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Flashcards in Posterior Triangle Deck (50):

Sternocleidomastoid Muscle

SCM. Originates from sternum and clavical. Inserts at the mastoid



AKA collarbone. Long S-shaped bone that connects sternum to scapula.


Mastoid Process

Bony, conical prominence projecting from the undersuface of the temporal bone. Just dorsal to the external acoustic meatus, lateral to styloid process, posterior to "ear"


External Jugular Vein

Crosses across SCM obliquely. Becomes prominent when straining/flexing. Drains into the subclavian vein at the base of the neck. Used to monitor blood pressure.


Spinous process of axis

Unlike atlas (C1), axis (C2) has a very thick spinous process. Functions as an attachment point for many muscles.


External occipital protuberance

Protruberance at the back & bottom of the skull. Highest point of the skull is the inion.



highest point of the external occipital protruberance


Typical Cervical Vertebrae

C3-C6. Bifid spinous process. Small vertebral bodies. Pedicles directed laterally and backward.



C1. Atypical cervical vertebra. No spinous process. Small vertebral body.



C2. Atypical cervical vertebrae. Thick spinous process for muscles to attach to. Has Dens, a protruberance where axis and atlas connect



Protruberance of C2 where it connects with C1.


Boundaries of Posterior Triangle of Neck

Anterior: Posterior border of SCM. Posterior: Anterior border of trapezius. Inferior. Middle third of clavicle. Base of triangle formed by clavicle. Apex of triangle formed where SCM and trapezius muscles come close to each other at occipital bone.


Divisions of the Posterior Triangle

Subclavian triangle and occipital triangle. Divided by inferior belly of omohyoid as it crosses over inferior portion of posterior triangle.


Subclavian Triangle

Aka supraclavian triangle. Bounded by the inferior belly of the omohyoid , SCM and the middle 1/3 of clavicle. Smaller of the triangles. Parts of external jugular vein and the subclavian artery lie in this triangle


Occipital Triangle

Larged of the two divisions of the Posterior Triangle. Bounded inferiorly by omohyoid, ventrally by SCM, and posteriorly by trapezius. Apex at occipital bone. CN XI (Spinal accessory nerve) crosses this triangle.


Superficial Cervical Fascia

Fatty subcutaneous tissue. Thin in the neck. Lies beneath skin and investing layer of deep cervical fascia. Contains cutaneous nerves/blood vessels/lymphatic vessels, superficial lymph nodes, fat/connective tissue elements, and the platysma muscle


Platysma Muscle

Innervated by cervical branch of CN VII. Originates from subcutaneous fascia over pectoral region of chest wall. Travels over posterior and anterior cervical triangles crosses over the mandible to blend w/ muscles of the face. No bony attachments- moves the skin


Deep cervical fascia

Lies deep to the superficial fascia. Supports organs and blood vessels. Forms cleavage spaces, and allows movements of organs and the turning head.


Investing layer

most superficial part of deep fascia. It splits to go on both sides of the superficial muscles (trapezius, SCM and the strap muscles). In the anterior part of the neck it will also split to surround the submandibular gland and forms the capsule of the parotid gland


Prevertebral Layer

surrounds the vertebral column and muscles closely associated with it. Extends from hyoid to thorax, where it bends with the pericardium. Tubular sheath that surrounds the deep back muscles. Extends from the base of the skull to ~T3, extending laterally as the axillary sheath. Forms floor of the posterior triangle


Pretracheal layer

Thin layer located anterior part of anterior triangle. Surrounds the trachea and thyroid gland, and helps form the visceral compartment. Blends laterally with the carotid sheath.


Carotid sheath

Fascia around vessels of the neck, forming a neurovascular compartment of the neck


Retropharyngeal space

Space between the prevertebral fascia and the fascia of the pharynx


Fascial Carpet

Lateral prolongation of prevertebral layer of deep cervical fascia. Covers muscles of floor of posterior triangle.


