Spine Anatomy / Bony Markings

Cervical vertebrae

Seven vertebrae labeled C1–C7

Atlas

C1; supports the skull and has no vertebral body

Axis

C2; contains the dens

Dens / odontoid process

Tooth-like projection of C2 that allows the head and C1 to rotate

Transverse foramen

Openings in cervical transverse processes for passage of vertebral vessels

Bifid spinous process

Split spinous process commonly seen in cervical vertebrae

Vertebral body

Large anterior portion of a vertebra that supports weight

Vertebral foramen

Opening through which the spinal cord passes

Pedicle

Short bridge connecting the vertebral body to the posterior elements

Lamina

Portion of the vertebral arch between the transverse and spinous processes

Spinous process

Posterior projection of a vertebra; muscle and ligament attachment site

Transverse process

Lateral projection from a vertebra; muscle and ligament attachment site

Superior articular process

Projection that articulates with the vertebra above

Inferior articular process

Projection that articulates with the vertebra below

Intervertebral foramen

Opening between adjacent vertebrae through which spinal nerves exit

Thoracic vertebrae

Twelve vertebrae labeled T1–T12 that articulate with the ribs

Costal facets

Articular surfaces on thoracic vertebrae for rib attachment

Lumbar vertebrae

Five large vertebrae labeled L1–L5 designed for weight bearing

Sacrum

Triangular bone formed by five fused sacral vertebrae

Sacral promontory

Anterior projecting edge of the first sacral vertebra

Sacral foramina

Openings in the sacrum for passage of nerves

Sacral canal

Continuation of the vertebral canal through the sacrum

Coccyx

Terminal portion of the vertebral column; usually formed by fused coccygeal vertebrae

Zygapophyseal joints

Facet joints between the articular processes of adjacent vertebrae

Intervertebral disc

Fibrocartilage structure between vertebral bodies that cushions the spine