LATERAL CERVICAL TRIANGLE

Superficial Cervical Fascia Contains: Platysma muscle Superficial veins Cutaneous nerves

Prevertebral Fascia Covers: Extends: Muscles of the lateral triangle Around anterior surface of the cervical vertebrae across anterior midline.

Boundaries of Triangle Anterior: Posterior border of the sternocleidomastoid Posterior: Anterior border of the trapezius Inferior: Clavicle Moore: Fig. 6.29

Roof of Triangle Skin Superficial layer of deep cervical fascia: Also called investing fascia. Splits to enclose: Trapezius Sternocleidomastoid

Muscular Floor Triangle Prevertebral fascia covers muscular floor consisting of: Splenius capitis Levator scapulae Scalenus posterior Scalenus medius Scalenus anterior Omohyoid

Nerves of Triangle Lesser occipital (C2) Supraclavicular (C3,4) Accessory (CN XI): To trapezius and sternocleidomastoid

Vessels of Triangle Occipital artery Transverse cervical artery Subclavian vein: Crosses first rib Subclavian artery: External jugular vein

Spinal Accessory Nerve Spinal root Arises from C1-C5. Fibers pass superiorly through foramen magnum and join cranial root. Cranial root Arises from medulla.

Spinal Accessory Nerve Both roots exit through jugular foramen and separate. Spinal root innervates: Sternocleidomastoid Trapezius