Surface anatomy Plan fascia of the neck Dr. H.A.Jaafar Al-Nahrain University- college of Medicine Dept. Of Anatomy

Objectives: we should be able to know : The subcutaneous tissue nerves, veins of the neck, The main anatomical potential space in the neck which lead to Spread Infections to the mediastinum. Three major fascial compartments of the neck Where the viscera of the neck are located.

It is strengthened by cervical part of vertebral column, The Neck lies between lower margin of mandible above & suprasternal notch & upper border of clavicle below. It is strengthened by cervical part of vertebral column, is convex forward supports skull. Behind the vertebrae is ………………….a mass of extensor muscles in front is …………………………………..a smaller group of flexor muscles . In central region are :…………………parts of respiratory system, larynx & trachea, behind are parts of alimentary system, pharynx & esophagus. At sides of these structures are vertically running : carotid arteries, internal jugular veins, vagus nerve, deep cervical lymph nodes

Landmarks of the neck Sternocleidomastoid Suprasternal fossa Greater supraclaviclar fossa

Landmarks of the neck Hyoid bone Thyroid cartilage Cricoid cartilage

lines of cleavage of skin are constant Skin of Neck lines of cleavage of skin are constant run …..horizontally …..around neck. an incision : along a cleavage line will heal as a narrow scar, crosses lines will heal as a wide or heaped-up scar.

The natural line of cleavage of the skin are constant and run almost horizontally around the neck

Fascia of Neck

1-Superficial Fascia 2-deep Fascia

1-Superficial Fascia

Superficial Fascia forms a thin layer encloses platysma muscle. embedded in it are : cutaneous nerves, superficial veins, superficial lymph nodes.

Cervical Subcutaneous Tissue &Platysma Structures in neck: are surrounded by a layer of subcutaneous tissue (superficial fascia) are compartmentalized by layers of deep cervical fascia. fascial planes determine direction in which an infection in neck may spread. Cervical Subcutaneous Tissue &Platysma superficial cervical fascia is a layer of fatty connective tissue lies between dermis of skin & investing layer of deep cervical fascia It is usually thinner than in other regions, anteriorly. It contains : cutaneous nerves, blood & lymphatic vessels, superficial lymph nodes variable amounts of fat. Platysma……..Anterolaterally

external jugular vein (EJV) descending from angle of mandible to middle of clavicle are superficial to main cutaneous nerves of neck. covers anterolateral aspect of neck.

Platysma flat plate is a broad, thin sheet of muscle in subcutaneous tissue of neck is supplied by cervical branch of CN VII. Its fibers arise in deep fascia covering superior parts of deltoid & pectoralis major muscles sweep superomedially over clavicle to inferior border of mandible. anterior borders of the two muscles decussate over chin blend with facial muscles. Inferiorly, fibers diverge, leaving a gap anterior to larynx & trachea

tenses skin, producing vertical skin ridges releasing pressure on superficial veins. use in shaving in a grimace. depress the mandible and draw corners of mouth inferiorly Acting its inferior attachment convey tension or stress.

Contents Platysma Superficial veins Cutaneous nerves Anterior jugular v. External jugular v. Cutaneous nerves Lesser occipital n. Greator auricular n. Transverse nerve of neck Supraclavicular n. Cervical branch of facial n.

Regions of neck Neck Anterior region of neck Sternocleidomastoid region Lateral region of neck

Triangles of posterior (lateral) region of neck Occipital triangle supraclavicular triangle (greater supraclavicular fossa)

2-Deep Cervical Fascia

Deep Cervical Fascia: investing, pretracheal, & prevertebral.

condenses around : ……… to form carotid sheath support : viscera (thyroid gland), muscles, vessels, & deep lymph nodes. condenses around : ……… to form carotid sheath common carotid arteries, internal jugular veins (IJVs), & vagus nerves form natural cleavage planes tissues may be separated during surgery, limit the spread of abscesses (collections of pus) afford slipperiness allows structures in neck to move and pass over one another without difficulty, swallowing and turning the head and neck.

Deep Cervical Fascia: investing,

most superficial deep fascial layer, Investing Layer most superficial deep fascial layer, surrounds entire neck deep to skin and subcutaneous tissue. splits into superficial and deep layers to enclose (invest) : trapezius & sternocleidomastoid (SCM) muscles. Superiorly, attaches to : Superior nuchal line of occipital bone. Mastoid processes of temporal bones. Zygomatic arches. Inferior border of mandible. Hyoid bone. Spinous processes of cervical vertebrae. also splits to enclose : submandibular gland; posterior to mandible, it splits to form fibrous capsule of parotid gland.

