Spinal cord Flashcards
Describe the Spinal Cord
Roughly cylindrical (about 45 cm long)
Continuous: Above with medulla oblongata – at the level of foramen magnum
Tapers below into conus medullaris – at the level of the lower border of L1
What is the Cervical Enlargement of the Spinal Cord?
- Contains Roots C5- T1
- Forms the brachial plexus
- opposite vertebra
What is the Lumbosacral enlargement of the spinal cord?
- Roots L2 to S3
- Lumbar and sacral plexus
- T9 to L1
Spinal Cord at 3rd month of fetal life
occupies the full extent of the vertebral canal (S2)
Spinal Cord at Birth
reach the level of L3 (due to rapid growth of vertebral and dura mater than the spinal cord)
Spinal cord by adolescence
reach a definitive position approximately at the level of the disc between L1 and L2 (due to further differential growth)
What is the Filum Terminal?
At the apex of conus medullaris – the prolongation of pia mater is known as Filum terminal
it extends among the roots of the cauda equina
What is a Lumbar Punture?
A Lumbar tap (puncture) is carried out to obtain a sample of CSF for examination
subarachnoidal space (CSF space) is used to inject antibiotics, chemotherapeutic agents, and anesthetics.
What is the Anatomical basis for the lumbar puncture?
Spinal cord ends at the lower border of L1 Subarachnoid space extends to the lower border of S2
What is the ideal site for a lumbar puncture?
below the 1st lumbar vertebra
between L4 and L5
in the lateral flexed position
List the structures pierced when performing a lumbar puncture.
- Skin
- Superficial Fascia
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flavum
- Areolar tissue containing internal vertebral venous plexus
- Dura Mater
Why is only a small volume aspirated in a lumbar puncture?
can lead to herniation of the brain matter
especially in case of high intracranial pressure
What is regarded as a spinal segment?
A region of the spinal cord that gives rise to a single spinal nerve.
What forms a spinal nerve?
A number of rootlets arising from the spinal cord
Within the subarachnoid space
How many pairs of spinal nerves from the spinal cord?
31
Components of a basic spinal nerve.
Ventral/ anterior root – motor/ efferent root
Dorsal/ posterior root – Sensory/ afferent root
Where do the ventral and dorsal roots of a spinal cord unite?
they pass through the subarachnoid space
unite in the intervertebral formaina
Where doe the posterior root ganglion lie?
intervertebral foramen
The general internal structure of the spinal cord.
The inner core of grey matter (surrounding the central canal)
Enclosed by an outer covering of white matter
almost divided into two halves by the anterior median fissure and the posterior median sulcus
What is spinal grey matter?
H-shaped pillar:
Dorsal/ Posterior grey horn
Ventral/ Anterior grey horn
Connected by Grey rami communicants
How is the spinal grey matter different in the thoracic and lumbar regions?
A small lateral horn is present
What are the 4 nerve cell groups in the dorsal grey horn?
- Substantia Gelatinosa
- Nucleus Propria
- Nucleus Dosalis (Clarke Column)
- Visceral afferent nucleus
The 2 nerve cell groups that are present throughout the spinal cord.
Substantia Gelatinosa
Nucleus Propria (Main cell bulk)
Where is the Nucleus dorsalis?
C8 -L4
