Spinal meninges Flashcards
Dura mater
tough, fibrous membrane that forms the spinal dural sac
Epidural space
a space that exists between the dura mater of the spinal cord and the periosteum of the vertebrae- it contains fat, arachnoid trabeculae and a venous plexus
arachnoid mater
thin, avascular membrane that lines the dural sac and the dural root sheaths
subarachnoid space
lies between the arachnoid mater and pia mater, it contains cerebrospinal fluid, arteries and veins
pia mater
thin, transparent membrane that directly covers the spinal cord, the roots of the spinal nerves and the spinal blood vessels
Dural root sheaths
lateral extensions of the spinal dura mater which surround the nerve roots
Denticulate ligament
fibrous sheet of pia mater, which suspends the spinal cord in the dural sac- it extends laterally from the spinal cord and attaches to the inner surface of the dural sac
What level does the spinal cord terminate?
level of L1
Where do the spinal meninges terminate
level of S2- between L1 and S2 is the dural sac- samples of CSF may be withdrawn from the dural sac
Lumbar puncture:
needle is usually inserted between L3/L4 vertebrae (or L4/L5)
How is the level of L4 determined for a lumbar puncture?
the spinous process of L4 is determined by the supracristal plane- this transects the highest points of the iliac crests
what is spina bifida occulta?
this is failure of the vertebral arch fusion alone, a dimple or tuft of hair may overlie the abnormality
What is meningomyelocele?
failure of vertebral arch fusion, herniation of the meninges and elements of the spinal cord- may result in paralysis of the limbs and faecal and urinary incontinence
What is meningocele?
failure of vertebral arch fusion, with herniation of the meninges- may be corrected with surgery with minimal consequences (no elements of spinal cord)
