the vertebral body at the base of the skull</small>
|<small>The anterior portion of the vertebral body at the sacrum</small>
|<small>Limits extension of the vertebral column.</small>
<small>Reinforces the intervertebral disc.</small>
|
|
|<small>Attaches to lateral masses of atlas</small>
|<small>Anchors dens in place</small>
|-
|-
|[[Posterior longitudinal ligament|<small>Posterior longitudinal ligament</small>]]
|<small>'''Apical ligament'''</small>
|<small>The body of C2</small>
|<small>Dens of the axis</small>
|<small>Posterior surface of the sacrum</small>
|<small>Foramen magnum</small>
|<small>Limits flexion of the vertebral column.</small>
|Connects the dens of the axis to the foramen magnum
<small>Reinforces the intervertebral disc.</small>
<small>Stabilises the skull on the spine</small>
|
|-
|<small>'''Alar ligament'''</small>
|<small>Dens of the axis</small>
|<small>Occiput</small>
|Connects the dens of the axis to the occiput
<small>Limits atlanto-axial rotation</small>
|-
|-
|<small>[[Ligamentum flavum]]:</small>
|<small>'''Cruciform or cruciate ligament'''</small>
<small>A series of short ligaments that connect the laminae of each vertebra. There are two ligamenta flava at each vertebra.</small>
 
<small>Each ligament is divided into:</small>


<small>'''The medial portion:''' passes to the back of the next lower lamina and across the gap between the adjacent vertebrae, fusing with the [[/www.physio-pedia.com/Interspinous ligament|interspinous ligament]]</small>
<small>1. Superior longitudinal band</small>


<small>'''The lateral portion:''' passes in front of the [[/www.physio-pedia.com/Facet Joints|facet joint,]] attaches to the anterior aspect of the inferior and superior articular processes and forms the anterior capsule. The most lateral fibres extend beyond the superior articular process to the pedicle below.</small>
<small>2. Inferior longitudinal band</small>
|<small>The lower half of the anterior surface of the lamina above</small>
|<small>The posterior surface and upper margin of the lamina below</small>
|<small>Their high elastin content prevents the ligament from buckling into the spinal canal.</small>
<small>Assists with lumbar spine flexion and extension.</small>


<small>Compresses the intervertebral discs.</small>
<small>3. Transverse band</small>
|
|
|-
# <small>Superior: transverse band</small>
|<small>Intertransverse ligaments</small>
# <small>Inferior: transverse band</small>
|<small>Transverse processes of the vertebra above</small>
# <small>Transverse: dens of the axis</small>
|<small>Transverse processes of the vertebra below</small>
|<small>Contributes to the stability of the lumbar spine.</small>
<small>Limits lateral flexion.</small>
|<small>To palpate the '''transverse process''', position the patient in sitting. The transverse processes of the lumbar spine are most likely located directly in line with the spinous process of the corresponding vertebra. Start by palpating the spinous process of the L1 vertebra and move directly lateral to find the transverse process of L1.</small>
|-
|<small>Supraspinous ligament</small>
|<small>Tip of spinous processes of the vertebra above from the seventh cervical vertebra to the third or fourth lumbar vertebra</small>
|<small>Tip of spinous processes of the vertebra below</small>
|<small>Prevents the separation of the spinous processes during forward flexion, thus limiting lumbar spine flexion</small>
|<small>You can palpate the '''spinous processes''' in the centre of the patient's back.</small>
<small>Start with finding T12 by palpating the patient's lowest rib and following your finger along the border of the rib towards the centre of the spine.T12 spinous process is in line with the 12th rib that inserts into the spinal segment. Below T12, you can palpate L1 and continue along the spinous process of L2, L3, and L4.</small>
|-
|<small>Interspinous ligament</small>
|<small>Spinous processes of the vertebra above between the ligamenta flava anteriorly and the supraspinous ligament posteriorly</small>
|<small>Spinous processes of the vertebra below between the ligamenta flava anteriorly and the supraspinous ligament posteriorly</small>
|<small>Limits forward flexion of the vertebral column.</small>
|
|
# <small>Superior: foramen magnum</small>
# <small>Inferior: second vertebral body</small>
# <small>Transverse: between the lateral masses of the atlas</small>
|<small>Holds dens in place</small>
|}
|}
<ref name=":1" />
<nowiki>**</nowiki> ligaments in spinal column
{| class="wikitable"
|+'''Ligaments Unique to Cervical Spine'''
!'''Ligament'''
!'''Origin'''
!'''Insertion'''
!'''Role/Function'''
!'''Key Palpation Points'''
|-
|<small>Nuchal ligament</small>
|<small>occiput</small>
|<small>tips of the spinous process from C1-C7</small>
|<small>limit hyperflexion</small>
|<small>proximal attachment for rhomboids and trapezius</small>
|-
|<small>Transverse ligament</small>
|
|<small>connects lateral masses of atlas</small>
|<small>anchors dens in place</small>
|
|-
|<small>Apical ligament</small>
|<small>dens of the axis</small>
|<small>foramen magnum</small>
|<small>stabilises skull on spiine</small>
|
|-
|<small>Lar Ligament</small>
|<small>dens of the axis</small>
|<small>occiput</small>
|<small>limits atlanto-axial rotation</small>
|
|-
|<small>Cruciform or Cruciate Ligament</small>


<small>1. superior longitudinal band</small>
== Muscles of the Cervical Spine ==
The muscles of the cervical spine can be divided by location or by function.[[File:Prevertebral neck muscles.png|thumb|271x271px|Anterior vertebral muscles]]


<small>2. inferior longitudinal band</small>
=== Anterior (Prevertebral) Vertebral Muscles ===
* [[Rectus Capitis Anterior|Rectus capitis anterior]]
* [[Rectus Capitis Lateralis|Rectus capitis lateralis]]
* [[Longus Capitis|Longus capitis]]
* [[Longus Colli|Longus colli]]/ Longus cervicis (3 portions: superior oblique, inferior oblique, vertical)
These muscles are also known as the deep cervical (neck) flexors.


<small>3. transverse band</small>
=== Lateral Vertebral Muscles ===
|
[[Scalene|Scalenes]]
# <small>superior: transverse band</small>
# <small>inferior: transverse band</small>
# <small>transverse: dens of axis</small>
|
# <small>superior: foramen magnum</small>
# <small>second vertebral body</small>
# <small>transverse ligament: between lateral masses of atlas</small>
|<small>hold dens in place</small>
|
|}


== Muscles of the Cervical Spine ==
* [[Anterior Scalene|anterior]]
''T''he muscles of the neck can be grouped according to their function and location.
* [[Middle Scalene|middle]]
* [[Posterior Scalene|posterior]]
* [[Scalenus Minimus|minimus]] (not always present)


When grouped according to '''function''', the muscles of the cervical spine can be organised as follows:
[[File:Neck triangles.png|thumb|Lateral view of cervical muscles]]


* Flexors:  rectus capitis anterior, longus colli, longus capitis,  anterior scalene,  sternocleidomastoid
=== Posterior Vertebral Muscles ===
* Extensors:  obliques capitis superior, oblique capitis inferior, rectus capitis posterior major, rectus capitis posterior minor
These can be further divided into intrinsic and extrinsic muscles.
* Lateral flexors:
* Rotators:


When grouped according to '''location''', the muscles of the cervical spine can be divided as follows:
==== Extrinsic muscles ====


* The intrinsic (deep) group:
* [[Trapezius]]
** Superficial layer: splenius cervicis, splenius capitis, trapezius
* [[Levator Scapulae|Levator scapulae]]
** Middle (deep) layer: erector spinae
** Deepest layer:
*** prevertebral
*** transversospinalis (rotatores cervicis, multifidus,  semispinalis cervicis,)


