The spinal cord constitutes the portion of the central nervous system located within the vertebral canal. It is responsible for establishing connections between the brain and peripheral nerves and for the formation of reflexes. In adults, it extends from the level of the foramen magnum to the level of the L1-2 vertebrae. It is continuous with the medulla oblongata above. Below, it extends as the filum terminale. The spinal cord consists of 31 segments. Thirty-one pairs of spinal nerves emerge from each segment, corresponding to its number. When viewed in a transverse section, the spinal cord consists of two parts: the gray matter internally and the white matter externally. The substantia grisea (gray matter) is composed of nuclei. It is examined in three parts: the anterior horn, posterior horn, and lateral horn. The anterior horn consists of motor neurons, the posterior horn consists of sensory neurons, and the lateral horn consists of autonomic neurons. The central canal passes through the center of the gray matter and contains cerebrospinal fluid (CSF). The substantia alba (white matter) consists of tracts and fasciculi. It consists of the anterior funiculus, posterior funiculus, and lateral funiculus. The spinal cord is enclosed in a covering called the meninges, which is formed by the spinal dura mater, spinal arachnoid mater, and spinal pia mater. The subarachnoid space is located between the spinal arachnoid mater and the spinal pia mater. This space is filled with cerebrospinal fluid (CSF).