Botox for TMJ Dysfunction
Temporomandibular disorder (TMD) is a nonspecific term used to describe orthopedic and myofascial disorders that affect the TMJ. The prevalence of TMD is between 30% and 44%, with up to 25% of the population seeking professional care for TMD. Symptoms are commonly related to pain surrounding the joint and may include headache, periauricular pain, neck pain, decreased jaw excursion, jaw locking, and noise at the joint with movement. In general, TMD is divided into myofascial TMD or arthrogenic TMD. Myofascial TMD is associated with the pain from hyperfunctioning muscles of mastication leading to chronic myositis. In contrast, arthrogenic TMD is associated intracapsular pathology with pain at the level of the joint itself.
Anatomy of temporomandibular joint (TMJ)
The temporomandibular joint (TMJ) is a hinged synovial joint that connects the mandible to the temporal bone at the skull base, and the posterior border of the TMJ is the anterior border of the external auditory canal. The TMJ is one of the few synovial joints with an articular disc and it functions as both a hinge joint and a sliding joint. It is therefore classified as a ginglymoarthrodial joint. Adduction of the mandible, or mouth closing, is performed by the actions of the masseter, temporalis, and medial pterygoid muscles. Abduction, or mouth opening, is performed by the lateral pterygoids and digastric musculature. The lateral deviation occurs by the action of the contralateral lateral pterygoid muscles, and protrusion of the mandible occurs when right and left lateral pterygoid muscles contract simultaneously.