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Posterior triangle of the neck Deep fascia of the neck Boundary of posterior triangle Contents of posterior triangle: muscles, vessels, nerves Dept. of Anatomy Zhou Hong Ying Skeleton of neck & Important landmarks Cervical part of spinal column Hyoid bone Cartilage of the respiratory tracts larynx and trachea lower border of mandible & mandibular angle Mastoid process Bones and cartilages of neck Landmarks Palpate following structures on your own neck: Hyoid bone Thyroid cartilage: laryngeal prominence Cricoid cartilage Trachea SCM Superficial structure----platysma Deep Fascia of the Neck ▪ investing layer ▪ pretracheal layer ▪ prevertebral layer ▪ alar fascia & carotid sheath Deep fascia Fascial Spaces of the Neck ▪ pretracheal space ▪ retropharyngeal space ▪ fascial space within prevertebral layer ▪ alar fascia connects the carotid sheathes ▪ buccopharyngeal fascia is the posterior portion of the pretracheal layer Superficial Muscles of the Neck The Posterior Cervical Triangle ▪ occipital triangle ▪ supraclavicular triangle Omohyoid Muscle & SCM Boundaries of Posterior Cervical Triangle • bounded by the SCM, trapezius and middle third of the clavicle • Apex: SCM and trapezius meet on the superior nuchal line of the occipital bone. • A roof : investing layer of the cervical fascia. • A floor: muscles covered by the prevertebral layer of the cervical fascia. Boundaries of Posterior Cervical Triangle Main contents in posterior △ • Muscles scalenus anterior, medius, posterior; levator scapulae, splenius • Nerves : cervical plexus, brachial plexus (root of neck), and accessory N. • Vessels external jugular vein, subclavian a and its branches & v (root of neck) and thyrocervical trunk • Cervical lymph nodes . Muscles in the Posterior Cervical Triangle ▪ omohyoid muscle ▪ muscles form the floor - anterior scalene muscle - middle scalene muscle - posterior scalene muscle - levator scapulae muscle - splenius capitis muscle The Scalene Muscles The Structures of Posterior Cervical Triangle ▪ nerves - accessory nerve - cervical plexus - brachial plexus ▪ arteries - subclavian artery ▪ veins - subclavian vein the external jugular vein the junction of the posterior auricular vein and the posterior division of the retromandibular vein. crosses the SCM in the superficial fascia, at a point about 3~5cm above the clavicle, usually end by emptying into the subclavian vein. External Jugular Vein ▪ retromandibular vein ▪ posterior auricular vein ▪ transverse cervical vein ▪ suprascapular vein ▪ anterior jugular vein Subclavian v.: being continuous with axillary v., Ant. to the scalenus Ant., uniting with internal jugular v. to form brachiocephalic v. posterior to the sternoclavicular joint Arteries of posterior triangle Subclavian a. Post. to the subclavian v. Anteroinferior to the brachial plexus in scalenus space Transverse cervical a. from thyocervical trunk superior to the clavicle deep to the omohyoid Suprascapular a. from thyrocervical trunk Posterior to clavicle Arteries of posterior triangle The accessory nerve CNⅪ a motor nerve supplies the sternocleidomastoid muscle & the trapezius muscle The accessory nerve crosses the posterior △ , superficial to the deep fascia covering the floor CNⅪ Cervical nerve plexus This plexus is formed by 1st to 4th cervical nerves. The Cervical Plexus Cutaneous Branches of the Cervical Plexus ▪ lesser occipital nerve - the scalp posterior to auricle ▪ great auricular nerve - the skin covering the parotid gland & mandibular angle ▪ transverse cervical nerve - the skin of anterior portion of the neck ▪ superaclavicular nerves - the skin of anterior thoracic wall above the 2nd costal space & of the shoulder The phrenic N motor nerve supply the diaphragm arises from the ventral primary rami 3rd 4th and 5th cervical N. sensory branches: the central part of the pleural and peritoneum of the diaphragm. Descends obliquely across anterior scalenus. Outline Chief Contents of the Posterior Cervical Triangle ▪ nerves - accessory nerve - cervical plexus: lesser occipital nerve great auricular nerve transverse cervical nerve superaclavicular nerves * phrenic nerve - brachial plexus ▪ arteries - transverse cervical artery - superascapular artery ▪ veins - external jugular vein Dissection Layers of Posterior Cervical Triangle Deep dissection • The investing layer of the deep cervical fascia has been removed. Although the spinal accessory nerve (CN XI) is superficial to it, the brachial plexus and motor nerves of the cervical plexus run deep to the prevertebral layer of deep cervical fascia that covers the floor of the triangle.