fascia of the neck.docx

7/29/2019 Fascia of The Neck.docx

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Note: all the slides related to this lecture are included in this script but you

can go back to it to see the pictures.

By the end of the last lecture we have finished speaking about the hard

tissue of the head (skull) then the cervical vertebrae, today we will start

speaking about the soft tissue of the neck at first then the soft tissue of the

head.

Firstly we should learn basic principles in human anatomy:

There are three coverings in the human body:

Skin from outside and two types of fascia covering the muscles and bones

*fascia is a connective tissue and its 2 types:

> the one which is the most outside closer to the skin is the superficial fascia

and its consist of adipose tissue just a fat (subcutaneous fat) and we know

that adipose tissue is part of the connective tissue

Cutaneous is adjective of the skin, sub means below (subcutaneous

fat=superficial fascia)

>After the fat we have tough connective tissue dance fascia very tough

membranous layer covering the muscles, the deep fascia of the human body

(the muscle fascia because its covering the muscle)

So the three basic covering in the human body

1-The skin

2-The superficial fascia (a fat layer)

3-Deep fascia (tough membranous layer)

After that we have the muscles and the bones


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Now in the nick we will speak about the covering (skin and the fascia) the

next lecture will be about the muscles.

Neck: The region of body that extends superiorly: from the inferior border

of the mandible and the nuchal line

Inferiorly: suprasternal notch and the clavicle

Another principle we have to learn is how to divide the neck anatomically

When we speak about the neck we speak about the anterior and lateral

aspect only because in anatomy the neck is divided into 2 parts:

1- The anteriolateral aspect which we have in this course

2- Posterior aspect which considered a part of the back which we will not

have it in details just briefly

in the neck 2 reference muscles we use them to distinguish the borders

between the anteriolateral and posterior aspect:

1- Sternocleidomastoid muscle (SCM): sterno from the sternum, cleido fromthe clavicle, mastoid the way up to the mastoid process of temporal bone

behind the auricle

SCM divide the anterior aspect from the lateral one, anterior to SCM the

anterior aspect looks like an inverted triangle (anterior triangle of the neck,

anterior because its anterior to the reference muscle the SCM) and posterior

to it the lateral aspect looks like triangle in a normal position (the posterior

triangle of the neck, posterior because its behind the reference muscle the

SCM but its actually in the lateral aspect of the neck).


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2- Trapezius muscle ( ): demarcating the end of the lateral aspect of

the neck and start of the posterior part of the neck which is part of the

back>>>to summarize

The neck divided into

1-Anteriolateral aspect.2-Posterior aspect the superior part of the back that covered by the

trapezius muscle.

Now the anteriolateral aspect is dividing by the SCM into anterior triangle

and posterior triangle.

Going back to the covering of the neck just like any part in the human body

(the skin, superficial fascia, and the deep fascia) we can see them in across

section.

1-The skin is consist of layers just like what we learn in histology2- The superficial fascia (the fat layer) we can see in it:

a)4 cutaneous nerves: nerves going to the skin so its a sensory onenot motor (note the motor go to the muscle so its called muscular

nerve) and we should know their names, origin and the area they

provide sensory innervations to.

Cutaneous nerves at the posterior aspect coming from the posterior

rami of C2-C5 (C2 is the greater occipital nerve), while the cutaneous

nerve at the anterior aspect coming from the anterior rami of C2-C4 (C1

has no cutaneous branches, muscular only), we have 4 cutaneous

nerves at each aspect


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names originthe area they provide sensory

innervations to

1-lesser occipital nerve

anterior ramus of C2

second cervical spinal nerve

-skin in the area behind the auricle

-skin in the area over the mastoid

process

-even provide supply to the mediasurface of the auricle

2- Great auricular nerve

anterior rami of C2 and C3 -the skin over the parotid gland

-the lower part of auricle (lobule o

auricle the fat part)

