Pelvis · Irregular bone
Ischium
The ischium is the lower, back part of each hip bone — the "sitting bone" you rest on when seated. It also forms part of the hip socket.
What it is
The ischium is one of the three parts of the hip bone, forming its lower and back portion.
Where it is
The lower, rear part of the pelvis on each side.
What it does
Bears weight when sitting, forms part of the hip socket, and anchors muscles of the buttock and thigh.
Connections
Joints and connections
- Part of the hip joint
When things go wrong
Common injuries and conditions
- Ischial bursitis ("weaver's bottom")
- Hamstring-origin injuries at the sitting bone
Education and reference only. This explains the anatomy in plain terms; it is not a diagnosis. A severe injury, a visibly deformed limb, or the inability to move or bear weight needs urgent assessment — call 999 or go to A&E for a serious injury.
Did you know?
An interesting fact
The ischial tuberosities — the "sitting bones" — are what you feel taking your weight on a hard chair.
Answers
Ischium: frequently asked questions
What is the sitting bone?
The sitting bone is the ischium, the lower back part of each hip bone that takes your weight when seated.
Explore the pelvis
Related bones
Sources
Where this is drawn from
- NHS — Anatomy and body systems
- Gray's Anatomy for Students (Drake, Vogl, Mitchell)
- TeachMeAnatomy — skeletal system
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