Anatomy Flashcards
What does the subarachnoid space consist of?
Cerebrospinal fluid - protects brain from movement and delivers nutrients to it
Spider-like projections
Which part of the brain sits in the middle cranial fossa of the skull?
Temporal lobes
At what age does the “soft spot” on the top of a baby’s head close up?
18-24 months
What is the medical term for the soft spot?
Anterior fontanelle
The sagittal suture of the skull lies between which bones?
Parietal - Parietal
What are the 3 layers of the meninges
Dura mater (outermost) - outer is periosteal layer, inner. is meningeal layer. Thick, Inelastic Arachnoid mater - spider-like projections and CSF in subarachnoid space Pia mater (innermost) - thin, delicate 2 cell thick surface of the brain
What are the 3 fossae of the skull
Anterior cranial fossa —> frontal lobes
Middle cranial fossa —> temporal lobes
Posterior cranila fossa —> brainstem and cerebellum, this fossa is covered by layer of meninges
What are the 3 main sutures of the superior and posterior views of the skull
coronal, sagittal, lamboid
What is junction of bones on each side of skull
pterion
- H shaped formation of sutures on each side of skull
- forms junctions between 4 bones: greater wing of sphenoid bone, temporal bone, parietal bone, frontal bone
- weak spot, a blow to it can cause intercranial bleeding
difference in dura between skull and vertebral column?
dura is adherent to bone/skull in. cranial cavity
there is space between dura and bone/vertebra when you come out of foramen magnum. The space is extra-dural space where extradural/epidural anaesthesia can be injected for pain relief
What do the 2 layers of the dura form when they separate at points around the brain?
The form venous sinuses where blood circulates around cranial cavity eg superior Sagittal sinus - the largest one
Name the folds of the dura that spilt the brain
Falx cerebri and falx cerebelli split brain sagittally
Tentorium cerebelli forms a tent over the the cerebellum
What is the lambda
The meeting point of the Saggittal suture and lamboid suture
Layers of the scalp
Skin - hair follicles and sebaceous glands
Connective tissue - richly innervated, blood vessels are closely adherent to it so can’t fully construct if lacerated therefore the scalp can be a site fo profuse bleeding
Aponeurosis - thin and tendon like, contains occipitalis and frontalis muscles
Loose areolar tissue - contains emissary veins which connect extra cranial veins of scalp to inter cranial venous sinuses, so are a potential pathway for spread of infection from scalp to inter cranial space
Periosteum - outer layer of skull bone
What is the difference in bone thickness between occipital and pterion?
Bone is thickest at occipital region and thinnest at pterion
What type of intercranial haemorrhage is associated with damage to the middle meninges artery?
Epidural/extradural haemorrhage - occurs between dura mater and skull
2 arterial sources of the circle of Willis?
Internal carotid arteries (branch of the common carotid artery) Vertebral arteries (branch off from first part of subclavian artery)
What is the name of the pituitary fossa?
Sella Turcica
Where is cavernous sinus in relation to the sella turcica?
Lateral to it
CN 1
Olfactory
CN 2
Optic
CN 3
Oculomotor
CN 4
Trochlear
CN 5
Trigeminal
CN 6
Abducens
CN 7
Facial
CN 8
Vestibulocochlear
CN 9
Glossopharyngeal
CN 10
Vagus
CN 11
Accessory
CN 12
Hypoglossal
Describe an epidural/extradural haemorrhage
Due to meninges vessels
Due to blood collection between dura and inner periosteal (bony) layer of cranium
On CT scan, is a lens shaped haematoma - blood looks white on Ct scan
Describe a subarachnoid haemorrhage
Due to rupture of aneurysms (bulge in blood vessel due to weakness in blood vessel - so the wall bulges outwards when blood passes through that part of the vessel)
Due to blood collection in subarachnoid space
CSF becomes heavily blood stained
On CT scan, looks like dense extensive area of blood in subarachnoid space (blood looks white on ct scan)
Describe subdural haemorrhage
Due to cerebral veins or venous sinuses
Due to blood collection between dura and arachnoid layer
On CT scan, is a long crescent shaped haematoma
Facial nerve exits skull base through which foramen?
Stylomastoid foramen
At what vertebral level does the adult spinal cord end?
L2
What is the structural name for the chin
Symphysis menti
What is the bony prominence behind the ear called?
Mastoid process
