Session 1 - General organisation of Head and Neck

Question 1

What supplies the muscles of mastication?

Answer 1

• Muscles of mastication – supplied by the mandibular division of the trigeminal nerve (branch of CN 5)

Question 2

What does the facial nerve supply? What CN is the facial nerve?

Answer 2

Facial nerve (CN 7) supplies the superficial muscles of the neck and chin, muscles of facial expression, buccinators, muscles of the ear, and the occipitofrontalis muscle.

Question 3

Answer 3

Question 4

What is the most common non trauma cause of facial paralysis? Where does it occur? What happens?

Answer 4

• Most common non trauma cause is inflammation of the facial nerve near its exit from the cranium at the stylomastoid foramen:
  
  • Inflammation causes edema which compresses the nerve at the intracranial facial canal.
  • Results in affected area sagging

Question 5

What structure does the facial nerve pass through? Why is this clinically relevant? Where can disease of this structure refer to?

Answer 5

• Nerve passes through the parotid gland and therefore vulnerable to injury during surgery on the gland or disease of the gland:
  
  • Parotid gland disease can cause pain in the temporal region and auricle of the ear.

Question 6

Answer 6

Question 7

Where can the facial artery be palpated?

Answer 7

Inferior border of the mandible

Question 8

Answer 8

Question 9

What does the facial vein drain into?

Answer 9

Internal jugular

Question 10

What structures drain into the external jugular vein?

Answer 10

Superficial temporal, maxillary

Question 11

Where do the jugular veins drain into?

Answer 11

Subclavian vein

Question 12

What determines where an infection in the neck can spread?

Answer 12

Fascial planes

Question 13

What are the green, orange, purple and red fascia in the pic?

Answer 13

Green - investing layer

Purple - Pretracheal layer

Orange - Prevertebral layer

Red - Carotid sheath

Question 14

What is the superficial cervical fascia?

Answer 14

Layer of fatty connective tissue that lies between the dermis of the skin and the layer of deep cervical fascia.

Question 15

What is the platysma? Where is it found and what supplies it? What is its function?

Answer 15

• Broad thin sheet of muscle in the superficial cervical fascia.
• Supplied by the facial nerve
• Depresses the mandible and draws the corners of the mouth inferiorly.

Question 16

What is the 3 functions of the deep cervical fascia?

Answer 16

• Supports the viscera, muscles, vessels, and lymph nodes
• Limit the spread of abscesses due to infection
• Reduce friction with regards to swallowing and turning the head and neck.

Question 17

What does the muscular layer of the pretracheal layer enclose?

Answer 17

Infrahyoid muscle

Question 18

What does the visceral layer of the pretracheal layer enclose?

Answer 18

Thyroid gland, trachea, oesophagus

Question 19

Up to Where does the pretracheal layer extend inferiorly?

Answer 19

to the thorax where it blends with the fibrous pericardium

Question 20

From where to where does the prevertebral layer extend to superiorly? Where does it extend to laterally

Answer 20

Extends from base of the cranium to the 3rd thoracic vertebra

Extends laterally as the axillary sheath that surrounds the axillary vessels and the brachial plexus.

Question 21

What CN is the vagus nerve?

Answer 21

10

Question 22

Where can an infection spread:

a) between investing and muscular pretracheal
b) between investing and visceral pretracheal
c) between prevertebral and investing

Answer 22

a) cant spread beyond manubrium (superior part of sternum)
b) can spread into thoracic cavity anterior to pericardium
c) can spread laterally in the neck, may perforate fascial layer and enter retropharyngeal space resulting in a bulge in the pharynx and difficulty swallowing and speaking (dysphasia and dysphonia).

Question 23

What is the retropharyngeal space? Where does it run to?

Answer 23

• Potential space between prevertebral fascia and carotid sheath fascia.
• Major route of spread of infection from the neck to the thorax. Runs to the diaphragm.

Question 24

What is the borders of the anterior triangle of the neck?

Answer 24

Superiorly – Inferior border of the mandible (jawbone)
Laterally – Medial border of the sternocleidomastoid
Medially – Imaginary sagittal line down midline of body

Question 25

What 4 triangles can the anterior triangle be subdivided into? Where are they located?

Answer 25

4 - submandibular triangle

5 - submental triangle

6 - Carotid triangle

7 - Muscular triangle

Question 26

Answer 26

Question 27

What are the borders of the posterior triangle of the neck?

Answer 27

Anterior: Posterior border of the SCM.
Posterior: Anterior border of the trapezius muscle.
Inferior: Middle 1/3 of the clavicle.

Question 28

What are the 2 subdivisions of the posterior triangle? Which ones are they on the diagram?

Answer 28

Occipital triangle - 2

Omoclavicular triangle - 3

Question 29

What is contained in the occipital triangle?

Answer 29

• Spinal Accessory Nerve (CN XI)
• Trunks of Brachial Plexus
• Part of external jugular vein
• Posterior branches of cervical plexus
• Cervicodorsal trunk
• Cervical lymph node

Question 30

What is contained in the omoclavicular triangle?

Answer 30

• 3rd part Subclavian Artery
• Part of Subclavian Vein
• Suprascapular artery
• Supraclavicular lymph nodes

Question 31

What is the function of the hyoid muscles? What do they attach to?

Answer 31

Steady or move the hyoid and larynx. Attach to hyoid bones

Question 32

Answer 32

Question 33

Name the suprahyoid muscles

Answer 33

• Mylohyoid
• Geniohyoid
• Stylohyoid
• Digastric muscles (2 bellies - anterior and posterior)

Question 34

name the superficial infrahyoid muscles

Answer 34

• Sternohyoid
• Omohyoid (2 bellies, superior and inferior)

SO superficial

Question 35

Name the deep infrahyoid muscles

Answer 35

• Sternothyroid
• Thyrohyoid

Question 36

What muscle might be damaged in a forceps delivery in the neonate? How would they present?

Answer 36

SCM

tilt of the head towards normal side, called toticollis

Question 37

What is the neurocranium and the viscerocranium?

Answer 37

neurocranium - skull base and calvarium

Viscerocranium - Facial bones

Question 38

What artery supplies the neurocranium and the viscerocranium?

Answer 38

neurocranium - ICA

viscercranium - ECA