Dr. Martin's notes

Friday September 2, 2016

The Spinal Column

Also known as the vertebral column is broken down into 5 regions: Cervical, Thoracic, Lumbar, Sacral, and Coccygeal. There are two types of spinal curves, two concave (Cervical and Lumbar) and two convex (Thoracic and Sacral).

Spine = 7 Cervical (neck), 12 Thoracic (middle back) with ribs attached, 5 lumbar, 1 sacral & 2 pelvic
Vertebra(e) consist of a body (weight bearing part), lamina & pedicles (which form arch), spinous process and 4 articular processes

The spinal column is made up of 24 individual segements, plus the sacrum and the coccyx (tailbone). At birth the sacrum consists of 5 separate segements and the coccyx consists of 4 segments. These segments have no disc material between them and ossify (fuse) generally by age 12-14.

A vertebra (plural vertebrae) consists of the body, the round weight bearing portion of the segment, the spinal arch, consisting of the lamina and pedicles (which make up the opening for the spinal canal), the spinous process (where the two lamina meet....the bumps you feel up your back) and the transverse processes, wing like projections from the sides of the segment. At the lamina/pedicle junction there are superior and inferior articular facets that meet with the opposing vertebral segment. Between each segment is a tough, tensile material that allows for movement. This is the spinal disk and it consists of two parts, the outer ring (annulus) which is attached to the bone with strong Sharpie's Fibers, and a soft middle section, the nucleus, which moves around like a ball bearing in the disk.

The Cervical spine consists of 7 segments, which are smaller and have articular surfaces that allow for rotation, flexion, extension and tilting of the head. These segments are unique because one of the major arteries to the brain pass through the transverse processes.

The Thoracic spine consists of 12 vertebrae and is less moveable, due to the attachment of the ribs. All 12 pairs of ribs attach to the spine, but only the top 10 pairs come all the way around to the front to articulate with the sternum. The bottom two pairs are called "floating ribs".

The Lumbar spine consists of 5 vertebrae, and are the largest in size, due to supporting the weight of the body. The lumbar curve apexes at the L3-4 level often causing undue stress on L4 and L5. Consequently, this is where the majority of low back injuries occur.

The Sacrum and Coccyx are part of the Pelvis which also includes the two large illiac bones. There are sockets in the illiac bones for the leg (femur) called the acetabular cavities. There are two large openings in the front of the pelvis called the obturator foramen. Where the illiacs meet in the front is called the symphysis pubes.

Each joint between the vertebrae has a disk which is made up of a tough annulus (ring) and soft nucleus (center) and articular capsules (shock absorbers), ligaments and muscle attachments
There are articulations for the ribs between each thoracic vertebral motor unit.

NOTE: Cervical injuries are approached with the most caution because if not handled properly, you can CAUSE further injury.