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== Description  ==
== Description  ==
[[File:IMG 2582.JPG|thumb|TMJ shown in the box]]


The temporomandibular joint (TMJ) is the joint between condylar head of the mandible and mandibular fossa of the temporal bone.&nbsp; It is a condylar and hinge-type joint that has thousands of repetitive movements daily.&nbsp; The joint involves fibrocartilaginous surfaces and a disc which divides the joint into two cavities.&nbsp; <ref>Magee D. Orthopedic physical assessment. 4th ed Philadelphia: Saunders. 2002.</ref><span id="fck_dom_range_temp_1245889699406_939"></span>  
The temporomandibular joint (TMJ), or jaw joint, is a synovial joint that allows the complex movements necessary for life. It is the joint between condylar head of the mandible and the mandibular fossa of the temporal bone. This system is made up of the TMJ, teeth and soft tissue and it plays a role in breathing, eating and speech.<ref>Di Fabio RP. Physical therapy for patients with TMD: a descriptive study of treatment, disability, and health status. Journal of orofacial pain. 1998 Apr 1;12(2).</ref>  


== Motions Available ==
The TJM is defined as a ginglymoarthrodial joint<ref>Maini K, Dua A. Temporomandibular Joint Syndrome. 2020 Nov 17. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 31869076.</ref> because it has a rotational movement in the sagittal plane and a translation movement on its own axis - this translation movement generates more movement.<ref>Reboredo V. Introduction to the Temporomandibular Joint Course. Plus. 2021.</ref> These movements are constrained by various passive factors, as well as passive tension of the ligaments and muscles.<ref>Abdi AH, Sagl B, Srungarapu VP, Stavness I, Prisman E, Abolmaesumi P et al. [https://www.frontiersin.org/articles/10.3389/fnhum.2020.00188/full Characterizing motor control of mastication with soft actor-critic]. Front Hum Neurosci. 2020;14:188.</ref>


Mandibular depression and elevation, right and left lateral excursion/deviation, and protrusion and retrusion.&nbsp;
Dysfunction of the TMJ can cause severe pain and lifestyle limitation.  


== Ligaments &amp; Joint Capsule<br> ==
[[Temporomandibular Disorders|Temporomandibular disorders]] are common and sufferers will often seek physiotherapy advice and treatment.  


The articular disc of the TMJ is divided into anterior, intermediate, and posterior zones and is thinnest in its intermediate zone and thickest in its posterior zone helping maintain disc positioning on the condyle. The disc is firmly attached at the medial and lateral poles by the collateral or discal ligaments, to the highly vascular and innervated retrodiscal tissue posteriorly, and to the joint capsule and the superior lateral pterygoid muscle anteriorly. The capsule and extracapsular ligaments help stabilize the TMJ.&nbsp; <ref>Harrison AL, The temporomandibular joint. In: Malone TR, McPoil T, Nitz AJ editors. Orthopedic and sports physical therapy. St Louis: Mosby, 1997. p555-93.</ref>
Good knowledge of the anatomy of the TMJ and related structures is essential to correct diagnosis and appropriate treatment.


== Muscles ==
== Joint ==
 
TMJ is a synovial, condylar and hinge-type joint.  The joint involves fibrocartilaginous surfaces and an articular disc which divides the joint into two cavities.<ref name=":0">Magee DJ. Orthopedic physical assessment. 6th ed. Elsevier; 2014</ref> These superior and inferior articular cavities are lined by separate superior and inferior synovial membranes<ref name=":1">Moore KL, Dalley AF, Agur AM. Clinically oriented anatomy. Lippincott Williams & Wilkins; 2017 Sept 13.</ref>.
 
'''Capsule -&nbsp;'''The capsule is a fibrous membrane that surrounds the joint and attaches to the articular eminence, the articular disc and the neck of the mandibular condyle.
 
'''Articular disc -&nbsp;'''The articular disc is a fibrous extension of the capsule that runs between the two articular surfaces of the temporomandibular joint. The disc articulates with the mandibular fossa of the temporal bone above and the condyle of the mandible below. The disc divides the joint into two sections, each with its own synovial membrane. The disc is also attached to the condyle medially and laterally by the collateral ligaments. The anterior disc attaches to the joint capsule and the superior head of the lateral pterygoid. The posterior portion attaches to the mandibular fossa and is referred to as the retrodiscal tissue<ref>Miloro, M; Ghali, GE; Larsen, P; Waite, P; Peterson's principles of oral and maxillofacial surgery, Volume 2, Chapter 47, 2004.</ref>.
 
