The Spine: Support System for Body Parts of the Spine The spine is composed of many parts that function together to allow you to move...and a whole lot of other things! Let’s focus on movement for now. VERTEBRAE - The Bones of the Spine The vertebrae are the bony segments of your spine. They are joined to each other throughout the spine by "articulations" that allow smooth movement between the bones. The round part of the vertebra is called the "body" and the pointy part to the back is the "spinous process." Within each section, there are a number of bones named for their number in the segment: 7 cervical vertebrae (C1-C7), 12 thoracic vertebrae (T1-T12), 5 lumbar vertebrae (L1-L5), 1 sacrum made of 5 fused vertebrae, 1 coccyx made of 4 fused coccygeal vertebrae. The coccyx is the lowest point of the spine that bends when you sit down and acts like a shock absorber while you sit. It's also known more commonly as the tailbone. FACET JOINTS Facet joints connect the vertebrae of the spine and allow movement. One faces up and one faces down to connect with the adjacent vertebrae. DISC The intervertebral disc (or disc for short) acts like the shock absorber of the spine. There are cervical spine intervertebral discs, lumbar spine intervertebral discs, and thoracic spine intervertebral discs. It holds the bony vertebrae apart and gives space in the spinal canal for the spinal cord and its nerves to pass through on their way to the extremities of the body. Its center is the “nucleus pulposus” which is normally 80% water-filled. The outer part is the “annulus fibrosus” which is made of rubberband-like rings (annular fibers) which hold the nucleus in place. SPINAL NERVES Spinal nerves receive information from the disc and the facet joints, muscles, tendons, and ligaments. The nerves interpret this information as to touch, pressure, temperature, and, if the nerves are excessively compressed or irritated, produce pain. The spinal nerves conduct messages from the body and send them to brain for interpretation, and the brain produces a response to irritation whether that be a response of comfort or pain. CURVES and SECTIONS The spinal column has 4 curves - cervical, thoracic, lumbar and sacral - and 5 sections - cervical (C1-C7), thoracic (T1-T12), lumbar (L1-L5), sacral (S1-S5), and coccygeal. Two curves are concave posteriorly (cervical and lumbar). Two are concave anteriorly (thoracic and sacral). So, what's up with your spine? Take a quiz or just simply contact your knowledgeable Fort Wayne chiropractor at Cox Chiropractic Medicine Inc. We'll figure it out together, and get you back to enjoying your life! References Muhle C: Biomechanical aspects of the subarachnoid space and cervical cord in healthy individuals examined with kinematic magnetic resonance imaging. Spine 1998;(23)5 "This information and website content is not intended to diagnose, guarantee results, or recommend specific treatment or activity. It is designed to educate and inform only. Please consult your physician for a thorough examination leading to a diagnosis and well-planned treatment strategy. See more details on the DISCLAIMER page. Content is reviewed by Dr. James M. Cox I."