posterior triangle pdf - د. نوفل الحديثي



Fascia of the Neck



The Posterior Cervical Triangle

 To define neck fascia

 To demonstrate the borders, roof & floor of the

posterior triangle

 To list the main contents of the triangle (vessels,

nerves, nodes,

…)

 To relate to some clinical conditions

Boundaries of cervical triangles:

1- Anterior:

Midline

Mandible (lower border)

Anterior border of SCM

2- Posterior:

Clavicle (middle third)

Anterior border of trapezius

Posterior border of SCM

Sternocliedomastoid:



Arises from the manubrium sterni & medial third of clavicle



Inserted in the mastoid process & lateral third of superior nuchal line



Supplied by the spinal accessory nerve



Action:

Unilateral:

-Approaching the mastoid process to the shoulder (ipsilateral lateral flexor)

-Turns the face to the opposite side (contralateral rotator)

Bilateral:

-Extends the skull

-Flexes the neck

-Accessory muscle of respiration

TORTICOLLIS

SCM contracture

Trapezius:



Arises from the skull, ligamentum nuchae & thoracic spines



Descending fibers are inserted into the lateral 1/3 of clavicle (bound

the triangle)



Supplied by the spinal accessory nerve



Trapezius shrugs the shoulder

Whenever you decide to do an operation, you have to know the

followings

before you start

1- How not to leave a scar

…

Langer lines

2- How to give local ansthesia

…

Cutaneous nerves

3- Expected structures in each layer

…

Successive layers of the neck

4- What the mass could be

…

Contents of the area

Layers of the neck:

1- skin

2- Superficial fascia

3- Investing part of the deep fascia

4- Neck spaces

The general pattern of the neck

Skin incisions in the Head & Neck

…

Surgical incisions should follow a map of skin lines called tension lines

Tension lines of the skin (Langer or cleavage lines):

-Follow collagen arrangement

-Incisions along them end with minimum scars

-In the neck, they are transverse

-Senile wrinkles follow these lines

Structures within the superficial fascia:

1- Platysma (modified part of the panniculus adiposus):

Origin;

Upper part of pectoral fascia

Insertion;

Lower border of the mandible & skin of the corners of the mouth

Nerve supply;

Cervical branch of VII

Action;

Depresses the corner of the mouth & lower border of the mandible

2- Veins:

External jugular vein:

•Formed just below the auricle

•Extends between the angle of mandible
& the middle of the clavicle

•Drains into the subclavian vein

•Contains 2 weak valves

•Distended in heart failure & increased
intrathoracic pressure

Anterior jugular vein:

•Formed below the chin

•Run each side of the midline

•Connected to each other by the jugular
venous arch in the suprasternal space

•Empty in the EJV

3- Nerves (cutaneous branches of cervical plexus):

Lesser occipital (C2):

-Along the posterior border of SCM

-Supplies skin & subcutaneous tissue at the insertion of the muscle

Great auricular (C2,3):

-Ascends in the direction of the auricle

-Supplies the auricle (except the upper

½ of lateral surface) & skin over the

angle of mandible

Anterior cervical cutaneous (C2,3):

-Crosses SCM horizontally forward

-Supplies skin & subcutaneous tissues of the cylinder of the neck

Supraclavicular (C4):

- Medial; skin over manubrium sterni

- Intermediate; skin over the pectoral region down to the sternal angle

- Lateral; skin over deltoid as far as the distal 1/2 of muscle

Deep fascia of the neck:

1- Investing

2- Prevertebral

3- Pretracheal

4- Carotid sheath

The investing fascia:



Double layered fascial cylinder

surrounding the neck



Attached

superiorly

the

superior nuchal line

– zygomatic

arch

– mandible



Attached inferiorly to the clavicle

& spine of scapula



Has hyoid bone attachment



Encloses two muscles on each

side (sternomastoid & trapezius)



Encloses 2 glands on each side

(parotid & submandibular)



