Pelvic girdle
The pelvic brim is defined by a line formed by the upper margin of the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory the anterior margin of the superior sacrum posteriorly.
The medial tract has a "straight" interspinalesintertransversariiand spinalis and an "oblique" multifidus and semispinalis component, both of which stretch between vertebral processes; the former acts similar to the muscles of the lateral tract, while the latter function unilaterally as spine extensors and bilaterally as spine rotators.
Pelvic Inlet The pelvic inlet marks the boundary between the greater pelvis and lesser pelvis. The pubis curves medially, where it joins to the pubis of the opposite hip bone at a specialized joint called the pubic symphysis.
A simple method of measurement was described by the British orthopedist Philip Willes and is performed by using an inclinometer. The pelvic inlet determines the size and shape of the birth canal, with the prominent ridges key areas of muscle and ligament attachment.
This represents the lateral border of the pelvic inlet.
The pubic body is joined to the pubic body of the opposite hip bone by the pubic symphysis. The Hip Bone.
Pelvic girdle anatomy
The anthropoid pelvis is characterized by an oval shape with a greater anteroposterior diameter. Mens, J. The extensors and flexors act on the knee joint, while the adductors mainly act on the hip joint. The android pelvis is a female pelvis with masculine features, including a wedge or heart shaped inlet caused by a prominent sacrum and a triangular anterior segment. Its irregular fibers blend with the periosteum. The dorsal hip muscles are either inserted into the region of the lesser trochanter anterior or inner group or the greater trochanter posterior or outer group. This serves as the attachment for the posterior thigh muscles and also carries the weight of the body when sitting. Homo erectus and all later fossil hominins, including Neanderthals , had fully modern pelvises. A pillow to support the bump and legs while in bed can also minimise the pain. In heavy mammals, especially in quadrupeds, the pelvis tend to be more vertically oriented because this allows the pelvis to support greater weight without dislocating the sacroiliac joints or adding torsion to the vertebral column. Fig 4 — The borders of the pelvic outlet.The iliopsoas consists of psoas major and occasionally psoas minor and iliacusmuscles with separate origins but a common insertion on the lesser trochanter of the femur. The pelvis has several important functions. During pregnancy it is also produced by the placentachorionand decidua.
Giving birth with this type of pelvis is associated with problems, such as transverse arrest. Other animals[ edit ] The pelvic girdle of the dinosaur Falcarius utahensis The pelvic girdle was present in early vertebratesand can be tracked back to the paired fins of fish that were some of the earliest chordates.