Chapter 26. The Temporomandibular Joint

At the completion of this chapter, the reader will be able to:

1. Describe the anatomy of the temporomandibular joint (TMJ), including the bones, ligaments, muscles, and blood and nerve supply.

2. Describe the biomechanics of the TMJ, including the movements, normal and abnormal joint barriers, kinesiology, and reactions to various stresses.

3. Summarize the various causes of temporomandibular dysfunction (TMD).

4. Describe the close association between the TMJ, the middle ear, and the cervical spine.

5. Perform a comprehensive examination of the temporomandibular musculoskeletal system, including palpation of the articular and soft tissue structures, specific passive mobility and passive articular mobility tests, and stability tests.

6. Evaluate the total examination data to establish a diagnosis.

7. Recognize the manifestations of abnormal TMJ function and develop strategies to correct these abnormalities.

8. Apply active and passive mobilization techniques to the TMJ, using the correct grade, direction, and duration.

9. Describe and demonstrate intervention strategies and techniques based on clinical findings and established goals.

10. Evaluate the intervention effectiveness in order to progress or modify an intervention.

11. Plan an effective home program and instruct the patient in this program.

Housed within the skull are the components of the stomatognathic system, which includes the TMJ, the masticatory systems, and the related organs and tissues such as the inner ear and salivary glands.1 An interrelationship exists between the stomatognathic system and the head and neck due to their proximity and shared embryological development. An understanding of this relationship is vital to understand the reasons for the myriad of symptoms that this region can exhibit.

The embryologic structures from which the head, the face, and the neck originate are segmentally organized during development with the appearance and modification of six paired branchial or pharyngeal arches.1 These branchial arches contain the cranial nuclei of the trigeminal nerve (ophthalmic; maxillary and mandibular), the facial, the glossopharyngeal, and the laryngeal branch of the vagus nerve as well as the hypoglossal nerve.

The first of these arches, the mandibular arch, consists of a large anterior (ventral) part (mandibular process of Meckel's cartilage) and a small posterior (dorsal) (maxillary) process. As development progresses, both processes disappear except for two small portions at the posterior (dorsal) ends, which persist. The first brachial arch forms

• the mandible;
• the rudiments of the inner ear bones, the malleus, and incus;
• the anterior malleolar and sphenomandibular ligaments of the TMJ;
• the tensor tympani and the tensor veli palatini of the inner ear;
• the mylohyoid and the anterior belly of the digastric muscle;
• the trigeminal mandibular nerve.

The second pharyngeal arch (the hyoid arch) consists of Reichert's cartilage. This arch is involved in the formation of

• the superior component of the hyoid bone and the lesser cornu bone;
• the stapes muscle;
• the temporal styloid process;
• the stylohyoid ligament;
• the stapedius muscle;
• the stylohyoid muscle;
• the posterior belly of the digastric muscle;
• the muscles of facial expression and mastication;
• the ...