Chapter 6: The Temporomandibular Joint

Anatomy Overview

Introduction

The temporomandibular (TM) joint is unique in both structure and function. Structurally, the mandible is a horseshoe-shaped bone (Fig. 6–1) that articulates with the temporal bone at each of its posterosuperiorly located condyles and produces two distinct but highly interdependent articulations. Each TM joint contains a disc that separates the joint into an upper and a lower articulation. Functionally, mandibular movement involves concurrent movement in the four distinct joints (two per TM joint), resulting in a complex structure that moves in all planes of motion to achieve normal function.

A discussion of the structure and function of the TM joint will allow the reader to appreciate and understand its unique features, its relationship with the cervical spine, and the impact of impairments and pathologies of the TM joint. Although the purpose of this chapter is to discuss the normal function and structure of the TM joint, TM disorders are a common subgroup of orofacial pain disorders.¹ This chapter will introduce some of the common conditions that involve deviations of normal structure.

Structure and Function of the TM Joint

Structure

Articular Structures