Head and Neck Anatomy: Ear Structure and Facial Nerve Pathways

Vocabulary flashcards covering ear anatomy, middle ear dynamics, auditory reflexes, clinical conditions (mastoiditis, acoustic neuroma), and facial nerve (CN VII) anatomical pathways and branches.

Pars Flaccida

The small, relaxed, superior portion of the tympanic membrane.

Pars Tensa

The larger, tense, inferior portion of the tympanic membrane that forms most of its surface area.

Pterygoid Hamulus

A hook-like process of the sphenoid bone around which the tensor veli palatini muscle bends; it is not anchored in individuals with a cleft palate.

Stylomastoid Foramen

The bony foramen situated between the styloid process and mastoid process through which the facial nerve ($\text{CN VII}$) exits the skull.

Tensor Tympani Muscle

A middle ear muscle attached to the handle of the malleus and innervated by a branch of $\text{V}_3$ that pulls the malleus inward to dampen sound vibrations from explosive noises.

Stapedius Muscle

A middle ear muscle attached to the stapes and innervated by $\text{CN VII}$ that pulls the stapes outward to reduce movement and dampens the sound of chewing.

Attenuation Reflex

A protective auditory reflex involving the contraction of the tensor tympani and stapedius muscles to reduce sound transmission and amplitude reaching the inner ear.

Mastoiditis

Inflammation of the mastoid air cells within the temporal bone that can spread to the labyrinth, facial nerve, and meninges.

Acoustic Neuroma

A benign tumor on the vestibulocochlear nerve that causes enlargement of the internal acoustic meatus and can compress $\text{CN VII}$, $\text{CN VIII}$, and the cerebellum.

Geniculum of Facial Nerve

The sharp bend in the facial nerve path that contains the geniculate ganglion, which houses cell bodies of primary sensory neurons.

Greater Petrosal Nerve

A branch arising from the geniculum of the facial nerve; damage to it inhibits parasympathetic secretions to the lacrimal glands, nasal glands, and paranasal sinuses.

Chorda Tympani

A branch of $\text{CN VII}$ that provides special sensory taste function to the anterior $\frac{2}{3}$ of the tongue and secretomotor innervation to the submandibular and sublingual glands.

Posterior Auricular Nerve

A motor branch of the facial nerve that exits near the stylomastoid foramen to innervate intrinsic and extrinsic outer ear muscles.

Parotid Gland

A large salivary gland traversed by the facial nerve, though not innervated by it, before the nerve divides into its terminal motor branches.

Glossopharyngeal Nerve ($\text{CN IX}$)

The cranial nerve that innervates the stylopharyngeus muscle and carries taste and general sensation from the posterior $\frac{1}{3}$ of the tongue.

Terminal Motor Branches of Facial Nerve

The five motor divisions of $\text{CN VII}$—Temporal, Zygomatic, Buccal, Marginal Mandibular, and Cervical—that supply the muscles of facial expression.