Fact Checked

What is the Pelvic Ring?

Marisa O'Connor
Marisa O'Connor

The pelvic ring, also known as the pelvic girdle, is a ring of bones shaped like a basin that connects the torso to the legs. It supports the weight of the upper body and transfers some of the weight to the lower limbs when standing. It provides protection to vulnerable organs and supports posture.

The primary function of the pelvic ring is to support the weight of the upper body while standing and sitting. When standing and walking, the pelvic girdle transfers the weight from the axial skeleton, which consists of the 80 bones of the head and trunk of the body, to the lower limbs. It is very strong and sturdy with limited mobility, maintaining strong bonds with the powerful muscles of the legs.

An X-ray of the pelvis.
An X-ray of the pelvis.

The two hip bones connect and make up the pelvic ring. It is formed where the hip bones meet at the pubic symphysis and connect with the sacrum at the sacroiliac joints. The pubic symphysis is the cartilaginous joint where the left and right pubic bone meet. The sacrum is a large triangular bone, attached to the last lumbar vertebra and the tailbone, which is wedged between the two hip bones. This is connected to the hip bones by the sacroiliac joints.

The pelvic ring is a ring of bones that connect the legs to the torso.
The pelvic ring is a ring of bones that connect the legs to the torso.

The pelvic ring contains five joints. It has two sacroiliac joints, where the hip bones meet the sacrum. There are two hip joints, where the hip bones connect to the femurs, or leg bones. Lastly, there is the symphysis pubis, which connects the left and right pubic bones.

Each of these joints have limited mobility, with the exception of the hip joints, as the pelvis is responsible for carrying the weight of the upper body. When weight is placed on the ring, as when sitting or standing, it transforms from a loose structure to a load-bearing stable one. This transformation is triggered when pressure travels down through the spine and causes the sacroiliac ligaments to tighten.

The pelvic ring helps protect the body's internal organs.
The pelvic ring helps protect the body's internal organs.

The pelvic ring also provides and home and protective shelter for internal organs. It protects internal reproductive organs, such as the uterus and ovaries, as well as inferior parts of the urinary tracts. These bones also protect and are attached to muscles and membranes of the external reproductive organs.

Posture is also affected by the pelvis ring. These bones are held in a delicate balance that determines the curve of the spine. If the pelvic girdle is abnormally tilted, it will cause poor posture, which can lead to serious injury and discomfort.

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Discussion Comments

I know a lot of elderly people who have had problems with a pelvic ring injury. I guess a lot of them have some degree of osteoporosis, which makes the pelvic bones particularly vulnerable to cracking or breaking.

You always hear about old people falling down and breaking their hips. What they are actually breaking are their pelvic bones.

My neighbor fell and had to have plates and screws placed in his pelvic ring. The doctor said his injury had made the bones unstable, so they would have to be secured by the hardware.


@orangey03 – That sounds like a particularly bad pelvic fracture. My little sister injured her pelvis while playing sports in junior high, but she didn't have to have surgery.

The area was swollen and very sore, and her doctor told her that she would have to use crutches for three months. That should give the fracture time to heal. He told her it was important that she avoid placing weight on the pelvis during that time.

He also gave her pain medication and a medicine to thin her blood. He said that because she would not be using her legs very much, she would be at risk of getting a blood clot, so the blood thinner would prevent this.


I've heard that the pelvic ring will expand and loosen up when you are pregnant. I've never been pregnant, but my sister has, and she said that this made her develop a sort of waddling gait.

The pelvic ring wants the baby to be able to fit through it, so it will give way to accommodate the baby. It will get looser as time progresses so that when it is time to give birth, the bones won't be in the way so much.

I love how our body parts are designed to work with each other like this. It would be awful if the pelvic ring didn't give the baby extra room to exit!


You know, people tend to think of the pelvis as one hard bone, but there's more to it than that! The pubic symphysis that the article mentions? It's not bone, right? It's cartilage. So it loosens during pregnancy (that's why pregnant women waddle - I had a teacher in high school who called it "independent suspension").

And especially by the end of pregnancy, changing position can therefore cause the shape of the pelvis to change.

This all becomes really important in childbirth! Some doctors seem to think we have an epidemic of babies with heads too big for their mom's pelvises, but many midwives feel that using positions like squatting that better "open up" the pelvis can get out more babies than just having women lie in bed.


I have a friend who suffered a broken pelvis. She got into a bad car accident, and she had have surgery to repair her pelvic ring.

The doctor used what is called an “external fixator.” This is a kind of frame that sits outside the body but is attached to the pelvic bones by screws.

It took her months to heal up enough to attempt walking. Even then, she had to use crutches for many more months.

A broken pelvis is serious business. When you break bones in the middle of your body like that, it affects your entire body.

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    • An X-ray of the pelvis.
      By: Allen Penton
      An X-ray of the pelvis.
    • The pelvic ring is a ring of bones that connect the legs to the torso.
      By: James Steidl
      The pelvic ring is a ring of bones that connect the legs to the torso.
    • The pelvic ring helps protect the body's internal organs.
      By: nerthuz
      The pelvic ring helps protect the body's internal organs.