26 - Anatomy of the Scalp, Face and Parotid

Question 1

Extent of the scalp

Answer 1

External occipital protuberance posterioraly, extends to the supra-orbital margins.

Laterally to the zygomatic arches.

Question 2

Layers of the scalp

Answer 2

Skin
Connective tissue (dense)
Aponeurosis (of occipitofrontalis) 
Loose areolar tissue
Pericranium (periosteum of skull)

Question 3

Shape of occipitofrontalis

Answer 3

Two muscle bellies, separated by an aponeurosis.

Frontalis over the face, occipitalis over the occipital part of the skull

Question 4

Significance of the structure of the loose areolar tissue of the scalp

Answer 4

Very good for infection.

Infections of the scalp often localise here, then spread through diploic veins into deeper layers of the skull.

Question 5

Layers of dura

Answer 5

Periosteal layer (lies against skull, an endosteal layer)
Meningeal layer (lies against arachnoid, splits from periosteal layer to form dural septa (falx, etc)

Question 6

Neurovascular plane of the scalp location

Answer 6

Dense connective tissue layer

Question 7

Neurovascular plane of the scalp location

Answer 7

Anastamosis of internal and external carotid arteries.

Question 8

Why do scalp lacerations bleed heavily?
1
2
3
4

Answer 8

1) Rich anastamosis between internal and external carotid arteries.
2) Frontalis belly and occipitalis belly will pull wounds open, because of centrally-placed aponeurosis of occipitofrontalis muscle.
3) Fibrous septa through structure of connective tissue. Arteries are attached to these, holding arteries open
4) Hard to compress arteries, as they aponeurose circumferentially.

Question 9

Layer of scalp through which emissary veins travel

Answer 9

Dense connective tissue

Question 10

Layers of skin of face

Answer 10

Four (same as skull, without loose connective tissue layer).

No aponeurosis like in scalp. Instead has muscles of facial expression

Question 11

Origins and attachments of muscles of facial expression

Answer 11

All originate on bone, attach to skin of face.
All arrange around orifices and either encircle orifices to act as sphincters, or radiate out from orifice to act as a dilator.

Question 12

Muscle encircling mouth (sphincter)

Answer 12

Orbicularis oris

Question 13

Number of pharyngeal arches

Answer 13

Initially six, number five never develops (so five in the end)

Question 14

Facial supply of the trigeminal nerve

Answer 14

Travel in bands, which point upwards to scalp.

Opthalmic division supplies superior scalp, face until tip of nose, just below eyes.

Maxillary division - Temples down to between tip of nose and upper lip.

Mandibular division - Mid-scalp to between lower lip and mandible.

Question 15

Sensory supply of posterior scalp

Answer 15

Dorsal rami of cervical spinal nerves (C2 and C3 - C1 has no cutaneous branches). C2 is above ear. C3 below ear, onto back of neck).

Question 16

Part of skull near which the trigeminal ganglion sits

Answer 16

Petrous part of temporal bone.

Question 17

Face supplied by internal carotid artery

Answer 17

Centre of face above eyes (supra-trochlear and supra-orbital branches of ophthalmic artery, which is a branch of the internal carotid)

Question 18

Superficial blood supply of face

Answer 18

Internal and external carotid arteries

Question 19

Most-important branch of the external carotid supplying the face

Answer 19

Facial artery

Question 20

Path of the facial artery

Answer 20

Branches from the external carotid.
Travels over inferior border of the mandible.
Tortuous course over face towards the medial border of the eye.

Question 21

Blood supply of the sides of the scalp

Answer 21

Superficial temporal artery

Question 22

Blood supply of the posterior scalp

Answer 22

Posterior auricular artery (behind ear)
Occipital artery (occipital region)

Question 23

Four branches of the external carotid supplying face and scalp

Answer 23

1) Facial artery
2) Superficial temporal artery
3) Posterior auricular artery
4) Occipital artery

Question 24

Major venous drainage from the face

Answer 24

Facial vein

Question 25

Path of the facial vein

Answer 25

Runs posterior, superficial to artery.

Has a straighter course than the facial artery

Question 26

Venous drainages of the face
1
2

Answer 26

1) Facial vein (major path of drainage).
2) Drainage into skull through emissary veins into the cavernous sinus (goes via superior, inferior opthalmic veins, deep facial veins).

Question 27

Lymphatic drainage of head

Answer 27

Drain into a ring of lymph nodes around the base of skull (submental nodes, submandibular nodes, pre-auricular and parotid nodes, upper and deep cervical nodes, mastoid nodes, occipital nodes)

Question 28

Location of the parotid gland
1
2
3
4
5

Answer 28

Below zygomatic arch.
Above angle of the mandible.
In front of the ear.
Behind masseter.  
Superficial to styloid process

Question 29

Parotid duct

Answer 29

Emerges from front of gland, travels along masseter, pierces buccinator to enter oral cavity.

Question 30

Where does the parotid duct enter the oral cavity?

Answer 30

Opposite the second, upper molar

Question 31

Structures, superficial to deep, contained within parotid gland
1
2
3

Answer 31

1) Facial nerve
2) Retromandibular vein
3) External carotid artery

Question 32

External course of CNVII
1
2
3

Answer 32

1) Exits skull through stylomastoid foramen (between styloid process and mastoid process)
2) Pierces parotid gland.
3) Within parotid gland, splits into six branches: Posterior auricular nerve, temporal, zygomatic, buccal, mandibular and cervical

Question 33

Facial path of CNVII
1
2
3
4
5

Answer 33

1) Sends branch to occipitofrontalis
2) Facial nerve (exits skull just behind parotid gland)
3) Penetrates parotid gland, forms a plexus (called pes anserinus)
4) Splits into five terminal branches, which emerge from anterior border of parotid gland
5) Temporal, zygomatic, buccal, mandibular, cervical

Question 34

Retromandibular vein

Answer 34

Formed by union of superficial temporal and maxillary veins

Question 35

Path of external carotid within parotid gland

Answer 35

Penetrates parotid, divides into two terminal branches (superficial temporal and maxillary)

Question 36

Maxillary artery

Answer 36

Deeper branch of the external carotid.

Gives rise to middle meningeal artery

Question 37

Appearance of people with damaged facial nerve

Answer 37

Drooping lower eyelid, drooping mouth, flattening of naso-labial fold.

Question 38

Most common cause of Bell’s palsy

Answer 38

Idiopathic. No known aetiology.