Posterior Triangle Flashcards
Sternocleidomastoid Muscle
SCM. Originates from sternum and clavical. Inserts at the mastoid
Clavicle
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.
Inion
highest point of the external occipital protruberance
Typical Cervical Vertebrae
C3-C6. Bifid spinous process. Small vertebral bodies. Pedicles directed laterally and backward.
Atlas
C1. Atypical cervical vertebra. No spinous process. Small vertebral body.
Axis
C2. Atypical cervical vertebrae. Thick spinous process for muscles to attach to. Has Dens, a protruberance where axis and atlas connect
Dens
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