Question

Describe in your own words the anatomical structure of the spinal cord. For example, you can describe the spinal cord from the superior to the inferior part.

Answer 1

The spinal cord is a cylindrical structure of nervous tissue composed of white and gray matter,The spinal cord extends from the base of the skull to the first or second lumbar vertebra. spinal cord is having bundle of nervous tissue, the bundle of nervous tissue emerging from dorsal part are called dorsal root, bundles of fibers emerging from the ventral part  are called ventral root, dorsal root and ventral root merge to form spinal nerves, there are 31 spinal nerve. The spinal nerve goes to two branches one branch goes to the front part of the body and the other goes to back part of the body. Branch which goes to front part is known as ventral ramus and which goes to back part of body is known as dorsal ramus.

The spinal cord is divided into four different regions: the cervical, thoracic, lumbar and sacral regions. The cord is segmentally organized. There are 31 segments, defined by 31 pairs of nerves exiting the cord. These nerves are divided into 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal nerve.

In the cervical segments, there are 7 cervical vertebrae and 8 cervical nerves C1-C7 nerves exit above their vertebrae whereas the C8 nerve exits below the C7 vertebra. It leaves between the C7 vertebra and the first thoracic vertebra. Therefore, each subsequent nerve leaves the cord below the corresponding vertebra. The first cervical vertebrae is known as atlas and second is known as axis.

In thoracic vertebrae there are 12 pairs of thoracic nerves, these nerves emerge below thoracic vertebrae.

In the abdomen region, there are five lumbar vertebrae, and five pair of lumbar nerves emerge below vertebrae.

Sacrum is the fusion of five different bones, through this five pair of sacral nerve emerge.

Coccyx is formed by fusion of four bones, but through this only single coccygeal nerve passes.

The spinal cord is sheathed in the same three meninges as is the brain: the pia, arachnoid and dura. The dura is the tough outer sheath, the arachnoid lies beneath it, and the pia closely adheres to the surface of the cord