It roofs all neck triangles

The prevertebral fascia:



Surrounds the vertebral column & surrounding muscles



Extends from skull base down to T4



Forms the floor of posterior cervical triangle



Forms the axillary sheath

The pretracheal fascia:



Surrounds the thyroid gland



Attached to thyroid cartilage of larynx



Makes the thyroid moves up with swallowing

The carotid sheath:



Surrounds the carotid arteries, IJV & vagus nerve



Extends from skull base (margins of carotid canal) down to aortic arch



Fuses laterally with investing fascia



Fuses medially with pretracheal fascia

Tissue spaces of the neck:



Behind the prevertebral fascia (

perivertebral space

Reaches the lowest attachment of the fascia at T4



In front of the prevertebral fascia:

From the base of the skull down to the posterior mediastinum

Divided into

retropharyngeal & posterior cervical spaces



Anterior to the pretracheal fascia (

visceral space

Reaches down through the superior to the anterior mediastinum

The posterior cervical triangle:

Apex lies in the back of the head just below the superior nuchal line

Base lies anteriorly (middle 1/3 of the clavicle)

Anterior border (posterior border of SCM)

Posterior border (anterior border of trapezius)

Roof (investing fascia)

Floor (prevertebral fascia)

Spinal accessory nerve (CN XI):

Extends between SCM & trapezius

supplying them

Nearer to the roof (easily injured)

Its injury due to penetrating

trauma

surgery

results in

torticollis (wry neck)

Distribution

Position

Nucleus

Modality

Nerve

Accessory (XI)

Join X nerve & distributed to

pharyngeal & laryngeal

muscles

Medulla

N ambiguus

SVE

Cranial

Motor to trapezius & SCM

Spinal

cord

Anterior

horn cells

C1-4

GSE

Spinal

Wry neck (torticollis)

Un-apposed unilateral spasm of trapezius & sternomastoid

resulting in turning of the face to the .?. side

Motor branches of cervical plexus:

fibers

distributed

hypoglossal nerve as:

1- Meningeal branch

2- Superior ramus of ansa C.

3- Nerve to thyrohyoid

4- Nerve to geniohyoid

2- Inferior root of ansa cervicalis

(C2,3).

3- Phrenic nerve C4).

Lymph nodes:

1- Occipital:

-Along the occipital artery

-In the apex of triangle

2- Supraclavicular:

-Along

transverse

cervical

suprascapular arteries

-In the base of the triangle

-They represent a group of deep

cervical nodes

Supraclavicular lymphadenopathy

Right

Mainly thoracic disease

Left

Mainly abdominal disease

(Virchow’s node)

Troisier sign

Enlargement of Virchow’s node secondary to abdominal malignancy

Muscles in the floor:

Removing the fascial carpet of

the floor of the triangle will

expose the following muscles:



Splenius



Levator scapulae



Scalenus posterior



Scalenus medius



Scalenus anterior

Vital structures are emraced between scalenus anterior & medius:

1- The roots of brachial plexus

2- The subclavian artery

Subclavian artery:



Arises from the brachiocephalic

trunk on the right & from aortic arch

on the left side



Passes behind scalenus anterior

which divides it into three parts



Continues beyond the outer border

of the first rib as the axillary artery

surrounded by fascial sheath

Branches:

First part:

1- Vertebral artery:

- Ascends in F transversaria of C6-C1

Supplies the neck muscles, spinal

cord & hinbrain

2- Internal thoracic artery:

-Descends to the chest wall

-Supplies the anterior chest wall,

pericardium & breast

3- Thyrocervical artery:

Form arched trunk which gives:

-Ascending cervical; ascends on

scalenus anterior

-Suprascapular; to scapular region

-Transverse cervical; divides into

deep cervical & dorsal scapular

-Inferior thyroid; enters the gland

Second part:

Costocervical trunk:

-Gives the deep cervical & superior

intercostal branches