Which nerve injury is related to a sacral fracture?

A sacral fracture is closely associated with injuries to the cauda equina, which is a collection of nerve roots that arise from the lower end of the spinal cord. The cauda equina is responsible for the innervation of the legs, bladder, and bowel. When a sacral fracture occurs, it can lead to compression or damage to these nerve roots, resulting in a condition known as cauda equina syndrome. This syndrome may present with symptoms such as lower back pain, loss of bowel or bladder control, and lower extremity weaknesses.

The other nerve injuries related to the choices do not have a direct association with sacral fractures. The peroneal nerve primarily innervates the muscles of the anterior and lateral compartments of the leg and is often injured due to trauma to the knee or fibula. The radial nerve is involved in arm and hand function and is most commonly affected by humeral shaft fractures. The sciatic nerve, though it runs through the pelvis and can be involved in injuries, is more typically related to hip or upper thigh damage rather than isolated sacral fractures.

Thus, the cauda equina is the most relevant nerve injury associated with sacral fractures due to the anatomical and functional implications of the nerve roots