Week 6 SDL: Contents of vertebral canal/ column Flashcards
In adulthood, why is the spinal cord much shorter than the length of the vertebral column?
during development, the vertebral column grows at a much faster rate
At which level does the spinal cord end in newborns?
L3
At which level does the spinal cord end in adults?
Between L1 and L2
What is the conus medullaris?
the tapered end of the spinal cord from which a thin pial thread, the filum terminale, continues downwards to attach to the coccyx
What is the cauda equina?
made up of lower lumbar, sacral and coccygeal nerve roots descending through the lumbar cistern i.e the region of the subarachnoid space between the level of termination of the cord and the level at which the dura and arachnoid coverings terminate (about S2)
Where is the epidural space and what does it contain?
- space between the dura and vertebra. contains fat, veins, spinal arteries and lymphatics
- terminates at L1
Which arteries supply the spinal cord?
- ASA - originates from the vertebral artery and descends down to supply the anterior aspect of the spinal cord
- 2 x PSA - originates from the vertebral artery and supplies the dorsal third of the spinal cord
Which arteries reinforce the anterior and posterior spinal arteries?
radicular branches of the intercostal and lumbar arteries which enter the vertebral canal through the intervertebral foramina
Explain the venous drainage of the spinal cord
- anterior spinal vein (parallel to the anterior median fissure)
- posterior spinal vein (parallel to the posterior median sulcus)
- these drain into the internal vertebral plexus embedded in the epidural fat of the VC
- at each vertebral level, there is drainage of the internal vertebral plexus into segmental thoracic, abdominal and intercostal veins and the external vertebral venous plexus to eventually connect with major systemic veins
Do spinal nerves have valves
no
What is the functional difference between the dorsal and ventral nerve roots?
- The dorsal root bears a dorsal root ganglion containing cell bodies of sensory neurones
- The ventral (or motor) root consists of axons from the LMNs in the ventral horn of the spinal cord
What is the function of dorsal rami?
Dorsal branch of spinal nerves innervate skin of back, intrinsic muscles of the back and sympathetics to the skin
What is the function of ventral rami?
innervates all muscles (except intrinsic back musckes) and cutaneous regions of the body. visceral pain
How many spinal nerves are associated with each region?
cervical = 8 thoracic = 12 lumbar = 5 sacral = 5 coccygeal = 1 = 31 pairs of spinal nerves
In which clinical conditions is the composition of CSF altered?
- meningitis
- intracranial tumours
- subarachnoid haemorrhage
- cerebral infarction
Starting with the skin, list the layers pierced by the lumbar puncture needle
- Skin
- Subcutaneous tissue
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flavum
- Epidural space
- Dura
- Arachnoid
- Sub arachnoid space
Moving the needle through which ligament causes a ‘pop’ during an LP?
Ligamentum flavum
What are the signs and symptoms of sciatica?
- Lower back pain
- Numbness or tingling in shoulders, back, arms, hands, legs or feet
- Neck pain
- Problems bending or straightening your back
- Muscle weakness
- Pain in buttocks, hips or legs if the disc is pressing on the sciatic nerve
Which region of the spinal cord has the most white matter and why?
cervical level because ascending and descending fibres from and to all levels must pass through the cervical cord
In which sections is the dorsal white matter subdivided into two columns on each side? What type of information runs in these columns?
- Above T6
- Cuneate fascicle is responsible for transmitting vibration, proprioception, and fine (discriminative) touch sensations from upper body
- Gracile fasciculus carries sensory information from the lower half of the body entering the spinal cord at the lumbar level.
- The cuneate fasciculus carries sensory information from the upper half of the body, entering the spinal cord at the cervical level
In which spinal cord segments in the ventral grey horn enlarged and why?
- in the cervical and lumbar segment
- due to the accumulation of motor neurones for innervation of the limbs
Where are the lordosis on the back?
cervical and lumbar regions
What are the distinguishing features of a cervical vertebrae?
bifid spinous process and foramina in the transverse process (there are no foramina in the thoracic and lumbar vertebrae)
why does cervical vertebrae have transverse foramina?
The transverse foramina of the cervical vertebrae provide a passageway by which the vertebral artery, vein and sympathetic nerves can pass. The only exception to this is C7 - where the vertebral artery passes around the vertebra, instead of through the transverse foramen.