'''Retrodiscal tissue -&nbsp;'''Unlike the disc itself, the retrodiscal tissue is vascular and highly innervated. As a result, the retrodiscal tissue is often a major contributor to the pain of Temporomandibular Disorder (TMD), particularly when there is inflammation or compression within the joint<ref name="Langendoen">Langendoen, J; Müller, J; Jull, GA, Retrodiscal Tissue of the Temporomandibular Joint: Clinical Anatomy and its Role in Diagnosis and Treatment of Arthropathies, Manual Therapy, 2(4), 191-198, 1997.</ref><br>
 
<br>
 
[[Image:TMJdisc.jpg|center|500px]]
 
<br>
 
== Ligaments  ==
 
The ligaments give passive stability to the TMJ.
 
'''The temporomandibular ligament''' is the thickened lateral portion of the capsule, and it has two parts, an outer oblique portion and an inner horizontal portion.
 
[[Image:TMJLatLigs.jpg|center|200px]]
 
<br> '''The stylomandibular ligament''' runs from the styloid process to the angle of the mandible. '''The sphenomandibular ligament''' runs from the spine of the sphenoid bone to the lingula of mandible.
 
<br>
 
[[Image:TMJMedLigs.jpg|center|270px]]


'''Muscles of Mastication''':  
<br> '''The oto-mandibular ligaments''' are the '''discomalleolar ligament''' (DML), which arises from the malleus (one of the ossicles of the middle ear) and runs to the medial retrodiscal tissue of the TMJ, and the '''anterior malleolar ligament''' (AML), which arises from the malleus and connects with the lingula of the mandible via the sphenomandibular ligament<ref>Loughner BA, Larkin LH, Mahan PE. Discomalleolar and anterior malleolar ligaments: possible causes of middle ear damage during temporomandibular joint surgery. Oral Surg Oral Med Oral Pathol. Jul; 68(1):14-22, 1989.</ref><ref>Rowicki, T; Zakrzewska, J. "A study of the discomalleolar ligament in the adult human." Folia Morphol. (Warsz). 65 (2): 121–125, 2006.</ref>. The oto-mandibular ligaments may be implicated in tinnitus associated with TMD. A positive correlation has been found between tinnitus and ipsilateral TMJ disorder<ref>Kuttila, S; Kuttila, M; Le Bell, BY; Alanen, P; Suonpaa, J. Recurrent tinnitus and associated ear symptoms in adults. Int. J. Audiol., 44:164-70, 2005.</ref><ref>Ren, YF; Isberg, A. Tinnitus in patients with temporomandibular joint internal derangement. Cranio, 13:75-80, 1995.</ref>. &nbsp;It has been proposed that a TMJ disorder may stretch the DML and AML, thereby affecting middle ear structure equilibrium<ref>Cheynet, F; Guyot, L; Richard, O; Layoun, W; Gola, R. Discomallear and malleomandibular ligaments: anatomical study and clinical applications. Surg. Radiol. Anat., 25:152-7, 2003.</ref><ref>Eckerdal, O. The petrotympanic fissure: a link connecting the tympanic cavity and the temporomandibular joint. Cranio, 9:15-22, 1991.</ref><ref>Kim, HJ; Jung, HS; Kwak, HH; Shim, KS; Hu, KS; Park, HD; Park, HW; Chung, IH. The discomallear ligament and the anterior ligament of malleus: an anatomic study in human adults and fetuses. Surg. Radiol. Anat., 26:39-45, 2004.</ref><ref>Wright, EF; Bifano, SL. Tinnitus improvement through TMD therapy. J. Am. Dent. Assoc., 128:1424-32, 1997.</ref>. “It thus seems that otic symptoms (tinnitus, otalgia (ear pain), dizziness and hypoacusis) corresponding to altered ossicular spatial relationships (such as conductive middle ear pathologies) can also be produced from masticatory system pathologies.” <ref>Ramírez, LM; Ballesteros, ALE; Sandoval, OGP. A direct anatomical study of the morphology and functionality of disco-malleolar and anterior malleolar ligaments. Int. J. Morphol., 27(2):367-379, 2009.</ref>


Temporalis: superior attachment to temporal bone and inferior attachments to coronoid process and anterior ramus of mandible, involved with elevation and retrusion, ipsilateral lateral excursion and clenching
<br>


Masseter: fibers run obliquely from zygomatic arch to the angle of the mandible, involved in ipsilateral lateral excursion and clenching
[[Image:TMJMalleusLig.jpg|center|250px]]


Medial pterygoid: fibers&nbsp;attach at the pterygoid fossa to the medial aspect of the angle of the mandible, involved in elevation and protrusion and&nbsp;unilaterally in ''contralateral'' excursion.&nbsp; Also involved in grinding.
<br>


Superior lateral pterygoid: attaches at sphenoid and neck of the condyle, anterior capsule, and ''disc''.&nbsp; Fires in conjuction with mandibular elevators, plays a role in positioning the disc at end range closure and with resistance closure with chewing.  
== Movements ==
A variety of movements occur at the TMJ. These movements are mandibular depression, elevation, lateral deviation (which occurs to both the right and left sides), retrusion and protrusion.


