Biology 122 Spring, 2008

Laboratory 27

The Ear and Tympanic cavity

OBJECTIVES

At the end of this laboratory you should be able to describe:

1. The osteological features of the temporal bone (squamous, tympanic and petrous portions) and the representation of these basic parts in radiographs.

2. The position, structural organization, and functions of the three major subdivisions of the ear (external ear, middle ear and inner ear).

3. The course of the VIIth (facial) nerve through the different parts of the ear and temporal bone, including the position of the geniculate ganglion and the course of the initial parts of the greater petrosal and chorda tympani nerves.

4. The landmarks on the medial and lateral walls of the tympanic cavity, and the continuity between the mastoid air cells, the tympanic cavity and the auditory tube.

PRELAB PREPARATION

1. Read the portions of your textbook on the ear (pp. 1022-1037), with most attention to the middle ear and Fig. 7.75.

2. Study the functional components of the VIIth and VIIIth cranial nerves. Learn the course and distribution of the secretomotor and special sensory components of VII (pp. 1143-1146) and the special sensory component of VIII (pp. 1146).