The pelvic girdle consists of a pair of i know well bones, additionally known together the coxal bones. Every bone is consisted of of three individual bones the fuse with each other over the first 20 years of life. These bones are recognized as the ilium (IL-e-um; plural, ilia), ischium (ISH-e-um, ischia), and pubis (PU-bis). The ilium is the many superior and largest portion of the coxal bone. It is firmly connected to the sacrum by the sacroiliac joint. The ischium forms the most inferior and posterior part of the coxal bone; the is the portion of the pelvic girdle the supports the body as soon as seated and it is typically known as the “sits bone”. The pubis creates the many anterior section of the pelvic girdle and also joins the 2 coxal bones with each other at the pubic symphysis joint.

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The ilium is the largest and also the most superior of the three bones that form the coxa (hipbone or hip joint). The largest region of the ilium is the ala, an area the resembles the shape of one elephant’s ear, has a huge flat surface ar that is slightly concave as soon as viewed from an anterior direction. Along the superior edge of the ala is a widened bony ridge recognized as the iliac crest. The iliac comb protrudes laterally towards the body’s surface it is the palpable ridge the the hip and acts as critical muscle attachments site. In ~ the finish of the iliac crest, the ilium narrows toward its center to kind the anterior superior iliac spine (A.S.I.S.) and the posterior superior iliac spine(P.S.I.S.) of the ilium. The then transforms again just inferior to this spines to form the anterior inferior iliac spine (A.I.I.S.) and the posterior worse iliac spine (P.I.I.S.).

Inferior come the ala, the ilium widens to type the body. In between the ala and the human body is the greater sciatic notch, a big V-shaped notch in the posterior ilium that allows the sciatic nerve to pass through the pelvis in order come innervate the reduced limb.


The ischium is the posterior inferior part of the pelvis. Posteriorly, bony prominences kind the ischial tuberosity or every side that the within pelvis and support the weight of the human body in a sitting position. The ischial ramus is a the thin, flattened component of the coxal bone, i beg your pardon ascends from the lower part of the body and also joins the inferior ramus of the pubis joint, suggested in adults by a increased line. The an unified rami space sometimes called the ischiopubic ramus. The obturator foramen a big opening created by both rami that the ischium and the pubis. This opening permits for the i of significant blood vessels and also nerves come the legs and feet.


The pubis forms the many anterior section of the coxal bones. The huge medial section of the pubis is recognized as the pubic body. Located superiorly on the body is a tiny protrusion the is well-known as the pubic tubercle. The superior pubic ramus is the segment the bone the passes laterally indigenous the pubic body to connect to the ilium. The narrow ridge that runs follow me the exceptional margin of the exceptional pubic ramus is the pectineal line. The pubic arch is a bony landmark developed by the pubic symphysis. Expanding downward and also laterally indigenous the human body is the inferior pubic ramus. The worse pubic ramus extends bottom to join the ischial ramus. With each other these sign up with to type the ischiopubic ramus, i m sorry extends indigenous the pubic human body to the ischial tuberosity. The turning back V-shape developed as the ischiopubic rami indigenous both political parties come with each other at the pubic symphysis and also is called the subpubic angle.

Together, the ilium, ischium and pubis and type the acetabulum, a cup-like framework that develops the socket of the i know good joint and also articulates through the head of the femur. The articular surface ar of the acetabulum is 5cm and also has a smooth moon-like appearance called the lunate surface.

Figure 1. Chart demonstrating the coxal bone’s three regions. These regions are made up of people bones the were fused with each other over the first 20 years of human life. The ilium creates the large, fan-shaped remarkable portion, the ischium forms the posterioinferior section and the pubis develops the anteromedial portion.

Sacrum and also Coccyx

The sacrum (SAY-crum) forms the posterior aspect of the pelvis. It is a triangular shaped bone consisted of of 5 sacral vertebrae (S1-S5), which starts to fuse during adolescence and also finishes fusing by early on adulthood. It has four bag of anterior and posterior foramen, i beg your pardon decrease in size inferiorly. The sacrum transmits the load of the body and helps stabilize the pelvis. The sacrum articulates top top its superior facet (the basic of the sacrum) v the lumbar vertebrae (L5) at the lumbosacral joint; on its lateral facets with the iliac bones at the sacroiliac joint; and on that is posterior element (the apex the the sacrum) with the coccyx in ~ the sacrococcygeal joint.

The coccyx (cocs-ICKS), or tailbone, is the many inferior part of the human vertebral column. It is consisted of of 2 to four fused skeletal (Co1-Co4) and is the remnant of a vestigial tail. The basic of the coccyx has a pair that transverse processes and cornua and also articulates through the sacrum in ~ the sacrococcygeal joint.

Figure 2. Diagram summarizing the anterior (left) and also posterior (right) that the sacrum and also coccyx bony features and landmarks.

The pelvis have the right to be divided into the true pelvis (lesser pelvis) and also the false pelvis (greater pelvis). The true pelvis boundaries extend native either next of the sacrum base, in addition to the arcuate line, pectineal line right into the pubic symphysis. The bony attributes of the true pelvis include a boney ridge, pelvic brim and also the enclosed space is the pelvic inlet. ~ above the other hand, the false pelvis is the upper part of the pelvis and also its boundaries include portions of the premium ilium to the pelvic brim.

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Comparison the Male and also Female Pelvis

The differences between the male and female structure of the pelvis are pertained to human duty and body size. In general, the skeleton of a male pelvis room thicker and heavier, i m sorry is an adaptation to help support the an ext muscular and physical build of males. In comparison, the main differences in the form of male and females are due to physiological adaptation the childbirth. The female pelvis is bigger and broader and usually smoother compared to the males that have actually a rougher, larger oval inlet in shape. The political parties of the male’s pelvis converge indigenous the inlet to the outlet, vice versa, the sides of the female pelvis are more comprehensive apart. The angle in between the inferior pubic rami is acute (roughly 70 degrees) in men, yet obtuse (90-100 degrees) in women. The males sacrum is longer, narrower, straighter and has a pronounced sacral promontory. The woman sacrum is shorter, wider, curved more posteriorly and also has a less pronounced sacral promontory. The acetabula are wider apart in females contrasted to males which is more narrow. The acetabulum faces more laterally in males and more anteriorly in females. Consequently, the leg have the right to move forward and also backward in a solitary plane when males walk. In females, the leg must swing forward and inward, from whereby the pivoting head of the femur move the leg earlier in another plane. The change in edge of the femoral head provides the female gait its characteristic of swinging hips.