The following tables group muscles according to their function. Please note, that when a muscle has multiple functions, it is included in all relevant tables. These tables only list muscle actions associated with the cervical spine.  If a muscle acts on other joints, these actions are discussed on the relevant page. ''F'''or example, psoas major is also a major hip flexor - this role is detailed on the [[Functional Anatomy of the Hip|Functional Anatomy of the Hip page]].'''''
==== Intrinsic muscles ====
[[File:Cervical Spine Muscles.jpg|thumb|500x500px|Posterior muscles of the cervical spine]]
* Superficial muscles :
** [[Splenius Capitis|splenius capitis]]
** [[Splenius Cervicis|splenius cervicis]]
* Deep muscles:
** suboccipital group
*** [[Rectus Capitis Posterior Major|rectus capitis posterior major]]
*** [[Rectus Capitis Posterior Minor|rectus capitis posterior minor]]
*** [[Obliquus Capitis Inferior|obliquus capitis inferior]]
*** [[Obliquus Capitis Superior|obliquus capitis superior]]
** transversospinalis muscles
*** [[Semispinalis Capitis|semispinalis capitis]]
*** [[Semispinalis Cervicis|semispinalis cervicis]]
*** rotatores cervicis
*** multifidus (these are also known as deep neck extensors)
** interspinales and intertransversarii


=== Cervical Spine Flexors ===
=== Movement ===
{| class="wikitable"
{| class="wikitable"
|+
|+
!''Muscle''
!<small>'''Motion'''</small>
!''Origin''
!<small>'''Flexion'''</small>
!''Insertion''
!<small>'''Extension'''</small>
!''Innervation''
!<small>'''Lateral Flexion'''</small>
!''Action''
!<small>'''Rotation'''</small>
|-
|-
|rectus capitis anterior
|<small>'''Muscles'''</small>
|atlas
|occiput
|
|flexion
|-
|longus colli
|transverse processes of C3 to C5 and the vertebral bodies of C5 to T3
|anterior tubercle of C1, the vertebral bodies of C2 to 4, and the transverse processes of C5 and C6.
|
|flexion
|-
|longus capitis
|transverse processes of  C3 to C6
|occipital bone
|
|flexion
|-
|anterior scalene
|transverse processes of  C3 to C6
|first rib
|
|flexion, respiration
|-
|sternocleidomastoid
|manubrium and the medial portion of the clavicle
|mastoid process of the temporal bone
|
|
|-
|paravertebral cervical muscles '''('''rectus capitis anterior, longus colli. longus capitis, rectus capitis lateralis)
|
|
* [[Longus Colli|<small>Longus colli</small>]]
* <small>[[Sternocleidomastoid]]</small>
* [[Scalene|<small>Scalene anterior</small>]]
* [[Longus Capitis|<small>Longus capitis</small>]]
* <small>[[Rectus Capitis Anterior|Rectus capitis anterior]] (head only)</small>
|
|
* [[Iliocostal Cervicis|<small>Iliocostal cervicis</small>]]
* [[Splenius Cervicis|<small>Splenius cervicis</small>]]
* [[Splenius Capitis|<small>Splenius capitis</small>]]
* <small>[[Trapezius]]</small>
* [[Erector Spinae|<small>Erector spinae</small>]]
* <small>[[Rectus Capitis Posterior|Rectus capitis posterior,]] [[Rectus Capitis Posterior Major|major]] and [[Rectus Capitis Posterior Minor|minor]] (head only)</small>
* <small>Sternocleidomastoid</small>
* <small>Longissimus capitis</small>
* <small>Spinalis capitis</small>
|
|
* <small>Scalene anterior, medius and posterior</small>
* <small>Sternocleidomastoid</small>
* <small>Splenius capitis</small>
* <small>Trapezius</small>
* <small>Erector spinae</small>
* <small>[[Rectus Capitis Lateralis|Rectus capitis lateralis]] (head only)</small>
* <small>Spinalis capitis</small>
|
|
* [[Semispinalis Cervicis|<small>Semispinalis cervicis</small>]]
* <small>Multifidus</small>
* <small>Scalene anterior</small>
* <small>Splenius cervicis and capitis</small>
* <small>Sternocleidomastoid</small>
* <small>Inferior oblique (head only)</small>
* <small>Rectus captitis posterior major (head only)</small>
* <small>Longissius capitis</small>
* <small>Spinalis capitis</small>
|}
|}
<ref>Palastanga, N., & Soames, R. (2012). Anatomy and human movement (6th ed.). Edinburgh: Churchill Livingstone.</ref>
The following tables identify the origin, insertion, innervation and action of key cervical muscles. Muscles with multiple functions are repeated in the relevant tables.


=== '''Cervical Spine Extensors''' ===
=== Cervical Spine Flexors ===
{| class="wikitable"
{| class="wikitable"
|+
|+
!''Muscle''
!<small>'''Muscle'''</small>
!''Origin''
!<small>'''Origin'''</small>
!''Insertion''
!<small>'''Insertion'''</small>
!''Innervation''
!<small>'''Innervation'''</small>
!''Action''
!<small>'''Action'''</small>
|-
|-
|obliques capitis superior
|<small>'''Rectus capitis anterior'''</small>
|transverse process of the atlas  
|<small>Lateral mass and transverse process of atlas (C1)</small>
|occipital bone
|<small>Basilar part of occipital bone</small>
|<small>Anterior rami of 1st and 2nd cervical spinal nerves (C1, C2)</small>
|
|
|stabilises atlanto-occipital joint
* <small>Flexion of the head at the atlanto-occipital joint</small>
|-
|-
|oblique capitis inferior
|<small>'''Longus colli'''</small>
|spinous process of the axis and inserts into the transverse process of the atlas,
|<small>Transverse processes of C3-C5 and the vertebral bodies of C5-T3</small>
|tansverse process of atlas
|<small>Anterior tubercle of C1, the vertebral bodies of C2-C4, and the transverse processes of C5 and C6.</small>
|<small>Anterior rami of the 2nd to 6th cervical spinal nerves (C2-C6)</small>
|
|
|stabilises atlanto-occipital joint
* <small>Unilateral contraction: neck lateral flexion (ipsilateral), neck rotation (contralateral)</small>
* <small>'''Bilateral contraction: neck flexion'''</small>
|-
|-
|rectus capitis posterior major
|<small>'''Longus capitis'''</small>
|spinous process of C2
|<small>Transverse processes of C3-C6</small>
|occipital bone
|<small>Occipital bone</small>
|<small>Anterior rami of 1st to 3rd cervical spinal nerves (C1-C3)</small>
|
|
* <small>Unilateral contraction: rotation of the head (ipsilateral)</small>
* <small>'''Bilateral contraction: flexion of the head and neck'''</small>
|-
|<small>'''Anterior scalene'''</small>
|<small>Transverse processes of  C3-C6</small>
|<small>First rib</small>
|<small>Anterior rami of 4th to 6th cervical spinal nerves (C4-C6)</small>
|
|
* <small>Unilateral contraction: neck lateral flexion (ipsilateral), neck rotation (contralateral), elevation of the first rib</small>
* <small>'''Bilateral contraction: neck flexion'''</small>
* Accessory muscle of respiration
|-
|-
|rectus capitis posterior minor
|<small>'''Sternocleidomastoid'''</small>
|posterior tubercle of the atlas
|<small>Manubrium and the medial portion of the clavicle</small>
|occipital bone
|<small>Mastoid process of the temporal bone</small>
|
|<small>Accessory nerve (CN XI), branches of cervical plexus (C2-C3)</small>
|
|
* <small>Unilateral contraction: '''ipsilateral lateral flexion''', elevation of the chin, contralateral rotation of head</small>
* <small>Bilateral contraction: '''flexes the neck''', extension of the upper vertebral joints, extension of the neck and head, elevation of the head, elevation of the sternum and clavicle, expansion of the thoracic cavity</small>
|-
|-
|rotatores cervicis
|<small>'''Rectus capitis lateralis'''</small>
|inconsistent and blend with other muscles
|<small>Transverse process of atlas (C1)</small>
|<small>Jugular process of occipital bone</small>
|<small>Anterior rami of 1st and 2nd cervical spinal nerves (C1-C2)</small>
|
|
|
* <small>Lateral flexion of the head (ipsilateral)</small>
|aid in stabilisation of spinal column
* <small>'''Neck flexion'''</small>
* <small>Stabilisation of the atlanto-occipital joint</small>
|}
 
