Triangles of the Neck: Part II

46 terms by niquee12

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Ansa Cervicalis

Innervates some of the strap muscles; loops around the jugular vessels; lies on top of the carotid sheath; supplies infrahyoid muscles (except thyrohyoid); provides sensory fibers to CN XI

Phrenic Nerve

Formed at the lateral borders of the anterior scalene muscles; travels through thorax to the mediastinum and supplies the diaphragm

Phrenic Nerve

Has motor, sensory, and sympathetic nerve fibers; mainly from C4, but C3 and C5 also contribute

Common Carotid

No branches; usually bifurcates into internal and external carotid arteries at the thyroid (C4), but this is variable

Right common carotid

Branches off brachiocephalic trunk; travels up the neck towards the brain

Left common carotid

Usually comes off of aortic arch; travels up the neck towards the brain

Internal Carotid

Travels superiorly to the base of the skull; no branches; more medial and posterior

External Carotid

More anterior and lateral; numerous branches for viscera of face, neck, and mouth; terminal branches are the maxillary and superficial temporal artery

Superior thyroid, lingual, and facial

Major Branches of the External Carotid

Superior Thyroid

Travels inferiorly through the neck to supply the thyroid gland

Lingual

Deep; supplies tongue

Facial Artery

Runs laterally over the edge of the mandible across the face

Vertebral Artery

Branches off first part of subclavian artery that ascends through the foramina of the transverse processes of the cervical vertebrae

Thyrocervical Trunk

Comes off subclavian; branches

Inferior thyroid, transverse cervical, and suprascapular arteries

Thyrocervical trunk branches

Internal Jugular Vein

Drains head and neck; deep inside the carotid sheath; drains all blood from the brain and much of the head and neck; can be variable

Retromandibular, superior thyroid, and middle thyroid veins

Drain into IJV

Retromandibular Vein

Drains the large venous plexus behind the mouth and face

Superior and Middle Thyroid Veins

Drains the thyroid gland

Hypoglossal (CV XII)

Motor nerve that supplies the tongue and part of the pharyngeal plexus; exits the skull through the hypoglossal canal and travels to the tongue

Vagus (CN X)

Autonomic, parasympathetic, motor (primarily to larynx), and sensory (to the pharyngeal region); follows carotid artery within the carotid sheath and runs into the thorax

Superior and Inferior Laryngeal Nerves

Vagus nerve branches:

Superior Laryngeal Nerve

Consists of the external laryngeal nerve and the internal laryngeal nerve

External Laryngeal Nerve

A motor nerve that innervates the cricothyroid muscle and external portion of vocal cords

Internal Laryngeal Nerve

A sensory nerve that innervates the mucosa of larynx

Inferior Laryngeal Nerve (Recurrent Laryngeal Nerve)

Located in the groove between the esophagus and the trachea; motor supply to the laryngeal muscles which produce vocation; can be cut during surgery, causing the patient to become hoarse; if cut on both sides, can lose voice completely

Glossopharyngeal (CN IX)

Supplies two structures at the carotid bifurcation

Carotid Body

Lies on the medial side of the bifurcation; is highly vascularized; contains chemoreceptors that detect blood CO2 levels; if CO2 levels get too high, a reflex is stimulated that tells the brain to increase respiratory rate, cardiac rate, and blood pressure

Carotid Body

Monitors blood pH and regulates ventilation to keep CO2 levels correct; innervated by vagus and carotid sinus nerves

Carotid Sinus

Enlargement of the internal carotid artery; contains baroreceptors/pressuroreceptors that monitor blood pressure and react to changes in arterial blood pressure

Carotid Sinus

Innervated by the glossopharyngeal and vagus nerves

Autonomic Nerves

Nerves include CN IX, X, sympathetic trunk, and carotid nerves

Sympathetic Trunk

Sympathetic fibers first exit spinal cord at the level of T1; preganglionic fibers travel up the trunk to snapse in the cervical ganglia and postganglionic fibers traverse out into the head and neck on blood vessels

Sympathetic Trunk

A continuation of the trunk in the thorax; however, the cervical portion contains only three cervical sympathetic ganglia

Superior, middle, and inferior

Three cervical sympathetic ganglia

Superior sympathetic ganglia

Largest in cervical sympathetic trunk; good landmark for locating sympathetic trunk at C1,2 level; sympathetic trunk stops at the base of the skull at the superior cervical ganglion

Middle cervical ganglia

Usually small and occasionally absent; lies in anterior aspect of the inferior thyroid artery at C6 level

Inferior sympathetic ganglia

May fuse with the first thoracic ganglion form the stellate ganglion at C7 level

Lymphatics

All drain toward the carotid sheath through deep cervical nodes; lymph feeds into the lymphatic trunk, which drains into the subclavian vein at junction of IJV

Right lympathic duct

Drains right side of head, neck, and trunk, as well as the right upper extremity

Thoracic duct

Drains left side of head, neck, and trunk, as well as the lower body

Thyroid Gland

Largest endocrine gland; sits at the base of the neck; bilobed with isthmus connection at 2rd-3rd tracheal ring; very vascular

Superior and inferior thyroid arteries

Thyroid gland blood supply

Parathyroid Gland

Controls the metabolism of phosphorus and calcium in the blood; responsible for releasing calcium and stimulates osteoclasts

Cricothyrotomy

Palpate and cut hole through cricothyroid membrane and inserts tube to establish airway; vocal cords are in danger

Tracheostomy

A more permanent procedure; surgical procedure done to establish airway in patients with upper airway obstruction or respiratory failure. An opening is made in the trachea between the 2nd-3rd tracheal rings. A tracheal tube is then put in the trachea and secured. Danger in vocal cords, and in infants, the esophagus is vulnerable due to their soft trachea.

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