Fascial Layers/ Muscles of the Neck

Question 1

Give overview of fascial layers

Answer 1

superficial fascia - platysma (+ superficial veins/ lymph nodes/ fat)
deep fascia:
- superficial (investing layer) = SCM + trapezius
- middle = pretracheal fascia + carotid sheath
- deep = prevertebral fascia

Question 2

What is the function of the platysma muscle?

Answer 2

• muscle of fascial expression - depresses mandible
• shaving muscle - tenses skin of neck when contracted
• forms wrinkles in neck with age

Question 3

What is the innervation of the platysma muscle?

Answer 3

cervical branch of facial nerve

Question 4

What superficial vein is found in superficial fascia?

Answer 4

external jugular vein

Question 5

Give the attachments of the superficial layer of deep fascia

Answer 5

superior: superior nuchal line/ occipital protuberance
inferior: spine/ acromion/ clavicle/ manubrium
anterior: hyoid bone
posterior: nuchal ligament of posterior column

Question 6

What is the function of the SCM?

Answer 6

• unilateral contraction: ipsilateral flexion of neck & contralateral rotation
• bilateral contraction: head & neck extension, accessory inspiratory muscle

Question 7

What is the innervation of the SCM?

Answer 7

• accessory nerve

- branches of the cervical plexus C2-C3

Question 8

What can be felt in the middle 1/3 of the front edge of SCM?

Answer 8

lies over the carotid sheath = carotid pulse

Question 9

What landmark is used for insertion of central line?

Answer 9

medial edge of SCM

Question 10

Where is Erb’s point and what is its significance?

Answer 10

dorsal to SCM -branches of plexus merge for puncture of LA

Question 11

What vein passes over lateral border of SCM to pass behind the clavicle and join the subclavian vein?

Answer 11

external jugular vein

Question 12

What is the innervation of the trapezius?

Answer 12

spinal accessory nerve

Question 13

Where does the pretracheal layer span between?

Answer 13

hyoid bone & thorax where it fuses with the pericardium

Question 14

What does pretracheal fascia enclose?

Answer 14

muscle: infrahyoid muscles
viscera: thyroid gland, trachea & oesophagus

Question 15

What are the contents of the carotid sheath?

Answer 15

• common and internal carotid artery
• internal jugular vein
• vagus nerve
• deep cervical lymph nodes

Question 16

What does the prevertebral layer surround?

Answer 16

vertebral column and muscles associated with it + muscles of the back

Question 17

Name the 4 suprahyoid muscles

Answer 17

• stylohyoid
• mylohyoid
• geniohyoid
• digastric

Question 18

What action do the suprahyoid muscles produce?

Answer 18

elevate hyoid bone to initate swallowing?

Question 19

What is the arterial supply of the suprahyoid muscles?

Answer 19

branches of the facial artery, occipital artery & lingual artery

Question 20

Give another action of geniohyoid and its innervation

Answer 20

• depresses mandible

- C1 root within hypoglossal nerve

Question 21

Give another action of mylohyoid and its innervation

Answer 21

• floor of oral cavity/ supports floor of mouth

- inferior alveolar nerve (branch of V2)

Question 22

Give another action of digastric and its innervation

Answer 22

• depresses mandible
• anterior belly: inferior alveolar nerve
• posterior belly: digastric branch of facial nerve

Question 23

Give another action of stylohyoid and its innervation

Answer 23

• pulls hyoid bone posterior & superior direction

- stylohyoid branch of facial nerve (proximal to parotid gland)

Question 24

Which suprahyoid muscle is a thin (short diameter) muscle?

Answer 24

stylohyoid

Question 25

Which suprahyoid muscle is close to the midline of the neck?

Answer 25

geniohyoid

Question 26

Which suprahyoid muscle is split into two bellies connected by a tendon, attached to hyoid bone via fibrous sling?

Answer 26

digastric

Question 27

Which suprahyoid muscle is a large triangular shaped muscle?

Answer 27

mylohyoid

Question 28

Name 4 infrahyoid muscles

Answer 28

- omohyoid - sternohyoid - thryohyoid - sternothyroid

Question 29

What is the vasculature of the infrahyoid muscles?

Answer 29

superior/ inferior thyroid arteries with corresponding venous drainage

Question 30

Which infrahyoid muscles are in the superficial and deep plane?

Answer 30

- superficial: omohyoid/ sternohyoid | - deep: thyrohyoid/ sternothyroid

Question 31

Give the action and innervation of muscles in the superficial plane of infrahyoid muscles

Answer 31

- depresses hyoid | - anterior rami of C1-3

Question 32

Give the action and innervation of the sternothyroid

Answer 32

- depresses thyroid cartilage | - anterior rami of C1-3

Question 33

Give the action and innervation of the thyrohyoid

Answer 33

- depresses hyoid/ elevates larynx (if hyoid is fixed) | - anterior rami of C1 within hypoglossal

Question 34

Which short infrahyoid muscle is found lateral to sternum?

Answer 34

thyrohyoid

Question 35

What actions do the scalene muscles produce?

Answer 35

- accessory muscles of respiration | - flexion at the neck

Question 36

Give innervations of the scalenes

Answer 36

- anterior: C5-6 - middle: C3-8 - posterior: C6-8

Question 37

What structures pass between the anterior and middle scalenes? - why is this significant?

Answer 37

brachial plexus and subclavian artery - useful for interscalene block in anaesthetics

Question 38

What structure runs down the anterior scalene?

Answer 38

phrenic nerve

Question 39

What structure crosses the anterior scalene?

Answer 39

subclavian vein

Question 40

Where are the prevertebral muscles and what actions do they produce/

Answer 40

- deep cervical muscles laterally enveloped into the prevertebral layer - ventral flexion/ lateral flexion of the cervical column

Question 41

Name the prevertebral muscles

Answer 41

- longus capitis - longus calli - rectus capitis (anterior/ lateralis) - secondary back muscles

Question 42

Where are the suboccipital muscles located? | - give their innervation and action

Answer 42

- beneath occipital bone - deep to the sternocleidomastoid, trapezius, splenius and semispinalis muscles. - suboccipital nerve - extend/ rotate head

Question 43

name the suboccipital muscles

Answer 43

- rectus capitis posterior (major/minor) | - oblique capitis (superior/ inferior)