Floor of the posterior triangle

Muscular floor consisting of 3 sets muscles: splenius capitis, levator scapulae, and the scalenus muscles (anterior, medius, and posterior)


Splenius capitis

Apex of the muscles of the floor of the posterior triangle. Connects from ligament nuchae and spinous process of C7-T3 to occipital bone and mastoid process. Lies below the fascial carpet


Levator Scapulae

processes of C1-C4 to the superior aspect of the medial border of the scapula (elevates scapula).


Scalenus Muscles

Anterior Scalene, Middle Scalene, and Posterior Scalene


Anterior Scalene

anterior tubercles of the transverse cervical processes to the scalene tubercle of the 1st rib


Middle Scalene

posterior tubercles of all of the transverse cervical processes to the first rib


Posterior Scalene

posterior tubercles of the transverse cervical processes to the 2nd rib


Roots of brachial plexus

Roots of the brachial plexus, which innervates VENTRAL RAMUS of lower cervical and T1. Proceeds through neck, axilla, and into arm.


Cervical plexus

Plexus of the the ventral rami of C1-C5. Primary contribution is C2-C4, some from C1-C5. Located in neck, deep to SCM.


Lesser Occipital Branch of Cervical Plexus

Sensory branch of Cervical Plexus. Innervated by C2 and occasionally C3. Supplies skin of neck and scalp posterosuperior to the ear


Greater Auricular

Sensory branch of the Cervical Plexus, innervated by C2 & C3. Travels superomedially across the SCM with the external jugular vein. Supplies the skin inferior to the ear over the parotid gland and posterior part of the ear


Transverse Cervical

Sensory branch of the Cervical Plexus, innervated by C2 & C3. Goes across the SCM. Supplies the skin over the anterior triangle



Sensory branch of the Cervical Plexus, , innervated by C3 & C4. Starts as 1 trunk, but divides into 3: medial branch, intermediate branch, and lateral branch. Supply the skin over the clavicle and the superior wall of the chest and anterolateral part of the shoulder


Cervical plexus block

Anesthesia method: subcutaneous block of nerves of the anterolateral neck. Injection of local anesthetic into cervical plexus. Will also anesthetise the diaphragm because of the phrenic nerve


Ansa cervicalis

a loop in the cervical plexus consisting of fibers from the first three cervical nerves. Branches of the ansa cervicalis supply the strap muscles of neck (sternohyoid, sternothyroid, superior and inferior bellies of omohyoid)


Superior root of Ansa Cervicalis

Fibers from a loop between the C1 and C2 spinal nerves accompany the hypoglossal nerve for a short distance. Innervates superior portions of omohyoid, sternothyroid, and sternohyoid muscles.


Inferior root of the Ansa Cervicalis

Fibers from a loop between the C2 and C3 spinal nerves. Sends off branches to inferior belly of omohyoid and lower parts of sternothyroid and sternohyoid muscles.


Strap muscles of the neck

Sternohyoid, sternothyroid, superior/inferior bellies of the omohyoid


Phrenic Nerve

C3,C4,C5. Sole motor nerve to the diaphragm also supplies pericardium & part of the pleura. Damage to phrenic nerve will cause paralysis to 50% of the diaphragm on affected side. Sensory to the central part of the diaphragm.


Spinal Accessory Nerve

CN XI. Motor supply to trapezius and SCM. Courses obliquely across posterior triangle, dividing it into two equal halves


Subclavian vein

Joins with internal jugular vein to form brachiocephalic vein.


Transverse Cervical Artery

Artery in neck. Passes transversely above inferior belly of omohyoid to the anterior margin of trapezius. Under trapezius, divides into a superficial and a deep branch.


Suprascapular artery

Arises from thyrocervical trunk. Close to origin of the transverse cervical artery.


Thyrocervical trunk

Branch of subclavian artery. 


Brachial Plexus

Superior, middle, and inferior trunks of brachial plexus located between anterior and middle scalene muscles. Supraclavicular brachial plexus block goes in superior to midpoint of clavicle.


Lymph Nodes

Superficial group of cervical nodes located along the external jugular vein