The pinyin of sacrum: dǐ gǔ.
Related explanation
The sacrum (sacrum) is composed of 5 sacral vertebrae. It is divided into the sacrum base, sides, sacral tip, pelvic surface and dorsal surface. It is in the shape of an inverted triangle. The lower end of the upper and posterior wall of the pelvic cavity is the tip of the sacrum, which articulates with the coccyx.
The broad base at the upper end combines with the fifth lumbar vertebra to form the lumbosacral angle. The sacropelvic surface is concave and the dorsal surface is kyphotic to increase the pelvic capacity. The sacrum has obvious gender differences. Men are long and narrow, and women are short and wide to adapt to the needs of women during childbirth.
The front edge of the sacrum base protrudes and is called the sacral promontory. The oval bone surface above the sacrum base is the upper surface of the first sacral vertebral body and forms the lumbosacral joint with the lower surface of the fifth lumbar vertebral body. The two sides of the base are smooth and are called sacral wings.
The upper parts of both sides of the sacrum are rough, which is caused by the union of the transverse processes of the upper three sacral vertebrae. This part is auricular-shaped, also known as the auricular surface, and the corresponding articular surface with the ilium forms the sacroiliac joint. The lower edge of the auricular surface is usually located in the middle and lower part of the third sacral vertebra, but it can be as high as the second sacral vertebra or as low as the upper part of the fourth sacral vertebra.
The height of the sacroiliac joint is not directly related to the height of the sacrum. If the sacrum is tall and long, the sacroiliac joint can be short, while if the sacrum is low and short, the sacroiliac joint can be long. The narrow part of the lateral edge of the sacrum below the sacroiliac joint is the attachment point of the sacrotuberous ligament and sacrospinous ligament.
The height of the sacrum is related to the number of sacral vertebrae. Due to the migration of the lumbar vertebrae or coccyx vertebrae, the number of sacral vertebrae may increase. For example, when the sacrum contains the fifth lumbar vertebra, it is called lumbar sacralization. The lumbar sacralization may be complete or incomplete. Usually one side is underdeveloped, or only the transverse processes are fused while the lumbar body and spinous process are still separated.
Related diseases and treatments
The incidence of sacral tumors is low, and early symptoms are insidious. The tumors are often large when patients seek treatment, and the blood supply to the sacrum is very rich. The surrounding anatomical structures are complex and local There is little soft tissue coverage and the operation is difficult. Surgical treatment involves serious complications such as sacral nerve root injury, pelvic organ injury, non-healing of the incision and infection, etc.
Anterior approach. For high sacrum (such as S2 and above), and the soft tissue mass is huge, and the tumor cannot be completely removed by the posterior approach alone, the tumor should be freed by the anterior approach first, and then the posterior approach can be performed. During anterior surgery, a supine position is used, an inverted figure-of-eight incision is made in the lower abdomen, and the tumor is freed outside the peritoneum. While freeing the tumor, the internal iliac artery can also be ligated to reduce bleeding during posterior surgery.