Flashcards in Interval 11: Infratemporal fossa, suprahyoid region Deck (74):
The hyoid bone is situated in the anterior triangle at the level of what vertebrae?
The infrahyoid muscles consist of 4 pairs of strap-like muscles that have attachments to the sternum, scapula, thyroid cartilage, and hyoid bone. Name them.
-superior and inferior bellies of omohyoid
Name the innervation of the infrahyoid muscles
-sternohyoid, sternothyroid, superior and inferior bellies of omohyoid= muscular branches of cervical plexus via ansa cervicalis
-Thyrohyoid: C1 fibers
2 roots of the ansa cervicalis
-superior root: C1 VR that hitchhikes with hypoglossal nerve
-inferior root: C2 and C3 VR that joins with superior root anterior to carotid sheath
The suprahyoid muscles have attachments to the styloid process, mandible, and hyoid bone. Name them.
-geniohyoid, mylohyoid, stylohyoid, anterior and posterior bellies of digastric
Name the innervation of the suprahyoid muscles
-mylohyoid and anterior belly of digastric= trigeminal nerve
-stylohyoid and posterior belly of digastric= facial nerve
-geniohyoid= C1 from cervical plexus
The trachea begins inferior to the ___________ at the level of __________.
-cricoid cartilage at the level of C6
The trachea extends inferiorly into the mediastinum and ends by bifurcating into the left and right primary bronchi at the disk between ________.
-T4 and T5
The trachea consists of cartilage rings that are ____________.
-incomplete posteriorly and a posterior wall of smooth muscle
What partially covers the trachea?
-lobes and isthmus of the thyroid gland
The lobes of the thyroid are lateral to the trachea; the isthmus passes where and does what?
-passes anterior to the 2nd or 3rd tracheal rings
-interconnects the lobes
What is the function of the thyroid?
-produces and secretes T3, T4, and calcitonin
Location and function of parathyroid glands
-pair of superior PTG and a pair of inferior PTG are situated posterior to the lobes of the thyroid
-produce and secrete parathyroid hormone (PTH)
What arteries supply the thyroid and parathyroid and what do these arteries course with/near?
-superior thyroid artery: courses with external branch of the superior laryngeal nerve of the vagus
-inferior thyroid artery: recurrent laryngeal nerve courses in groove between trachea and esophagus in close proximity
Hyoid bone plays a key part in what mechanism?
Why does displacement of the hyoid bone also displace the base of the tongue and the larynx?
-it is located between the base of the tongue and the larynx
-it is attached to the tongue by the hyoglossus muscle and to the larynx by the thyrohyoid membrane and muscle
Function of infra vs. suprahyoid muscles
-infrahyoid: all depress the hyoid bone
-suprahyoid: elevate hyoid bone; those attached to the mandible (geniohyoid, mylohyoid, and anterior belly of digastric) also pull it anteriorly and muscles attached to the skull (stylohyoid, posterior belly of digastric) also pull it posteriorly
What forms the carotid sheath?
-pretracheal, prevertebral, and investing layers of deep cervical fascia
The carotid sheath contains the common carotid artery, which branches into what and where?
-internal and external carotid arteries at the upper border of the thyroid cartilage
Name the branches of the internal carotid artery in the neck.
-there are none
The internal carotid artery enters the skull through the __________; gives rise to the ________ artery, which supplies what? It then ends by branching into what?
-supplies the orbit, retina, and part of the nasal cavity and face
-ends by branching into an anterior and a middle cerebral artery
The internal carotid artery conveys a ________________ from the superior cervical ganglion into the skull.
-periarterial plexus of postganglionic sympathetic axons
The external carotid artery has _____ branches in the neck and ends posterior to the ________ by dividing into what?
-superficial temporal artery and a maxillary artery
Name the 6 branches of the external carotid artery in the neck.
-superior thyroid artery
-ascending pharyngeal artery
-posterior auricular artery
What does the superior thyroid artery arise from., supply, and give rise to?
-arises from external carotid artery in the neck
-supplies the thyroid gland and gives rise to the superior laryngeal artery which passes through the thryohyoid membrane to supply the laryngopharynx and larynx
Where does the ascending pharyngeal artery arise from and supply?
-arises from posterior part of the external carotid
Where does the lingual artery arise and supply?
-arises from external carotid
-passes deep to the mylohyoid to supply the tongue
Where does the facial artery arise and supply?