=== '''Cervical Spine Extensors''' ===
{| class="wikitable"
|+
!<small>'''Muscle'''</small>
!<small>'''Origin'''</small>
!<small>'''Insertion'''</small>
!<small>'''Innervation'''</small>
!<small>'''Action'''</small>
|-
|-
|multifidus
|<small>'''Obliquus capitis superior'''</small>
|articular processes of C4 to C7
|<small>Transverse process of the atlas</small>
|spinous processes
|<small>Occipital bone</small>
|<small>Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))</small>
|
|
|aid in stabilisation of spinal column
* <small>'''Bilateral contraction: head extension'''</small>
* Unilateral contraction: rotation of head to the ipsilateral side
* <small>Stabilises the atlanto-occipital joint during head movements</small>
|-
|-
|semispinalis cervicis
|<small>'''Obliquus capitis inferior'''</small>
|transverse processes of T1 to T5 and inserts into the spinous processes of C2 to C5.
|<small>Spinous process of the axis</small>
|spinous processes of C2 to C5.
|<small>Tansverse process of atlas</small>
|
|<small>Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))</small>
|
|
* <small>'''Bilateral contraction: head extension'''</small>
* <small>Unilateral contraction: rotation of head to the ipsilateral side</small>
* <small>Stabilises the atlanto-axial joint</small>
|-
|-
|semispinalis capitis
|<small>'''Rectus capitis posterior major'''</small>
|transverse processes T1 to T7 and articular process of C4-C7
|<small>Spinous process of C2</small>
|occipital bone
|<small>Occipital bone</small>
|
|<small>Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))</small>
|
|
* <small>Unilateral contraction: head rotation (ipsilateral)</small>
* <small>'''Bilateral contraction: head extension'''</small>
|-
|-
|spinalis capitis
|<small>'''Rectus capitis posterior minor'''</small>
|spinous processes of C7 and T1
|<small>Posterior tubercle of the atlas</small>
|occipital bone
|<small>Occipital bone</small>
|
|<small>Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))</small>
|
|
* <small>Head extension</small>
|-
|-
|longissiumus capitis
|<small>'''Iliocostal cervicis'''</small>
|transverse process of T1-T5 and articular process of C4-C7
|<small>Ribs 3-6</small>
|mastoid process of temporal bone
|<small>Transverse process of C4-C6</small>
|
|<small>Dorsal rami of the upper thoracic and lower cervical spinal nerves</small>
|
|
* <small>Laterally flexes and '''extends the lower [[Cervical Anatomy|cervical region]]'''</small>
|-
|-
|longissium cervis
|<small>'''Trapezius'''</small>
|transverse process of T1-T5
|<small>Occipital bone, nuchal ligament and spinous process C7-T12</small>
|transverse processes of C2-C6
|<small>Lateral third of the clavicle, acromian and spine of the scapula</small>
|
|<small>Spinal [[Accessory Nerve Cranial Nerve 11|root of accessory nerve]] (CN XI) (motor)</small>
 
<small>Cervical nerves (C3 and C4) ([[Pain Assessment|pain]] and [[proprioception]])</small>
|
|
* <small>Supports the spinal column to remain erect</small>
* '''Neck extension when scapulae are fixed'''
* Ipsilateral lateral flexion of neck
|-
|-
|iliocostal cervicis
|<small>'''Splenius cervicis'''</small>
|ribs 3-6
|<small>Spinous process of T3-T6</small>
|transverse process of C4-C6
|<small>Transverse process of C1-C3</small>
|
|<small>Dorsal rami of cervical spinal nerves (C5-C8)</small>
|
|
* <small>'''Acting bilaterally: extend the neck'''</small>
* <small>Acting unilaterally: lateral flexion and rotation of the head and neck to the ipsilateral side</small>
|-
|-
|spelnius cervicis
|<small>'''Splenius capitis'''</small>
|spinous process T3-T6
|<small>Spinous process of C7-T3 and nuchal ligament</small>
|transverse process of C1C3
|<small>Occipital bone</small>
|
|<small>Posterior rami of the 2nd and 3rd cervical spinal nerves</small>
|
|
* <small>'''Acting bilaterally: extension of the head and neck'''</small>
* <small>Acting unilaterally: lateral flexion and rotation of the head and neck to the ipsilateral side</small>
|-
|-
|splenius capitis
|'''<small>Spinalis capitis</small>'''
|spinous process C7-T3 and nuchal ligament
|<small>Spinous process of C7 and T1</small>
|occipital bone
|<small>Occipital bone</small>
|
|<small>Dorsal rami of spinal nerves</small>
|
|
* <small>'''Acting bilaterally: extension of the neck'''</small>
* <small>Acting unilaterally: ipsilateral lateral flexion and r</small><small>otation</small>  <small>of the neck</small>
|-
|-
|trapezius
|<small>'''Longissimus capitis'''</small>
|occipital bone, nuchal ligament and spinous process C7-T12
|<small>Transverse process of upper 4 thoracic vertebrae and articular process lower three cervical vertebrae</small>
|lateral third of clavicle, the acromian and the spine of s scapula
|<small>Mastoid process</small>
|
|<small>Posterior/dorsal rami of spinal nerves</small>
|
|
* '''<small>Acting bilaterally: extension of neck</small>'''
* <small>Acting unilaterally: ipsilateral lateral flexion and rotation  of the neck</small>
|}
|}


== Lumbar Spine Lateral Flexors ==
<nowiki>**</nowiki> <small>The transversospinal muscles (rotatores, multifidus, semispinalis) are the deep muscle of the spine. They attach between the transverse and spinous process of the vertebrae. They stabilise and extend the spine. The rotatores also provide rotation.</small>
 
=== Cervical Spine Lateral Flexors ===
{| class="wikitable"
{| class="wikitable"
|+
|+
!''Muscle''
!<small>'''Muscle'''</small>
!''Origin''
!<small>'''Origin'''</small>
!''Insertion''
!<small>'''Insertion'''</small>
!''Innervation''
!<small>'''Innervation'''</small>
!''Action''
!<small>'''Action'''</small>
|-
|-
|rectus capitis lateralis
|<small>'''Splenius cervicis'''</small>
|transverse process of the atlas
|<small>Spinous process of T3-T6</small>
|suboccipital bone
|<small>Transverse process C1-C3</small>
|<small>Dorsal rami of cervical spinal nerves (C5-C8)</small>
|
|
|stabilising atlanto-occipital joint
* <small>'''Acting unilaterally: lateral flexion and rotation of the head and neck to the ipsilateral side'''</small>
* <small>Acting bilaterally: extend the neck</small>
|-
|-
|obliquus capitis
|<small>'''Splenius capitis'''</small>
|<small>Spinous process of C7-T3 and nuchal ligament</small>
|<small>Occipital bone</small>
|<small>Posterior rami of the 2nd and 3rd cervical spinal nerves</small>
|
|
* <small>'''Acting unilaterally: lateral flexion of the head and neck and rotation of the head to the ipsilateral side'''</small>
* <small>Acting bilaterally: extension of the head and cervical spine</small>
|-
|<small>'''Sternocleidomastoid'''</small>
|<small>Manubrium and the medial portion of the clavicle</small>
|<small>Mastoid process of the temporal bone</small>
|<small>Accessory nerve (CN XI), branches of cervical plexus (C2-C3)</small>
|
|
* <small>'''Unilateral contraction: ipsilateral lateral flexion''', elevation of the chin, contralateral rotation of head</small>
* <small>Bilateral contraction: flexes the neck, extension of the upper vertebral joints, extension of the neck and head, elevation of the head, elevation of the sternum and clavicle, expansion of the thoracic cavity</small>
|-
|'''Anterior scalene'''
|<small>Transverse processes of  C3-C6</small>
|First rib
|<small>Anterior rami of 4th to 6th cervical spinal nerves (C4-C6)</small>
|
|
* <small>'''Unilateral contraction: neck lateral flexion (ipsilateral)''', neck rotation (contralateral), elevation of the first rib</small>
* <small>Bilateral contraction: neck flexion</small>
* Accessory muscle of respiration
|-
|<small>'''Middle scalene'''</small>
|<small>Posterior tubercles of the transverse processes of C1-C7</small>
|<small>Scalene tubercle of the first rib</small>
|<small>Anterior rami of C3-C8</small>
|
|
* <small>Elevation of the first rib</small>
* <small>'''Ipsilateral contraction causes ipsilateral lateral flexion of the neck'''</small>
* Respiration
|-
|-
|<small>'''Posterior scalene'''</small>
|<small>Posterior tubercles of the transverse processes of C4-C6</small>
|<small>2nd rib</small>
|<small>Anterior rami of C6-C8</small>
|
|
* <small>Elevation of the second rib</small>
* <small>'''Ipsilateral lateral flexion of the neck'''</small>
* Respiration
|-
|<small>'''Trapezius'''</small>
|<small>Occipital bone, nuchal ligament and spinous process C7-T12</small>
|<small>Lateral third of the clavicle, the acromian and the spine of s scapula</small>
|<small>Spinal [[Accessory Nerve Cranial Nerve 11|root of accessory nerve]] (CN XI) (motor)</small>
<small>Cervical nerves (C3 and C4) ([[Pain Assessment|pain]] and [[proprioception]])</small>
|
|
|
* <small>Supports the spinal column to remain erect</small>
|
* <small>Neck extension when scapulae are fixed</small>
|
* <small>'''Ipsilateral lateral flexion of the neck'''</small>
|-
|-
|<small>'''Rectus capitis lateralis'''</small>
|<small>Superior surface of the transverse process of atlas</small>
|<small>Inferior surface of the jugular process of the occipital bone</small>
|<small>Anterior rami of C1-C2 spinal nerves</small>
|
|
|
* <small>'''Lateral flexion of the head (ipsilateral)'''</small>
|
* <small>Deep neck flexion</small>
|
* <small>Stabilisation of the atlanto-occipital joint</small>
|
|-
|-
|'''<small>Spinalis capitis</small>'''
|<small>Spinous process of C7 and T1</small>
|<small>Occipital bone</small>
|<small>Dorsal rami of spinal nerves</small>
|
|
|
*<small>Acting bilaterally: extension of the neck</small>
|
* '''<small>Acting unilaterally: ipsilateral lateral flexion and r</small><small>otation</small>  <small>of the neck</small>'''
|
|
|-
|-
|<small>'''Longissimus capitis'''</small>
|<small>Transverse process of upper 4 thoracic vertebrae and articular process lower three cervical vertebrae</small>
|<small>Mastoid process</small>
|<small>Posterior/dorsal rami of spinal nerves</small>
|
|
|
*<small>Acting bilaterally: extension of the neck</small>
|
*'''<small>Acting unilaterally: ipsilateral lateral flexion and r</small><small>otation</small>  <small>of the neck</small>'''
|
|
|}
|}


