Scalp, Face & Parotid

Question 1

What are the layers of the scalp?

Answer 1

Skin
Dense connective tissue 
Aponeurosis 
Loose connective tissue 
Periosteum

Question 2

What structures does the scalp extend from?

Answer 2

External occipital protruberence posteriorly to the supraorbital margins anteriorly and to the level of the zygomatic arches laterally

Question 3

What plane is the neuromuscular bundle in?

What is clinically significant about this?

Answer 3

Dense connective tissue layer

Emissary veins from this layer communicate with the superior sagittal sinus, thus infection from the scalp can be transmitted to the brain

Question 4

Which layers of the scalp are adherent to each other?

Which layer allows movement of the scalp on the periosteum (skull)?

Answer 4

The skin, dense connective tissue and aponeurosis are firmly attached
The loose connective tissue layer beneath allows these adherent layers to be moved over the skull

Question 5

Why do scalp lesions bleed so profusely?

Answer 5

Scalp is highly vascular (rich anastomoses between the internal & external carotid arteries)

The aponeurosis is of muscles which attach anteriorly & posteriorly, therefore a laceration will lead to gaping due to muscular pull of the aponeurosis

The vascular bundle is within the dense connective tissue layer which is firmly adhered to the skin & aponeurotic layers of the scalp, therefore fibrous septa connect these layers to the vessels, holding them open & preventing them constricting

Question 6

What are the features of the muscles of facial expression?
What is the nervous supply?
What do they develop from?

Answer 6

Muscles which arise from the underlying bone/fascia and attach to the skin of the face
They can act as sphincters (orbicularis…) or dilators (levators/depressors..)

Developed from the 2nd of 6 pharyngeal arches

All are supplied by CN VII (Facial)

Question 7

What are the 5 terminal branches of the cranial nerve supplying the muscles of facial expression?

Answer 7

CN VII - Facial nerve
Temporal 
Zygomatic 
Buccal
Mandibular 
Cervical

Question 8

What is Bell’s Palsy?

Answer 8

Damage to the facial nerve (CN7) resulting in:
Partial or complete paralysis of the muscles of fascial expression ON THE SAME SIDE as the injury

Droopy eye and droopy corner of the mouth
Can have dry eyes/excess tears and dry mouth/impaired taste

Question 9

What are the facial/scalp branches of the INTERNAL carotid artery?

What do they supply?

Answer 9

Supraorbital
Supratrochlear

Supply forehead (anterior aspect of scalp)

Question 10

What are the facial/scalp branches of the EXTERNAL carotid artery?
What is there course?
What do they supply?

Answer 10

Facial artery

• Main supply to face
• Anterior aspect of ECA, travels deep in neck to inferior border of mandible (anterior to masseter), turns onto face & runs upwards & medially towards medial corner of eye (finishes as angular artery)

Superficial temporal artery

• Continues upwards and laterally along face, anterior to the ear, past the ear it branches anteriorly & posteriorly
• Supplies lateral scalp

Posterior auricular artery

• Small artery arising from posterior aspect of the ECA
• Supplies small area of scalp behind ear

Occipital artery

• Posterior aspect of ECA
• Runs backwards & upwards, through deep back musculature and emerges on scalp to supply large posterior region

Question 11

What is the neurovascular supply to face and scalp (anterior to vertex)?
What are the divisions of this nerve?

Answer 11

CN V (Trigeminal nerve)

V1 = opthalmic division - middle face till nose & superior scalp
V2 = maxillary division - between bottom of nose and bottom lip  and small part of lateral face
V3 = mandibular division - between lower lip and chin and majority of lateral head & scalp

Question 12

What is the neurovascular of the posterior scalp (posterior to the vertex)?

Answer 12

Dorsal rami from C2 and C3
C2 = back of head
C3 = back of neck

Question 13

What is the lymph node arrangement for the head?

Where do they drain?

Answer 13

Ring structure of lymph nodes for the head
Sub-mental (anterior, inferior aspect of chin), sub-mandibular (inferior, lateral aspect of chin), mastoid/posterior auricular (behind ears), occipital (back of head)

All drain to the deep cervical nodes

Question 14

What is the relative position of the parotid gland?

Answer 14

Deep to masseter muscle
Below the zygomatic arch, in front of mastoid process, superior to angle of the mandible and superficial to the styloid process

Question 15

Why is an infected parotid gland painful?

Answer 15

The gland is enclosed in a dense, fibrous fascia which has little give
Infection (i.e. Mumps) results in swelling and increased pressure within the gland as the fascia doesn’t allow for expansion

Question 16

What is the course of the parotid duct?

Answer 16

Parotid duct emerges from the anterior border of the gland onto masseter muscle, travels along and at the medial edge of masseter turns deeply

Pierces the buccinator muscles to open into the oral cavity at the 2nd upper molar

Question 17

From superficial to deep, what are the structures within the substance of the parotid gland?

Answer 17

NVAL

Facial nerve
Retromandibular vein
External carotid artery
Lymph nodes

Question 18

What is the intra- and extra-cranial course of the facial nerve?

Answer 18

Enters the petrous part of the temporal bone via the internal auditory meatus, travels through the facial canal and exits the temporal bone via the stylomastoid foramen

Then enters the substance of the partoid, forms a plexiform arrangement (pes anserinis) and divides into its terminal branches (temporal, zygomatic, buccal, mandibular & cervical)

Question 19

What is the course of the retromandiublar vein within the parotid gland?

Answer 19

Formed within the gland by the joining of the superficial temporal and maxillary veins

Usually divides into anterior & posterior branches BEFORE exiting the gland

Question 20

What is the course of the external carotid artery within the parotid gland?

Answer 20

Enters the parotid and its deep inferior border
Gives off posterior auricular branch and then divides into the superficial temporal and maxillary arteries which then emerge from the upper border of the parotid

Question 21

What structure is most vulnerable to damage in surgery of the parotid gland?
What symptoms might result?

Answer 21

The facial nerve (CN7)
Facial nerve forms a plexiform arrangement in the gland and divides into its terminal branches - therefore difficult to separate during surgery

Supplies the muscles of facial expression, anterior 2/3s of tongue and lacrimal & salivary glands
Bell’s palsy type symptoms - paralysis of muscles of facial expression, drooping of corner of mouth & eye, drooling, dry mouth, excessive tears or dry eyes, abnormal taste