Inferior lateral pterygoid: attaches to the lateral pterygoid plate and the neck of the condyle.&nbsp; Involved in gliding the condyle anteriorly during mouth&nbsp;opening and during protrusion.&nbsp; Unilaterally involved in ''contralateral'' excursion.&nbsp;&nbsp;<ref>Harrison AL, The temporomandibular joint. In: Malone TR, McPoil T, Nitz AJ editors. Orthopedic and sports physical therapy. St Louis: Mosby, 1997. p555-93.</ref>
Each of these movements are performed by a number of muscles working together to perform the movement while controlling the position of the condyle within the mandibular fossa.


== Closed Packed Position  ==
Chewing and talking require a combination of jaw movements in a number of directions<ref>Saladin, KS; Human Anatomy. New York, NY: McGraw-Hill, 2005.</ref><ref>Standring, S, Editor, Gray’s Anatomy, 40th edition, Elsevier, Churchill Livingstone, 2008.</ref>.&nbsp;


Teeth tightly clenched
{{#ev:youtube|v=SCS4MiHJ5Xw&feature=youtu.be|}}<ref>Functional Anatomy of the TMJ. Movements of the TMJ. Available from https://www.youtube.com/watch?v=SCS4MiHJ5Xw [last accessed 07/01/2018]</ref>


== Open Packed Position ==
== Muscles ==
For more detailed description, see the [[Muscles of Mastication]] page.
{| class="wikitable"
!Muscles
!Actions
|-
|Temporalis
|Elevates mandible
|-
|Masseter
|Elevates mandible
|-
|Lateral pterygoid
|Protracts mandible, depresses chin, lateral deviation of mandible
|-
|Medial pterygoid
|Works with masseter to elevate mandible, aids in protrusion,
|-
|Digastric
Stylohyoid


Resting position: mouth slightly open, lips together, teeth not in contact, tongue on hard palate.
Mylohyoid


== Other Important Information  ==
Geniohyoid
|Depresses the mandible against resistance when infrahyoid muscles stabilize or depress hyoid bone
|-
|Platysma
|Depresses mandible against resistance
|}
Adapted from Moore<ref name=":1" />


During opening of the TMJ, the hinging motion predominates for the first 20 mm of motion and is primarily due to gravity. Then anterior translation and rotation of the condyle makes the superior lateral pterygoid relax as the condyle approaches the intermediate zone of the disc. As this occurs the shape of the disc along with the attachment of the collateral ligaments results in anterior translation of the disc. The inferior lateral pterygoids contract, resulting in continue anterior translation. At full opening, the condyle resides in a slightly anterior position on the disc, the disc and condyle rest on the articular eminence of the temporal bone, the superior lateral pterygoid is on slack, and the retrodiscal tissue is stretched.&nbsp;
{|
|-
| [[Image:TMJMassTempMuscles.jpg|250px]]
| [[Image:TMJPterygoids.jpg|250px]]
| [[Image:TMJDigastricHyoids.jpg|250px]]
|}


Normal movements:&nbsp;Normal opening is approximately 35-40 mm or 2-3 finger between upper and lower incisors, protrusion is 3-7 mm, lateral deviation is 5-12 mm.&nbsp; <ref name="Clarkson">Clarkson HM. Musculoskeletal assessment: joint range of motion and manual muscle strength. 2nd ed. Philadelphia: Lippincott Williams and Wilkins. 2000.</ref>  
== Resting Position and Close-Packed Position ==
The resting position of the TMJ is with the mouth slightly open, the lips together and the teeth not in contact. This is in contrast to the closed-pack position in which the teeth are tightly clenched.<ref name=":0" />


== Resources  ==
== Nerve Supply ==
<div class="researchbox">
The muscles that act on the TMJ are innervated by the mandibular nerve ([[Cranial Nerves|CN V]]), the facial nerve ([[Cranial Nerves|CN VII]]), C 1, C 2 and C 3.<ref name=":1" />
== Recent Related Research (from [http://www.ncbi.nlm.nih.gov/pubmed/ Pubmed])  ==