 
=== Cervical Spine Rotators ===
Of the intrinsic back muscles involved in lateral flexion, we have the multifidus of the transversospinalis group, the longissimus cervicis, and the iliocostalis cervicis of the erector spinae group and the splenius cervicis and capitis. Next we have the scalenes, of which there are three subgroups. The posterior scalene originates from the transverse processes of C4 to C6 and inserts into the second rib. The middle scalene originates from the transverse processes of C1 to C7 and inserts into the first rib. The anterior scalene we've mentioned already in neck flexion. While the scalenes aid in lateral flexion of the neck, they are also involved in respiration as they insert into the ribs.
 
The levator scapula originates from the transverse processes of C1 to C4 and inserts into the medial border of the scapula. While this is primarily a scapular muscle, it can aid in lateral flexion of the neck when the scapula is fixed. Lastly, the sternocleidomastoid and the trapezius muscle both aid in lateral flexion as well. Let's look at the movement again.
 
Finally, the last movement is cervical rotation, where you turn your head to the left or right to look across your shoulder. Here we can see it overlaid with the goniometer, showing a normal range of around 70 degrees. All of the following muscles have been discussed already as they are involved in multiple movements. When these muscles work unilaterally, they aid in neck rotation. Whether it's ipsilateral or contralateral will depend on the angle of insertion. The obliques capitis inferior is responsible for ipsilateral rotation of the atlanto-axial joint. The rectus capitis posterior major aids in ipsilateral rotation of the head on the neck. Of the transversospinalis muscles, both the multifidus and the semispinalis capitis aid in contralateral neck rotation. Of the erector spinae muscles, the spinalis capitis and the longissimus capitis both aid in ipsilateral neck rotation. Both splenius cervicis and splenius capitis are also involved in ipsilateral neck rotation. Finally, the sternocleidomastoid rotates the head contralaterally. Let's look at the movement again.
 
The muscles of the neck are innervated by nerves originating from the cervical plexus and the dorsal and ventral rami of the rest of the cervical spinal nerves. The cervical plexus is a network of nerves arising from the ventral rami of nerve roots C1 to C4. Note that in the cervical spine, each nerve root exits above its corresponding vertebra. For example, the C3 nerve exits above the C3 vertebra. However, there is an additional cervical nerve root, C8, that exits below the seventh cervical vertebra. There is also one cranial nerve involved and that is the accessory nerve or cranial nerve XI. It innervates the sternocleidomastoid as well as the trapezius. This means that resistance testing of the sternocleidomastoid or the trapezius muscle can be used for the assessment of cranial nerve XI. The dorsal rami of C1 or the suboccipital nerve innervates all four suboccipital muscles. The cervical dorsal rami innervates the splenius cervicis and capitis, erector spinae, and transversospinalis. The cervical ventral rami innervates the longus capitis, longus colli, scalenes, and levator scapulae. Branching off the ventral ramus of C5, the dorsal scapular nerve innervates the levator scapulae.
 
The last thing to look at is a general overview of the vascular supply related to the cervical region. The neck is supplied primarily by the vertebral arteries, one on each side coursing through the transverse foramen of the cervical vertebrae. These arteries arise from the subclavian arteries that originate directly from the arch of the aorta on the right side, and via the brachiocephalic trunk on the left side.
 
 
=== ''Lumbar Spine Rotators'' ===
{| class="wikitable"
{| class="wikitable"
|+
|+
!'''''Muscle'''''
!'''<small>Muscle</small>'''
!'''''Origin'''''
!'''<small>Origin</small>'''
!'''''Insertion'''''
!'''<small>Insertion</small>'''
!'''''Innervation'''''
!'''<small>Innervation</small>'''
!'''''Action'''''
!'''<small>Action</small>'''
|-
|-
|<small>'''Rectus capitis posterior major'''</small>
|<small>Spinous process of C2</small>
|<small>Occipital bone</small>
|<small>Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))</small>
|
|
* <small>'''Unilateral contraction: head rotation (ipsilateral)'''</small>
* <small>Bilateral contraction: head extension</small>
|-
|<small>'''Rectus capitis posterior major'''</small>
|<small>Spinous process of C2</small>
|<small>Occipital bone</small>
|<small>Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))</small>
|
|
* <small>'''Unilateral contraction: head rotation (ipsilateral)'''</small>
* <small>Bilateral contraction: head extension</small>
|-
|<small>'''Sternocleidomastoid'''</small>
|<small>Manubrium and the medial portion of the clavicle</small>
|<small>Mastoid process of the temporal bone</small>
|<small>Accessory nerve (CN XI), branches of cervical plexus (C2-C3)</small>
|
|
* <small>Unilateral contraction: ipsilateral lateral flexion, elevation of the chin, c'''ontralateral rotation of head'''</small>
* <small>Bilateral contraction: flexion of the neck, extension of the upper vertebral joints, extension of the neck and head, elevation of the head, elevation of the sternum and clavicle, expansion of thoracic cavity</small>
|-
|<small>'''Splenius capitis'''</small>
|<small>Spinous process  ofC7-T3 and nuchal ligament</small>
|<small>Occipital bone</small>
|<small>Posterior rami of the 2nd and 3rd cervical spinal nerves</small>
|
|
* <small>Acting unilaterally: lateral flexion of the head and neck and '''rotation of the head to the ipsilateral side'''</small>
|-
|<small>'''Splenius cervicis'''</small>
|<small>Spinous process T3-T6</small>
|<small>Transverse process C1-C3</small>
|<small>Dorsal rami of cervical spinal nerves (C5-C8)</small>
|
|
* <small>Acting unilaterally: lateral flexion and '''rotation of the head and neck to the ipsilateral side'''</small>
|-
|-
|'''<small>Spinalis capitis</small>'''
|<small>Spinous process of C7 and T1</small>
|<small>Occipital bone</small>
|<small>Dorsal rami of spinal nerves</small>
|
|
|
* <small>Acting bilaterally: extension of the neck</small>
|
* <small>'''Acting unilaterally: ipsilateral lateral flexion and rotation  of the neck'''</small>
|
|
|-
|-
|<small>'''Longissimus capitis'''</small>
|<small>Transverse process of upper 4 thoracic vertebrae and articular process lower three cervical vertebrae</small>
|<small>Mastoid process</small>
|<small>Posterior/dorsal rami of spinal nerves</small>
|
|
|
* <small>Acting bilaterally: extension of the neck</small>
|
* <small>'''Acting unilaterally: ipsilateral lateral flexion and rotation  of the neck'''</small>
|
|
|}
|}


