deep fascia of the neck (A12)

Question 1

two layers of skin

Answer 1

• epidermis (epithelium = keratinized stratified squamous)
• > inert/waterproof/non-vascular
• dermis (dense connective tissue)
• > vascular/lymphatics/innervated by nerves/strengthens and nourishes the epithelium

Question 2

two layers of fascia

Answer 2

• superficial fascia (subcutaneous tissue, distributes vessels and nerves/allows skin mobility/thermal and mechanical insulation)
• deep fascia (separates superficial from deep structures, is strong, very robust and protective)

Question 3

type of epithelium covering the skin

Answer 3

keratinized stratified squamous epithelium

Question 4

superficial cervical (neck) fascia

Answer 4

• immediately under skin, between skin and deep fascia/investing layer of cervical/deep fascia
• structures in the neck are surrounded by a layer of subcutaneous adipose tissue
• sub=deep
• cutaneous=skin
• adipose connective tissue
• usually a thin layer in the neck

Question 5

deep cervical (neck) fascia

Answer 5

• structures in the neck are compartmentalized (kept separate from each other) by deeper layers (tubes) of bandaging: the deep fascia
• these ‘tubes’ of deep fascia run between and connect, the superior mediastinum to the base of the skull
• the deep fascia helps to prevent the spread of infection (if develops in the neck) from one compartment to another due to thickness
• infection tends to spread within fascial compartments by opening up ‘potential spaces’ (fascial planes) between the layers of fascia
• fibrous connective tissue
• deep cervical/neck fascia is divided into 3 distinct layers

Question 6

mediastinum

Answer 6

a membranous partition between two body cavities or two parts of an organ, especially that between the lungs

Question 7

contents of superficial neck fascia

Answer 7

• sensory nerves (of the cervical plexus)
• platysma muscles (one of the most inferior muscles of facial expression) -> right and left platysma muscles
• blood vessels (superficial veins)
• lymphatic vessels and superficial lymph nodes

Question 8

sensory receptors in skin

Answer 8

• respond to touch, temperature, pain etc by triggering ‘sensory’ action potentials
• anterior ramus (sensory action potentials into spinal nerve) -> spinal nerve (mixed) -> posterior root (sensory), anterior root = motor

Question 9

the cervical plexus

Answer 9

• plexus = single nerves intertwining
• the anterior rami of cervical spinal nerves C2,C3 and C4 mix their nerve fibres
• sensory to skin and fascia of neck, shoulder and face (over the angle of the mandible)
• sensory nerves leave the skin and superficial fascia and pierce the deep fascia to reach the posterior aspect of the spinal cord

Question 10

brachial plexus

Answer 10

• C5,6,7,8 and T1 anterior rami
• nerve supply to upper arm
• 5 named nerves merge together to form single trunks
• > 5 ‘new named’ nerves re the result from the mixing nerve fibres from different anterior rami in the plexus
• > radial nerve
• > ulnar nerve
• > median nerve (C5,6,7,8 and T1)
• > musculocutaneous nerve
• > axillary nerve

Question 11

5 ‘new named’ nerves that arise from the combining of several anterior rami in the plexus

Answer 11

• > radial nerve
• > ulnar nerve
• > median nerve (C5,6,7,8 and T1)
• > musculocutaneous nerve
• > axillary nerve

Question 12

dermatome

Answer 12

= area of skin innervated/supplied by single spinal nerves

Question 13

sensory nerve supply to remainder of face that is not supplied by cervical plexus

Answer 13

trigeminal nerve (CN V)

Question 14

sensory nerves that make up cervical plexus

Answer 14

• great auricular nerve (C2,C3) (winding to ear, contributes to supply of mandible)
• transverse cervical nerve (C2,C3) (passes transversely across neck region across belly of SCM)
• lesser occipital nerve (C2) (passing to posterior superior aspect of neck)
• supraclavicular nerves (C3,C4) (has 3 branches/end terminals - medial, intermediate and lateral)
• > sensory nerves of the cervical plexus begin superficial to investing layer and SCM

Question 15

‘nerve point’ of the neck

Answer 15

• where the cervical plexus nerves go deep, posterior to middle of SCM’s posterior border
• where nerves pierce through deep fascia
• about half way down SCM muscle belly on posterior border

