The spinal cord and its membranes

Abstract 

The spinal cord is 45 cm long in the adult. In the early foetus, it extends the length of the vertebral canal; differential growth results in its termination at L3 in the newborn. In the adult it terminates, as the conus medullaris, at the disc between L1 and L2, although there is a range from T12 to L3. Inferiorly, the nerve roots form the cauda equina, while the lower end of the cord is attached by the filum terminale, of pia mater, to the coccyx. The dural sac terminates usually at the second segment of the sacrum. The cord receives its arterial supply from the anterior and posterior spinal arteries, which descend from the foramen magnum. They are reinforced serially via the intervertebral foramina from segmental vessels, especially the arteria magna. The three layers of the meninges are the dura mater, arachnoid mater and pia mater. The cerebrospinal fluid is contained within the subarachnoid space. The epidural space contains fat, blood vessels, lymphatics and the nerve roots.

Keywords: arachnoid mater, arteria radicularis magna, conus medullaris, dura mater, pia mater, spinal cord