-arises from external carotid
-passes deep to the submandibular gland, crosses the body of the mandible, and supplies facial muscles and skin up to the medial corner of the eye
Where does the occipital artery arise and supply? What is it crossed by?
-arises from external carotid
-crossed by hypoglossal nerve and supplies posterior neck and posterior scalp
Where does the posterior auricular artery arise and supply?
-arises from external carotid
-supplies posterior scalp
What is the carotid body and where is it located?
-chemoreceptor situated at the bifurcation of the common carotid artery that monitors arterial levels of oxygen and CO2
What is the carotid sinus and where is it located?
-baroreceptor in the proximal part of the internal carotid artery that monitors arterial blood pressure
The carotid body and carotid sinus are innervated by branches of what nerves?
-glossopharyngeal and vagus nerves
-nerves convery signals from baroR and chemoR into CNS and influence parasympathetic and sympathetic innervation of the heart, lungs, and blood vessels
Baroreceptor reflex action and disruption
-maintains BP in response to changes in posture
-disruption of the baroreceptor reflex results in orthostatic hypotension, a decrease in blood pressure when the patient assumes an upright position
Chemoreceptor flex action
-maintains blood gases by adjusting respiration, cardiac output, and peripheral blood pressure
-decrease in O2 tension and increase in CO2 tension result in increase in respiration, heart rate, and peripheral BP
The __________ courses through the sheath ________ to the common carotid artery.
-internal jugular vein
Where does the internal jugular vein form, by what junction, and what veins feed into it?
-just inferior to the jugular foramen at the junction of the inferior petrosal sinus and sigmoid sinus
-receives facial, lingual, pharyngeal, and middle thyroid veins
What nerve courses through the length of the neck in the carotid sheath and what is its location in the sheath?
-posterior to the internal jugular vein and the common carotid artery
Name the 3 components in the carotid sheath
-internal jugular vein
-common carotid artery
What nerves pass through the superior part of the sheath?
-glosspharyngeal in route to pharynx
-accessory in route to posterior triangle
-hypoglossal in route to tongue
Where can the cervical sympathetic trunk be found and what ganglia does it contain?
-posterior and medial to the carotid sheath
-contains superior, middle, and inferior cervical sympathetic ganglia
The superior cervical ganglion receives preganglionic sympathetic axons mainly from _____. What does it give rise to?
-T1 segment of spinal cord
-gives rise to postganglionic symp. axons which supply sweat glands and vascular SM in face and scalp
-it innervates dilator pupillae and superior tarsal muscles in the orbit
What do the postganglionic sympathetic axons from the superior cervical plexus form, course with, and give rise to?
-periarterial plexuses which course with internal and external carotid arteries and their branches
-gives rise to gray rami that course with branches of C1-C4 spinal nerves supplying the neck
The inferior cervical ganglion is frequently fused with what? What does it give rise to?
-first thoracic ganglion to form the stellate ganglion
-gives rise to gray rami that course with branches of C7 and C8 VR supplying the upper limb
The infratemporal fossa is medial to what and what does it contain (5)?
-medial to ramus of the mandible and zygomatic arch
-contains TMJ, muscles of mastication, branches of the maxillary artery, branches of the mandibular nerve (CN V3) and chora tympani CN VII
What is the head of the mandible called?
What is the articulation at TMJ?
-the head, condylar process, of the mandible articulates with the mandibular fossa of the temporal bone
The TMJ contains an articular disk, which subdivides the joint into 2 joint cavities. What are the cavities responsible for?
-superior part of the joint cavity is a gliding joint that allows the mandible to protruded and retruded
-inferior part is a hinge joint where the mandible can be elevated and depressed
The combined actions at both cavities of the TMJ permit movement of the mandible about a coronal axis through the ____________.
There are 4 muscles of mastication. Name them and which are found within and outside of the infratemporal fossa
-temporal, lateral pterygoid, medial pterygoid are in the fossa
-masseter is lateral to the fossa
All of the muscles of mastication are innervated by what nerve?
-branches of the mandibular nerve of CN V3
The maxillary artery courses through the infratemporal fossa and then enters the __________ through the ________.
-pterygopalatine fossa through the pterygomaxillary fissue
What are the main branches of the maxillary artery in the infratemporal fossa?
-middle meningeal artery
-inferior alveolar artery
-deep temporal arteries
Why do we worry about lateral skull fractures?