== ''Innervation of the Lumbar Spine and Abdominal Wall'' ==
== Innervation of the Cervical Spine ==
Nerves originating from the cervical plexus innervate the muscles of the neck. Each nerve root in the cervical spine exits above its corresponding nerve root. There are eight pairs of cervical nerves despite there being seven cervical vertebrae. The C8 nerve root exits below the seventh cervical vertebra. The accessory nerve, which is cranial nerve XI innervates sternocleidomastoid and trapezius.<ref name=":0" />
{| class="wikitable"
{| class="wikitable"
|+
|+
!'''''Nerve'''''
!'''<small>Nerve</small>'''
!'''''Origin'''''
!'''<small>Motor</small>'''
!'''''Branches'''''
!'''<small>Sensory</small>'''
!'''''Motor fibres'''''
!'''''Sensory fibres'''''
|-
|-
|
|'''<small>C1</small>'''
|
|<small>Flexion of the head and neck</small>
|
<small>Rectus capitus anterior and lateralis, longus capitis</small>
|
|
|
|-
|-
|
|'''<small>C2</small>'''
|
|<small>Flexion of the head and neck</small>
|
<small>Rectus capitus anterior and lateralis, longus capitus, prevertebral muscles and sternocleidomastoid</small>
|
|<small>Lateral occiput and submandibular area</small>
|
|-
|-
|
|'''<small>C3</small>'''
|
|<small>Head and neck flexion and rotation</small>
|
 
|
<small>Longus capitus, longus colli, prevertebral muscles and sternocleidomastoid, diaphragm, levator scapulae, trapezius and scalenus medius</small>
|
|<small>Lateral occiput and lateral neck, overlapping C2</small>
|-
|-
|
|<small>'''C4'''</small>
|
|<small>Head and neck flexion and rotation</small>
|
<small>Longus capitus, longus colli, levator scapulae, scaleni, trapezius, diaphragm</small>
|
|<small>Lower lateral neck and medial shoulder area</small>
|
|-
|-
|
|'''<small>C5</small>'''
|
|<small>Deltoid, biceps, bicep tendon reflex</small>
|
|<small>Clavicle level and lateral arm</small>
|
|
|-
|-
|
|'''<small>C6</small>'''
|
|<small>Biceps, wrist extensors (brachioradialis tendon reflex)</small>
|
|<small>Lateral forearm, thumb, index and half of 2nd finger</small>
|
|
|}
 
== ''Vascular Supply of the Lumbar Spine and Abdominal Wall'' ==
{| class="wikitable"
|+
!''Artery''
!''Origin''
!''Branches''
!''Supply''
|-
|-
|
|'''<small>C7</small>'''
|
|<small>Wrist flexors, triceps (triceps tendon reflex)</small>
|
|<small>Second finger</small>
|
|-
|-
|
|'''<small>C8</small>'''
|
|<small>Finger flexors, interossei</small>
|
|<small>Medial forearm, ring and little finger</small>
|
|-
|-
|
|<small>'''T1'''</small>
|
|<small>Interossei</small>
|
|<small>Medial arm</small>
|
|}
|}


== ''Clinical Relevance'' ==
== Vascular Supply of the Cervical Spine ==
A disc herniation is a condition where the nucleus pulposus, which is the gel-like centre of the disc, protrudes through the annulus fibrosis, which is the surrounding ring of collagen fibres. While disc herniations in the cervical spine are a lot less common than in the lumbar spine, it can still occur. Typically, it occurs at the level of C5 to 6 and C6 to 7.  
Vertebral arteries, veins and nerves pass through the transverse foramina of the cervical vertebrae except for in C7, where the vertebral artery passes around the vertebra instead of through the transverse foramen.<ref name=":1" /> The neural components sit posterior to the vertebral artery.<ref>Joshi N, Klinger N, Halalmeh DR, Tubbs RS, Moisi MD. [https://www.cureus.com/articles/26181-the-neural-sulcus-of-the-cervical-vertebrae-a-review-of-its-anatomy-and-surgical-perspectives#!/ The Neural Sulcus of the Cervical Vertebrae: A Review of Its Anatomy and Surgical Perspectives]. Cureus. 2020 Jan 18;12(1)</ref>
 
The cervical spine vascular supply is primarily provided by the vertebral arteries on each side of the spine. These arteries arise from the subclavian arteries, which originate directly from the arch of the [[aorta]] on the right and the brachiocephalic trunk on the left.
 
<nowiki>**</nowiki> The common carotid artery bifurcates into the internal and external carotid arteries at the C3 segmental level. Only the external carotid artery provides any blood supply to the neck.


Conditions like rheumatoid arthritis can affect the stability of the atlanto-axial joint, which can result in serious neurological consequences due to the proximity of the spinal cord. Laxity in the transverse ligament is also present in 14% to 22% of individuals with Down syndrome.  sternocleidomastoid is wry neck, or torticollis, where the head appears to be tilted at an odd angle.
== Clinical Relevance ==


prevertebral cervical muscles, that can be thought of as the equivalent of the core of the neck and play an important role in the stabilisation of the neck. Dysfunction in these muscles can play a part in cervicogenic pain. Let's look at the flexion movement again.  
* Atlanto-axial instability (AAI) can have serious neurological consequences:
** conditions with the potential for AAI include:
*** rheumatoid arthritis
*** Down syndrome:
**** laxity in the transverse ligament is present in 14-22% of individuals with Down syndrome.


Trigger points that develop in the suboccipital muscles can refer pain to the head causing headaches.
* A tight [[sternocleidomastoid]] muscle can cause torticollis.
* Disc herniation:
** disc herniations in the cervical spine are a lot less common than in the lumbar spine
** typical locations:
*** C5-C6
*** C6-C7
* Because the prevertebral cervical muscles stabilise the neck, dysfunction in these muscles can cause cervicogenic pain
* Trigger points that develop in the suboccipital muscles can refer pain to the head, causing cervicogenic headaches<ref name=":3">Xuan D.  Exploring Cervical Spine Anatomy Course. Plus, 2023.</ref>


== Resources ==


(daphne)
* [[Functional Anatomy of the Thoracic Spine and Rib Cage]]
# ''Disc herniations are a common low back condition. They occur when the nucleus pulposus displaces from the intervertebral space. According to Yoon et al., when there is imaging confirmation of lumbar disc herniation that is "consistent with clinical findings, and failure to improve after six weeks of conservative care", surgical intervention may be required. You can read more about the management of disc herniation symptoms [[Disc Herniation|here.]]''
* [[Functional Anatomy of the Lumbar Spine and Abdominal Wall]]
# ''Spinal stenosis is a narrowing of the spinal canal. Spinal stenosis can be caused by a range of conditions, such as tumours or bone spurs. You can learn about low back pain assessment and prognosis by taking this course.''
* [[Cervical Deep Neck Extensors]]
# ''Diastasis recti is a very common condition where the linea alba stretches and produces a gap between the two sides of the rectus abdominis muscle. Learn more about diastasis recti [[Diastasis recti abdominis|here]].''
* [[Cervical Deep Neck Flexors]]


== References ==
== References ==
<references />
[[Category:Anatomy]]
[[Category:Cervical Spine]]
[[Category:Musculoskeletal/Orthopaedics]]
[[Category:Neurology]]
[[Category:Course Pages]]
[[Category:Plus Content]]

Latest revision as of 10:49, 1 September 2023

Original Editor - Robin Tacchetti based on the course by Daphne Xuan
Top Contributors - Robin Tacchetti, Jess Bell, Kim Jackson, Tarina van der Stockt, Ewa Jaraczewska and Vidya Acharya


Introduction[edit | edit source]

The cervical spine supports the weight of the head and enables head and neck movement.[1] [2] Intervertebral discs maintain the spaces between the vertebrae. These discs act like shock absorbers throughout the spinal column to cushion the bones as the body moves. Ligaments hold the vertebrae in place, and tendons attach the muscles to the spinal column. The cervical spine is subjected to a range of extrinsic factors such as repetitive movements, whole-body vibrations and static load.[3]

Cervical spine

Key Terms[edit | edit source]

Axes: lines around which an object rotates. The rotation axis is a line that passes through the centre of mass. There are three axes of rotation: sagittal passing from posterior to anterior, frontal passing from left to right, and vertical passing from inferior to superior. The rotation axes of the foot joints are perpendicular to the cardinal planes. Therefore, motion at these joints results in rotations within three planes. Example: supination involves inversion, internal rotation, and plantarflexion.

