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46 terms

Triangles of the Neck: Part II

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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.