-they may lacerate the middle meningeal artery and cause an epidural hematoma
-MMA passes through the foramen spinosum and enters the middle cranial fossa to supply the skull and dura
What 3 things does the roof of the infratemporal fossa contain?
What does the foramen ovale transmit?
-mandibular division and motor root of V3 and the lesser petrosal nerve of CN IX
The lesser petrosal nerve is transmitted through the foramen ovale and contains _______________ axons that synapse ____________ which does what?
-preganglionic parasympathetic axons that synapse in the otic ganglion
-the otic ganglion is in the infratemporal fossa just below the foramen ovale and its axons innervate the parotid gland
What does the foramen spinosum transmit?
-middle meningeal artery
-meningeal branch of CN V3
What does the petrotympanic fissure do?
-communicates with the middle ear cavity and transmits the chorda tympani of CN VII
What does the chorda tympanic contain?
-taste fibers from the anterior 2/3 of the tongue and preganglionic parasympathetic axons that synapse in the submandibular ganglion which is in the floor of the mouth
Where is the mandibular nerve (CN V3) formed? by what union? what does it contain?
-formed just below the foramen ovale by union of mandibular division with the motor root
-contains fibers that convey general sensations of touch, pain, temperature and skeletal motor axons
What do muscular branches of the mandibular nerve (CN V3) supply?
-4 muscles of mastication (temporalis, masseter, medial pterygoid, lateral pterygoid)
-tensor tympani and tensor veli palatini
-nerve to mylohyoid (longest muscular branch) supplies mylohyoid and anterior belly of digastric
Name the main general sensory branches of the mandibular nerve
-4 cutaneous/mucosa branches
-buccal nerve, auriculotemporal nerve, inferior alveolar nerve, lingual nerve (BAIL)
Give the 2 sensory branches of V3 that are involved with "hitch-hiking"
-lingual nerve: carries taste and parasympathetic fibers of the chorda tympani of CN VII
-auriculotemporal nerve: carries parasympathetic axons from CN IX that have synapses in the otic ganglion to the parotid gland
What may result form a lesion to the motor root of the mandibular nerve?
-weakness of muscles of mastication and a deviation of the jaw on protrusion to the side of the injured nerve
The pterygopalantine fossa is a space at a "crossroad" of the skull. Describe what it communicates with laterally, medially, anteriorly, and posteriorly.
-laterally: infratemporal fossa
-medially: nasal cavity
-inferiorly: oral cavity
-posteriorly: middle cranial fossa and base of skull
The pterygopalatine fossa contains the pterygopalatine ganglion and the preganglionic and postganglionic parasympathetic axons associated with it. Where are these parasympathetics coming from and where are they going to?
-preganglionic para course in the greater petrosal nerve (CN VII)
-postganglionics supply mucous glands in nasal cavity , oral cavity, nasopharynx, and the lacrimal gland
2 fissures, 2 foramina, and 2 major canals open into the pterygopalatine fossa. Name them and what they transmit.
1) pterygomaxillary and inferior orbital fissures
2) foramina rotundum and foramina sphenopalatine
3) pterygoid and palatine canal
The maxillary divisions of the trigeminal nerve traverses the _________, becomes the maxillary nerve in the pterygopalatine fossa, and gives rise to what 3 main sensory branches?
-ZIP: zygomatic, infraorbital nerves, pterygopalatine
What happens to the pterygopalatine nerves of V2?
-pass through pterygopalatine ganglion without synapsing and become renamed as they emerge from the ganglion as the lesser and greater palatine nerves, nasopalatine nerve, posterior lateral nasal nerve, and pharyngeal nerve
What does the pterygoid canal contain?
-nerve of the pterygoid canal which is formed by the deep petrosal nerve and greater petrosal nerve which join in the foramen lacerum
What is the greater petrosal nerve? What is the deep petrosal nerve?
-mixed branch of facial nerve that carries preganglionic parasympathetic fibers that synapse in the pterygopalatine ganglion and taste fibers from the palate
-deep: branch of periarterial plexus on internal carotid artery that carries postganglionic sympathetic axos from superior cervical ganglion
The tongue has intrinsic and extrinsic muscles. Name the 4 extrinsic muscles and their innervation.
-hyoglossus, genioglossus, styloglossus, and palatoglossus
-both intrinsic and extrinsic are innervated by the hypoglossal nerve except the palatoglossus which is innervated by the pharyngeal branch of the vagus nerve through the pharyngeal plexus