Sacral vertebrae (S1-S5): located in the pelvisīetween the vertebral bodies (except cervical vertebrae 1 and 2) are discs serving as a supportive structure for the spine.Lumbar vertebrae (L1-L5): located in the lower back.Thoracic vertebrae (T1-T12): located in the upper back and attached to the ribcage.Cervical vertebrae (C1-C7): located in the neck.

The spine itself is divided into four sections, not including the tailbone: Five vertebrae are fused together to form the sacrum (part of the pelvis), and four small vertebrae are fused together to form the coccyx (tailbone). The spinal cord lies inside the spinal column, which is made up of 33 bones called vertebrae. A fibrous band called the filum terminale begins at the tip of the conus medullaris and extends to the pelvis.Īt the bottom of the spinal cord (conus medullaris) is the cauda equina, a collection of nerves that derives its name from the Latin translation of 'horse's tail' (early anatomists thought the collection of nerves resembled a horse's tail).Ĭerebrospinal fluid (CSF) surrounds the spinal cord, which is also shielded by three protective layers called the meninges (dura, arachnoid and pia mater). The cervical (neck) and lumbar (lower back) segments house the spinal cord's two areas of enlargement. The spinal cord is about 18 inches (45 centimeters) in length and is relatively cylindrical in shape. The spinal cord begins at the bottom of the brain stem (at the area called the medulla oblongata) and ends in the lower back, as it tapers to form a cone called the conus medullaris.Īnatomically, the spinal cord runs from the top of the highest neck bone (the C1 vertebra) to approximately the level of the L1 vertebra, which is the highest bone of the lower back and is found just below the rib cage. The spinal cord is an extension of the central nervous system (CNS), which consists of the brain and spinal cord.

Spine labeled