Final answer:
A herniated intervertebral disc between the fifth and sixth cervical vertebrae compresses the spinal nerve exiting through the intervertebral foramen, causing pain and muscle weakness in the affected nerve's supply regions.
Step-by-step explanation:
Herniation of the intervertebral disc between the fifth and sixth cervical vertebrae will compress the spinal nerve at the point where it exits through the intervertebral foramen. This herniation occurs when the inner part of the disc, called the nucleus pulposus, protrudes through the weakened fibrous outer layer known as the annulus fibrosis. The compression of a spinal nerve can lead to pain and/or muscle weakness in the areas of the body that the nerve supplies. Intervertebral discs are composed of fibrous cartilage and lie between adjacent vertebral bodies. Their main functions are to act as ligaments that bind vertebrae together, to form joints allowing for spinal movement, and to absorb shocks from activities such as walking and running. The disc's gel-like nucleus pulposus enables it to change shape and provide cushioning, but it can herniate if the annulus fibrosus becomes weakened, leading to nerve compression.