Temporomandibular Joint (TMJ) Anatomy: Muscles and How the Jaw Opens and Closes

Temporomandibular Joint (TMJ) Anatomy: Muscles and How the Jaw Opens and Closes

We use the jaw joint thousands of times a day when biting, talking or yawning, and we only notice it when something stops working smoothly. In our Antalya Konyaaltı clinic we often explain to people with jaw complaints that opening the mouth is not a simple hinge movement: it is a mechanism in which rotation and gliding work together. Move the slider in the interactive diagram above to follow it step by step.

What Structures Make Up the Jaw Joint?

The temporomandibular joint (TMJ) is formed between the hollow in the temporal bone (the mandibular fossa) and the rounded end of the lower jaw, the condyle. These two bony surfaces do not touch directly; a fibrocartilage articular disc sits between them.

• Condyle: The articulating head of the lower jaw; it both rotates and glides forward.
• Articular disc: A small pad concave on both sides. It divides the joint into a lower space (rotation) and an upper space (gliding).
• Fossa and articular eminence: The sloping surface along which the condyle slides during wide opening.
• Ligaments: The temporomandibular, sphenomandibular and stylomandibular ligaments support the joint and set the limits of movement.

Tap any item under "Joint structures" in the diagram to read a short description.

What Happens in the Joint as the Mouth Opens?

Movement happens in two phases:

1. Phase 1 · Rotation: At the start of opening, the condyle simply rotates in place within the fossa. This happens in the lower joint space and is enough for small openings such as speaking.
2. Phase 2 · Translation: In wider opening, the condyle and disc glide forward and downward along the slope of the articular eminence. This happens in the upper joint space; the disc travels roughly half the distance of the condyle.

Closing reverses the sequence. Keeping the disc controlled on the condyle matters during closing; when this balance works, the jaw opens and closes quietly and symmetrically.

Chewing Muscles: What Opens and What Closes?

The motor of jaw movement is the group of chewing muscles supplied by the mandibular branch of the trigeminal nerve (V3).

| Muscle | Origin → Insertion | Main action | |---|---|---| | Masseter | Zygomatic arch → outer ramus and angle of the jaw | Closes the mouth | | Temporalis | Temporal fossa → coronoid process | Closes the mouth; posterior fibres pull the jaw back | | Medial pterygoid | Lateral pterygoid plate → inner ramus | Closes the mouth, helps side-to-side grinding | | Lateral pterygoid | Sphenoid bone → condylar neck and disc | Lower head pulls the condyle forward on opening; upper head controls the disc on closing | | Digastric and suprahyoid muscles | Mastoid / chin → hyoid bone | Draw the jaw downward to assist opening |

When you press Play, you will see the lateral pterygoid and digastric lines stand out while opening, and the masseter, temporalis and medial pterygoid while closing. Gravity also helps opening.

Jaw Muscles and the Neck: Why Think of Them Together?

The jaw, neck and shoulder girdle belong to one kinetic chain. A forward head posture can influence the resting position of the jaw and the tension of the chewing muscles. That is why an assessment for jaw complaints is not limited to the joint; neck movement and posture are reviewed too.

Complaints Commonly Described Around the Jaw

The following may be associated with loading of the structures around the TMJ; the exact cause is determined only by a physician's assessment:

• Aching or a feeling of fullness at the temple and cheek (may be related to temporalis and masseter tension).
• Clicking when opening, or the jaw deviating to one side.
• Limited mouth opening, or the jaw "catching".
• Pain or pressure around the ear.

How Does Physiotherapy Approach This?

Physiotherapy begins after a physician's diagnosis and referral. The assessment looks at mouth opening, the path the jaw follows, tenderness of the chewing muscles and neck posture. The plan may include individual manual therapy techniques, movement and awareness exercises for the jaw and neck, and daily-habit advice. The programme is usually planned as a set number of sessions; duration and outcome vary from person to person. Working in coordination with your dentist or maxillofacial surgeon is essential.

For a more clinical look at the topic, see our articles on Night Teeth Grinding (Bruxism) and Jaw Joint Pain and Jaw Pain After Dental Treatment, and our Jaw Joint Problems service page for the neck connection.

🚫 What to Avoid

• Forcing the jaw open and closed to "show" a click.
• Continuing wide yawning, hard foods and chewing gum while it hurts.
• Waiting when there is severe locking, sudden limited opening or complaints after trauma; see a physician first in these cases.

📚 Academic References

• Standring S. (ed.) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Elsevier — chapters on the temporomandibular joint and muscles of mastication.
• Okeson JP. Management of Temporomandibular Disorders and Occlusion. Elsevier — jaw biomechanics and muscle function.
• Schiffman E. et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications. J Oral Facial Pain Headache. 2014.

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Physiotherapy Support in Antalya Konyaaltı

If your physician has assessed your jaw joint, we can plan your physiotherapy process together.

📍 Ali Öksüz | Fizyoterapist | Özel Sağlık Meslek Hizmet Birimi
Toros Mah. 801. Sok. No:4/4 Konyaaltı / Antalya

👉 For a preliminary consultation and appointment, contact us via WhatsApp.

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Legal Notice

This page does not replace a physician's diagnosis or imply a guaranteed recovery. The diagram on this page is an educational, AI-assisted drawing and is not an image of a real procedure. It has been prepared on the basis of physiotherapy science in line with the Health Advertising Regulation to raise health awareness.