Anterior Scalene: Difference between revisions

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== Description  ==
== Description  ==


Anterior Scalene, AKA Scalenus anterior ( or even Scalenus anticus) is one of the lateral muscles of the neck, belonging to the Scalene group. It is deeply placed, lying behind [[Sternocleidomastoid|Sternocleidomastoid]].  
The anterior scalene, AKA scalenus anterior (scalenus anticus; Latin: musculus scalenus anterior) muscle is one of the lateral muscles of the neck, belonging to the scalene group. It is deeply placed, lying behind the [[Sternocleidomastoid|Sternocleidomastoid]].


It is located between the subclavian vein and the subclavian artery; the roots of the [[Brachial plexus|brachial plexus]] pass posterior to it; the phrenic nerve crosses its anterior surface.<br>  
It is located between the subclavian vein and the subclavian artery. The roots of the [[Brachial Plexus|brachial plexus]] pass posterior to it. The phrenic nerve crosses its anterior surface.<ref>Harry WG, Bennett JD, Guha SC. Scalene muscles and the brachial plexus: anatomical variations and their clinical significance. Clinical Anatomy: The Official Journal of the American Association of Clinical Anatomists and the British Association of Clinical Anatomists. 1997;10(4):250-2.</ref><br> [[Image:Scalenus anterior - animation04.gif|center|300x300px]]<br>  
 
[[Image:Scalenus anterior - animation04.gif]]<br>  


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== Origin  ==
== Origin  ==
 
Anterior tubercles of the transverse processes of [[Cervical Vertebrae|cervical vertebrae]] C3-C6 <ref name=":0">Sam Bernes.[https://teachmeanatomy.info/neck/muscles/scalene/ The Scalene Muscles] .Teach Me Anatomy.Accessed 28 April 2020.
C3-6
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Anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth [[Cervical Vertebrae|cervical vertebrae.]]


== Insertion  ==
== Insertion  ==
 
By a narrow, flat tendon attaches into the scalene tubercle on the inner border of the first rib, and into the ridge on the upper surface of the rib in front of the subclavian groove.
1st rib
 
By a narrow, flat tendon into the scalene tubercle on the inner border of the first rib, and into the ridge on the upper surface of the rib in front of the subclavian groove.  


== Nerve Supply  ==
== Nerve Supply  ==
 
Anterior branches of the cervical nerves C5-C7.
Brachial plexus, C5-7
 
Anterior branches of the Cervical nerves 5 to 7


== Blood Supply  ==
== Blood Supply  ==
Ascending cervical branch of the inferior thyroid artery.


Ascending cervical branch of the inferior thyroid artery
== Action and Function  ==


== Action  ==
Anterior scalene can perform individually or in synergistic group with other two scalenes ([[Middle Scalene|Middle]] and [[Posterior Scalene|Posterior]])
* Individually, bends the neck laterally on the same side - '''side flexor'''
* In synergistic group:


Acts with[[Middle Scalene|Middle]] and [[Posterior Scalene|Posterior Scalenes]]
** Bilateral contraction causes anterior flexion of the neck - '''flexors'''
** Ipsilateral contraction of the anterior scalene muscle primarily results in lateral flexion of the neck to the same side and elevation of the first rib during forced inspiration.
** Elevate the 1st rib and are '''accessory muscles of respiration'''


When the Scalenes act from above, they elevate the first and second ribs.  
== Clinical Significance ==
 
Accessory muscles of respiration-The Scalene muscles help in elevation of the first and second ribs in increasing the intrathoracic volume.To aid in breathing,these muscles act as accessory muscles of respiration in patients with respiratory distress.The important clinical sign is the usage of accessory muscles in respiratory distress<ref name=":0" />
Acting from below, they produce side flexion of the vertebral column; if the muscles of both sides act, the vertebral column is slightly flexed.
 
All 3 scalene muscles produce rotation of the cervical spine to the same side<ref>J Orthop Sports Phys Ther. 2002 Oct;32(10):488-96. Actions of the scalene muscles for rotation of the cervical spine in macaque and human. Buford JA, Yoder SM, Heiss DG, Chidley JV.</ref>.
 
== Function  ==
 
When acting from above, they help to elevate the 1st rib and are accessory muscles of respiration.
 
Acting from below they are cervical flexors and rotators.
 
== Resources  ==
 
== Recent Related Research (from [http://www.ncbi.nlm.nih.gov/pubmed/ Pubmed])  ==
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== References  ==


References will automatically be added here, see [[Adding References|adding references tutorial]].
== Referencest  ==


<references />  
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[[Category:Cervical_Anatomy]]
[[Category:Anatomy]]
[[Category:Cervical Spine - Anatomy]]
[[Category:Cervical_Spine]]
[[Category:Muscles]]
[[Category:Musculoskeletal/Orthopaedics]]
[[Category:Cervical Spine - Muscles]]

Latest revision as of 18:59, 8 March 2024

Original Editor - Wendy Walker

Lead Editors - Kim Jackson, Wendy Walker, Chrysolite Jyothi Kommu, Admin, Evan Thomas, WikiSysop and Milijana Delevic

Description[edit | edit source]

The anterior scalene, AKA scalenus anterior (scalenus anticus; Latin: musculus scalenus anterior) muscle is one of the lateral muscles of the neck, belonging to the scalene group. It is deeply placed, lying behind the Sternocleidomastoid.

It is located between the subclavian vein and the subclavian artery. The roots of the brachial plexus pass posterior to it. The phrenic nerve crosses its anterior surface.[1]

Scalenus anterior - animation04.gif



Origin[edit | edit source]

Anterior tubercles of the transverse processes of cervical vertebrae C3-C6 [2]

Insertion[edit | edit source]

By a narrow, flat tendon attaches into the scalene tubercle on the inner border of the first rib, and into the ridge on the upper surface of the rib in front of the subclavian groove.

Nerve Supply[edit | edit source]

Anterior branches of the cervical nerves C5-C7.

Blood Supply[edit | edit source]

Ascending cervical branch of the inferior thyroid artery.

Action and Function[edit | edit source]

Anterior scalene can perform individually or in synergistic group with other two scalenes (Middle and Posterior)

  • Individually, bends the neck laterally on the same side - side flexor
  • In synergistic group:
    • Bilateral contraction causes anterior flexion of the neck - flexors
    • Ipsilateral contraction of the anterior scalene muscle primarily results in lateral flexion of the neck to the same side and elevation of the first rib during forced inspiration.
    • Elevate the 1st rib and are accessory muscles of respiration

Clinical Significance[edit | edit source]

Accessory muscles of respiration-The Scalene muscles help in elevation of the first and second ribs in increasing the intrathoracic volume.To aid in breathing,these muscles act as accessory muscles of respiration in patients with respiratory distress.The important clinical sign is the usage of accessory muscles in respiratory distress[2]

Referencest[edit | edit source]

  1. ↑ Harry WG, Bennett JD, Guha SC. Scalene muscles and the brachial plexus: anatomical variations and their clinical significance. Clinical Anatomy: The Official Journal of the American Association of Clinical Anatomists and the British Association of Clinical Anatomists. 1997;10(4):250-2.
  2. ↑ 2.0 2.1 Sam Bernes.The Scalene Muscles .Teach Me Anatomy.Accessed 28 April 2020.


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