The sacrum supports the lumbar vertebral column and transmits loads from the trunk to the pelvic girdle and into the lower limbs. It consists of five rudimentary vertebrae fused to form a single wedge-shaped bone. The upper border articulates with the fifth lumbar vertebra. The inferior border articulates with the coccyx. Laterally, the sacrum articulates with the iliac bones to form the sacroiliac joints. The vertebral foramina together form the sacral canal. The sacral canal contains the nerve roots of the lumbar, sacral, and coccygeal spinal nerves and the filum terminale.
The coccyx consists of four vertebrae fused together to form a triangular bone, which articulates with the sacrum. Except for the first vertebra, the remaining coccygeal vertebrae consist of bodies only.
Injuries of the sacral spine and nerve roots are very unusual. When they occur, they are frequently associated with fractures of the pelvis. There are multiple different classification schemes of sacral fractures that help to predict neurologic deficits and establish treatment protocols. In general, transverse fractures through the body are most significant in that they cause injury to part or all of the cauda equina. Longitudinal fractures may cause radiculopathy. If there is involvement of the central sacral canal, however, bowel or bladder dysfunction may also occur.5 Careful neurologic evaluation is essential. Motor and sensory evaluation of the sacral nerve roots should be performed. Rectal examination will assess anal sphincter tone and the bulbocavernosus reflex.
Coccygeal injuries are usually associated with direct falls onto the buttocks. Patients typically describe intense pain with sitting and straining. Diagnosis of fracture is made on rectal examination. Pain will be elicited with motion of the coccyx. X-rays are not needed. Treatment is symptomatic, and includes analgesics and use of a rubber doughnut pillow.
Was this article helpful?
This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.