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Flashcards in Anterior Triangle Deck (59):

Anterior Cervical Triangle

Boundaries: Anterior midline of the neck, inferior border of the mandible, anterior border of SCM. Apex of triangle is jugular notch. Base of triangle is inferior border of mandible.


Roof of triangle

Comprised of superficial fascia, platysma, and skin


Subdivisions of the Anterior Triangle

Submandibular (Diagastric), Submental, Carotid, and Muscular


Submandibular Triangle

Aka Digastric triangle. Superior boundary: Inferior border of mandible. Lateral boundary: Posterior belly of digastric muscle. Medial border: anterior belly of digastric muscle


Digastric muscle

Muscle inferior to the jaw with two bellies: anterior and posterior. These two bellies, along with the inferior border of the mandible, form the digastric/submandibular triangle. Act to elevate the hyoid bone.


Digastric Muscle (Anterior belly)

Arises from the lower border of the mandible. Forms medial border of submandibular triangle.


Digastric Muscle (Posterior belly)

Longer of the two. Arise from mastoid notch near mastoid process. Forms lateral boundary of submandibular triangle.


Floor of submandibular triangle

Formed by the mylohyoid and hypoglossal muscles


Contents of the submandibular triangle

Submandibular gland, submandibular ganglion, submandibular lymph nodes, hypoglossal nerve, and facial artery/vein


Submandibular Gland

Salivary gland


Submandibular ganglion

Parasympathetic ganglion located next to the submandibular gland


Submandibular lymph nodes

Lie superficial to the submandibular gland


Hypoglossal nerve



Submental Triangle

Located at the anterior midline of the neck above the hyoid bone. Inferior boundary: hyoid bone (base of triangle). Lateral boundaries: anterior bellies of digastric muscle. Floor: mylohyoid muscle.


Hyoid bone

Horseshoe shaped bone situated anterior midline of neck between chin and thyroid cartilage. At rest, lies at he level of the base of the mandible.


Mylohyoid muscles

Form floor of both submandibular and submental triangles. Rune from mandible to hyoid bone. Join at the midline, forming a raphe (space of 2 muscles intermeshing)


Contents of submental triangle

Submental lymph nodes, beginning of anterior jugular veins


Carotid triangle

Described as most important triangle. Lies anterior to the superior part of SCM. Infrahyoid muscles do not overlap the carotid arteries. Anterior boundary: superior belly of omohyoid muscle. Superior boundary: Posterior belly of digastric muscle. Lateral boundary: anterior border of SCM.


Contents of carotid triangle

Carotid sheath, common carotid artery, internal carotid artery, external carotid artery + branches, internal jugular vein, Vagus Nerve


Carotid sheath

Extends from base of neck to base of skull. Contains vagus nerve posteriorly, common carotid/internal carotid arteries medially, and internal jugular vein laterally


Vagus Nerve

CN X. Longest cranial nerve. Exits the skull through jugular foramen, enters the carotid sheath. Gives rise to reccurent laryngeal, cardiac branches, superior laryngeal, and contributes to pharyngeal plexus.



Internal Jugular Vein



Runs laterally through the carotid sheath. Begins outside skull at eternal surface of jugular foramen as a dilated structure known as the jugular bulb. Descends inferiorly in the carotid sheath. Terminates by joining subclavian vein to form brachiocephalic vein



Common carotid artery

Ascend medially through carotid sheath. Terminates at superior border of the thyroid cartilage by dividing to form external and internal carotid arteries. Occulsion can obstruct bloodflow to brain leading to stroke or transient ischemic attack (TIA)


Internal carotid artery

After split, ascendes medially through carotid sheath. Provides no branches in the neck. Courses directly superiorly in the carotid sheath to enter skull via carotid canal.


