Where is the sacrum

When it comes to the sacrum, many people are unfamiliar with it, but it is indeed a very important part of the human body. The sacrum refers to the bone located below the fifth lumbar vertebra and above the coccyx. The sacrum is also a very fragile part of the human body. Therefore, if you are not careful, it will easily cause sacrum injury or related diseases. Understanding the knowledge related to the sacrum is of great significance for preventing related diseases.

1. Where is the sacrum?

The human sacrum is below the fifth lumbar vertebra. It is formed by the fusion of five sacral vertebrae and is triangular in shape, with the base facing upward and the tip facing downward. It is connected to the fifth lumbar vertebra. Below the sacrum is the coccyx.

2. Sacrum

It is formed by the fusion of five sacral vertebrae, and is divided into the sacral base, side, sacral apex, pelvic surface and dorsal surface. It is in an inverted triangle and constitutes the posterior superior wall of the pelvic cavity. The lower end is the sacral apex, which articulates with the coccyx, and the wide base at the upper end is combined with the fifth lumbar vertebra to form the lumbar sacral angle. The sacral pelvic surface is concave and the dorsal surface is kyphotic to increase pelvic capacity. The sacrum has obvious gender differences, being long and narrow in men and short and wide in women to accommodate the needs of childbirth.

3. Related diseases and treatment

The incidence of sacral tumors is low, and early symptoms are hidden. When patients seek medical treatment, the tumors are often large. The sacrum has a very rich blood supply, the surrounding anatomical structure is complex, and there is little local soft tissue coverage, making surgery difficult. Surgical treatment involves serious complications such as sacral nerve root injury, pelvic organ injury, non-healing of incisions and infection.

Anterior approach: For high-positioned sacrum (such as above S2) and huge soft tissue mass, when the tumor cannot be completely removed by the posterior approach alone, anterior surgery is performed first to free the tumor, and then the posterior approach is performed. During anterior approach surgery, the patient is in the supine position, an inverted eight-shaped incision is made in the lower abdomen, and the tumor is freed extraperitoneally. While freeing the tumor, the internal iliac artery can also be ligated to reduce bleeding during posterior approach surgery.

Posterior approach: The basic incision is a posterior midline straight incision or an inverted Y-shaped incision. The gluteal muscles and erector spinae muscles on both sides are pulled apart to the sides, the tip of the coccyx is touched and the surrounding soft tissue is peeled off. Then the sacrotuberous ligament, sacrospinous ligament and piriformis muscle are cut off from bottom to top, and the anterior sacral fascia is separated with the fingers. At this time, pay attention to protecting the rectum, and use wet gauze to plug the soft tissue gap in front of the rectum and sacrum, and push the rectum forward.

Tumor resection: For primary malignant tumors of the sacrum and some low-lying metastatic tumors, large-scale complete resection was performed, and for giant cell tumors of the bone and benign lesions of the sacrum (one case was fibrous dysplasia), surgical curettage was performed.

Sacral reconstruction: Restoration of pelvic ring stability after S1 corpectomy. The lower lumbar spine and pelvic internal fixation reconstruction technique was used according to the extent of resection.

The patient is required to fast as usual after the operation and eat liquid food after the gas is discharged; a normal pressure drainage tube is placed for drainage for more than 1 week; and a urinary catheter is retained for 1 week.