Subdivisions of Anterior Triangle: Carotid triangle, submental triangle and submandibular triangle Flashcards
Carotid triangle:
Named because of common carotid artery
Boundries of carotid triangle
- superior belly of omohyoid
- posterior belly of digastric
- anterior border of the sternocleidomastoid muscle
CN XI
(Accessory nerve)Supplies sternocleidomastoid and trapezius. its found near the mastoid process.
What can you find around the the tip of the greater horn of hyoid bone?
- Hypoglossal n (CN XII) turns forward towards tongue just superior to the tip of greater horn
- fibers from C1 and C2 (Mostly C1) hitchhike on CN XII split off at this point to supply thyrohyoid bone.
- posterior belly of digastric is lateral to CN XII
Occipital A
Loops over CNXII to digastric muscle
Ansa Cervicalis
Superior root (Descendents hypoglossi; mostly C1; Separate a from CNXII deep to digastric muscle. -Inferior root of ansa( mostly C2-C3 fibers) joins superior root to form a loop or ansa. branch from the loop supply strap muscle.
Vagus nerve
lies within the carotid triangle
Superior laryngeal n
branches of vagus nerve. in the submandibular triangle but sends two branches to the carotid triangle.
Internal Laryngeal n
appears in the carotid triangle just inferior to the tip of the greater horn of the hyoid bone.
penetrates thyrohyoid membrane in company with superior laryngeal a. to supply sensibility to superior half of larynx
External laryngeal n
Appears in carotid triangle posterior to the internal laryngeal n. Travels with the superior thyroid a.
It provides a motor function to cricothyroid muscle. And adjacent inferior constrictor m.
Deep vessles of the neck include
- carotid sheath.
- common carotid a
- internal carotid a
- carotid body
- carotid sinus
- external carotid a
Carotid sheath
connective tissue sheath that encloses vagus, common and internal carotid arteries as well as the internal jugular vein.
Common carotid artery
Has no collateral branches.
-bifurcates into internal and external carotid artery. just inferior to the tip of greater horn of hyoid bone.
internal carotid artery
- Provides primary supply of brain and special senses
- enters the carotid canal at the base of the skull
- has no branches in the neck.
Carotid body
Located on the medial surface of the carotid bifurcation; responds to O2 and CO2 concentrations.
Carotid sinus
A dialation at beginning of internal and end of common carotids; sensitive to pressure.
External carotid artery
Primary supply to braincase and face. Branches into: -Facial a - Occipital a -lingual a -ascending pharyngeal a -superior thyroid a
Facial artery
Usually branches just superior to lingual a. But the two may have a common stem (Faciolinual a)
- usually originates deep to digastric m
- loops toward the inferior border jaw to supply face
Occipital artery
branches posteriorly at the same level as facial artery
-runs to occiput
lingual artery
just superior to the tip of hor of the hyoid.
- roughly parallel CN XII
- supplies tongue and floor of mouth
Ascending pharyngeal artery
(NOt shown) usually the 1st branch of the external carotid
- branches of media surface near the bifurcation
- supplies the back wall of the pharynx
Superior Thyroid artery:
found at the inferior and posterior to the tip of the greater horn of hyoid.
-supplies the superior pole of the thyroid
Superior laryngeal a
branch off superior thyroid artery that pierces through the thyrohyoid membrane in accompany with the internal laryngeal artery.
Internal jugular vein
Drains the braincase and the face. Exits skull at the jugular foramen. Receives -occipital vein -common facial v -lingual vein -superior thyroid vein -inferior thyroid vein
And empties into brachiocephalic vein.
Joins right subclavian vein to form the right brachiocephalic vein that drains in SVC.
Submental Triangle Boundaries
- Body of hyoid bone
- right and left anterior bellies of the digastric muscle
- mylohyoid muscle forms the floor of the triangle.
Submandibular triangle boundaries
- Inferior border of mandible
- anterior belly of the digastric muscle
- posterior belly of digastric muscle.
Submandibular gland
occupies most of the submandibular triangle. one of the 3 major salivary glands. Wraps around the free edge of mylohyoid muscle.
-Facial artery and Vein contact the gland.
Digastric muscles
joined by an intermediate tendon and the tendon is bound to the hyoid bone through a fibrous sling.
-both muscles serve to depress mandible and raise the hyoid bone.
posterior belly of the digastric muscle
- attaches to the medial surface of mastoid process
- supplied by the CNVII (also supplies stylohyoid)
Anterior belly of digastric muscle
- Attaches to digastric fossa of mandible
- supplied by CN V
Mylohyoid nerve
branch of the CN V3 is wedged between anterior digastric muscle. The body of mandible on the surface of the mylohyoid muscle and supplies both muscles.
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