Neck Anatomy PDF

NECK Lect3 Dr. Eman Ghanim Skin of the Neck Skin of the Neck The natural lines of cleavage of the skin are constant and run almost horizontally around the neck (These lines represent the direction of arrangement of the collagen...

NECK Lect3 Dr. Eman Ghanim Skin of the Neck Skin of the Neck The natural lines of cleavage of the skin are constant and run almost horizontally around the neck (These lines represent the direction of arrangement of the collagen bands in the skin). This is important clinically because an incision along a cleavage line will heal as a narrow scar whereas one that crosses the lines will heal as a wide scar  Superficial Fascia & Platysma Formed of loose areolar & fatty tissues Replaced anteriorly by platysma Contains the cutaneous vessels & nerves and lymph node which lie deep to platysma. Platysma ❖ Origin: Deep fascia over pectoralis major and deltoid ❖ Insertion: Body of mandible and angle of mouth ❖ Nerve Supply: Facial nerve( cervical branch) ❖ Action: Depresses mandible and angle of mouthAlso drew the skin of the neck superiorly when teeth are clenched.  Superficial Veins External Jugular Vein The external jugular vein begins just behind the angle of the mandible by the union of the posterior auricular vein with the posterior division of the retromandibular vein. It descends obliquely across the sternocleido mastoid muscle and, just above the clavicle in the posterior triangle, pierces the deep fascia and drains into the subclavian vein Tributaries: - Posterior EJV from the back of neck - Anterior JV from the anterior part of the neck - Suprascapular & transverse cervical vv  Deep Cervical Fascia: deep’ to the superficial fascia and platysma muscle. This fascia is organised into several layers : 1- investing layer: The investing layer is a thick layer that encircles the neck. It splits to enclose the trapezius and the sternocleidomastoid muscles. 2-pretracheal layer : suround the trachea, oesophagus, thyroid gland and infrahyoid muscles 3- prevertebral layer:surrounds the vertebral column and its associated muscles 4 – Carotid Sheath are paired structures on either side of the neck, which enclose an important neurovascular bundle of the neck. The contents of the carotid sheath are: Common carotid artery Internal jugular vein. Vagus nerve  Sternocleidomastoid muscle Origin:- it has two heads: a- sternal head arise from manubrium sterni. b- clavicular head arise from the upper surface of medial 1/3 of clavicle. Insertion:- anterior part inserted into mastoid process, while posterior part inserted into the lateral part of superior nuchal line. Nerve supply:- motor by spinal part of accessory nerve, while sensory by ventral rami of C2. Action:- acting alone, it tilts the head to its own side and rotates it, so the face turned towards the opposite side, two muscles acting together flex the neck, but raise the sternum and assisted in forced inspiration.  congenital torticollis congenital torticollis : are a result of excessive stretching with injury of the sternocleidomastoid muscle during a difficult labor  Triangles of the Neck : Muscular Triangles of the Neck Sternocleidomastoid muscle divides the neck into anterior and posterior triangles The posterior triangle Boundaries:- 1-Anteriorly:- posterior border of sternocleidomastoid muscle. 2-Posteriorly:- anterior border of trapezius muscle. 3-Inferiorly:- by intermediate third of clavicle. 4-Roof:- covered by skin, superficial fascia, platysma muscle and deep fascia, in addition to supraclavicular nerve and lymph vessels run in these fascia. 5-Floor:- is formed by muscles which are covered by prevertebral fascia these muscles from above downward are semispinalis capitis, splenius capitis, levator scapulae and scalenus medius muscle ❖ The posterior triangle is divided by inferior belly of omohyoid muscle in to occipital triangle and supraclavicular triangle.  Contents 1-Arteries:- 3rd part of subclavian artery, transverse cervical artery, suprascapular artery and occipital artery. 2-Veins:- external jugular vein, subclavian vein. 3-Muscle:- inferior belly of omohyoid muscle. 4-Nerve:- spinal part of accessory nerve, cutaneous branches of cervical plexus, upper and middle root of brachial plexus between scalenus anterior and scalenus medius muscles and dorsal scapular nerve.  Accessory nerve Is 11th cranial , motor nerve arises by two roots, spinal roots from the upper five cervical segments which ascends upward through foramen magnum to join the cranial root which arises from medulla oblongata, both roots united together and leave the skull through jugular foramen with the vagus (10th cranial nerve) and glossopharyngeal (9th cranial nerve). In the jugular foramen the cranial part separates and joining the vagus and distributed in its branches to supply muscles of pharynx, palate, and larynx. -The Spinal root run downward and laterally to enter the deep surface of sternocleidomastoid m. to supply it, then crosses the posterior triangle of neck to supply trapezius m  cervical plexus The cervical plexus is formed deeply inside scalenus medius by the ventral rami of upper four cervical nerves, this plexus gives rise to the followings 1-Cutaneous branches of cervical plexus. 2-Ansa cervicalis. 3-Phrenic nerve. 4-Direct muscular branches. 5-Contribution to accessory nerve. Cutaneous branches of cervical plexus are:- 1-Great auricular nerve:- arises under posterior border of sternocleidomastoid muscle and turned upward in front of the auricle supplies the skin of auricle and the skin over the parotid gland. 2-Lesser occipital:- passes upward along the posterior border of sternocleidomastoid muscle supplies the skin of the auricle and scalp posteriorly. 3-Transverse cervical branch of the neck:- which crosses sternocleidomastoid muscle and runs anteriorly to the skin of the neck. 4-Supraclavicular nerve:- arises from C3 and C4 , this nerve divided into medial, intermediate and lateral branches supplies the skin over the chest, breast and over the shoulder joint. Thank you Muscle Origin Insertion Nerve Supply Action Sternohyoid Manubrium sterni and clavicle Body of hyoid bone Ansa cervicalis; Depresses hyoid bone Sternothyroid Manubrium sterni Oblique line on lamina of thyroid cartilage Ansa cervicalis Depresse larynx Thyrohyoid Oblique line on lamina of thyroid cartilage Lower border of body of hyoid bone 1st cervical nerve Depresses hyoid Omohyoid Inferior belly Upper margin of scapula and suprascapular ligament intermediat tendone Ansa cervicalis; C1, Depresses hyoid bone Superior belly Lower border of body of hyoid bone