-the skin over the angle of the

mandible

3- transverse cervical

nerve

From C2 and C3 -it goes in transverse direction

anteriorly to provide innervations

the skin over the anterior triangle

of the neck from the mandible to

the sternum

4- supraclavicular nerve

from C3 and C4 this nerve has three branches to

cover a very wide area at the root

the neck (the branches are median

intermediate and lateral) so its

innervate: -the skin of the lower

lateral aspect of the neck which is

the lower posterior triangle

-the skin over the clavicle and

sometimes goes to the level of the

first rib in the thoracic region

-the skin over the upper half of theshoulder


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>>all the sensory innervations of the face coming from the fifth cranial

nerve (Trigeminal nerve by its branches: ophthalmic, maxillary and

mandibular nerve) except the area over the angle of the mandible the

sensation come from the great auricular nerve so at the maxillofacial

surgeon or a plastic surgeon they have to anaesthetize the trigeminal nerve

but also they shouldnt forget to anaesthetize the great auricle nerve (below

the angle of the mandible)

>> Motor innervations to the muscles of facial expressions by the seventh

cranial nerve (facial nerve).

Some notes related the previous cutaneous nerves:

-Great auricular nerve named great not greater because there is no lesser its just one

auricle

-parotid gland (the largest salivary gland located between the mandible and the

mastoid process)

-since the Great auricular nerve provides sensory innervations to the skin over the

angle of the mandible now this is a facial region not cervical to provide sensation there

thats why its great

- transverse cervical nerve has another name: transverse cutaneous nerve as in our

book but our doctor.Alloh not prefer this name because there is many nerves in our

body going transversely and providing sensation to the skin so to specify this from all

other transverse cutaneous nerves we add cervical but since the name is used in our

book the two names are correct)


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The second thing we can find in the superficial fascia of the neck:

b) Platysma muscle

Specific kind of muscle not covered with a deep fascia its located in the

superficial fascia, platysma muscle considered a muscle of facial expression,

specific group of skeletal muscle "its skeletal because we can control it but

they are attached to bone at one end and to the skin on the other end so

they have to pass throw the superficial fascia.

When they contract they move the skin of the face produce the expressions(like smiling and closing eye).

muscles of facial expressions located in the face and neck once it located inthe neck we call it platysma muscle, when we look to platysma muscle its

just straps - bundles of muscle fibers that goes from the deep fascia that

covering the pectoralis and deltoid muscle (deltopectoral fascia) and going

up to the inferior border of the mandible and medially to angles of the

mouth when this muscle contract it will depress the angle of the mouth.

>>All muscles of facial expression are innervated by the seventh cranial

nerve (facial nerve) is providing motor innervations to all muscles of facial

expressions.

(Skeletal muscle called skeletal because its attached to bone when they

contract they move they produce emotion like the biceps thats why platysma is

specific one because its doesnt produce movement)


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The third thing we can find in the superficial fascia of the neck:

c) superficial veins : we refere to it as an external jugular vein (jugularmean related to the neck) now going back to our reference muscle the SCM,

any vein superficial to it is an external (superficial) jugular vein, and any vein

deep to the SCM is an internal (deep) jugular vein.

external jugular vein start from the angle of the mandible all the way down

to the middle third of the clavicle, its located in the superficial fascia, its

formed by tow veins one of them come from behind the auricle (posterior

auricular vein) and the other behind the mandible(retromandibular vein)

the retromandibular vein when it reach the angle of the mandible it divide

into anterior and posterior divisions the anterior branches goes anteriorly

towards the facial vein and the posterior division will join the posterior

auricular vein to form the external jugular vein

>> so the external jugular vein formed by the posterior jugular vein and the

posterior division of the retromandibular vein, then its descend external to

the SCM all the way across the neck to the middle third of the clavicle there it

perforates the deep fascia to go and drain into a deep vein (either the

internal jugular or in the subclavian vein, the one is closer to its root)

Venous system differ from the arterial system: veins are two types superficial veins in

the superficial fascia (we can see them specifically in the limbs, face and in the neck

region) and deep veins covered by the deep fascia but the arteries always deep

covered by the deep fascia there is no superficial artery because the blood pressure is

high and we need to protect them more because the injury in the artery is very serious


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3-deep fascia is dividing into 4 different types according to which parts they

are covering (specification in the neck):

a)Investing Layer of the Deep Cervical Fascia: the largest one because itinvest the all neck from anterior to posterior, it covers two muscles(the

two reference muscles: SCM and trapezius), two salivary glands(the

parotid and the submandibular gland) and the jugular venous arch, its

attach to the: inferior border of the mandible, hyoid bone, zygomatic

arch, base of the skull, mastoid and styloid process, nuchal ligament,

manubrium, clavicle, acromion and spine. The third salivary gland is the sublingual gland located in the oral

cavity, the investing layer (deep cervical fascia covering anything in the

neck) doesnt cover it because it doesnt reach it.

