Spinal column

The human spinal column is made up of 24 separate bones called vertebrae. From top to bottom, it consists of:

7 cervical (neck) vertebrae named, top to bottom: C1, C2, C3 to C7.

12 thoracic (mid-back) vertebrae named: T1, T2…T12

5 lumbar (lower back) vertebrae named: L1. L2…L5

One sacrum made up of 5 fused segments: S1-S5

One coccyx (beneath the sacrum) (Co)

Note: C1 is also named the atlas, after the Greek god that held the globe of the earth on his shoulders. C2 is also named the axis.

The ribs connect to the thoracic vertebrae in the back and to the sternum (breastbone) in the front.

Discs (illustration)

Intervertebral discs are between adjacent vertebrae. They separate and connect the vertebrae and help give the spine its curves, flexibility and strength. For example, the L4/L5 disc is between L4 and L5; the L5/S1 disc is between L5 and S1.

Note: There is no disc between C1 and the skull and between C1 and C2. There is a disc between the pubic bones and between the jaw and the skull (TMJ).

Cranial (skull) bones

The human skull is composed of 22 cranial bones, many of them paired. All have names.

To make things more interesting, no two skulls are identical; with different shapes, sizes, and even number of bones slightly varying from person to person.