Lab 12: Ear

Extends from the auricle to the tympanic membrane. Lateral 1/3 is cartilaginous, medial 2/3 is bony. Somatic sensory innervation is carried by CN X ("vagus behind tragus") and the auriculotemporal nerve (CN V3).

The incus is connected to the malleus by a ball-and-socket joint at the articular facet. The lenticular process articulates with the head of the stapes.

The malleus is the largest and heaviest of the three ossicles. The manubrium is attached to the medial surface of the tympanic membrane.

The stapes is the smallest bone in the body. Each crus has a channel on its inner surface to reduce mass. The footplate has both osseous and cartilaginous components. The footplate is fixed within the oval window of the cochlea.

A thin plate of the petrous part of the temporal bone that separates the cranial cavity and middle ear

A visible phenomenon which occurs upon examination of the tympanic membrane with an otoscope, which causes a cone-shaped reflection of light to appear in the anterior inferior quadrant

The "ear drum." It separates the external from the middle ear. It functions as a sound pressure receptor and transformer. It's external surface is innervated (sensory) by the vagus (CN X) & the auriculotemporal nerve (CN V3). It's inner surface is innervated (sensory) by the glossopharyngeal nerve (CN IX).

Extends from the anterior wall of the middle ear to the lateral wall of the nasopharynx, approximately at the level of the inferior nasal concha. It equalizes pressure in middle ear and allows drainage of fluid. Salpingopharyngeus (CN X: pharyngeal plexus), levator veli palatini (CN X), tensor veli palatini (CN V3, MAST MATT) are the muscles that open the tube.