<rss>http://eutils.ncbi.nlm.nih.gov/entrez/eutils/erss.cgi?rss_guid=1DC34RKGsqmK2gVSxF-KG5-qPsMRMdOfP37PqJiCR9uTfEOk9|charset=UTF-8|short|max=10</rss>
</div>
== References  ==
== References  ==


References will automatically be added here, see [[Adding References|adding references tutorial]].
<references /><br>


<references />
[[Category:Anatomy]]
[[Category: Head - TMJ]]
[[Category:Musculoskeletal/Orthopaedics]]
[[Category:Head - Muscles]]

Latest revision as of 11:48, 18 August 2022

Original Editor - Heather Mariner

Top Contributors - Laurel, Janine Rose, Admin, Kim Jackson, WikiSysop, Jess Bell and Wendy Walker  

Description[edit | edit source]

TMJ shown in the box

The temporomandibular joint (TMJ), or jaw joint, is a synovial joint that allows the complex movements necessary for life. It is the joint between condylar head of the mandible and the mandibular fossa of the temporal bone. This system is made up of the TMJ, teeth and soft tissue and it plays a role in breathing, eating and speech.[1]

The TJM is defined as a ginglymoarthrodial joint[2] because it has a rotational movement in the sagittal plane and a translation movement on its own axis - this translation movement generates more movement.[3] These movements are constrained by various passive factors, as well as passive tension of the ligaments and muscles.[4]

Dysfunction of the TMJ can cause severe pain and lifestyle limitation.

Temporomandibular disorders are common and sufferers will often seek physiotherapy advice and treatment.

Good knowledge of the anatomy of the TMJ and related structures is essential to correct diagnosis and appropriate treatment.

Joint[edit | edit source]

TMJ is a synovial, condylar and hinge-type joint.  The joint involves fibrocartilaginous surfaces and an articular disc which divides the joint into two cavities.[5] These superior and inferior articular cavities are lined by separate superior and inferior synovial membranes[6].

Capsule - The capsule is a fibrous membrane that surrounds the joint and attaches to the articular eminence, the articular disc and the neck of the mandibular condyle.

Articular disc - The articular disc is a fibrous extension of the capsule that runs between the two articular surfaces of the temporomandibular joint. The disc articulates with the mandibular fossa of the temporal bone above and the condyle of the mandible below. The disc divides the joint into two sections, each with its own synovial membrane. The disc is also attached to the condyle medially and laterally by the collateral ligaments. The anterior disc attaches to the joint capsule and the superior head of the lateral pterygoid. The posterior portion attaches to the mandibular fossa and is referred to as the retrodiscal tissue[7].

Retrodiscal tissue - Unlike the disc itself, the retrodiscal tissue is vascular and highly innervated. As a result, the retrodiscal tissue is often a major contributor to the pain of Temporomandibular Disorder (TMD), particularly when there is inflammation or compression within the joint[8]


TMJdisc.jpg


Ligaments[edit | edit source]

The ligaments give passive stability to the TMJ.

The temporomandibular ligament is the thickened lateral portion of the capsule, and it has two parts, an outer oblique portion and an inner horizontal portion.

TMJLatLigs.jpg


The stylomandibular ligament runs from the styloid process to the angle of the mandible. The sphenomandibular ligament runs from the spine of the sphenoid bone to the lingula of mandible.


TMJMedLigs.jpg


The oto-mandibular ligaments are the discomalleolar ligament (DML), which arises from the malleus (one of the ossicles of the middle ear) and runs to the medial retrodiscal tissue of the TMJ, and the anterior malleolar ligament (AML), which arises from the malleus and connects with the lingula of the mandible via the sphenomandibular ligament[9][10]. The oto-mandibular ligaments may be implicated in tinnitus associated with TMD. A positive correlation has been found between tinnitus and ipsilateral TMJ disorder[11][12].  It has been proposed that a TMJ disorder may stretch the DML and AML, thereby affecting middle ear structure equilibrium[13][14][15][16]. “It thus seems that otic symptoms (tinnitus, otalgia (ear pain), dizziness and hypoacusis) corresponding to altered ossicular spatial relationships (such as conductive middle ear pathologies) can also be produced from masticatory system pathologies.” [17]


TMJMalleusLig.jpg


Movements[edit | edit source]

A variety of movements occur at the TMJ. These movements are mandibular depression, elevation, lateral deviation (which occurs to both the right and left sides), retrusion and protrusion.

Each of these movements are performed by a number of muscles working together to perform the movement while controlling the position of the condyle within the mandibular fossa.

Chewing and talking require a combination of jaw movements in a number of directions[18][19]

[20]

Muscles[edit | edit source]

For more detailed description, see the Muscles of Mastication page.

