Relations of the Temporomandibular Joint (TMJ)

Anterior Relations

• Lateral pterygoid muscle - its superior head attaches to the articular disc and the pterygoid fovea on the anterior surface of the condylar neck. This is the most important anterior relation.
• The articular eminence (tubercle of the temporal bone) lies anteriorly within the joint itself and is the surface over which the condyle glides.
• Masseteric nerve and deep temporal nerves (branches of V3) approach the joint anteriorly.

Posterior Relations

• External acoustic meatus (EAM) - the TMJ is intimately related to the EAM posteriorly. This is why TMJ disorders can produce earache, and why EAM infections or tumors can involve the joint.
• Squamotympanic and petrotympanic fissures - the posterior capsule attaches here. The superior lamina of the retrodiscal tissue also attaches to the anterior margin of the squamotympanic fissure.
• Tympanic plate of the temporal bone separates the joint from the middle ear.
• Superficial temporal artery runs just behind and lateral to the joint.

Lateral Relations

• Skin and fascia (the joint is subcutaneous laterally, making it accessible for injection/aspiration)
• Lateral ligament (temporomandibular ligament) - the main supporting ligament, running from the articular tubercle to the lateral surface of the condylar neck
• Auriculotemporal nerve - a branch of V3 that runs just deep to the superficial temporal vessels, passes within the capsule adjacent to the neck of the mandible and behind the TMJ before winding round to supply the joint and scalp
• Superficial temporal vessels (artery and vein) cross the lateral aspect

Medial Relations

• Maxillary artery (and its branches: anterior tympanic and deep auricular) - lies medial to the joint. The deep auricular branch arises in the parotid gland behind the TMJ and pierces the cartilage of the external meatus
• Auriculotemporal nerve loops medially around the condylar neck before running upward
• Middle meningeal artery passes upward medially
• Chorda tympani (from CN VII) passes close medially
• There is no medial ligament - medial stability relies on the lateral ligament of the opposite side

Superior Relations

• Middle cranial fossa - the roof of the mandibular fossa is a thin bony plate separating the joint from the middle cranial fossa. Severe condylar fractures or tumors can breach this
• Temporalis muscle and temporal fascia lie superolaterally
• Middle meningeal vessels in the extradural space above

Inferior Relations

• Neck of mandible - the capsule is attached below to the neck of the condyle
• Medial pterygoid muscle lies inferiorly and medially
• Parotid gland - its deepest (retromandibular) part wraps around the condylar neck. Parotid tumors, especially deep-lobe tumors, can directly involve the TMJ

Nerve Supply (and its clinical significance)

Blood Supply

Key Clinical Correlations

1. Referred otalgia: The auriculotemporal nerve explains why TMJ disorders commonly cause earache - the joint and external ear share sensory supply via V3.
2. Parotid tumors: Deep-lobe parotid tumors grow into the parapharyngeal space and can directly involve the TMJ capsule.
3. Condylar fractures: The thin neck of the condyle is a weak point; fractures can drive the condyle through the roof of the fossa into the middle cranial fossa.
4. External acoustic meatus: Posterior wall of EAM is directly adjacent to the TMJ - erosion by TMJ pathology or vice versa is possible.
5. Frey syndrome: Due to the proximity of the auriculotemporal nerve, parotidectomy can result in inappropriate sweating over the TMJ/temporal area during eating.