Spinal Cord Structure Flashcards
Where does the spinal cord end in adults?
Opposite the IV disc between the L1 and L2 vertebrae
It may however end as high as T12 or as low as L3
Where does the spinal cord begin?
The medulla or caudal part of the brain stem
The cervical enlargement runs from which vertebral segments?
C4-T1 (The anterior rami of these spinal nerves form the brachial plexus that innervates the upper limb)
The lumbar enlargement runs from which vertebral segments?
L1-S3 (Anterior rami from these spinal nerves form the lumbar and sacral plexuses that innervates the lower limb)
The lumbar cistern is the subarachnoid space that holds what?
Cauda equina
Posterior roots of spinal nerves contain what kind of fibers?
Afferent or sensory fibers (from the skin, subcutaneous and deep tissues, and often viscera)
The anterior roots of spinal nerves contain what kind of fibers?
Efferent or motor fibers (run to skeletal muscle and contain many presynaptic autonomic fibers)
Each spinal nerve divides almost immediately into the dorsal and ventral rami. What does the dorsal ramus supply? What does the ventral ramus supply?
Dorsal ramus: skin and deep muscles of the back
Ventral ramus: limbs and rest of the trunk
Where is the filum terminales most inferior attachment? What is it composed of?
It is composed primarily of pia mater, but also includes vestiges of neural, connective and neuroglial tissue. Takes on layers of arachnoid and dura mater as it penetrates the inferior end of the dural sac and passes through the sacral hiatus to ULTIMATELY attach to the coccyx posteriorly.
The filum terminale serves as an anchor for what?
The dural sac, the continuation of the dura inferior to the conus medullaris.
What are the 3 protective coverings of the spinal cord starting with the most superficial?
Dura mater, arachnoid mater, pia mater.
The subarachnoid space sits between what two spinal meninges?
The arachnoid mater and pia mater. In this space you can find the CSF, arachnoid trabeculae (connects arachnoid to pia), radicular, segmental, medullary, and spinal arteries and veins.
Inferior to the conus medullaris the pia mater continues as what?
The filum terminale.
What is the function of the denticulate ligaments? Where can you find them?
Attach the spinal cord to the arachnoid-lined dural sac. In the dural sac, made up mostly of pia mater.
How many longitudinal arteries supply the spinal cord?
- One anterior and two posterior spinal arteries. Each is a branch of either the vertebral artery or the posterior inferior cerebellar artery.
