VAN 121: Veterinary Gross Anatomy-II (2+2)

GRAY MATER

• The gray mater of the spinal cord in transverse section resembles roughly the capital letter ‘H.’
• The cross bar being the gray commissure. Each half consists of a dorsal and a ventral horn.
• The dorsal horn is elongated, narrow and reaches the surface of the cord at the dorsolateral fissure at the entrance of the dorsal root fibres. It contains sensory neurons.
• The apex of the dorsal column is covered by a mass of translucent nervous tissue called substantia gelatinosa that contains cell bodies in the pain and thermal pathways. From the middle of the cervical region to the lumbar region, there is a medial projection of gray mater at the ventral part of the dorsal column known as nucleus dorsalis.
• A pointed projection from the lateral surface of gray mater, opposite the gray commissure is known as lateral horn or intermedio-lateral column and is seen only in the thoracic, lumbar and middle sacral levels. It contains autonomic motor neurons.
• The ventral horn is rounded, wider and is separated from the surface of the cord by the white mater through which pass the ventral root fibres. It contains somatic motor neurons.