External carotid artery

Branches from common carotid artery at superior border of thyroid cartilage. Supplies structures outside the skull. Terminates in the parotid gland by bifurcating into superficial temportal and maxillary arteries. Provides following branches to head and neck: superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, superficial temporal, maxillary


Muscle Triangle

Lies posterior to the hyoid bone. Anterior boundary: anterior miline of neck. Lateral boundary: Superior belly of the omohyoid muscle. Inferior boundary: anterior border of the SCM


Contents of muscle triangle

Thyroid and parathyroid gland (C6 level). Infrahyoid muscles, sternothyroid, sternohyoid, thyrohyoid, omohyoid (both bellies)


Right common carotid artery

Branch of brachiocephalic trunk


Left common carotid artery

Direct branch of aorta


Checking carotid pulse- When? How?

Routinely checked during CPR. Checked at level of thyroid cartilage- deep to anterior border of SCM


Carotid sinus

Dilated initial segment of internal carotid artery. Located at the bifurcation of interior and external carotid arteries. Innervated by CN IX and X. Acts as a receptor for monitoring arterial blood pressure.


Subclavian artery

*Right subclavian artery is pictured.* Left subclavian artery differs in that it stems directly from the aorta. Divided into three parts by the anterior scalene muscle. First part of subclavian extends from origin to the medial border to the anterior scalene. Second part lies behind the anterior scalene. Third part extends from lateral margin of anterior scalene to the outer border of the first rib --> becomes the axillary atery.


Right subclavian artery

Originates from brachiocephlic artery


Left subclavian artery

Originates from the aorta


1st part of subclavian artery

Extends from subclavian artery origin (left: origin; right: brachiocephalic artery) to the border of the anterior scalene muscle. Provides the following branches: Vertebral artery, internal thoracic artery, thyrocervical trunk. Thyrocervical trunk branches to transverse cervical artery, suprascapular artery, and inferior thyroid artery.


Thyrocervical trunk

Branch of 1st part of subclavian artery. Branches further to suprascapular, transverse cervical, ascending cervical, and inferior thyroid arteries


Suprascapular artery

Branch of thyrocervical trunk


Transverse cervical

Branch of thyrocervical trunk


Ascending cervical

Branch of the inferior thyroid artery off of the thyrocervical trunk


Inferior thyroid

Branch of thyrocervical trunk


2nd part of subclavian artery

Posterior to the anterior scalene muscle. Gives rise to costocervical trunk


Costocervical trunk

Branch of 2nd part of subclavian artery. Splits into deep cervical artery and superior intercostal artery


Deep cervical artery

Branch of costocervical trunk


Superintercostal artery

Branch of costocervical trunk


3rd part of subclavian artery

Extends from lateral porder of anterior scalene to the first rib. Gives rise to one branch: dorsal scapular artery


Dorsal scapular artery

Branch of 3rd part of subclavian artery


Anterior Jugular Vein

Begins in submental triangle below mandible. Descends along anterior midline of neck. Drains into external jugular vein.


Recurrent Laryngeal

Branch of vagus nerve


Pharyngeal plexus

Network of nerve fibers innervating larynx, pharynx, palate. Contributed to by vagus nerve


Cardiac branches

Cardiac branches of the vagus nerve


Superior laryngeal

branch of vagus nerve


Ansa cervicalis

Loop of nerves, part of the cervical plexus. Innervate infrahyoid, including sternothyroid, sternohyoid, and omohyoid. Motor component of the cervical plexus.


Hypoglossal Nerve (CN XII)

innervates muscle of the tongue


Sympathetic trunk

Longitudinal strands of autonomic fibers. Begins at level of C1. Courses inferiorly through the neck anterior to the vertebral column and deep to the carotid sheath. Cervical component contains 3 ganglia: Superior Cervical Ganglion, Middle Cervical Ganglion, and Inferior Cervical Ganglion.


Superior Cervical Ganglion

Largest ganglion in sympathetic chain. At level of C1/C2


Middle cervical ganglion

Located at level of cricoid cartilage (C6)


Inferior cervical ganglion

Sometimes fused with first thoracic ganglion (then known as stellate ganglion [pictured]). Located at level of C7 (superior border of first rib)


External Jugular Vein

receives the greater part of the blood from the exterior of the cranium and the deep parts of the face


Subclavian Vein

runs from the outer border of the first rib to the medial border ofanterior scalene muscle. From here it joins with the internal jugular vein to form the brachiocephalic vein