10.27.11+-+Temporal+Region

Temporal Region


 * 1. Describe the temporal region, temporal fossa, infratemporal fossa and pteygopalatine fossa.**

The temporal region is the side of the head and includes the three fossae described below. The temporal fossa is bounded superiorly by the superior temporal line and inferiorly by the zygomatic arch. The temporalis muscle and temporal fascia cover it. The pterion is contained within it.

The infra temporal fossa is the space deep to the zygomatic arch and mandible. It is bounded anteriorly by the maxillary process. Superiorly by the zygomatic arch. Medially by the mandibular rams. Posteriorly by the tympanic plate, styloid process, and mastoid process.

The pterygopalatine fossa is the space deep to the infra temporal fossa. It is upside-down teardrop shaped and anteriorly bound by the maxilla and posteriorly bound by the sphenoid bone. The foramen rotundum (superiorly), inferior orbital fissure (anteriorly), palatine foramina (inferiorly), pterygomaxillary fissure (laterally), aperture of pterygoid canal (posteriorly) and sphenopalatine foramen (medially) all open to the pterygopalatine fossa.


 * 2. Describe parts of the mandible, the TMJ, and the pterygoid process.**

The mandible is divided into a body, angle, and ramus. From the ramus branches a neck and head. The head articulates with the mandibular fossae and articular tubercle of the temporal bone to form the TMJ (a synovial hingeish joint that can protrude, retried, depress, and elevate. The mandible has the mandibular foramen interiorly on the ramus and the mental foramen exteriorly on the body. The pterygoid process is the inferior protrusion of the sphenoid bone. It includes the medial and lateral pterygoid plates bilaterally. The space in-between them is called the pterygoid fossa. The medial pterygoid plate has an extension called the hook of hamulus.


 * 3. Identify muscles of mastication, their origins, insertions, actions, and innervation.**

There are 4 muscles of mastication. Masseter, medial pterygoid, and temporalis elevate. Lateral pterygoid depresses. Lateral pterygoid protrudes (medial pterygoid and masseter help). Temporalis and masseter retrude. Pterygoids shift side to side. All are innervated by muscular branches of V3.

Masseter originates from the zygomatic arch and inserts on the angle and ramus of mandible. Medial pterygoid originates from the tuberosity of maxilla and the medial surface of the lateral plate and inserts on the medial surface of the mandibular ramus. Lateral pterygoid originates from the greater wing of sphenoid and the lateral surface of the lateral plate and inserts on the joint capsule and neck of mandible. Temporalis originates from the temporal wall and inserts on the coronoid process.


 * 4. Describe the maxillary artery, its three parts and their branches. Describe the pterygoid venous plexus.**

The maxillary artery is one of the two terminal branches of the external carotid artery. The other terminal branch is the superficial temporal a.

The maxillary artery branches from the external carotid a. in the infra temporal fossa. There are three parts to it: posterior to lateral pterygoid belly, deep/superficial to lateral pterygoid belly, anterior to lateral pterygoid belly.

Part 1: 5 branches, but we know two of them: middle meningeal (going into cranial vault through foramen lacerum) and inferior alveolar a. (entering mandible via mandibular foramen) Part 2: 5 branches to the 4 muscles of mastication (including the deep temporal aa.) and the buccal a. Part 3: 5 branches to infraorbital, posterior superior alveolar, descending palatine, sphenopalatine, and a. of the pterygoid canal

The branching pattern of the external carotid artery: Superior Thyroid Ascending Pharyngeal Lingual Facial Occipital Posterior Auricular Maxillary Superficial Temporal

The pterygoid venous plexus is extensive and layered with the deep temporal aa. between the pterygoids and temporal muscle. It connects with the facial v. via the cavernous sinus. Infections travel this way.


 * 5. Describe the mandibular nerve and its branches.**

The mandibular nerve is the third branch of the trigeminal nerve. It exits the calvarium via the foramen ovale and puts off muscular branches to the muscles of mastication, tensor tympani and tensor veli palatine. It also puts off 3 major sensory nerves: the auriculotemporal n. which encircles middle meningeal a., then reconstitutes and heads superiorly to cutaneously innervate the temporal region; the buccal n. which heads to the cheek region; and the lingual n. which heads deeply to the tongue. The mandibular nerve then branches into the inferior alveolar nerve and the mylohyoid nerve. The mylohyoid nerve runs along the surface of the mandible to provide motor innervation to the anterior belly of digastric and mylohyoid. The inferior alveolar nerve provides sensory innervation to the teeth and gingiva then exits the mental foramen to provide sensory innervation of the lower lip and chin.

The chordae tympani (carrying parasympathetic innervation to submandibular gland and special sensory to taste buds) comes off of CN-VII and hitchhikes with mandibular to head through lingual.


 * 6. Describe the otic ganglion, its location, and branches.**

The otic ganglion is associated with the lesser petrosal n. (carrying parasympathetic) of CN IX. The lesser petrosal n. enters the otic ganglia, where parasympathetic nerve fibers synapse and then take the auriculotemporal n. to the parotid gland where they get off and innervate the gland. The otic ganglia is in the infra temporal fossa inferior to foramen ovale and medial to the mandibular n.


 * 7. Describe the pterygopalatine fossa and its openings and contents.**

The openings are listed above, but its contents are the pterygopalatine ganglion and its many branches superiorly, inferiorly, anteriorly, and posteriorly.

The ganglion receives fibers superiorly and posteriorly, then sends them out inferiorly and anteriorly. Superiorly it gets the ganglionic branches of the maxillary nerve just after it has exited foramen rotundum. Posteriorly it gets the nerve of the pterygoid canal, a combo of deep (parasympathetic) and greater (sympathetic) petrosal nerves. Anteriorly it sends out the nasal cavity branches: nasociliary which runs along the wall of the septum and posterior superior lateral nasal branch which runs along the middle concha. Inferiorly it sends out the greater and lesser palatine nn. which innervate the hard (greater) and soft (lesser) palates.