Flashcards in H&N Deck (409)
What can damage to the middle meningeal A lead to?
Tearing of A resulting in epidural haematoma - pooling of blood between dura and bone inc. pressure
What is the circle of Willis?
Cerebral arterial circle supplied by internal CA, post. by basilar and vertebral A
Branches to ant. middle and post cerebral
Provides uninterrupted, continuous blood supply to brain even if one A is blocked
What are the boundaries of the scalp?
Ant.: sup. orbital margin
Post.: sup. nuchal line
Laterally: zygomatic arch
What are the 5 layers of the scalp?
S - skin
C - CT
A - aponeurosis
L - loose areolar tissue
P - pericranium
Describe the skin layer of the scalp
Outer most layer
Contains hair, sebaceous and sweat glands
Blockage of glands leads to dryness and dandruff
Describe the CT layer of scalp
Dense network of fibro-fatty tissue
Connects skin with aponeurosis
Large blood vessels and nerves
Injury to scalp results in vessels being unable to contract so profuse bleeding which can cause haematoma causing pain
Describe the aponeurosis layer of scalp
Epicranius muscle and aponeurosis - raises eyebrows and causes horizontal wrinkles of forehead
Continual contraction results in headaches
Tightly attached to CT
Describe the pericranium
Periosteum of skull
Continuous with endosteum at sutures
What are the 3 meninges of the cranium?
Cerebral dural mater
Cerebral pia mater
Cerebral arachnoid mater
Describe the dura mater
Thick, dense inelastic membrane
2 layers: inner/meningeal and outer/endosteal
What are the 4 folds of the dura mater?
Describe the cerebri falx
Separates cerebral hemispheres
Attaches ant. to crista galli of ethmoid; post. blends into cerebri tentorium
Describe the cerebri tentorium
Roof of post. cranial fossa
Describe the cerebelli falx
Between cerebellar hemispheres
Along post. wall of post. cranial fossa
Describe the diaphragma sella
Fold Oliver sella turcica
What are the 3 falx cerebri sinuses?
Sup. sagittal: follows sagittal suture ant. from falx cerebri post.
Straight: connects inf. to sup. at confluence
What are the sinuses of the falx cerebelli?
Trans: transverse along endosteal
Sigmoid: drains venous blood into IJV
Describe the cavernous sinuses
Lies bilaterally on either side of sella turcica
Internal CA and abducent nerve run through
Oculomotor, trochlear, ophthalmic and maxillary of trigeminal lie in lateral wall
Where are the sup. and inf. petrosal sinuses?
Petrous part of temporal bone
Describe the blood flow in dural sinus
Sup. sagittal drains directly to confluence
Inf. sagittal drains to confluence through straight
Confluence drains to transverse
Cavernous drains to sup. and inf. petrosal
Sup. drains into transverse
Inf. drains directly to IJV
Transverse drains to sigmoid
Sigmoid drains to IJV
What is the facial vein made up of?
Supraorbital and supratrochlear veins: collect blood from forehead and supraorbital regions
How does the facial vein communicate with cavernous sinus?
Through ophthalmic vein via supraorbital fissure
What happens to the facial vein as it descends?
Joined by: deep facial, ptyergoid, retromandibular to form common facial vein that drains to IJV
Where does the deep facial vein join?
Angle of mouth bringing pytergoid drainage
What is the pytergoid plexus?
Network of veins behind ramus
Describe the retromandibular vein
Made of maxillary and superficial temporal veins
Passes through parotid gland
Ant: joins facial vein
Post: joins post. auricular vein to form EJV
Where is the maxillary vein located?
Adjacent to sphenomandibular ligament
What is the function of the lymphatic system?
Drain excess interstitial fluid
Transport dietary lipids and lipid soluble vits
What are the 5 regional groups of the lymphatic system?
1. Post of head
2. Ant of head
3. Beneath mandible
4. Along superficial jugular veins