Anatomy of the Central Nervous System (cont.)

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Medical Author:

Fernando Dangond, MD

Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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The Spinal Cord

The spinal cord is an extension of the brain and is surrounded by the vertebral bodies that form the spinal column (see Multimedia File 3). The central structures of the spinal cord are made up of gray matter (nerve cell bodies), and the external or surrounding tissues are made up of white matter.

Within the spinal cord are 30 segments that belong to 4 sections (cervical, thoracic, lumbar, sacral), based on their location:

Eight cervical segments: These transmit signals from or to areas of the head, neck, shoulders, arms, and hands.

Twelve thoracic segments: These transmit signals from or to part of the arms and the anterior and posterior chest and abdominal areas.

Five lumbar segments: These transmit signals from or to the legs and feet and some pelvic organs.

Five sacral segments: These transmit signals from or to the lower back and buttocks, pelvic organs and genital areas, and some areas in the legs and feet.