Bursae: reduce friction between the moving parts of the body joints. A bursa is a fluid-filled sac. There are four types of bursae: adventitious, subcutaneous, synovial, and sub-muscular.

Capsule: one of the characteristics of the synovial joints. It is a fibrous connective tissue which forms a band that seals the joint space, provides passive and active stability and may even form articular surfaces for the joint. The capsular pattern is "the proportional motion restriction in range of motion during passive exercises due to tightness of the joint capsule."

Closed pack position: the position with the most congruency of the joint surfaces. In this position, joint stability increases. For example, the closed pack position for the interphalangeal joints is full extension.

Degrees of freedom: the direction of joint movement or rotation; there is a maximum of six degrees of freedom, including three translations and three rotations.

Ligament: fibrous connective tissue that holds the bones together.

Open (loose) pack position: position with the least joint congruency where joint stability is reduced.

Planes of movement: describe how the body moves. Up and down movements (flexion/extension) occur in the sagittal plane. Sideway movements (abduction/adduction) occur in the frontal plane. The transverse plane movements are rotational (internal and external rotation).

Cervical Spine Structure[edit | edit source]

Cervical Vertebrae[edit | edit source]

There are seven cervical vertebrae, which are known as C1-C7. Their role is to support the head and neck and to promote head movement. The cervical spine is only exposed to small weight-bearing loads. Therefore, the cervical vertebral bodies do not need to be large and "an increased range of motion takes priority over vertebral size and rigidity".[2] However, because of this increased range of motion at the cervical spine, there is a heightened injury risk for the spinal cord and the associated neurovascular structures.[2]

The cervical vertebral bodies (C3-C6) have unique characteristics:[2][4]

  • vertebral bodies are smaller compared to the rest of the spine
  • vertebral foramen is triangular
  • spinous process is bifid (i..e. it splits into two distally)
  • there are openings in the transverse processes which allow passage for the vertebral artery, vein, and sympathetic nerves

The Atlas (C1), Axis (C2) and C7 have further distinguishing features:

Atlas (C1)
  • has no vertebral body or spinous process
  • instead, it has lateral masses for articulation with the occiput of the head and the second cervical vertebra (the Axis)
Atlas - C1

Axis (C2)
  • has a bony projection from the anterior portion called the dens, or the odontoid process, which articulates with the atlas
  • it is the primary weight-bearing bone of upper cervical region
Axis - C2

C7
  • singular spinous process
  • larger spinous process
  • spinous process is not bifid
C3-C6

**In supine, it may be difficult to palpate the spinous process of C3-C6 in individuals with normal cervical lordosis.

Intervertebral Discs (IVD)[edit | edit source]

The intervertebral discs make up 25% of the height of the entire spine. However, in the cervical region, they make up 40% of the height. This increased height relative to vertebral body height provides a mobility advantage.[5]

The nucleus pulposus of the cervical discs is gelatinous in children and young people. However, it dries out by the age of 30 years and becomes a firm, fibrocartilaginous plate.[6]

Intervertebral disc

The following are characteristics of the cervical spine intervertebral discs:

  • thicker anteriorly than posteriorly
  • concave superior surface
  • convex inferior surface
  • movement limited by the uncinate process
  • anteroposterior translation does occur

** Due to the location of the uncinate process, posterolateral disc herniations are less frequent.

Cervical Lordosis[edit | edit source]

Typically, the cervical spine has a lordotic curvature. A lordotic posture can resist large compressive loads. It also helps to decrease stress on vertebral end plates. Compressive loads are distributed differently in the cervical spine than in the thoracic and lumbar spine. In the cervical spine, the anterior column absorbs 36% of the load, and the posterior facet (zygapophyseal) joints absorb 64%.[7]

Kinematics and Joints of the Cervical Spine[edit | edit source]

Range of Motion in Cervical Spine

The cervical spine is the most mobile part of the vertebral column.

Flexion range of motion is usually around 40 degrees, and extension is around 50 degrees. The largest contributors to flexion/extension are:

  • C4/C5 and C5/C6 in sitting
  • C6/C7 in supine

C7/T1 contributes the least to flexion/extension.

Lateral flexion range of motion is normally close to 30 degrees. C3/C4 and C6/C7 allow for the most movement in this plane of motion.

Cervical rotation range of motion is usually close to 70 degrees. Flexibility in this plane is mainly achieved through the C1/C2 segment.[8]

Joints of the Cervical Spine[5][9]
Joint Location/Articulations Function Orientation/Composition
Intervertebral Disc Joint
  • Between the vertebral bodies
  • Bear weight
  • Facilitate motion
  • Absorb shock
Facet (Zygapophyseal) Joints
  • Formed by articulations between the superior and inferior articular processes of adjacent vertebrae
  • Guide motion at the segmental level
  • Determine the direction of motion
  • Upper cervical spine = horizontal
  • Lower cervical spine = more vertical
Uncovertebral Joint
  • Between the five lower cervical vertebral bodies
  • Anteromedially to the nerve root
  • Posteromedially to the vertebral artery
  • Control movement
  • Limit lateral flexion
Atlanto-Axial Joint
  • Between the atlas and axis
  • Two lateral: interior facets of the lateral masses of C1 and superior facets of C2
  • One medial: between the dens of C2 and the articular facet of C1
  • Cervical rotation (60% of cervical rotation occurs at this joint)
  • Lateral: plane-type synovial joint
  • Medial: pivot-type synovial joint
Atlanto-Occipital Joint
  • Between the spine and cranium
  • Between the superior facets of the lateral masses of the atlas and the occipital condyles
  • Flexion and extension of the head on the neck
  • Lateral flexion
  • Condyloid-type synovial joint

Spinal Ligaments[edit | edit source]

Ligaments present throughout the entire vertebral column:

  1. Anterior longitudinal ligament: anterior surface of the vertebral bodies; limits extension of the spine
  2. Posterior longitudinal ligament: posterior surface of the vertebral bodies; limits flexion of the spine
  3. Ligamentum flavum: connects the laminae of each vertebrae; series of short ligaments
  4. Intertransverse ligament: a series of short ligaments that connect the laminae of each vertebrae; preserves upright posture and prevents hyperflexion of the spine[10]
Ligaments Unique to the Cervical Spine
Ligament Origin Insertion Role/Function
Nuchal ligament Occiput Tips of the spinous process from C1-C7 Limits hyperflexion
Transverse ligament Attaches to lateral masses of atlas Anchors dens in place
Apical ligament Dens of the axis Foramen magnum Connects the dens of the axis to the foramen magnum

Stabilises the skull on the spine

Alar ligament Dens of the axis Occiput Connects the dens of the axis to the occiput

Limits atlanto-axial rotation

Cruciform or cruciate ligament

1. Superior longitudinal band

2. Inferior longitudinal band

3. Transverse band

  1. Superior: transverse band
  2. Inferior: transverse band
  3. Transverse: dens of the axis
  1. Superior: foramen magnum
  2. Inferior: second vertebral body
  3. Transverse: between the lateral masses of the atlas
 Holds dens in place

** ligaments in spinal column

Muscles of the Cervical Spine[edit | edit source]

The muscles of the cervical spine can be divided by location or by function.