Question 16

platysma muscles

Answer 16

• located within superficial cervical fascia
• platysma belongs to the ‘muscles of facial expression’ group
• this group of muscles is supplied by CN VII/facial nerve
• platysma is supplied by the cervical/5th branch of CN VII (there are 5 branches that supply the muscles of facial expression)
• not a very useful muscle
• contributes to sad face, straightens out and holds neck in place in young individuals (degenerates with age causing saggy skin)

Question 17

superficial veins of the neck

Answer 17

-lie within the superficial fascia of the neck
-all part of the jugular venous system
-superficial jugular veins:
->right and left external jugular veins
->right and left anterior jugular veins
->right and left superficial jugular communicating veins
(these veins are similar between individuals however veins within the neck are very variable)

Question 18

jugular venous system

Answer 18

• consists of various ‘superficial’ jugular veins that drain into ‘deep’ internal jugular veins
• superficial:
• retromandibular vein = formed by the union of the superficial temporal and maxillary veins (between ramus of mandible and SCM, retromandibular vein branches into anterior and posterior)
• > posterior branch of retromandibular joins with posterior auricular to form the external jugular vein
• > anterior branch of retromandibular vein joins with facial vein to form common facial vein (which pierces through deep fascia to join internal jugular vein which is deep) but also joins with anterior jugular via the superficial jugular communicating vein
• > anterior jugular joins with external jugular to drain into subclavian vein (deep)
• deep:
• > internal jugular vein
• > subclavian vein

Question 19

3 distinct layers of deep cervical/neck fascia (from superficial to deep)

Answer 19

• investing layer
• pretracheal layer
• prevertebral layer (in 3 parts including carotid sheaths)

Question 20

spread of infection and deep cervical fascia

Answer 20

• it is v. easy for infection to spread up and down the inside of one of tubes/layers or up and down between the tubes/layers
• however the deep fascia is tough, making it difficult for infection to spread from one tube to another

Question 21

investing layer of deep cervical fascia (including contents)

Answer 21

• surrounds the entire neck immediately deep to the superficial fascia
• within the neck it splits to contain:
• > trapezius muscles
• > sternocleidomastoid muscles
• splits superiorly to enclose/form protective ‘capsules’ for the submandibular and parotid (sits just in front of ears) salivary glands

Question 22

contents of prevertebral layer of deep cervical fascia

Answer 22

• surrounds/encloses postural muscles of back and cervical vertebrae
• carotid sheaths (2 separate tubes of fascia) are located lateral to pretracheal layer of deep cervical fascia and anterior to the large prevertebral fascia tube

Question 23

contents of pretracheal layer of deep cervical fascia

Answer 23

surrounds:

• > trachea
• > oesophagus
• > thyroid gland
• > 4 muscles anterior to thyroid gland (strap muscles)

Question 24

attachment sites of investing layer of deep cervical fascia

Answer 24

-ultimately attaches to:
->hyoid bone
->lower border of mandible
->zygomatic arches
->styloid processes
->mastoid processes
->superior nuchal line
->spinous process of cervical vertebrae
(attaches superiorly to each of the osteological land marks)

Question 25

(spinal) accessory cranial nerve/ CN IX

Answer 25

• deep to investing layer of deep cervical fascia
• also deep to both of the muscles it supplies that are contained within the investing layer of deep cervical fascia:
• > trapezius muscles
• > SCM muscles

Question 26

2 components of the pretracheal layer of deep cervical fascia

Answer 26

1. visceral/organ part (encloses the thyroid gland, trachea and oesophagus)
2. muscular part (encloses the ‘strap’ muscles, which attach from the hyoid bone onto the laryngeal cartilages for movement of the larynx)

Question 27

carotid sheaths

Answer 27

• right and left ‘tubular fascial bandages’ that run the full length of the neck
• connect the superior mediastinum to the jugular foraminae and carotid canals in the base of the skull
• lie between the investing, pretracheal and prevertebral layers of deep fascia
• contains major vessels and nerves

Question 28

contents of carotid sheaths

Answer 28

• the internal jugular veins
• the carotid arteries
• the vagus nerves (CN X)
• the deep cervical chain of lymph nodes and lymphatics

Question 29

what is the space between the pretracheal and prevertebral fascia called

Answer 29

• the retropharyngeal space
• infection within this space will travel right through neck (this can occur if punctured eg.due to running with pen in mouth etc)

Question 30

what is the pretracheal fascia called after passing superior to trachea

Answer 30

• buccopharyngeal fascia (continuous with pretracheal fascia inferiorly)
• sits posterior to pharynx and oral cavity