Head and Neck Anatomy Set 4

The inferior orbital fissure transmits the infraorbital and zygomatic branches of the maxillary nerve, the infraorbital vessels, the inferior ophthalmic veins, and the orbital branches of the pterygopalatine ganglion.

The superior meatus is a narrow passage, inferior to the superior nasal concha, in which the posterior ethmoidal sinuses open. The middle meatus contains openings to the frontal sinus, maxillary sinus, and anterior and middle ethmoidal sinuses.

The mandibular division of the trigeminal nerve innervates the tensor tympani.

The hypoglossal nerve innervates the four intrinsic muscles of the tongue in addition to the following three extrinsic muscles of the tongue: genioglossus, hyoglossus, and styloglossus. The vagus innervates the palatoglossus, which is both an extrinsic tongue muscle and a palate muscle.

Sweetness is detected on the apex, or tip, of the tongue, saltiness on the lateral margins, and sourness and bitterness on the posterior part.

The tensor veli palatini is innervated by the medial pterygoid nerve, which is a branch of the mandibular division of the trigeminal nerve.

The tympanic cavity contains the auditory ossicles, tympanic plexus, chorda tympani nerve, and stapedius and tensor tympani muscles.

The dorsal lingual arteries supply the posterior tongue and the palatine tonsil, while the deep lingual artery supplies the anterior tongue. The sublingual artery supplies the sublingual gland and the floor of the mouth. The dorsal lingual veins accompany the lingual artery, and the deep lingual veins drain the apex of the tongue, ultimately joining the sublingual vein.

The four types of lingual papillae are the vallate papillae, foliate papillae, filiform papillae, and fungiform papillae.

The medial and lateral walls of the nasal cavity are supplied by the sphenopalatine artery, anterior and posterior ethmoidal arteries, greater palatine artery, and superior labial artery.

Openings to the pterygopalatine fossa include the pterygomaxillary fissure, sphenopalatine foramen, inferior orbital fissure, foramen rotundum, and pterygoid canal.

The greater petrosal nerve (parasympathetic fibers of the facial nerve) joins the deep petrosal nerve (sympathetic nerves from the internal carotid plexus) to form the nerve of the pterygoid canal.

The genioglossus depresses the tongue and assists in protrusion. The hyoglossus depresses and retracts the tongue. The styloglossus retracts the tongue and draws it up for swallowing. The palatoglossus elevates the posterior part of the tongue. The superior and inferior longitudinal muscles curl the tip and sides of the tongue and shorten it. The transverse narrows and elongates the tongue, assisting in protrusion. The vertical flattens and broadens the tongue, assisting in protrusion.

The pharyngotympanic tube opens posterior to the inferior meatus of the nasal cavity and serves to equalize the pressure in the middle ear with atmospheric pressure. The tensor veli palatini and levator veli palatini work together to open the tube, which is supplied by the ascending pharyngeal artery, middle meningeal artery, and artery of the pterygoid canal.

The nerve of the pterygoid canal innervates the lacrimal gland, the palatine glands, the mucosal glands of the nasal cavity, and the mucosal glands of upper pharynx.

In respect to general sensation (touch and temperature), the mucosa of the anterior twothirds of the tongue is innervated by the lingual nerve, which is a branch of the mandibular division of the trigeminal nerve. The mucosa of the posterior one-third of the tongue is innervated by the lingual branch of the glossopharyngeal nerve, and the mucosa of the area just anterior to the epiglottis is innervated by small branches of the internal laryngeal nerve, which is a branch of the vagus. In respect to special sensation (taste), the chorda tympani, which is a branch of the facial nerve, innervates the anterior two-thirds of the tongue except for the vallate papillae in the posterior one-third of the tongue, which are innervated by the lingual branch of the glossopharyngeal nerve. Branches of the internal laryngeal nerve of the vagus innervate the area anterior to the epiglottis in respect to taste.

The nasal mucosa is innervated by the nasopalatine nerve, greater palatine nerve, anterior ethmoidal nerve, and posterior ethmoidal nerve.

The auricle is innervated by the great auricular nerve and auriculotemporal nerve. The external surface of the tympanic membrane is innervated by the auriculotemporal nerve and even a small branch of the vagus. The internal surface of the tympanic membrane is innervated by the glossopharyngeal nerve. The pharyngotympanic tube is innervated by the tympanic plexus (fibers from the facial and glossopharyngeal nerves). The sensory cell bodies of the vestibulocochlear nerve are located in the spiral and vestibular ganglia.

Parasympathetic and taste fibers from the chorda tympani reach their destination by joining the lingual nerve, a branch of the mandibular division of the trigeminal nerve.

The dura mater of the floor of the middle cranial fossa is superior to the tegmental roof. The internal jugular vein is inferior to the floor. The lateral membranous wall is formed by the epitympanic recess and contains the head of the malleus. The medial labyrinthine wall separates the tympanic cavity from the internal ear, which contains the cochlea. The anterior carotid wall separates the tympanic cavity from the carotid canal. The posterior mastoid wall guards the mastoid cells and the facial nerve.

The inferior nasal concha is a separate bone, whereas the superior and middle nasal conchae are simply extensions of the ethmoid bone.

The tensor veli palatini tenses the soft palate and opens the mouth of the auditory tube during swallowing and yawning.

The nasolacrimal duct drains into the inferior meatus.

The pterygopalatine fossa contains the third part of maxillary artery, the maxillary nerve, the nerve of the pterygoid canal, and the pterygopalatine ganglion.

The parotid gland is supplied by branches of the external carotid and superficial temporal arteries and innervated by the glossopharyngeal nerve. The submandibular gland is supplied by the submental artery and innervated by the parasympathetic fibers of the facial nerve that synapsed in the submandibular ganglion. The sublingual glands are supplied by the sublingual and submental arteries and innervated by parasympathetic fibers of the facial nerve.