Surface anatomy

Plan fascia of the neck

Dr. H.A.JaafarDr. H.A.Jaafar

Al-Nahrain University-Al-Nahrain University-

college of Medicine college of Medicine

Dept. Of AnatomyDept. Of Anatomy

Objectives:

we should be able to know :

1.The subcutaneous tissue nerves, veins of the neck,

2.The main anatomical potential space in the neck which lead to Spread Infections to the mediastinum.

3.Three major fascial compartments of the neck

4.Where the viscera of the neck are located.

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 :1. carotid arteries,

2. internal jugular veins,

3. vagus nerve,

4. deep cervical lymph nodes

Landmarks of the neck

• Sternocleidomastoid

• Suprasternal fossa

• Greater supraclaviclar fossa

Landmarks of the neck

• Hyoid bone

• Thyroid cartilage

• Cricoid cartilage

Skin of Neck

lines of cleavage of skin are constant

run …..horizontallyhorizontally …..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 cleavage of the skin are constant and run almost horizontally around the neck

Fascia of NeckFascia of Neck

1-Superficial Fascia1-Superficial Fascia

2-deep Fascia2-deep Fascia

1-Superficial Fascia1-Superficial Fascia

Superficial Fasciao forms a thin layer o encloses platysma muscle.

embedded in it are : cutaneous nerves, superficial veins, superficial lymph nodes.

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 Cervical Subcutaneous Tissue &PlatysmaPlatysma 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, cutaneous nerves, blood & lymphatic vessels, blood & lymphatic vessels, superficial lymph nodessuperficial lymph nodes variable amounts of fat. variable amounts of fat. PlatysmaPlatysma……..Anterolaterally

external jugular vein (EJV)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.

PlatysmaPlatysma•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 shavingin shaving

• in a grimace. grimace.

• depress the mandible and draw corners of mouth inferiorly• Acting its inferior attachment

• convey tension or stress.

Contents • Platysma• Superficial veins

– 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 trianglesupraclavicular triangle

(greater supraclavicular fossa)

2-Deep Cervical 2-Deep Cervical Fascia Fascia

Deep Cervical Fascia: Deep Cervical Fascia:

1.1.investing, investing,

2.2.pretracheal, & pretracheal, &

3.3.prevertebral. prevertebral.

support :1. viscera (thyroid gland),

2. muscles,

3. vessels, &

4. deep lymph nodes.

condenses around : ……… to form carotid sheath carotid sheath common carotid arteries, common carotid arteries, internal jugular veins (IJVs), &internal jugular veins (IJVs), & vagus nerves vagus nerves

form natural cleavage planes tissues may be separated during surgery,

• limit the spread of abscesses (collections of pus)

afford slipperinessallows structures in neck to move and pass over one another without difficulty,

swallowing and turning the head and neck.

Deep Cervical Fascia: Deep Cervical Fascia:

1.1.investing, investing,

Investing LayerInvesting Layer most superficial deep fascial layer, surrounds entire neck deep to skin and subcutaneous tissue. splits into superficial and deep layers to enclose (invest) :

1. trapezius &

2. 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; submandibular gland; posterior to mandible, it splits to form fibrous capsule of parotid glandparotid gland.

Investing LayerInvesting Layer

stylomandibular ligament stylomandibular ligament is a thickened modification

Inferiorly, attaches to : manubrium, clavicles, & acromions spines of scapulae.

continuous posteriorly continuous posteriorly

with :periosteum covering C7 spinous process, periosteum covering C7 spinous process, nuchal ligament nuchal ligament

a triangular membrane forms a median fibrous septum between muscles of two sides of neck

Deep Cervical Fascia: Deep Cervical Fascia:

pretracheal, pretracheal,

Pretracheal Layer of Deep Cervical FasciaPretracheal 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 heartpericardium covering heart.

includes a thin muscular part,

encloses :infrahyoid muscles, & infrahyoid muscles, & a visceral parta visceral part,

encloses thyroid gland, trachea, &esophagus pharynx

is continuous posteriorly & superiorly with buccopharyngeal fascia of pharynx.

blends laterally with carotid sheathscarotid sheaths.

Pretracheal Layer of Deep Cervical FasciaPretracheal Layer of Deep Cervical Fascia

In hyoid,

a thickening of pretracheal fascia forms a pulley or trochlea through intermediate tendon of digastric digastric muscle passes,

suspending hyoidsuspending hyoid.

tethers two-bellied omohyoid muscle, redirecting course of muscle between bellies.

Prevertebral Layer Prevertebral Layer

forms a tubular sheath for vertebral column & muscles associated with it,

such as :A. longus colli &longus capitis anteriorly,

B. scalenes laterally,

C. deep cervical muscles posteriorly

is fixed to cranial base superiorly.

Inferiorly, it blends with endothoracic fascia endothoracic fascia peripherally

fuses with anterior longitudinal ligament anterior longitudinal ligament centrally at approximately T3 vertebra

extends laterally as axillary sheath surrounds axillary vessels & brachial plexus. surrounds axillary vessels & brachial plexus.

sympathetic trunks cervical parts 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 :(1)(1) common and internal carotid arteries, common and internal carotid arteries,

(2)(2) internal jugular vein, internal jugular vein,

(3)(3) vagus nerve (CN X), vagus nerve (CN X),

(4)(4) deep cervical lymph nodes, deep cervical lymph nodes,

(5)(5) carotid sinus nerve, carotid sinus nerve,

(6)(6) sympathetic nerve fibers (carotid periarterial plexuses). 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 Retropharyngeal SpaceSpace

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 :alar fascia :• forms a further subdivision of retropharyngeal space. • is attached along midline of buccopharyngeal fascia from cranium to level of the C7 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

TrapeziusDeep Cervical Fascia

Investing layer of deep cervical fascia

Prevertebral fascia

Pretracheal fascia(visceral part)Caro

tid sheath

Buccopharyngeal fascia

Alar fascia

Pretracheal fascia(muscular part)

TE

Sternocleidomastoid

Trapezius

Posterior cervical trianglePosterior cervical triangle Anterior trianglesAnterior triangles

Sternocleidomastoid

Trapezius Deep Cervical Fascia

Investing layer of deep cervical fascia

Prevertebral fascia

Pretracheal fascia(visceral part)

Carotid sheath

Buccopharyngeal fascia

Alar fascia

Pretracheal fascia(muscular part)

T

E

Prevertebral musclesScalene muscles

Suprahyoidmuscles

Infrrahyoidmuscles

Trace the pathways for venous drainage from the neck into the brachial veins.

Ext. jugularInt. jugular

Ant. jugular

Sup. thyroid

Middle thyroid

Inf. thyroid

Platysma

Cutaneous nerves and superficial veins

External jugular vein

Anterior jugular vein

Lesser occipital n.

Greet auricular n.Transverse nerve of neck

Supraclavicular n.

Submendibular gland

OmohyoidSternohyoid

Sternothyroid

Superior thyroid a.

Cervical plexus

Phrenic n.

Ansa cervicalis

Vagus n.

Hypoglossal n.

Accessory n.Digastric