Most Things Biology

Time To Read

2–4 minutes

Date Last Modified

February 6, 2026

The pubisAnterior portion of the hip bone; meets its pair at the pubic symphysis. is the most anteriorThe front of the body or toward the front when standing in the anatomical position. of the three bones that are fused to form the coxal or hip bones.

Illustration contrasting medial and lateral views of the right coxal bone (hip bone). The medial view on the left reveals the obturator foramen. The lateral view on the right shows the acetabulum. — Right coxal bone illustration, medial and lateral views.

Superior pubic ramus
Inferior pubic ramus
Pubic crest
Obturator foramen
Acetabulum

Hip Bone Study Sheet

Let’s start with all the bones of the pelvis put together. This structure here can also be called the pelvic girdle indicating that it is a place where limbs attach. Humans also have a pectoral girdle, which is really your scapulaTriangular “shoulder blade” on posterior thorax; connects clavicle and humerus., clavicleS-shaped collarbone; connects sternum to scapula; helps brace the shoulder., and part of the humerusLong bone of the upper arm; articulates with scapula at shoulder and radius/ulna at elbow..

This structure that looks like a pad is the pubic symphysisCartilaginous joint connecting the two pubic bones at the midline.. This is an articulation or a joint, just like the hip’s ball and socket is a joint. This is a fibrous joint, held together by that pad of fibrocartilageA tough, shock-absorbing cartilage found in intervertebral discs and menisci.. This pad stretches out of shape in childbirth and can have difficulty in finding the right position. This can lead to pelvic floor issues which can then be complicated by the healing of a C-section incision. However, you can see that the hip bones are also called the coxal boneHip bone formed by fusion of ilium, ischium, and pubis; one on each side of pelvis.. They are known as the os coxa. These bones come together at this pubic symphysis.

Let’s do the easy stuff first. The big hole in the hip bone is called the obturator foramenLarge oval or round hole below acetabulum; lightens bone and allows passage of nerves/vessels.. The big depression in the hip bone is what you might want to call the hip socket. Of course, it has a more complicated name: acetabulumDeep, cup-like socket on lateral side where femur head articulates; shared by all three hip bone reg. This word means vinegar cup. The acetabulum shows us something fascinating. The hip bone is actually three different bones fused together. These bones are the iliumBroad, flaring upper portion of the hip bone; forms the “wings” of the pelvis., ischiumPosterior, lower part of the hip bone; what you sit on., and the pubis or the pubic bone. These three bones come together at the acetabulum, giving it its strength. Of course, these pictures label these structures on the right side of the pelvis. However, the acetabulum and obturator foramen are bilateral. They are on both the right and the left.

Diagram showing lateral and medial views of the right coxal bone (hip bone). Anatomical features are labeled, including the superior pubic ramus, inferior pubic ramus, and pubic crest. Anterior and posterior orientations indicated. Image labeled as Hip lateral letter 5. — Right coxal bone: lateral and medial views with labeled parts (superior/inferior pubic ramus, pubic crest). Hip lateral letter 5.

There’s this little point right at the superiorAbove or toward the upper part of the body./medial edge of the pubic symphysis. This is called the pubic crestRidge on superior surface of pubic body; attachment for abdominal muscles.. The next two structures, called rami (singular ramus) are very difficult to identify, even when presented with a 3D bone. A ramus is simply defined as a branch or an arm. That is not helpful. More specifically, a ramus can sometimes represent an extension of the body, or main portion of a bone. Sometimes, ramus is used to define an extension of a body into a slope or an angle. I think of a ski slope that branches off a main slope and has a different angle. But, I want to stress again that these seemingly borderless structures are always difficult to identify for student. For the rami on the pubic bone, I consider them in relation to the pubic crest. The superior ramus extends from the pubic crest almost to the acetabulum. The inferiorBelow or toward the lower part of the body. ramus extends from the pubic crest almost down to the ischial tuberosityRough, thick projection that bears body weight when sitting; major hamstring attachment. (the flattened portion of the ischium).