Gross Anatomy - 2008
Triangles and Associated Structures of the Neck- Part 1
-Omohyoid divides posterior triangle in 2 sections- 1. subclavian triangle 2. occipital triangle
Omohyoid
-Superior border: hyoid bone
-passes inferiorly and laterally across the neck and behind SCM
-attaches medial to suprascapular notch
-Innervation: Ansa Cervicales C1,2,3
-Function: depresses hyoid bone
Floor Muscles
Anterior Scalene
-attachment: Transverse process if C3-6; rib 1
-Function: elevates rib 1
-innervation: C 4, 5, 6
Middle Scalene
-attachment: Transverse process if C2-7
-Function: elevates rib 1 laterally
-innervation: C 5-6
Levator Scapulae
-attachment: Transverse process if C1-4; medial border of scapula
-Function: elevates scapula
-innervation: C 3,4; dorsal scapular nerve
External Jugular
-top of SCM
-formed by posterior auricular v. and retromandibular v.
-empties into subclavian V
-internal jugular + subclavian = brachiocephalic
Nerves Located in the Posterior Triangle
-cutaneous nerves (4)
1. Spinal Accessory Nerve
2. Branches of Cervical Plexus
-lesser occipital (C2)
-great auricular (C2,3)
-transverse cervical (C2,3)
-suprascapular (C3,4)
Subclavian Artery
-Segment 1
-Segment 2: covered by anterior scalene
-Segment 3
Occipital Artery
-runs through posterior triangle to back of head
Anterior Triangle and Its Subdivisions
1. Submental Triangle- unpaired
2. Submandibular triangle- under mandible
3. Muscular triangle- trachea; divided by omohyoid
4. Carotid triangle- carotid pulse
Submental Triangle:
Digastric Muscle
-2 bellies; tendinous intersection
-Posterior Belly:
Innervation: Facial N
Function: pulls hyoid posterior and up
-Anterior Belly
Innervation: N to Mylohyoid
Function: pulls hyoid anterior and up
Mylohyoid Muscle
-innervation: N to Mylohyoid
-Function: elevates mylohyoid bone
Stylohyoid Muscle
-innervation: Facial Nerve
-Function: moves hyoid posterior and up
Gross Anatomy
1. Muscle Anatomy: including attachments, functions, loss of function, and
innervations.
2. Nerve Anatomy: including origin, path, destination, location, function, injury and
loss of function.
3. Vasculature: including origin, path, destination of veins and arteries, and collateral
4. circulation.
5. Lymphatics: lymphatic drainage pattern, major lymphatic vessels within a region
and clusters of lymph nodes
Carotid Triangle
Boundaries: portion of carotid muscles
-posterior gastric
-SCM
-superior belly of omohyoid
Floor
- portions of thryohyoid m
- hypoglossus
- -middle and inferior constrictors of the pharynx
Contains
-carotid sheath: Internal carotid A, Internal Jugular V, Vagus N, Hypoglossal N
- External carotid A. with branches
- Deep cervical lymph nodes: jogulodigastric node, jogulomyohyoid node
Carotid System
- Common Carotid Bifurcation- at C3- C4 on top of thyroid cartliage
Carotid sinus
Carotid body
- Internal Carotid – passing through the neck (no branches in neck)
- External Carotid –(total of 8 branches: 2 terminal branches, 6 main branches)
Superior thyroid artery- goes to superior thyroid. Has tiny brachnes on top that
becom superior laryngeal
Ascending pharyngeal artery- travels to pharyngeal muscles, ascends medially
Lingual artery- travels to tongue( soft palate, floor of tongue, mandibula, and
sublingual glands)
Facial artery- travels to submandibular gland, and supplies arteries to the face
Occipital artery- supples back of posterior aspect of head (branches to SCM,
auricular region, etc)
Posterior auricular artery- to ear and parotid gland
Superficial temporal artery- (terminal branch)- tranvels to side of head,
temporalis muscle, parotid gland, transverse facial muscle
Maxillary artery- (terminal branch) is found deep behind mandibula.
- Carotid Sinus- innervated by glossopharyngeal
- a dilation of the lower end of the internal carotid
- the tunica intima is thinner and adventitia is thicker
- the adventitia includes nerve endings (mainly CN IX)
- functions as a baroreceptor
- Carotid Body
- a vascular organ; an arterial chemoreceptor (samples blood and monitors CO2 and pH
levels)
- a reddish-brown mass found at the bifurcation
- innervation by CN IX, CN X and pre-ganglionic sympathetic (post-ganglionics are in the
carotid body)
- Anatomoses between Enternal and Internal carotid prevents major complications when
ligation of the external carotid artery occurs
- Nerves found in the carotid triangle
Hypogloss an.
Descending branch & Ansa cervicalis
- Nerves
Vagus.: 3 branches( pharyngeal branch to posterior region of pharynx, branch to carotid
body, cardiac branches to plexus)
superior laryngeal- splits into internal and external branch
external laryngeal- innervates constrictor muscles
internal laryngeal- runs with superior laryngeal artery
Arrangement of Viscera in the Anterior Neck
Thyroid- needed for thyroxin which is important in metabolism
The thyroid is divided into two lobs with an isthmus inbetween.
Arteries: Superior thyroid A (supplies superior portion of gland), Inferior thyroid A (off of the
thyrocervical trunk off of subclavian, and it supplies posterior aspect of thyroid)
Veins- Superior thyroid vein into IJV, Middle thyroid vein into IJV, Inferior thyroid vein into
brachiocephalic.
**2 arteries, 3 veins** except when you have an extra artery called the thyroid ima (branches off
of brachiocephalic artery)
Pyramidal lobe- extra lobe caused by incomplete descent of thyroid. Can cause cyst and fistulas.
Parathyroid gland- 4 total (2 superior and 2 inferior) on the posterior side of the thyroid. Blood is
supplied inferior thyroid artery.