Inferiorly, attaches to : Investing Layer stylomandibular ligament is a thickened modification Inferiorly, attaches to : manubrium, clavicles, & acromions spines of scapulae. continuous posteriorly with : periosteum covering C7 spinous process, nuchal ligament a triangular membrane forms a median fibrous septum between muscles of two sides of neck

Deep Cervical Fascia: pretracheal,

Pretracheal Layer of Deep Cervical Fascia is limited to the anterior part of neck It extends inferiorly from hyoid into thorax, it blends with the fibrous pericardium covering heart. includes a thin muscular part, encloses : infrahyoid muscles, & a visceral part, encloses thyroid gland, trachea, & esophagus pharynx is continuous posteriorly & superiorly with buccopharyngeal fascia of pharynx. blends laterally with carotid sheaths.

a thickening of pretracheal fascia forms a pulley or trochlea through Pretracheal Layer of Deep Cervical Fascia In hyoid, a thickening of pretracheal fascia forms a pulley or trochlea through intermediate tendon of digastric muscle passes, suspending hyoid. tethers two-bellied omohyoid muscle, redirecting course of muscle between bellies.

Prevertebral Layer

is fixed to cranial base superiorly. forms a tubular sheath for vertebral column & muscles associated with it, such as : longus colli &longus capitis anteriorly, scalenes laterally, deep cervical muscles posteriorly is fixed to cranial base superiorly. Inferiorly, it blends with endothoracic fascia peripherally fuses with anterior longitudinal ligament centrally at approximately T3 vertebra extends laterally as axillary sheath surrounds axillary vessels & brachial plexus. sympathetic trunks cervical parts are embedded in it

Carotid Sheath

is a tubular fascial investment extends from cranial base to root of neck. blends : anteriorly with investing and pretracheal layers posteriorly with prevertebral layer contains : common and internal carotid arteries, internal jugular vein, vagus nerve (CN X), deep cervical lymph nodes, carotid sinus nerve, sympathetic nerve fibers (carotid periarterial plexuses). carotid sheath and pretracheal fascia communicate freely with: mediastinum of thorax inferiorly & cranial cavity superiorly. represent potential pathways for spread of infection and extravasated blood.

Retropharyngeal Space

Buccopharyngeal fascia is largest and most important interfascial space in neck It is a potential space consists of loose connective tissue between visceral part of prevertebral layer of deep cervical fascia & buccopharyngeal fascia surrounding pharynx superficially. Inferiorly, buccopharyngeal fascia is continuous with pretracheal layer alar fascia : forms a further subdivision of retropharyngeal space. is attached along midline of buccopharyngeal fascia from cranium to level of the C7 vertebra. it extends laterally and terminates in carotid sheath. permits movement of pharynx, esophagus, larynx, and trachea relative to vertebral column during swallowing. is closed : superiorly by cranial base and on each side by carotid sheath. It opens inferiorly into superior mediastinum Sternocleidomastoid Trapezius Deep Cervical Fascia Investing layer of deep cervical fascia Prevertebral fascia Pretracheal fascia (visceral part) Carotid sheath Buccopharyngeal fascia Alar fascia (muscular part) T E

Buccopharyngeal fascia Sternocleidomastoid Trapezius Posterior cervical triangle Anterior triangles Suprahyoidmuscles Infrrahyoidmuscles Sternocleidomastoid Trapezius Deep Cervical Fascia Investing layer of deep cervical fascia Prevertebral fascia Pretracheal fascia (visceral part) Carotid sheath Buccopharyngeal fascia Alar fascia (muscular part) T E Prevertebral muscles Scalene muscles

Trace the pathways for venous drainage from the neck into the brachial veins. Ext. jugular Int. jugular Ant. jugular Sup. thyroid Middle thyroid Inf. thyroid

Platysma

Cutaneous nerves and superficial veins Lesser occipital n. External jugular vein Greet auricular n. Transverse nerve of neck Supraclavicular n. Anterior jugular vein

Submendibular gland Digastric Accessory n. Hypoglossal n. Superior thyroid a. Cervical plexus Ansa cervicalis Sternothyroid Phrenic n. Sternohyoid Omohyoid Vagus n.