Anterior vertebral muscles

Anterior (Prevertebral) Vertebral Muscles[edit | edit source]

These muscles are also known as the deep cervical (neck) flexors.

Lateral Vertebral Muscles[edit | edit source]

Scalenes

Lateral view of cervical muscles

Posterior Vertebral Muscles[edit | edit source]

These can be further divided into intrinsic and extrinsic muscles.

Extrinsic muscles[edit | edit source]

Intrinsic muscles[edit | edit source]

Posterior muscles of the cervical spine

Movement[edit | edit source]

Motion Flexion Extension Lateral Flexion Rotation
Muscles
  • Scalene anterior, medius and posterior
  • Sternocleidomastoid
  • Splenius capitis
  • Trapezius
  • Erector spinae
  • Rectus capitis lateralis (head only)
  • Spinalis capitis
  • Semispinalis cervicis
  • Multifidus
  • Scalene anterior
  • Splenius cervicis and capitis
  • Sternocleidomastoid
  • Inferior oblique (head only)
  • Rectus captitis posterior major (head only)
  • Longissius capitis
  • Spinalis capitis

[11]

The following tables identify the origin, insertion, innervation and action of key cervical muscles. Muscles with multiple functions are repeated in the relevant tables.

Cervical Spine Flexors[edit | edit source]

Muscle Origin Insertion Innervation Action
Rectus capitis anterior Lateral mass and transverse process of atlas (C1) Basilar part of occipital bone Anterior rami of 1st and 2nd cervical spinal nerves (C1, C2)
  • Flexion of the head at the atlanto-occipital joint
Longus colli Transverse processes of C3-C5 and the vertebral bodies of C5-T3 Anterior tubercle of C1, the vertebral bodies of C2-C4, and the transverse processes of C5 and C6. Anterior rami of the 2nd to 6th cervical spinal nerves (C2-C6)
  • Unilateral contraction: neck lateral flexion (ipsilateral), neck rotation (contralateral)
  • Bilateral contraction: neck flexion
Longus capitis Transverse processes of C3-C6 Occipital bone Anterior rami of 1st to 3rd cervical spinal nerves (C1-C3)
  • Unilateral contraction: rotation of the head (ipsilateral)
  • Bilateral contraction: flexion of the head and neck
Anterior scalene Transverse processes of C3-C6 First rib Anterior rami of 4th to 6th cervical spinal nerves (C4-C6)
  • Unilateral contraction: neck lateral flexion (ipsilateral), neck rotation (contralateral), elevation of the first rib
  • Bilateral contraction: neck flexion
  • Accessory muscle of respiration
Sternocleidomastoid Manubrium and the medial portion of the clavicle Mastoid process of the temporal bone Accessory nerve (CN XI), branches of cervical plexus (C2-C3)
  • Unilateral contraction: ipsilateral lateral flexion, elevation of the chin, contralateral rotation of head
  • Bilateral contraction: flexes the neck, extension of the upper vertebral joints, extension of the neck and head, elevation of the head, elevation of the sternum and clavicle, expansion of the thoracic cavity
Rectus capitis lateralis Transverse process of atlas (C1) Jugular process of occipital bone Anterior rami of 1st and 2nd cervical spinal nerves (C1-C2)
  • Lateral flexion of the head (ipsilateral)
  • Neck flexion
  • Stabilisation of the atlanto-occipital joint

Cervical Spine Extensors[edit | edit source]

Muscle Origin Insertion Innervation Action
Obliquus capitis superior Transverse process of the atlas Occipital bone Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))
  • Bilateral contraction: head extension
  • Unilateral contraction: rotation of head to the ipsilateral side
  • Stabilises the atlanto-occipital joint during head movements
Obliquus capitis inferior Spinous process of the axis Tansverse process of atlas Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))
  • Bilateral contraction: head extension
  • Unilateral contraction: rotation of head to the ipsilateral side
  • Stabilises the atlanto-axial joint
Rectus capitis posterior major Spinous process of C2 Occipital bone Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))
  • Unilateral contraction: head rotation (ipsilateral)
  • Bilateral contraction: head extension
Rectus capitis posterior minor Posterior tubercle of the atlas Occipital bone Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))
  • Head extension
Iliocostal cervicis Ribs 3-6 Transverse process of C4-C6 Dorsal rami of the upper thoracic and lower cervical spinal nerves
Trapezius Occipital bone, nuchal ligament and spinous process C7-T12 Lateral third of the clavicle, acromian and spine of the scapula Spinal root of accessory nerve (CN XI) (motor)

Cervical nerves (C3 and C4) (pain and proprioception)

  • Supports the spinal column to remain erect
  • Neck extension when scapulae are fixed
  • Ipsilateral lateral flexion of neck
Splenius cervicis Spinous process of T3-T6 Transverse process of C1-C3 Dorsal rami of cervical spinal nerves (C5-C8)
  • Acting bilaterally: extend the neck
  • Acting unilaterally: lateral flexion and rotation of the head and neck to the ipsilateral side
Splenius capitis Spinous process of C7-T3 and nuchal ligament Occipital bone Posterior rami of the 2nd and 3rd cervical spinal nerves
  • Acting bilaterally: extension of the head and neck
  • Acting unilaterally: lateral flexion and rotation of the head and neck to the ipsilateral side
Spinalis capitis Spinous process of C7 and T1 Occipital bone Dorsal rami of spinal nerves
  • Acting bilaterally: extension of the neck
  • Acting unilaterally: ipsilateral lateral flexion and rotation of the neck
Longissimus capitis Transverse process of upper 4 thoracic vertebrae and articular process lower three cervical vertebrae Mastoid process Posterior/dorsal rami of spinal nerves
  • Acting bilaterally: extension of neck
  • Acting unilaterally: ipsilateral lateral flexion and rotation of the neck

** The transversospinal muscles (rotatores, multifidus, semispinalis) are the deep muscle of the spine. They attach between the transverse and spinous process of the vertebrae. They stabilise and extend the spine. The rotatores also provide rotation.

Cervical Spine Lateral Flexors[edit | edit source]

Muscle Origin Insertion Innervation Action
Splenius cervicis Spinous process of T3-T6 Transverse process C1-C3 Dorsal rami of cervical spinal nerves (C5-C8)
  • Acting unilaterally: lateral flexion and rotation of the head and neck to the ipsilateral side
  • Acting bilaterally: extend the neck
Splenius capitis Spinous process of C7-T3 and nuchal ligament Occipital bone Posterior rami of the 2nd and 3rd cervical spinal nerves
  • Acting unilaterally: lateral flexion of the head and neck and rotation of the head to the ipsilateral side
  • Acting bilaterally: extension of the head and cervical spine
Sternocleidomastoid Manubrium and the medial portion of the clavicle Mastoid process of the temporal bone Accessory nerve (CN XI), branches of cervical plexus (C2-C3)
  • Unilateral contraction: ipsilateral lateral flexion, elevation of the chin, contralateral rotation of head
  • Bilateral contraction: flexes the neck, extension of the upper vertebral joints, extension of the neck and head, elevation of the head, elevation of the sternum and clavicle, expansion of the thoracic cavity
Anterior scalene Transverse processes of C3-C6 First rib Anterior rami of 4th to 6th cervical spinal nerves (C4-C6)
  • Unilateral contraction: neck lateral flexion (ipsilateral), neck rotation (contralateral), elevation of the first rib
  • Bilateral contraction: neck flexion
  • Accessory muscle of respiration
Middle scalene Posterior tubercles of the transverse processes of C1-C7 Scalene tubercle of the first rib Anterior rami of C3-C8
  • Elevation of the first rib
  • Ipsilateral contraction causes ipsilateral lateral flexion of the neck
  • Respiration
Posterior scalene Posterior tubercles of the transverse processes of C4-C6 2nd rib Anterior rami of C6-C8
  • Elevation of the second rib
  • Ipsilateral lateral flexion of the neck
  • Respiration
Trapezius Occipital bone, nuchal ligament and spinous process C7-T12 Lateral third of the clavicle, the acromian and the spine of s scapula Spinal root of accessory nerve (CN XI) (motor)

Cervical nerves (C3 and C4) (pain and proprioception)