Muscles Actions
Temporalis Elevates mandible
Masseter Elevates mandible
Lateral pterygoid Protracts mandible, depresses chin, lateral deviation of mandible
Medial pterygoid Works with masseter to elevate mandible, aids in protrusion,
Digastric

Stylohyoid

Mylohyoid

Geniohyoid

Depresses the mandible against resistance when infrahyoid muscles stabilize or depress hyoid bone
Platysma Depresses mandible against resistance

Adapted from Moore[6]

TMJMassTempMuscles.jpg TMJPterygoids.jpg TMJDigastricHyoids.jpg

Resting Position and Close-Packed Position[edit | edit source]

The resting position of the TMJ is with the mouth slightly open, the lips together and the teeth not in contact. This is in contrast to the closed-pack position in which the teeth are tightly clenched.[5]

Nerve Supply[edit | edit source]

The muscles that act on the TMJ are innervated by the mandibular nerve (CN V), the facial nerve (CN VII), C 1, C 2 and C 3.[6]

References[edit | edit source]

  1. Di Fabio RP. Physical therapy for patients with TMD: a descriptive study of treatment, disability, and health status. Journal of orofacial pain. 1998 Apr 1;12(2).
  2. Maini K, Dua A. Temporomandibular Joint Syndrome. 2020 Nov 17. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 31869076.
  3. Reboredo V. Introduction to the Temporomandibular Joint Course. Plus. 2021.
  4. Abdi AH, Sagl B, Srungarapu VP, Stavness I, Prisman E, Abolmaesumi P et al. Characterizing motor control of mastication with soft actor-critic. Front Hum Neurosci. 2020;14:188.
  5. 5.0 5.1 Magee DJ. Orthopedic physical assessment. 6th ed. Elsevier; 2014
  6. 6.0 6.1 6.2 Moore KL, Dalley AF, Agur AM. Clinically oriented anatomy. Lippincott Williams & Wilkins; 2017 Sept 13.
  7. Miloro, M; Ghali, GE; Larsen, P; Waite, P; Peterson's principles of oral and maxillofacial surgery, Volume 2, Chapter 47, 2004.
  8. Langendoen, J; Müller, J; Jull, GA, Retrodiscal Tissue of the Temporomandibular Joint: Clinical Anatomy and its Role in Diagnosis and Treatment of Arthropathies, Manual Therapy, 2(4), 191-198, 1997.
  9. Loughner BA, Larkin LH, Mahan PE. Discomalleolar and anterior malleolar ligaments: possible causes of middle ear damage during temporomandibular joint surgery. Oral Surg Oral Med Oral Pathol. Jul; 68(1):14-22, 1989.
  10. Rowicki, T; Zakrzewska, J. "A study of the discomalleolar ligament in the adult human." Folia Morphol. (Warsz). 65 (2): 121–125, 2006.
  11. Kuttila, S; Kuttila, M; Le Bell, BY; Alanen, P; Suonpaa, J. Recurrent tinnitus and associated ear symptoms in adults. Int. J. Audiol., 44:164-70, 2005.
  12. Ren, YF; Isberg, A. Tinnitus in patients with temporomandibular joint internal derangement. Cranio, 13:75-80, 1995.
  13. Cheynet, F; Guyot, L; Richard, O; Layoun, W; Gola, R. Discomallear and malleomandibular ligaments: anatomical study and clinical applications. Surg. Radiol. Anat., 25:152-7, 2003.
  14. Eckerdal, O. The petrotympanic fissure: a link connecting the tympanic cavity and the temporomandibular joint. Cranio, 9:15-22, 1991.
  15. Kim, HJ; Jung, HS; Kwak, HH; Shim, KS; Hu, KS; Park, HD; Park, HW; Chung, IH. The discomallear ligament and the anterior ligament of malleus: an anatomic study in human adults and fetuses. Surg. Radiol. Anat., 26:39-45, 2004.
  16. Wright, EF; Bifano, SL. Tinnitus improvement through TMD therapy. J. Am. Dent. Assoc., 128:1424-32, 1997.
  17. Ramírez, LM; Ballesteros, ALE; Sandoval, OGP. A direct anatomical study of the morphology and functionality of disco-malleolar and anterior malleolar ligaments. Int. J. Morphol., 27(2):367-379, 2009.
  18. Saladin, KS; Human Anatomy. New York, NY: McGraw-Hill, 2005.
  19. Standring, S, Editor, Gray’s Anatomy, 40th edition, Elsevier, Churchill Livingstone, 2008.
  20. Functional Anatomy of the TMJ. Movements of the TMJ. Available from https://www.youtube.com/watch?v=SCS4MiHJ5Xw [last accessed 07/01/2018]