The spine is an assemblage of vertebrae from the cranium to the coccyx that allows for some movement in the thorax while simultaneously protecting the spinal cord, a bundle of nerves that transmits signals between the brain and the rest of the body. “Spine” comes from the Latin spina, which means “” and which was used already in antiquity to indicate the backbone. The spine is also known as the “” (Lat. columna vertebralis).

Each vertebra consists of a series of bony processes and openings or spaces. The latter are called by the Latin word for “opening,” (pl. ). The roughly cylindrical vertebral body is the largest part of the structure and contains a semifluid interior called the nucleus pulposus (“fleshy nucleus”; nucleus literally means “”), surrounded by a band of tissue called the anulus fibrosus (“fibrous little ”; sometimes incorrectly spelled “annulus”). On the opposite side of each vertebra is the spinous (“thornlike”) process, flanked by two transverse (“”) processes. The transverse processes are joined to the vertebral body by two , narrow stem-like structures that get their name from the Latin word for “little foot.” On the top and bottom of each vertebra are the superior (“”) and inferior (“”) articular processes, which as the names suggest are responsible for joining each vertebra with the one directly above and below it. The spinal cord itself (Lat. spinalis) runs through the main foramen and is composed of an inner core of gray matter, an outer layer of white matter, and the three meninges: the dura mater, arachnoid, and (see p. 147 for the etymologies of these terms).

The vertebrae are divided into sections based on their location along the spine. Directly above the sacrum and coccyx are the vertebrae (Lat. “loin”), which are located directly under the vertebrae (Grk. “breastplate”). As you know, the cervical vertebrae are those located in the (Lat. cervix). These are somewhat different in shape from the other vertebrae and contain more foramina (e.g., the transverse foramen, which houses the vertebral artery and vein). There are also present (“at the rear”) and (“at the front”) tubercles of the transverse process (“tubercle” is a diminutive term meaning “little swelling” or “little eminence”). Some cervical vertebrae are given special names: for example, the vertebra , the seventh and lowest, is so called because it has a particularly prominent spinous process. The first, which supports the base of the cranium, is named after the mythological character (see p. 328).