C: Spinal cord and Spinal Nerves Anatomy Flashcards
The vertebral column contains how many vertebrae?
30 (some say 33) 7 Cervical 12 Thoracic 5 Lumbar 5 Sacral 1(/4) coccygeal
How many spinal cord segments are there?
31
How many spinal nerves does each spinal cord segment give rise to?
1 pair of segmental spinal nerves
How many spinal nerves are there, and of what type?
31 8 cervical 12 thoracic 5 lumbar 5 sacral
Where does C1 spinal nerve pass out of the spinal cord?
Between the base of the skull and C1 vertebra
Where do the spinal nerves pass out relative to their corresponding vertebra?
Cervical spinal nerves pass out the vertebral column superior to the pedicles of their corresponding vertebra
Thoracic, lumbar and sacral and coccygeal pass out inferior to the pedicles of their corresponding vertebra
Where does spinal nerve C8 pass out of the vertebral column?
Between C7 and T1 vertebra
Where is the transition in nomenclature of nerves?
Between C7 and T1
How thick is the spinal cord?
About the thickness of a little finger
What 2 enlargements can be seen in the spinal cord and why?
Cervical enlargement - gives rise to the brachial plexus
Lumbar enlargement - gives rise to nerves supplying lower limb
What is the cauda equina?
Dorsal and ventral roots of lower lumbar and sacral and coccygeal segmental spinal nerves travelling to their corresponding vertebra
What is the filum terminale?
Fine strand coming from the conus medullaris which travels and attaches to the coccyx, its an extension of pia mater and a remnant of the developing spinal cord
How many layers of meninges surround the spinal cord?
3
What 3 layers of meninges surround the spinal cord?
Dura mater (meningeal layer)
Arachnoid mater adhered tightly to the dura mater due to pressure of underlying CSF
Pia mater
What separates the dura mater from bone?
Fat-filled epidural space
What is the nature of the dura mater supplying the spinal cord?
Tough, fibrous
What is the nature of the arachnoid mater surrounding the spinal cord?
Thin, delicate
What is the nature of the pia mater surrounding the spinal cord?
Thin layer attached to the surface of the cord
What lies between the arachnoid mater and pia mater?
Subarachnoid space containing CSF
How does CSF enter the subarachnoid space surrounding the spinal cord?
By leaving the lateral and median apertures of the ventricular system
What are denticulate ligaments?
Extensions of the pia mater, extending laterally from the spinal cord to attach to the walls of the spinal canal