Anatomy-Anterior Cervical Triangle Flashcards
What are the boundaries of the anterior triangle?
Lateral: SCM. Medial: Midline Superior: Mandible
What are the subdivisions of the anterior triangle?
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What nerves might you find during your dissection of the platysma?
CN VII (facial nerve motor innervation to platysma). Transversce cervical nerve (C2 & C3 nerve fibers providing neck sensation)
What vein is responsible for drainage of the sub mental triangle?
Anterior jugular vein
How does innervation of the muscle indicated below differ in its different regions?
Most medial muscles in the anterior triangle are innervated by the mylohyoid branch of CN V (V3). Most lateral muscles are innervated by CN VII (Facial nerve). This is the case of the digastric muscle with its anterior belly innervated by CN V3 and its posterior belly innervated by CN VII.
What muscle straddles the tendon of the posterior belly of the digastric muscle? What nerve is it innervated by?
Stylohyoid muscle. Innervated by CN VII because it is located laterally.
What nerve is mylohyoid innervated by?
It is located medially and is innervated by CN V3
What muscle originates at the hyoid bone and functions to raise and lower the tongue? What nerve is it innervated by?
Hyoglossis muscle. It is a tongue muscle so it is innervated by CN XII
What muscles are indicated below? What are they innervated by?
1) Superior belly of omohyoid (ansa cervicalis) 2) Sternohyoid (ansa cervicalis) 3) Sternothyroid (ansa cervicalis) 4) Thyrohyoid (C1: nerve to thyrohyoid)
What are the branches of the external carotid artery?
“Stop Alcohol Late Friday Or Puke More Saturday”. Superior Thyroid, Ascending Pharyngeal, Lingual, Facial, Occipital, Posterior Auricular, Maxillary, Superficial Temporal.
What structure runs in parallel and slightly deep to the superior thyroid artery?
External laryngeal nerve, a branch off of the vagus nerve.
What branch comes off of the superior thyroid artery?
Superior laryngeal artery.
What structure runs in parallel with the superior laryngeal artery?
Internal laryngeal nerve, a branch off of the vagus nerve.
What blood vessel gets sandwiched between the hypoglossal nerve and the hyoglossis muscle?
Lingual artery
What artery comes off of the external carotid opposite the facial artery and has the hypoglossal nerve sitting on top of it?
Occipital artery
How do the facial vein and the facial artery compare in relation to the submandibular gland?
Artery is under the gland, vein is ontop of the gland
What veins combine to form the common facial vein?
Facial vein + retromandibular vein
What structures are indicated in the drawing below?
These are the roots of the loop that forms the ansa cervicalis. 1) Superior root (C1 only) 2) Inferior root (C2 + C3 fibers)
In the anterior cervical triangle, what structures does the hypoglossal nerve cross anterior to and posterior to?
Anterior: Occipital Aa, Lingual Aa, Hyoglossus M. Posterior: Mylohyoid M.
Where does the vagus nerve exit the skull?
Jugular foramen. Note that it can be found between the external jugular vein and internal carotid artery.
What branches come off of the vagus nerve in the anterior cervical triangle?
Superior laryngeal nerve (further splits into internal & external laryngeal nerves) and Recurrent laryngeal nerve
Where does the spinal accessory nerve exit the skull?
Jugular foramen. Note it can be found in the deep belly of the SCM.
What arteries provide blood supply to the thyroid gland and where do they come from?
Superior thyroid arteries (external carotid) and inferior thyroid arteries (thyrocervical trunk off subclavian)
Why are patients at risk for suffocation when they have their thyroid glands removed?
First: the recurrent laryngeal nerve intermingles with the inferior thyroid artery as it enters the thyroid. Transection of this nerve during surgery can paralyze the vocal cords. Second: the inferior thyroid artery supplies blood to the parathyroid glands that produce PTH. If these become ischemic, PTH decreases, so do Ca2+ levels, tetany occurs and can close off the airway.
When performing a tracheotomy the patient begins bleeding profusely. What variation of thyroid blood supply may this patient have?
Thyroid IMA Artery
What veins drain the thyroid gland?
Superior, middle and inferior thyroid veins. The Superior and middle veins drain into the internal jugular vein. The inferior thyroid vein drains into the subclavian.
What branches come off of the medial portion of the subclavian artery?
Vertebral artery, Internal thoracic artery and thyrocervical trunk
What branches come off of the thyrocervical trunk?
Suprascapular artery, transverse cervical artery and inferior thyroid artery.
What branch comes off of the inferior thyroid artery?
Ascending cervical artery
What branches come off of the posterior subclavian artery?
Costocervical trunk
