[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) › TMJ disc [Joints and ligaments](https://durgical.com/en/anatomy/system/joints-and-ligaments/) · [Head and neck](https://durgical.com/en/anatomy/region/head-and-neck/) # TMJ disc The disc of the temporomandibular (jaw) joint is a small cushion between the jaw and the skull; if it slips, the jaw can click or lock. Official name: Articular disc of temporomandibular joint [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=head_neck&select=tmj_disc&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A small oval cushion between the jaw's condyle and the skull. ## What it does Slides forward with the condyle when the mouth opens; when it slips, the jaw clicks or locks. ## Key points - Biconcave: a thick anterior band, a thick posterior band and a thin, avascular intermediate zone on which the condyle normally sits - Anterior disc displacement with reduction gives a reciprocal click (on opening and on closing); without reduction it gives a closed lock with limited opening - The retrodiscal tissue (bilaminar zone) behind it is vascular and innervated, a source of pain when the disc slips forward and the condyle loads it ## Key facts **Where** Between the mandibular condyle and the articular fossa/eminence **Attaches** Medial and lateral poles of the condyle; front to the lateral pterygoid; back to the retrodiscal tissue **Function** Splits the joint into an upper (gliding) and lower (hinge) compartment; moves forward with the condyle on wide opening; displacement causes clicking ## Relations **Above** Articular fossa and eminence of the [temporal bone](https://durgical.com/en/anatomy/temporal-bone/), across the upper (gliding) compartment **Below** Condyle of the [mandible](https://durgical.com/en/anatomy/mandible/), across the lower (hinge) compartment **In front** Superior head of the [lateral pterygoid](https://durgical.com/en/anatomy/superior-head-of-lateral-pterygoid-muscle/), attached to the disc and capsule **Behind** Retrodiscal tissue (bilaminar zone), with an elastic upper lamina and a collagen lower lamina ## How to find it The disc itself cannot be felt; the click of a displaced disc can be felt with a fingertip in front of the tragus as the mouth opens and closes. ## Examination - Reciprocal click: a click on opening and another, often softer, on closing suggests disc displacement with reduction - Opening with deflection: limited opening with the jaw swinging to one side and not returning to midline suggests displacement without reduction on that side ## On imaging MRI with closed- and open-mouth views is the reference for disc position and shape; on proton density images the disc is a dark bow tie between the condyle and the eminence. ## Common problems - Clicking or popping when the disc slips forward and back. - Locking (the jaw cannot open fully). - Jaw pain linked to clenching or grinding (bruxism). ## How it is diagnosed Exam of jaw opening and the joint; MRI for the disc in persistent cases. ## Treatment - Soft diet, heat, jaw exercises and pain relief. - A night guard (splint) for grinding. - Joint washing (arthrocentesis) or surgery only rarely. ## Clinical notes - Long-standing displacement can deform the disc and lead to degenerative joint disease (osteoarthritis) of the condyle - A closed lock that does not settle is sometimes treated by arthrocentesis (washing out the upper compartment) or arthroscopy - A painless click with normal opening is common in the general population and is not a disease by itself ## Development Like other articular discs, it is mesenchyme left between the developing condyle and the temporal bone when the joint spaces open, which is why the joint has separate upper and lower compartments. ## Related conditions - [Temporomandibular disorder](https://durgical.com/en/conditions/temporomandibular-disorder/) ## Test yourself Think of the answer, then tap the question to see it. ## What is the shape of the TMJ disc, and where does the condyle normally sit on it? Biconcave, with thick anterior and posterior bands; the condyle sits on the thin, avascular intermediate zone. ## How do anterior TMJ disc displacement with and without reduction differ? With reduction: a reciprocal click on opening and closing. Without reduction: a closed lock with limited opening. ## Why does a forward-slipped TMJ disc cause pain? The condyle loads the retrodiscal tissue (bilaminar zone), which is vascular and innervated. ## Which muscle attaches to the front of the TMJ disc? The superior head of the lateral pterygoid. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/articular-disc-of-temporomandibular-joint/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** discus articulationis temporomandibularis TA2 1623 **Official Spanish (DeCS)** Disco de la Articulación Temporomandibular DeCS D019224 **English (TA2)** Articular disc of temporomandibular joint ## Related - [Mandible](https://durgical.com/en/anatomy/mandible/) - [Lateral pterygoid](https://durgical.com/en/anatomy/superior-head-of-lateral-pterygoid-muscle/) - [Temporal bones](https://durgical.com/en/anatomy/temporal-bone/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=32870&filter=ths_termall&q=Temporomandibular%20Joint%20Disc); [Anatomy, Head and Neck, Temporomandibular Joint](https://www.ncbi.nlm.nih.gov/books/NBK538486/); Anatomy of the Human Body (20th ed.): Development of the Joints (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/articular-disc-of-temporomandibular-joint/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/articular-disc-of-temporomandibular-joint/