Anatomy of Head Injuries Flashcards
The scalp consists of 5 layers. What are these?
S - skin (thick with numerous sebaceous glands)
C - connective tissue (rich vascular supply
A - Aponeurosis (flat tendon between the frontalis and occipitalis muscle).
L - Loose areolar layer (connected to the intra crania dural veinis sinuses by emissary (valveless veins).
P - Pericranium
What is a common histologically in the skin of the scalp & thus pathology?
Numerous sebaceous glands - pathology: Sebaceous cysts.
What unusual anatomical feature exists in the connective tissue layer of the scalp which is responsible for perfuse bleeding when these vessels are damaged?
In the scalp the second layer, the connective tissue layer contains a rich vascular supply.
The outer layer of the blood vessels - the tunica adventica is strongly attached to the surrounding fibrous layer. This means that if the blood vessels are damaged they are unable to vasospasm in an attempt to reduce loss of blood. Thus profuse bleeding is observed when blood vessels of the fibrous layer of the scalp are damaged.
What unusual anatomical feature exists in the connective tissue layer of the scalp which is responsible for perfuse bleeding when these vessels are damaged?
In the scalp the second layer, the connective tissue layer contains a rich vascular supply.
The outer layer of the blood vessels - the tunica adventica is strongly attached to the surrounding fibrous layer. This means that if the blood vessels are damaged they are unable to vasospasm in an attempt to reduce loss of blood. Thus profuse bleeding is observed when blood vessels of the fibrous layer of the scalp are damaged.
What are the names of the muscles attached to either side of the Galea aponeurosis?
Why must the aponeurosis be repaired separately when closing head wounds?
The aponeurosis is a tendon with the Frontalis and Occipitalis muscles each applying tension to either send it.
When a wound is sustained the aponeurosis gaps apart due to this tension and as such is often a wider wound than the outer two layers of the scalp.
In order to prevent infection etc the aponeurosis must be closed prior to closing the outer scalp.
Why is the fourth layer of the scalp considered the ‘dangerous layer’?
The fourth layer, the loose areolar layer contains valveless veins which drain directly into the veinous sinuses of the dura layer thus any infection in the loose areolar layer is very risky for direct access into the circulation.
The loose areolar layer is continuous beyond the scalp into two regions what are these?
Around the eye and behind the ear.
Think Panda bear sign.
What is the anatomical reason for the Panda Bear sign?
Bleeding into the loose areolar connect tissue layer of the scalp is continuous around the eye and behind the year thus any bleeding in this layer can collect / pool in these two areas and cause bruising.
Bleeding / swelling into the pericranial layer results in an unusual presentation. Please explain?
The pericranial layer is continuous with the dura mater underneath the cranial bones. The pericranial layer dives down in between the cranial sutures to achieve this continuous layer.
When there is bleeding in the pericranial layer it accumulates between the cranial bone and the pericranial layer of the affected cranial bone. Thus swelling reflects the affected bone. In this image that is the left parietal bone.
In a sample of Rhinorrhoea or Otorrhea where you are attempting to discern the prescence of CSF, what is detected in the fluid?
The fluid will be positive for Beta 2 transferrin if the fluid contains CSF.
What pathological condition does this image illustrate?
Haematotympanum
What pathological process is illustrated in this image?
Pneumocephalous
What signs and symptoms are observed in basilar skull fractures?
Racoon eyes - blood pools in the 4th layer of the scalp (around the eye and behind the ears).
Sub conjunctival hemorrage and exophthalmos can also be ovserved.
What signs and symptoms are observed in basilar skull fractures?
Racoon eyes - blood pools in the 4th layer of the scalp (around the eye and behind the ears).
Sub conjunctival hemorrage and exophthalmos can also be ovserved.
What pathological process is illustrated in this image?
Pneumocephalus
What is the sign illustrated in this image? It is refelctive of a basail skull fracture.
The image shows fluid levels within a sinus (sphenoid) demonstrating blood +/- CSF is leaking into this space. This is consistent with a sign of a base of skull fracture.
Basillar skull fractures occur most commonly in the anterior cranial fossa. Approximately 70%.
What are the signs of anterior crainial fossa skull fractures.
Eye related signs:
2. 1. Bleeding in to orbital cavity -> Exophthalmos.
2. Bleeding around the eyes -> Racoon eyes.
3. Bleeding in to the subconjunctival space -> subconjunctival haemorrage.
4. Damage to the optic canal / nerve -> vision changes / blindness.
5. Damage to eye muscles / nerves -> occular palsies, numbness of the forehead.
Nose related signs:
1. Rhinorrhoea (CSF) / Epistaxis / Meningitis risk.
2. Olfactor nerve / bulb damage -> anosmia (loss of sense of smell).
Label the attached:
A - Frontal bone
B - Parietal bone
C - Sagittal suture
D - Coronal Suture
E - Bregma
Label the attached:
J - Frontal sinus L
K - Grove for middle meningeal a. of the temporal bone (inner table).
L - Occipital bone
M - Lamdoidal suture
Label the attached:
N - Orbit
O - Ethmoid sinus
P - Sella turnica / pituitary fossa (dorsum sella)
Q - Lambdoid suture
Label the attached
R - Maxillary sinus
S - Zygomatic arch of temporal bone
T - Sphenoid sinus (just inferior to sella turnica
U - Petros part of temporal bone (divides cranium into posterior and middle cranial fossa’s).
Label the attached
V - Maxillary sinus
W - Tempromadibular joint
X - Mastoid air cells (are continious with the ear cavity & thus pharynx).
What pathology is indicated in this image?
Diastatic (saggital suture) & Linear fracture (R parietal bone).
MOI: diffuse blunt forced trauma.
Which important vascular structure lies below this diastatic fracture (sagittal suture).
The Diastatic fracture involves the sagittal suture. As the superior sagittal sinus lies rostrally (inferior) to this suture bleeding into this suture is a potential issue with venous sinus thrombosis a risk.
Describe this injury accurately (3 specific features).
Depressed (bones displaced inwards), compound (presence of gas within the cranium indicates connection from external to internal environment) commuted (multiple bone fragments) fractures of the frontal and parietal bones.
How has air entered this cranium? Fracture includes the frontal sinus or laceration to scalp is deep and allows air within the inner table of the cranium.
What has this fracture done to the underlying brain tissue?
What treatment is required?
The depressed bone has caused localised haemorrage to the underlying brain tissue.
Surgical elevation of depressed bone is required along with propholactic antibiotics.
