Overview
This lecture covers the anatomy and functions of the cervical spine, highlighting its key structures, movement, and the roles they play in protecting the spinal cord and supporting the skull.
Structure of the Cervical Spine
- The cervical spine supports the skull and enables head movement to direct vision.
- Seven vertebrae (C1-C7) form the cervical spine, with C1 (atlas) connecting to the skull and C7 joining the thoracic spine.
- The atlas (C1) is shaped to allow a wide opening for the spinal cord as it exits the skull.
- The axis (C2) has the dens, a bony projection allowing head rotation.
- Vertebrae are stacked to create the spinal column, the main upright support of the body.
Key Components and Features
- Each vertebra from C2 to C7 has a vertebral body and a bony ring formed by pedicles and laminae.
- The spinal canal, formed by stacked rings, protects the spinal cord.
- Spinous processes are posterior projections felt at the back of the neck.
- Transverse processes project sideways and have a transverse foramen for arteries supplying blood to the brain.
- Between each vertebra are facet joints covered by smooth articular cartilage for low-friction movement.
Joints, Ligaments, and Discs
- Facet joints connect vertebrae and allow neck movement; each vertebra (except the top) has two on each side.
- Neural foramen are openings between vertebrae for nerve roots to exit the spinal cord.
- Ligaments (anterior, posterior longitudinal ligaments, and ligamentum flavum) stabilize vertebrae.
- Intervertebral discs separate vertebrae and absorb shock, with the nucleus pulposis at the center and annulus around it.
Muscles and Spinal Segments
- Anterior cervical muscles connect the rib cage, collar bone, cervical vertebrae, jaw, and skull.
- Posterior cervical muscles cover the back of the spine and form much of the neck’s bulk.
- A spinal segment includes two vertebrae, the disc between them, facet joints, and nerve roots.
Key Terms & Definitions
- Anterior — front of the neck
- Posterior — back of the neck
- Cervical vertebrae (C1-C7) — the seven bones forming the neck portion of the spine
- Atlas (C1) — top vertebra supporting the skull
- Axis (C2) — second vertebra enabling head rotation
- Dens — upward bony projection on the axis
- Spinous process — posterior bony projection on vertebrae
- Transverse process — lateral bony projection with an artery passage (transverse foramen)
- Facet joint — joint between vertebrae enabling movement
- Intervertebral disc — cushion between vertebrae, composed of the nucleus pulposis and annulus
- Ligaments — connective tissues stabilizing the spine
Action Items / Next Steps
- Review the major structures and terms associated with the cervical spine.
- Study diagrams of the cervical vertebrae and their key features.
- Prepare questions on cervical spine anatomy for discussion next session.