Posterior Triangle Flashcards
C1
Atlas
C2
Axis
C3-C6
typical cervical vertebrae
C7
Vertebra prominens - very prominent spinous process
Posterior Triangle
SCM divides neck into anterior cervical triangle and posterior. Boundaries of posterior - anteriorly - posterior border of SCM, posteriorly - anterior border of trapezius,, inferiorly - the middle third of clavicle (base of triangle). Apex where SCM and trapezius come close at occipital bone.
Subclavian(supraclavicular) triangle
bounded by inferior belly of omohyoid, SCM and middle 1/3 of clavicle. parts of external jugular vein and subclavian vein lie in the triangle.
Occipital triangle
Larger of two triangles, bounded by omohyoid, SCM, and trapezius. apex is at occipital bone. CN XI - Spinal Accessory crosses this triangle.
Superficial Fascia
Fatty subcutaneous tissue, thin in neck, lies between skin and investing layer of deep cervical fascia. platysma is embedded anteriorly, cutaneous nerves, blood vessels and superficial lymph nodes lie here.
Deep cervical fascia
Compartmentalizes the neck - provides protection and allows structures to move without friction. allows movement of organs during swallowing and turning head. Investing layer, prevertebral layer, pretracheal layer, carotid sheath.
Platysma Muscle
Muscle of facial expression, innervated by CN VII(cervical branch), originates from sub-Q fascia over pectoral region of chest wall, travels over anterior/posterior triangles and crosses mandible blending with muscles of face. no bony attachments, moves the skin.
Investing layer
Surrounds the entire neck deep to the superficial fascia, it splits to go on both sides of the superficial muscles(trapezius, SCM, and 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
Extends from hyoid bone to the thorax where it blends with the pericardium, a tubular sheath that surround the deep back muscles, extends from the base of skull to about T3 vertebra, extends laterally as the axillary sheath, forms floor of the posterior triangle. Retropharyngeal space - potential space between the prevertebral fascia and fascia of pharynx.
Pretracheal Layer
very thin layer located in the anterior part of the anterior triangle. surrounds the trachea, esophagus, and thyroid gland. helps form the visceral compartment, blends laterally with the carotid sheath.
Roof of posterior triangle
Deep cervical fascia(investing layer), superficial fascia, platysma muscle, skin.
Floor of the posterior triangle
Prevertebral layer of deep cervical fascia(fascial carpet), splenius capitis, levator scapulae, posterior scalene, anterior/middle scalene, roots of brachial plexus.
Splenius Capitis
From ligamet nuchae and spinous process of C7-T3 to occipital bone and mastoid process
Levator Scapula
Transverse process of C2-C4 to superior medial angle of scapula
Posterior Scalene
Transverse process of C4-C6 to 2nd Rib
Anterior and middle scalenes
Transverse process of C4-C6 to 1st Rib
Cervical Plexus
Ventral rami of C2,C3,C4 nerves with contribution from C1 and C5. exit from posterior part of SCM - Nerve point
Lesser Occipital
Sensory branch from cervical plexus. C2, sometimes C3. supplies skin of the neck and scalp posterosuperior to auricle.
Great Auricular
Sensory branch from cervical plexus. C2,C3. supplies skin inferior to auricle and over parotid gland and posterior part of auricle. travels superomedially across SCM with EJ vein.
Transverse Cervical
Sensory branch from cervical plexus. C2,C3. goes across SCM. supplies skin over anterior triangle.
Supraclavicular
Sensory branch from cervical plexus.C3,C4. originates as a single trunk but divides into medial, intermediate and lateral branches. supply skin over clavicle and the superior wall of the chest and anterolateral part of shoulder.
Spinal accessory nerve
CN XI. motor supply to trapezium and SCM. divides posterior triangle into two equal halves.
