Skull, Vertebral Column and SC Flashcards
how many divisions are in the base of skull and what does it consists of?
- three divisions: anterior, middle and posterior
- anterior cranial fossa: frontal bone, ethmoid bone (cribriform plate + crista gali), sphenoid (lesser wing)
- middle cranial fossa: optic canal, hypophyseal fossa of sella turcica, foramen rotundum, foramen ovale, foramen spinosum, foramen lacerum, middle cranial fossa, temporal bone
- posterior cranial fossa: internal acoustic meatus, jugular foramen, hypoglossal canal, foramen magnum, occipital bone
what passes through these structures?
- ethmoid bone
- SOF
- optic canal
- carotid foramen/foramen lacerum
- jugular foramen
- internal acoustic meatus
- foramen magnum
- foramen spinousum
- cribriform plate/ ethmoid bone: olfactory nerve, anterior ethmoidal artery and vein
- SOF - oculomotor nerve, trochlear nerve, ophthalmic nerve, abducens nerve, superior ophthalmic vein
- optic canal - optic nerve, ophthalmic artery
- carotid foramen/foramen lacerum: internal carotid artery, greater petrosal nerve
- jugular foramen: CN glossopharyngeal, vagus, accessory nerve, internal jugular vein
- internal acoustic meatus - facial, vestibulocochlear nerve, labyrinth artery
- foramen magnum: vertebral arteries, anterior + posterior spinal arteries, SC
- foramen spinousum - meningeal artery
outline the following for raised intracranial pressure
- caused by:
- symptoms:
- signs:
- caused by: space occupying lesion (SOL- tumour, haematoma and abscess) + idiopathic intracranial hypertension
- symptoms: headache, nausea, visual disturbances and later altered consciousness levels
- signs: papilloedema and increased blind spot on visual field testing
Differentiate b/w the vertebral column segments and spinal cord nerve segments
Vertebral Column - 7C, 12T, 5L, 5S and 4C/more
Spinal Nerves - 8C, 12T, 5L, 5S and 1C
what does the vertebral canal consist of?
- the spinal cord + its coverings
2. the spinal nerves
the vertebral column shifts the body on the lower limb through which joints?
sacroiliac
what is vertebra prominent, which one is it and what are its characteristics?
- the upper most spinous process that is palpable (visible) is called vertebra prominent
- it is the 7th cervical vertebra
- it has long and non-bifid spine
outline the curvature changes from pre-birth to post birth
pre-birth - the vertebral column is in C shape with concavity facing anteriorly
post-birth - after birth secondary curvature develops with convexity at cervical (when the child holds its head) and lumbar (when the legs start bearing weight)
what are the range of movements of the following (in degrees) in VC?
forward flexion - 40
extension - 15
lateral flexion - 30
rotation - 40
in which region of the VC is the rotation maximum and minimum?
maximum - thoracic
minimum - lumbar
why is the flexion and extension is limited in the thoracic despite having maximum rotation?
flexion and extension is limited in the thoracic despite the maximum rotation is due to the presence of the rib cage around it
what are intervertebral discs, what does it consists of and its role?
- fibrocartilagenous structures
- consists of 2 layers of hyaline cartilage (upper and lower), nucleus pulposus and annulus fibrosus
- can withstand compressions but are flexible enough to allow movement t b/w the vertebrae
what are the two parts of intervertebral discs and what does it consists of?
- nucleus pulpousus surrounded by annulus fibrosus
1. nucleus pulpousus: hydrated gel of collagen, proteoglycan and cartilage cells
2. annulus fibrosus: 10-12 concentric layers of collagen
where do the spinal nerves exit the spinal canal?
spinal nerves exit the spinal canal from interverbral foramina
what is herniation?
nucleus pulposus is absent in annulus fibrosus and it bulges into the SC or intervertebral foramen that further compresses the nerve roots
which cases can result in narrow the intervertebral foramen and what will that result into?
- herniation of intervertebral disc
- arthritis of facet joints
- bony irregularities in pedicle or vertebral body
- all of these cases can narrow the intervertebral foramen and cause compression of nerve root
in which region of the vertebral column does the herniation most commonly occur?
lumbar region
what is radiculopathy and where is it commonly found (which region of VC)?
- it is the compression of nerve roots, most commonly due to prolapsed intervertebral disc
- mostly, L5/S1 in lumbar region or C6/7 in the neck
what normally causes a prolapse of disc?
herniation of nucleus pulpousus + defect in annulus fibrosus, together compressing the nerve root and cauda equina present in it
what is sciatica? what’s its symptoms and signs?
- it is the compression or irritation of sciatic nerve (L5)
- symptoms: 1. pain radiating down the buttock, into the leg down to cals and 2. abnormal gait - weakness on dorsiflexion causes foot drop
what is epidural space?
the space b/w vertebrae and dura matter of spinal cord
what does epidural consists of and what are its characteristics?
- small arteries - supplied blood SC and vertebral venous plexous
- Batson’s veins - contain no valves and communicate freely with intercostal veins and pelvic veins including veins draining the prostrate
- what is caudal equina syndrome?
- what are its signs and symptoms?
- what is it commonly caused by?
- what are the consequences and treatment?
- compression of nerve roots below the spinal cord termination (L1-S5)
- signs and symptoms: low back pain, sciatica, bladder dysfunction, faecal incontinence, decreased anal tone, sexual dysfunction, variable lower extremity motor and sensory loss, perineal parasthesia
- caused by: disc prolapse at L4/5 or L5/S1 level
- treatment: needs urgent investigation or loss of function will be permanent, neurological emergency
where does the SC end with respect to VC?
ends at the in serval of first and second lumbar
