Spinal cord, spinal nerve and meninges Flashcards
What are meninges
3 membranes which surround, protect and suspend the brain, spinal cord and spinal nerves
What do meninges contain
CSF in the subarachnoid space
What is the dura mater
Outermost, thick layer
What is the dura mater called in the vertebral canal
The dural sac
Where does the dura mater end
At the lower border of S2 vertebra, where it fuses with filum terminale
Where is epidural space
Between periosteum and dura
Where does the epidural space extend
Between the foramen magnum and sacral hiatus
What does the epidural space contain
Internal vertebral venous plexus within fatty tissue
Where is arachnoidea matter
It lies deep to and in contact with dura in the living
Where does the arachnoidea mater end
At lower border of S2 vertebra
What is the pia mater
- Innermost layer of meninx
- Thin and vascular closely adhered to the surface of the spinal cord
What does pia mater cover
The surface of spinal roots
What does the pia mater become
The filum terminale at the tip of conus medullaris, attached to the coccyx
What does the pia mater form between roots of spinal nerves
Denticulate ligaments
Describe the development of the spinal cord
- The vertebral column grows faster than spinal cord
- In the embryo, the spinal cord and vertebral canal are equivalent lengths
- In neonates, the spinal cord end at L3 vertebra
- In adults, the spinal cord extends from foramen magnum to disc between L1/L2
What is the inferior end of the spinal cord
The conus medullaris which narrows as filum terminale
What are the 2 enlargements of the spinal cord
- Cervical - between C4 - T1 (brachial plexus)
- Lumbosacral - between T11 - S1 (lumbosacral plexus)
How many pairs of spinal nerves are there
31
What are the anomalies of the vertebrae and spinal nerve relationship
- The are 7 cervical vertebrae but 8 cervical spinal nerves
- There are 1-4 coccygeal vertebrae but only 1 coccygeal nerve
Where do C2 - L5 spinal nerves emerge through
Their own intervertebral foramen
Where do S1-S4 spinal nerves emerge through
From anterior and posterior sacral foramina
How are spinal nerves numbered in the cervical region
According to the vertebra below
How are spinal nerves numbered below T1
According to the vertebra above
What nerves do not make plexuses
Thoracic except T1 retain their segmental distribution and do not make plexuses
What is the cauda equina
The root of lower lumbar and sacral spinal nerves, within the lumbar cistern
Why is lumbar puncture performed
- Sample CSF for blood
- Measure the pressure of CSF
- Injection of anaesthetics
- Injection of medications
Why is the spinal puncture safest from the lumbar cistern
- Spinal cord ends at L1/L2
- Subarachnoid space extends to S2
- Cauda equina unlikely to be damaged
What is the supracristal plane
A plane between the superior-most points of iliac crests, crossing L4 spinous process and L4/5 intervertebral disc
