Posterior margin of ischium, a gap below ischium of foramen magnum. The anterior boundary of ischial foramen is ischial body (ischial notch at the posterior edge of ischial foramen), the upper boundary is ischial spine and sacrospinous ligament, and the posterior boundary is sacral tubercle ligament. The structures passing through the ischial foramen include the obturator internus tendon and the nerve to the obturator internus muscle, the internal pudendal blood vessels and the pudendal nerve.
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1, anatomical structure
It consists of three bones, the ilium is on the top, the pubic bone is in the front and the ischium is in the back and the bottom. Before adulthood, these three bones were separated, and after adulthood, these three bones were combined into 1 hip bone at acetabulum. The acetabulum is a deep depression in the lateral middle of the hip bone, which accommodates the femoral head to form the hip joint. Hip bone is an integral part of pelvis.
A pelvic limb with bone consists of ilium, pubis and ischium. The three bones intersect at the acetabulum and are connected with each other through cartilage; The pubic bone and ischium are connected along the pelvis. Cartilage can continue to proliferate and ossify for a certain period of time, and the three bones will heal each other after stopping proliferation. In addition, the edges and corners of ilium and ischium still form bony processes during development.
2. Clinical anatomy
Liang Qiu is located in the lower part of the front thigh, with a distance of 65438 0.5 inches between the two sides. Two o'clock on one side.
Lateral point of hip: point under skin → subcutaneous tissue → lateral femoral muscle. There are anterior cutaneous branches of femoral nerve and lateral femoral cutaneous nerve in the superficial layer. In the deep layer, there are branches or branches of the descending artery and vein of the lateral circumflex femur.
Acupoints on the medial side of hip: subapical skin → subcutaneous tissue → medial thigh muscle. There are anterior cutaneous branches of femoral nerve in the superficial layer. There are muscular branches of deep femoral artery in the deep layer.
The ischium constitutes the posterior lower 2/5 of the acetabulum, with an average length of 85.85mm for males and 80.8mm for females, and is divided into two parts: ischium body and ischium branch. The ischium is similar to a triangular prism, which supports the weight of the body when sitting, and can be divided into front and rear edges and inner and outer edges. The leading edge is sharp, forming the obturator trailing edge. The posterior margin is thick and moves upward to form the posterior margin of ilium, which constitutes the lower part of the great sciatic notch.
The average height of the great sciatic notch is 36.9 mm for men and 34.5 mm for women. There is a triangular protrusion protruding backward and inward below it, which is the ischial spine, and levator ani, coccyx muscle, supramalleolar muscle and sacrospinous ligament are attached to it, which is the boundary of ischial foramen. A small ischial notch is formed below the spine, extending down to the ischial tubercle.
The lateral surface of the ischial body faces outward and downward, and the obturator external muscle is attached, while the medial surface is smoothly attached to the obturator internal muscle, followed by the attachment part of the hip joint capsule. The front end of the sciatic branch moves to the inferior pubic branch, and the back part of the transition between the sciatic body and the sciatic branch is thick and thick, which is the ischial tubercle.
The ischial tubercle is oval in appearance and triangular in cross section. It is divided into upper and lower parts by transverse ridge. Semimembranous muscle is attached to the upper part, while semitendinosus muscle, long head of biceps femoris and ischium of adductor muscle are attached to the lower part. Here, it is a traction epiphysis. In addition, the lateral margin of ischial tubercle still has the origin of quadratus femoris, the upper margin has the origin of lower ankle, and the lower part of medial margin is the attachment of sacral tubercle ligament.