Mylohyoid muscle: flat muscle going from one side of the mandible tothe hyoid bone then to the author side of the mandible, separating the

neck from the mouth (we refere to it as the floor of the mouth

because anything above it is in the oral cavity and anything below it is

in the neck), mylo means molar because its coming from the molar

teeth to the hyoid bone.

There is a thickening in the investing layer we refere to it as a ligamentbetween the area of the styloid process and the mandible called the

stylomandibular ligament and its important in supporting the TMJ

(this ligament is one of the accessory secondary supporting ligament)

its determine and limit the anterior movement of the mandible (the

anterior movement of the mandible called protrusion while the

posterior movement called retrusion)


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b) Pretracheal Layer: two parts:1-muscular part covering muscles (infrahyoid muscles below the hyoid

bone)

2- Visceral part (from viscous: Latin word means internal organ)Covering organs (thyroid, parathyroid glands, larynx, pharynx, and

down: trachea and oesophagus)

Attachments:

Superiorly: thyroid and cricoid cartilages

Laterally: carotid sheath

Inferiorly: extends into thorax and blend with the fibrous pericardium

c)Prevertebral Layer: the second largest layer, extend from the base ofthe skull to T3,Covering the vertebral muscles ( we know that the

Vertebral Column has muscles to move it' anterior, lateral and posterior

groups the same as the neck: it has anterior cervical vertebral muscles,

lateral and posterior muscles all of them are covered together by the

prevertebral layer), also covered spinal and phrenic nerves

Attachments:

Anteriorly: anterior longitudinal ligament

Posteriorly: nuchal ligament

There are very important organs in the neck the larynx and behind it the pharynx, at

the level of C6 (the root of the neck) the larynx anteriorly becomes the trachea, and the

pharynx behind it becomes the oesophagus. then these structures descend down to

the thorax and the Pretracheal layer follow it till this layer merges or blends in the

fibrous pericardium (the fibrous covering of the heart), this is considered a very

dangerous thing because any infection within the Pretracheal layer can lead to a

distribution down to the thorax affecting the thoracic cavity and the heart.


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d)Carotid Sheath: the smallest but the most dangerous and mostimportant layer (carotid refere to the carotid artery and sheath means

covering), extend from skull base to the root of the neck

Attachments:investing & pretracheal fasciae (ant.)Prevertebral fascia (post.)

Covered:Common carotid artery, external jugular vein, vagus nerve,deep cervical lymph nodes.

Cervical lymph node

lymph nodes which are superficial to our reference muscle the SCM called

superficial cervical lymph nodes if it deep of the SCM called deep cervical

lymph nodes, if it in the upper half of the neck called superior and if in the

lower half called inferior, so we have 4 region for the lymph nodes regarding

the SCM and the middle of the neck:

Superior superficial , inferior superficial, superior deep, inferior deep lymph

nodes.

>>In anatomy you should always remember that lymph nodes are always

joining or around the venous system (exe. deep cervical lymph nodes are

around the internal jugular vein and the superficial lymph nodes are around

the external jugular vein.

The last two slides the doctor didnt mentioned them but I put it if you like to

read:


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Retropharyngeal Space

The interval between the pharynx fascia (buccopharyngeal fascia) &

prevertebral fascia

The largest space in the neck

Allows movement of pharynx & esophagus during swallowing*Clinically:Provides major pathway for spread of infection into thoraxRet. Abscess

dysphagia, dysphonia, dyspnea

Muscles of Cervical Region

3 groups

1. Superficial muscles:platysma, SCM, Trapezius

2. Hyoid related muscles: supra & infra hyoid3. Cervical vertebral muscles: ant., lat. & post.


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I apologize if there are any mistakes

your colleague: Lina Hasan

fascia of the neck.docx

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