TMJ Injury and Dysfunction

Temporomandibular joint (TMJ) problems in sport fall into acute injuries (subluxation, dislocation and condylar fracture) and temporomandibular disorders (TMD), a chronic pain and dysfunction spectrum.

The key decisions are recognising injuries that need same-day care, separating TMD from its mimics (giant cell arteritis matters most), and knowing when maxillofacial (OMFS), dental or orofacial pain services should take over.

The TMJ is a paired synovial joint between the mandibular condyle and the glenoid fossa of the temporal bone. A fibrocartilaginous disc divides it into superior and inferior compartments and is anchored in front to the lateral pterygoid. Opening begins with rotation in the inferior compartment, then the condyle and disc glide forward over the articular eminence. Normal maximal mouth opening is at least 35 mm between the incisors.

Patterns:

• •Acute dislocation: usually anterior, with the mouth locked open and a palpable hollow in front of the ear. Posterior, lateral or superior dislocation is rare and usually comes with skull base injury
• •Condylar fracture: intracapsular, condylar neck or subcondylar. The condylar neck acts as a fuse, sparing the middle cranial fossa
• •Primary TMD: myofascial pain, disc displacement with or without reduction, and inflammatory or degenerative joint pain

Anterior dislocation can follow a wide yawn, dental treatment, vomiting, a seizure or a chin blow, and often recurs because of capsular laxity. Post-traumatic TMD can follow facial trauma, whiplash or a missed condylar fracture.