Anterior triangle of neck Dept. of Anatomy Zhou Hong Ying
Outline boundary and subdivisions of ant. triangle contents of the triangle Muscles: suprahyoid muscles, infrahyoid muscles Nerves: CNⅩ, CNⅪ, CNⅫ, sympathetic nerve, ansa cervicalis Arteries: common carotid a., ECA, ICA, subclavian a. & their branches Veins: internal jugular v., external jugular v., subclavian v. dissection of this area
Boundary of anterior triangle apex: jugular notch floor: the pharynx, larynx, and thyroid gland.
subdivisions Carotid triangle Muscular triangle Submandibular triangle Submental triangle
Muscles of anterior triangle SCM Hyoid muscles: suprahyoid group & infrahyoid group
Suprahyoid Muscles digastric stylohyoid mylohyoid geniohyoid hyoglossus
Infrahyoid muscles Superficial layer: sternohyoid medially & omohyoid laterally Deep layer: sternothyroid & thyrohyoid
Actions of the Suprahyoid & Infrahyoid Muscles
The Pharynx & Larynx
Subclavian artery Arteries of neck Common carotid artery(cca) Internal carotid artery (ICA) External carotid artery(eca)
common carotid artery
Carotid sinus Carotid body
Branches of ECA 1 branch arises medially (ascending pharyngeal) 2 branches arise posteriorly (occipital and posterior auricular) 3 branches arise anteriorly (superior thyroid, lingual, and facial).
The Veins of the Neck Internal jugular vein External jugular vein Subclavian vein Note that external jugular vein is tributary of subclavian vein.
The Veins of the Neck
Nerves of Anterior Cervical Triangle glossopharyngeal nerve hypoglossal nerve vagus nerve Ansa Cervicalis sympathetic nerves Ansa Cervicalis
Ansa cervicalis superior root comes from C1 via CN XII. inferior root is derived from C2 & C3. supply infrahyoid muscles except thyrohyoid.
The Ansa Cervicalis
Cranial Nerves CN Ⅸ(Glossopharyngeal nerve ) CNⅩ (vagus) CNⅪ (accessory) CNⅫ (hypoglossal)
Accessory nerve Glossopharyngeal nerve: innervates the stylopharyngeus muscle, send a branch to the carotid sinus, and sensory branches to the pharynx
Superior Laryngeal Never Vagus nerve
Hypoglossal nerve
Cervical Sympathetic trunk
The Cranial Nerves of Neck
Relationships of vessels and nerves
The Carotid Sheath
Submandibular, submental Anterior and posterior belly of digastric m, inferior border of mandible bone. R & L Anterior bellies of digastric m and hyoid bone
Floor of the Mouth mylohyoid muscle hyoglossus muscle geniohyoid muscle
Floor of the Mouth
Structures of the Submandibular Triangle
Structures of the Submandibular Triangle submandibular gland facial artery & vein lymph nodes hypoglossal nerve lingual nerve lingual artery
Dissect the vessels & nerves in the carotid
Superficial dissection of anterior cervical region
Cut the SCM at its middle point to expose: common carotid a, internal carotid a, external carotid a, and its branches nerves
CAROTID TRIANGLE Identify superficial veins: facial v., retromendibular v., & anterior jugular v. Clean & free SCM, then cut it in its middle & reflect both parts superiorly & inferiorly respectivly Clean infrahyoid muscles: sternohyoid, omohyoid, sternothyroid, & thyrohyoid. Notice: don t free their lateral margins through where nerves enter muscles
Confirm boundaries of carotid triangle Find ansa cervicalis on or within carotid sheath. Trace its superior root to hypoglossal nerve & inferior root to cervical plexus, as well as its branches to all infrahyoid, except thyrohyoid Open carotid sheath to expose internal jugular vein (IJV). Note its tributaries & then detach them Pull IJV to expose common carotid artery (CCA), which has no branches till it ascends to level of C4 where it bifurcates into external & internal carotid artery (ECA & ICA)
Note wall of end of CCA or beginning of ICA bulges out to form carotid sinus Within carotid sheath find vagus nerve between CCA (ICA) & IJV Trace ECA upward to posterior belly of digastric & try to find it five branches in carotid triangle