  • Supports the spinal column to remain erect
  • Neck extension when scapulae are fixed
  • Ipsilateral lateral flexion of the neck
Rectus capitis lateralis Superior surface of the transverse process of atlas Inferior surface of the jugular process of the occipital bone Anterior rami of C1-C2 spinal nerves
  • Lateral flexion of the head (ipsilateral)
  • Deep neck flexion
  • Stabilisation of the atlanto-occipital joint
Spinalis capitis Spinous process of C7 and T1 Occipital bone Dorsal rami of spinal nerves
  • Acting bilaterally: extension of the neck
  • Acting unilaterally: ipsilateral lateral flexion and rotation of the neck
Longissimus capitis Transverse process of upper 4 thoracic vertebrae and articular process lower three cervical vertebrae Mastoid process Posterior/dorsal rami of spinal nerves
  • Acting bilaterally: extension of the neck
  • Acting unilaterally: ipsilateral lateral flexion and rotation of the neck

Cervical Spine Rotators[edit | edit source]

Muscle Origin Insertion Innervation Action
Rectus capitis posterior major Spinous process of C2 Occipital bone Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))
  • Unilateral contraction: head rotation (ipsilateral)
  • Bilateral contraction: head extension
Rectus capitis posterior major Spinous process of C2 Occipital bone Suboccipital nerve (posterior ramus of 1st cervical spinal nerve (C1))
  • Unilateral contraction: head rotation (ipsilateral)
  • Bilateral contraction: head extension
Sternocleidomastoid Manubrium and the medial portion of the clavicle Mastoid process of the temporal bone Accessory nerve (CN XI), branches of cervical plexus (C2-C3)
  • Unilateral contraction: ipsilateral lateral flexion, elevation of the chin, contralateral rotation of head
  • Bilateral contraction: flexion of the neck, extension of the upper vertebral joints, extension of the neck and head, elevation of the head, elevation of the sternum and clavicle, expansion of thoracic cavity
Splenius capitis Spinous process ofC7-T3 and nuchal ligament Occipital bone Posterior rami of the 2nd and 3rd cervical spinal nerves
  • Acting unilaterally: lateral flexion of the head and neck and rotation of the head to the ipsilateral side
Splenius cervicis Spinous process T3-T6 Transverse process C1-C3 Dorsal rami of cervical spinal nerves (C5-C8)
  • Acting unilaterally: lateral flexion and rotation of the head and neck to the ipsilateral side
Spinalis capitis Spinous process of C7 and T1 Occipital bone Dorsal rami of spinal nerves
  • Acting bilaterally: extension of the neck
  • Acting unilaterally: ipsilateral lateral flexion and rotation of the neck
Longissimus capitis Transverse process of upper 4 thoracic vertebrae and articular process lower three cervical vertebrae Mastoid process Posterior/dorsal rami of spinal nerves
  • Acting bilaterally: extension of the neck
  • Acting unilaterally: ipsilateral lateral flexion and rotation of the neck

Innervation of the Cervical Spine[edit | edit source]

Nerves originating from the cervical plexus innervate the muscles of the neck. Each nerve root in the cervical spine exits above its corresponding nerve root. There are eight pairs of cervical nerves despite there being seven cervical vertebrae. The C8 nerve root exits below the seventh cervical vertebra. The accessory nerve, which is cranial nerve XI innervates sternocleidomastoid and trapezius.[2]

Nerve Motor Sensory
C1 Flexion of the head and neck

Rectus capitus anterior and lateralis, longus capitis

C2 Flexion of the head and neck

Rectus capitus anterior and lateralis, longus capitus, prevertebral muscles and sternocleidomastoid

Lateral occiput and submandibular area
C3 Head and neck flexion and rotation

Longus capitus, longus colli, prevertebral muscles and sternocleidomastoid, diaphragm, levator scapulae, trapezius and scalenus medius

Lateral occiput and lateral neck, overlapping C2
C4 Head and neck flexion and rotation

Longus capitus, longus colli, levator scapulae, scaleni, trapezius, diaphragm

Lower lateral neck and medial shoulder area
C5 Deltoid, biceps, bicep tendon reflex Clavicle level and lateral arm
C6 Biceps, wrist extensors (brachioradialis tendon reflex) Lateral forearm, thumb, index and half of 2nd finger
C7 Wrist flexors, triceps (triceps tendon reflex) Second finger
C8 Finger flexors, interossei Medial forearm, ring and little finger
T1 Interossei Medial arm

Vascular Supply of the Cervical Spine[edit | edit source]

Vertebral arteries, veins and nerves pass through the transverse foramina of the cervical vertebrae except for in C7, where the vertebral artery passes around the vertebra instead of through the transverse foramen.[4] The neural components sit posterior to the vertebral artery.[12]

The cervical spine vascular supply is primarily provided by the vertebral arteries on each side of the spine. These arteries arise from the subclavian arteries, which originate directly from the arch of the aorta on the right and the brachiocephalic trunk on the left.

** The common carotid artery bifurcates into the internal and external carotid arteries at the C3 segmental level. Only the external carotid artery provides any blood supply to the neck.

Clinical Relevance[edit | edit source]

  • Atlanto-axial instability (AAI) can have serious neurological consequences:
    • conditions with the potential for AAI include:
      • rheumatoid arthritis
      • Down syndrome:
        • laxity in the transverse ligament is present in 14-22% of individuals with Down syndrome.
  • A tight sternocleidomastoid muscle can cause torticollis.
  • Disc herniation:
    • disc herniations in the cervical spine are a lot less common than in the lumbar spine
    • typical locations:
      • C5-C6
      • C6-C7
  • Because the prevertebral cervical muscles stabilise the neck, dysfunction in these muscles can cause cervicogenic pain
  • Trigger points that develop in the suboccipital muscles can refer pain to the head, causing cervicogenic headaches[10]

Resources[edit | edit source]

References[edit | edit source]

  1. ↑ Frost BA, Camarero-Espinosa S, Foster EJ. Materials for the spine: anatomy, problems, and solutions. Materials. 2019 Jan;12(2):253
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Kaiser JT, Reddy V, Lugo-Pico JG. Anatomy, Head and Neck: Cervical Vertebrae. [Updated 2022 Oct 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539734/
  3. ↑ Petersen JA, Brauer C, Thygesen LC, Flachs EM, Lund CB, Thomsen JF. Prospective, population-based study of occupational movements and postures of the neck as risk factors for cervical disc herniation. BMJ open. 2022 Feb 1;12(2):e053999.
  4. ↑ 4.0 4.1 Teach me anatomy The cervical Spine Available from:https://teachmeanatomy.info/neck/bones/cervical-spine/
  5. ↑ 5.0 5.1 Learn muscles . Cervical spine joints. Available from: https://learnmuscles.com/blog/2017/08/01/cervical-spinal-joints/ (last accessed 29.1.2020)
  6. ↑ Peng B, Bogduk N. Cervical discs as a source of neck pain. An analysis of the evidence. Pain Medicine. 2019 Mar 1;20(3):446-55.
  7. ↑ Guo GM, Li J, Diao QX, Zhu TH, Song ZX, Guo YY, Gao YZ. Cervical lordosis in asymptomatic individuals: a meta-analysis. Journal of orthopaedic surgery and research. 2018 Dec;13(1):1-7.
  8. ↑ Lindenmann S, Tsagkaris C, Farshad M, Widmer J. Kinematics of the Cervical Spine Under Healthy and Degenerative Conditions: A Systematic Review. Annals of Biomedical Engineering. 2022 Dec 10:1-29.
  9. ↑ RSNA Joints of Luschka Available from: https://pubs.rsna.org/doi/10.1148/66.2.181 (last accessed 28.1.2020)
  10. ↑ 10.0 10.1 Xuan D. Exploring Cervical Spine Anatomy Course. Plus, 2023.
  11. ↑ Palastanga, N., & Soames, R. (2012). Anatomy and human movement (6th ed.). Edinburgh: Churchill Livingstone.
  12. ↑ Joshi N, Klinger N, Halalmeh DR, Tubbs RS, Moisi MD. The Neural Sulcus of the Cervical Vertebrae: A Review of Its Anatomy and Surgical Perspectives. Cureus. 2020 Jan 18;12(1)
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