Interval 11: Infratemporal fossa, suprahyoid region Flashcards
The hyoid bone is situated in the anterior triangle at the level of what vertebrae?
-C3
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.
- sternohyoid
- sternothyroid
- superior and inferior bellies of omohyoid
- thyrohyoid
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?
-swallowing
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?
- carotid canal
- ophthalmic artery
- 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?
- 6
- mandible
- 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
- lingual artery
- facial artery
- occipital 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
- supplies pharynx
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