Flashcards in Spinal Cord & Spinal Nerves Deck (74):
How many vertebrae are there?
How many vertebrae are there in each section of the spine?
CERVICAL - 7
THORACIC - 12
LUMBAR - 5
SACRAL - 5
COCCYX - 1 (/4)
How many spinal cord segments are there?
How many spinal cord segments are there in each region?
CERVICAL - 8
THORACIC - 12
LUMBAR - 5
SACRAL - 5
COCCYX - 1
Which 2 sections of the spine have an unusual number of spinal nerves?
CERVICAL - 7 vertebrae but 8 spinal nerve pairs
COCCYX - only 1 spinal nerve pair
What does each segment of the spinal cord give rise to?
1 pair of segmental spinal nerve.
-31 pairs in total
Where do spinal nerves leave the vertebral column in relation to vertebrae?
*C1-7 emerge superior to corresponding vertebrae
*C8 emerges inferior to vertebra C7
*T1-Co emerge inferior to corresponding vertebrae
What is another name for thoracic spinal nerves?
What is another name for T12 spinal nerve?
What is the cervical enlargement?
Spinal cord enlargement where brachial plexus leaves >> arms.
What is the lumbar enlargement?
Spinal cord enlargement where sciatic nerve leaves >> legs.
What sort of information do dorsal rootlets contain?
What sort of information do ventral rootlets contain?
Where does the spinal cord terminate (inferior tip) in adults?
Conus medullaris (L1-2).
What is the cauda equina?
Bundle of spinal nerves inferior to conus medullaris (L2 downwards).
-dorsal and ventral roots of lumbar, sacral and coccygeal spinal nerves
Which part of the nervous system does the cauda equina belong to?
What is the filum terminale?
Remnant of developing spinal cord.
-fine extension of pia mater from conus medullaris to coccyx.
What are the 2 parts of the filum terminale, and where do they terminate?
*Internum - ~lower S2
*Externum - coccyx
What are the 3 layers of meninges that surround the spinal cord?
How many layers of dura mater surround the spinal cord?
-unlike 2 that surround the brain
What separates the dura mater from surrounding bone?
Fat-filled epidural (extra) space.
What does the pia mater form laterally?
Flat denticulate ligaments.
Where is CSF located?
-between arachnoid mater and pia mater
How does CSF enter the subarachnoid space?
Through lateral and median apertures of the ventricular system.
What is the periosteal layer of dura mater continuous with?
Periosteum of the skull.
-doesn't surround spinal cord
What are denticulate ligaments?
Extensions from lateral pia mater to the canal wall.
-stabilise the cord
What is a ganglion (PNS)?
Collection of cell bodies.
What does the dorsal root ganglion (DRG) contain?
Cell bodies of 1* sensory fibres.
-take information from skin surface
What is an epidural?
Injection of local anaesthetic into epidural space.
-does not pass through dura mater
What is a spinal anaesthetic?
Injection of local anaesthetic into subdural space.
-pierces dura mater
-more spread effect
What is the lumbar cistern?
Enlargement of subarachnoid space between the conus medullaris and dura inferior end of dura mater.
(L1/2 - S2)
What does the lumbar cistern contain? (3)
What is the lumbar cistern good for clinically?
Lumbar puncture (to withdraw CSF).
-spinal cord not present
-cauda equina moves out of the way
How far down the vertebral canal does the spinal cord extend in a foetus (2-3 months)?
All the way down.
What happens to the spinal cord as the back stretches?
The spinal cord doesn't grow as fast as the vertebral canal, so regresses up it.
>> leaves filum terminale
What is the arterial supply to the spinal cord?
-Unpaired anterior spinal arteries
-Paired posterior spinal arteries
Where do spinal arteries typically arise?
What are the vertebral arteries supported by along the length of the cord?
-Segmental medullary arteries
What do spinal arteries come off in the neck?
What do spinal arteries come off in the thorax?
Posterior intercostal arteries.
What do spinal arteries come off in the abdomen?
What do spinal arteries come off in the pelvis?
Lateral sacral arteries.
What does white matter contain?
Tracts and axons.
-long myelinated pathways
What does grey matter contain?
Cell bodies of axons.
What sort of information does the dorsal grey horn contain?
What sort of information does the ventral grey horn contain?
What originates at the lateral grey horn?
-sympathetic and parasympathetic
Where does the pudendal nerve originate?
Lateral grey horn at S2-4.
-but it's somatic (not autonomic)
What sort of information do spinal nerves carry?
-motor & sensory
What is the epineurium?
Protective outer sheath of connective tissue.
-formed from meningeal coverings surrounding spinal nerves
What happens to the amount of white matter present as you ascend the cord?
Increased white matter as you ascend the cord.
Where in the cord do ventral grey horns enlarge?
Cervical and Lumbosacral enlargements.
-motor fibres >> limbs
What is present on either side of the midline above T6?
2 dorsal columns on each side.
What are the 2 dorsal columns either side of the midline above T6 called?
-Gracile fascicle (MED)
-Cuneate fascicle (LAT)
What information does the cuneate fascicle contain?
Sensory information from the arms.
What information does the gracile fascicle contain?
Sensory information from the legs.
How many dorsal column pathways are present below T6?
One on either side of the midline.
What are laminae in the spinal cord?
Specific regions in grey matter with sensory/motor nuclei that give rise to certain nerves.
At which cord level is the phrenic nucleus?
Which lamina is the phrenic nucleus in?
Is the dorsal column ipsilateral or contralateral?
What is the function of the dorsal column?
Is the lateral corticospinal tract ipsilateral or contralateral?
What is the function of the lateral coritcospinal tract?
Fine voluntary movement.
Is the ventral corticospinal tract ipsilateral or contralateral?
What is the function of the ventral corticospinal tract?
Fine voluntary movement.
Is the spinothalamic tract ipsilateral or contralateral?
What is the function of the spinothalamic tract?
What are the dorsal column, lateral&ventral corticospinal tract and spinothalamic tract?
Ascending and descending fibre tracts in the white matter.
Where does the spinal cord terminate at birth?
Where does the spinal cord terminate in adults?
What sort of information does the lateral grey horn contain?
At what levels of the spinal cord can the lateral grey horn be seen in a cross section?