Question

The Spinal Cord

Anatomical location: Use directional terms to describe the location such as superior to, inferior to, anterior, etc.

Anatomical description: Include only the anatomical description; do not include any function or microscopic description.

Types of cells and tissues present in the organ: Just include a microscopic description; do not include anything else.

Answer 1

Spinal cord--

• Anatomical location :

Spinal cord is the long (45 cm average) lower cylindrical part of central nervous system, occupying the upper two third of vertebral canal.

Superiorly, it begins at the Foramen Magnum as the continuation of medulla oblongata.

It usually terminates opposite to the intervertebral disc between L1 and L2 vertebra.

In the foetus, the spinal cord extends upto the level of lower border of S2 vertebra.

• Anatomical description :

The spinal cord is cylindrical structure, which is flattened anterior posteriorly to some extent.

Its lower end tapers into a cone forming structure called conus medullaris.

The spinal cord give rise to 31 pairs of spinal nerves.

The anterior aspect of spinal cord has a deep midline groove called anterior median fissure.

The posterior aspect of spinal cord presents a shallow posterior median sulcus.

The spinal cord provides the attachment of spinal nerve roots.

Spinal cord contents for regions - cervical, thoracic, lumbar and sacral.

The cauda equina is a leash of lumbar (except L1), sacral and coccygeal nerve roots around the filum terminal in the pool of CSF.

The two enlargements present on the spinal cord are - cervical enlargement and lumbar enlargement.

• Types of cells and tissues present in the spinal cord :

In the cross section of the spinal cord, the grey matter is seen as 'H' shaped or butterfly shaped fluted column extending through the length of the spinal cord.

The cut section of spinal cord shows inner grey matter and outer white matter.

The inner grey matter presents of pair of broad and short ventral horn and a pair of narrow and long posterior horn connected in the midline by grey commissure.

Some segments of spinal cord also have a pair of lateral horns on each side at the junction between the anterior and posterior horns.

The grey commissure is traversed longitudinally by central canal. The central canal is lined by ependymal cells.

The entire spinal cord is surrounded from outside inward by dura mater, arachnoid mater and pia mater.