Anterior Cervical Triangle

anterior triangle of neck is bound by

• SCM m.

• midline

• inferior border of mandible

anterior triangle of neck is divided into 4 sub-triangles by

digastric m. and superior belly of omohyoid m.

4 sub-triangles of anterior triangle of neck is divided into

• submental

• submandibular

• muscular

• carotid

submental triangle is located

between two anterior bellies of digastric muscles and hyoid bone

what innervates anterior belly of digastric m.

nerve to mylohyoid (CN V3)

origin and insertion of anterior belly of digastric m.

o: digastric fossa

i: hyoid bone via intermediate tendon

action of anterior belly of digastric m.

• depresses mandible

• raises and steadies hyoid bone

mylohyoid muscle forms

floor of submental triangle

what innervates mylohyoid m.

nerve to mylohyoid

origin and insertion of mylohyoid m.

o: mylohyoid line

i: hyoid bone, mylohyoid raphe

action of mylohyoid m.

elevates hyoid, floor of mouth, and tongue

contents of submental triangle

submental lymph nodes

muscular triangle is bound by

• SCM m.

• superior belly of omohyoid m.

• midline of neck

• hyoid bone

ansa cervicalis (C1 - C3) innervates

• superior belly of omohyoid m.

• sternohyoid m.

• sternothryoid m.

thyrohyoid m. is innervated by

C1

actions of infrahyoid muscles

• anchor hyoid bone

• depress hyoid and larynx during swallowing and speaking

ansa cervicalis is

loop of nerves derived from cervical plexus (C1 - C3) that is located in carotid triangle

ansa cervicalis is superifical to

carotid sheath and internal jugular v.

superior root of ansa cervicalis shares

same epineurium as hypoglossal nerve

superior thyroid a. branches off

external carotid a.

inferior thyroid a. branches off

thyrocervical trunk (largest branch)

thyroid is drained by

• superior thyroid v. (into internal jugular v.)

• middle thyroid v. (into internal jugular v.)

• inferior thyroid v. (into brachiocephalic v.)

submandibular triangle is bound by

• anterior and posterior bellies of digastric m.

• inferior border of mandible

anterior belly of digastric m. is innervated by

nerve to mylohyoid (V3)

posterior belly of digastric m. is innervated by

facial nerve (CN VII)

anterior belly of digastric m. is derived from

1st pharyngeal arch

posterior belly of digastric m. is derived from

2nd pharyngeal arch

mastoid notch

• furrow in temporal bone where posterior belly of digastric muscle attaches

contents of submandibular triangle

• submandibular gland and lymph nodes

• facial a. and v.

• marginal mandibular n. (VII)

• nerve to mylohyoid (V3)

• stylohyoid m.

• hypoglossal n. (CN XII)

stylohyoid m. is innervated by

CN VII

facial artery is located

• anterior/medial to facial vein

• travels deep to or pierces submandibular gland

facial vein travels

superficial to submandibular gland

antegoinal notch

small concavity on mandibular body where facial artery crosses onto face

marginal mandibular nerve travels

superficial to facial vein and artery

marginal mandibular nerve is branch of

facial nerve (CN VII)

marginal mandibular nerve innervates

muscles of lower lip and chin

nerve to mylohyoid is located

superficial to mylohyoid m.

nerve to mylohyoid (V3) innervates

mylohyoid m. and anterior belly of digastric m.

mylohyoid groove

shallow furrow from margin of mandibular foramen where mylohyoid nerve lies

stylohyoid m. splits around

tendon of digastric m. before inserting into hyoid bone

stylohyoid m. is innervated by

facial nerve (CN VII)

hypoglossal n. travels

superficial to hypoglossal m. and deep to mylohyoid m. (in between them)

superior root of ansa cervicalis comes off

hypoglossal n.

carotid triangle is bound by

• posterior belly of digastric m.

• superior belly of omohyoid m.

• SCM m.

carotid sheath contains

• common carotid a. (below C3)

• internal carotid a. (above C3)

• internal jugular v.

• vagus n. (CN X)

superiorly, carotid sheath is attached to skull around

jugular foramen and carotid canal

carotid body

chemoreceptor at bifurcation of common carotid a.

carotid sinus

baroreceptor at dilated portion of internal carotid a.

both carotid body and sinus are innervated by

carotid sinus branch of CN IX

what pierces thyrohyoid membrane

• superior laryngeal a.

• internal branch of the superior laryngeal n.

superior thyroid a. supplies

superior portion of thyroid gland

superior laryngeal a. branches off

superior thyroid a.

lingual a. travels with

hypoglossal n.

lingual a. travels

deep/medial to hyoglossus m.

hypoglossal n. travels

superficial to hyoglossus m.

facial a. originates from

external carotid a.

facial a. passes deep to

posterior belly of digastric m.

ascending pharyngeal a. originates near

carotid bifurcation and ascends to pharynx

occipital a. travels along

posterior border of posterior belly of digastric m.

superior laryngeal n. is branch of

vagus nerve (CN X)

internal branch of superior laryngeal n. pierces

thyrohyoid membrane

internal branch of superior laryngeal n. travels with

superior laryngeal a.

external branch of superior laryngeal n. travels with

superior thyroid a.

internal branch of superior laryngeal n. is made of

afferent fibers (and preganglionic parasympathetic) to mucous membrane of upper larynx

external branch of superior laryngeal n. is made of

efferent fibers to cricothyroid m.

deep cervical lymph nodes are located

alongside internal jugular vein