Chapter 26: The Temporomandibular Joint

CHAPTER OBJECTIVES

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.

OVERVIEW

Approximately 50–75% of the general population has experienced unilateral temporomandibular joint dysfunction (TMD) on a minimum of one occasion and that at least 33% have reported a minimum of one continuing persistent symptom.^1,2 The American Academy of Orofacial Pain uses orofacial pain as a collective term for a number of dysfunctions and sensory complaints associated with the TMJ, the masticatory muscles, and associated structures.³ It encompasses terms such as Costen syndrome, TMD, craniomandibular disorders, and mandibular dysfunction. TMD is a collective term used to describe a number of related disorders affecting the stomatognathic system and its related structures, all of which may have common symptoms. The term TMJ dysfunction as an overall descriptor of stomatognathic system dysfunction has been discontinued because it implies structural problems when none may exist, and does not include the many other factors that may be involved.

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.⁴ 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 embryological 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.⁴ 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 (the mandibular process ...