7.12&13&14&15 - Head, Neck & Spine 1 Flashcards
What are the features of the top of the skull?
- frontal bone
- parietal bone
- occipital bone
- coronal suture - separates frontal bone from parietal bone
- sagittal suture
- lambdoid suture - separates occipital bone from parietal bone
- bregma - where sagittal suture meets coronal suture
- lambda - where sagittal suture meets lambdoid suture
What is the squamous suture?
- separates squamous temporal bone and parietal bone
What are the features of the skull?
- bones - frontal, parietal occipital, temporal, sphenoid, maxilla, zygomatic ethmoid, palatine
- cranial fossae - anterior, middle, posterior
- main sutures - coronal, sagittal, lambdoid
- main fissures - superior orbital, inferior orbital
- mandible
What differences to an adult skull can we see when looking at a neonatal skull?
- juvenile skull - anterior and posterior fontanelles
- anterior fontanelle are where there is unfused bone, which gives the skull mild flexibility in case the birth canal is too tight
- also allows the brain to grow, and the bones to expand
- this ‘soft spot’ on the top of the baby’s head closes up at 18-24 months
Which joint in the head can move?
- the temporomandibular joint
- the sutures are rigid, immobile, thick fibrous joints
What is the name of the spot where the four cranial bones come together?
- pterion
- weakest part of the skull - a blow to this area may rupture the middle meningeal artery which runs beneath the pterion
- rupture may give rise to an epidural haematoma
What are the major bones of the skull?
- frontal
- parietal
- occipital
- temporal
- sphenoid (bow-shaped bone behind eyes)
- zygomatic (cheekbones, just below eyes)
- mandible (jawbone)
- maxilla (upper jaw, houses teeth)
- nasal
- lacrimal (located in eye socket)
- ethmoid (roof of nose, separates nasal cavity from brain)
- palatine (sides of nose)
- vomer (inside nose, divides right and left sides of nasal cavity)
Base of skull foramina
- foramina on cribriform plate
- optic canal
- superior orbital fissure
- foramen rotundum
- foramen lacerum - anterior to the opening of the carotid canal
- foramen spinosum
- foramen ovale (second biggest)
- internal acoustic meatus
- jugular foramen
- foramen magnum (biggest hole)
- hypoglossal canal
- opening of carotid canal
- stylomastoid foramen
What are the layers of the SCALP?
- skin
- connective tissue
- aponeurosis
- loose areolar tissue
- pericranium/periosteum
Blood supply of the scalp
External carotid artery branches:
- superficial temporal
- occipital
- posterior auricular
Internal carotid artery branches:
- supraorbital
- supratrochlear
- venous drainage through veins corresponding to the named arteries, and through emissary veins to the dural venous sinuses
Why do deep lacerations to the scalp tend to bleed profusely?
- the pull of the occipitofrontalis muscle prevents the closure of the bleeding vessel and surrounding skin
- blood vessels to the scalp are adhered to dense connective tissue, preventing the vasoconstriction that normally occurs in response to damage
- the blood supply to the scalp is made up of many anastomoses, which contribute to profuse bleeding
What is the falx cerebri?
- AKA cerebral falx
- large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres
What are dural reflections?
- the meningeal layer of dura mater folds inwards upon itself to form four dural reflections
- these reflections project into the cranial cavity, dividing it into several compartments - each of which houses a subdivision of the brain:
- falx cerebri - projects downwards to separate the right and left cerebral hemispheres
What are dural venous sinuses?
- venous drainage of the brain occurs through a system of cerebral and cerebellar veins, which in turn drain into the dural venous sinuses
- dural venous sinuses ultimately empty into the internal jugular veins which, together with the external jugular vein (draining the scalp and face), returns blood from the head and neck region back to the heart
- most are found adjacent to the falx cerebri and tentorium cerebelli
- cavernous sinus is clinically the most important dural venous sinus
What are the seven major dural venous sinuses?
- seven major dural venous sinuses located within the cranial cavity, specifically between the periosteal and meningeal layer of the dura mater
- superior sagittal
- inferior sagittal
- straight
- transverse
- sigmoid
- cavernous
- superior petrosal sinuses