Posterior Triangle
POSTERIOR TRIANGLE BY DR . M.MD. MUSTAFA SHARIFF DEPT OF ANATOMY SENIOR LECTURER SRMDC & H POSTERIOR TRIANGLE • This is a triangular depressed space present above the middle one third of clavicle and behind the sternocleidomastoid muscle. POSTERIOR TRIANGLE OFNECK • Boundaries • – Infront – posterior border of sternocleidomastoid muscle • Behind – anterior border of trapezius • Base – Superior surface of middle 1/3rd of clavicle • Apex – Superior nuchal line where sternocleidomastoid and trapezius muscles meet • Roof – Skin, superficial fascia (platysma), investing layer of deep cervical fascia STERNOCLEIDOMASTOID MUSCLE (SCM) Origin: • Sternal head --- manubrium • Clavicular head --- medial 1/3 of clavicle Insertion: • Mastoid process and lateral ½ of superior nuchal line Action: • When muscle of one side contracts, the head is tilted to the same side and chin is rotated to opposite side. • When muscles of both side contract the head and neck are flexed Nerve supply: • Spinal part accessory nerve , ventral rami of spinal nerves C2,C3 TRAPEZIUS MUSCLE Origin: ✓ Superior nuchal line, ext. occipital protuberance, lig. nuchae, spines of C7 – T12 Insertion: ✓ Lateral 1/3 of clavicle, acromion, spine of scapula Functions: ✓ Elevation of scapula (sup. fibers), ✓ Depression of scapula (inf. fibers), ✓ Retraction of scapula (middle fibers), ✓ Superior rotation of glenoid fossa of scapula (sup. + inferior fibers). ROOF OF THE POSTERIOR TRIANGLE • The ROOF of the posterior triangle is the platysma m. and the investing layer of deep cervical fascia. Investing layer of deep cervical fascia • The platysma is a muscle of facial expression and will be Platysma m. discussed later. Roof is pierced by : Nerves : ✓ Lesser occipital, Anterior ✓ Great auricular,Superior ✓ Transverse cutaneous nerve of the neck, Posterior ✓ Supraclavicular nerves, Inferior • The FLOOR of the post.
[Show full text]