The Scalp, Brain and Cranial Nerves Flashcards
What are the scalp layers?
SCALP mnemoic
skin
(dense) connective tissue
(epicranial) aponeurosis
loose connective tissue
pericranium
What does the skin contain?
where is it thickest?
Contains hair follicles, sweat & sebaceous glands;
Thickest over the occipital bone
What does the dense connective tissue contain?
Subcutaneous layer richly vascularised & with cutaneous nerves
What does the epicranial aponeurosis contain?
why is this layer important and what happens when it is compromised?
Tendon & muscle of occipitofrontalis; this layer prevents superficial wounds from gaping open;
when this layer is compromised (e.g. laceration), gaping wounds result that require sutures to close
What does the loose connective tissue contain and what does this allow
why may this be disadvantageous?
Loose areolar tissue (‘loose packing material’) that allows free movement of outer layers over underlying calvaria;
contains spaces susceptible to distension with fluid or infection spread (e.g. eyelids & root of nose)
What does the pericranium contain?
External periosteum of skull
What is important to regard between the aponeurosis and pericranium?
there are potential spaces for accumulation of fluid (e.g. blood) or spread of infection
▪ Fluid/infection can spread to the eyelids or root of nose
Why does the fluid/infection spread to eyelids or root of nose?
Frontal belly of occipitofrontalis inserts into skin & subcutaneous tissue not bone
posterior and lateral spread is limited due to the firm attachments of the occipital belly and temporal fascia.
How can scalp infections spread to intracranial structures?
via emissary veins
What is cutaneous/sensory innervation of scalp and face supplied by?
CN V (V1, V2, V3) & cervical nerves from C2 & C3
What branches of V1 provide cutaneous/sensory innervation?
Supraorbital
Supratrochlear
What branches of V2 provide cutaneous/sensory innervation?
zygomaticotemporal
What branches of V3 provide cutaneous/sensory innervation?
auriculotemporal
What is skin over angle of mandible supplied by?
not supplied by CN V, but by the cervical plexus with the great auricular nerve (C2 & C3)
What are the cervical nerves called that provide custaneous/sensory innervation to head?
C2 - Greater, Lesser Occipital
C3 - Third Occipital
C2,C3 - Great Auricular
What is the majority of the blood supply for the face and scalp from?
external carotid artery with some from the internal carotid artery
What are the main arteries of face and scalp?
internal carotid artery
- zygomaticofacial
- zygomaticotemporal
external carotid artery
- facial
- buccal (maxillary branch)
- mental (maxillary branch)
- infraorbital (maxillary branch)
- transverse facial (branch of superficial temporal)
Why is it easier to memorise branches of the internal carotid artery?
same name as nerves
Where can the pulse be taken?
from the facial artery at inferior border of mandible
or
from the transverse facial artery just anterior to the auricle
What is the venous drainage of the face?
- Facial vein drains most of the face to internal jugular vein
- Transverse facial vein drains some of the upper face