Which of the following is true concerning the structure of the temporomandibular joint (TMJ)?

a. The lower joint is formed by the articulation of the articular eminence of the mandible with the superior surface of the disc.
b. The upper joint is formed by the articulation of the anterior surface of the condyle with the posterior surface of the disc.
c. The lower joint is formed by the superior surface of the disc and the posterior surface of the condyle.
d. The upper joint is formed by the articulation of the articular eminence of the temporal bone and the superior surface of the disc.

ANS: D
The articular disc separates the TMJ into two separate spaces. The lower joint is formed by the
articulation of the anterior surface of the condyle and the inferior surface of the articular disc. This
space allows for rotation of the condyle under the disc. The upper joint is formed by the
articulation of the articular eminence and the superior surface of the articular disc. The joint space
allows for gliding of the disc and condyle along the temporal bone.