Spinal Motion Segment: C7-T1 (Cervicothoracic Junction) Animation

Video Transcript

The C7 T1 spinal motion segment, also called the cervicothoracic junction, is located where the cervical spine and thoracic spine connect. It consists of the C7 and T1 vertebrae, and the anatomical structures connecting them. This segment provides minimal flexibility, supports the neck and head above, and protects the spinal cord and nerve pathways.

The C7 and T1 vertebrae are connected in the back by a pair of facet joints that allow limited forward, backward, and twisting motions. The first rib attaches to the T1 vertebra at the costovertebral joint. This connection to the rib cage adds support and rigidity to the cervicothoracic junction.

Articular cartilage enables the facet joints to move smoothly, while muscles, tendons, and ligaments help hold the vertebrae together. A strain or tear to any of these tissues can cause neck pain and stiffness.

Between the vertebrae is an intervertebral disc that provides flexibility and shock absorption. The disc is made up of a tough outer ring called the annulus fibrosus, which encapsulates a gel-like interior called the nucleus pulposus.

The spinal cord lies within the vertebral foramen, a space formed by the vertebral arch and vertebral body.

The C8 spinal nerve branches out from the spinal cord and exits on each side through the intervertebral foramen. It receives sensory information from skin on the pinky side of the hand and forearm. The C8 nerve also has a motor component that sends signals to various muscles, such as the finger flexors.

Spinal conditions including disc herniation or facet joint osteoarthritis may irritate the C8 nerve and cause radicular pain, tingling, numbness, and weakness along the path of the nerve. If the spinal cord is compressed at the C8 spinal level, it may cause pain and neurological deficits in the arms, legs, or anywhere below the level of compression.