Ischial tuberosity
Capsule of hip-joint (distended). Posterior aspect. (Ischial tuberosity visible at bottom left.)
Details
Identifiers
Latin	tuber ischiadicum, tuberositas ischiadica
TA98	A02.5.01.204
TA2	1342
FMA	17010
Anatomical terms of bone [edit on Wikidata]

Theischial tuberosity (ortuberosity of the ischium,tuber ischiadicum), also known colloquially as thesit bones orsitz bones,^[1] or as a pair thesitting bones,^[2] is a largeposteriorbony protuberance on thesuperior ramus of theischium. It marks the lateral boundary of thepelvic outlet.

Whensitting, the weight is frequently placed upon the ischial tuberosity.^[3] Thegluteus maximus provides cover in the upright posture, but leaves it free in the seated position.^[4] The distance between acyclist's ischial tuberosities is one of the factors in the choice of abicycle saddle.

The tuberosity is divided into two portions: a lower, rough, somewhat triangular part, and an upper, smooth, quadrilateral portion.

• Thelower portion is subdivided by a prominent longitudinal ridge, passing from base to apex, into two parts:
  • The outer gives attachment to theadductor magnus
  • The inner to thesacrotuberous ligament
• Theupper portion is subdivided into two areas by an oblique ridge, which runs downward and outward:
  • From the upper and outer area thesemimembranosus arises
  • From the lower and inner, the long head of thebiceps femoris and thesemitendinosus

• 
  Muscles of the gluteal and posterior femoral regions, with ischial tuberosity highlighted in red
• 
  Right hip bone. External surface.
• 
  Right hip bone. Internal surface.
• 
  Plan of ossification of the hip bone
• 
  Diameters of inferior aperture of lesser pelvis (female)
• 
  Right hip-joint from the front
• 
  Theobturator externus
• 
  Anterior view of the pelvis with the ischial tuberosity labelled in the lower part of the image

• Ischial bursitis
• Sitting disability

This article incorporates text in thepublic domain frompage 235 of the 20th edition ofGray's Anatomy(1918)

• Goossens R, Teeuw R, Snijders C (2005). "Sensitivity for pressure difference on the ischial tuberosity".Ergonomics.48 (7):895–902.doi:10.1080/00140130500123647.PMID 16076744.S2CID 854065.
• Platzer, Werner (2004).Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.).Thieme.ISBN 3-13-533305-1.

• pelvis at The Anatomy Lesson by Wesley Norman (Georgetown University) (pelvisposterior,pelvislateral,pelvisinside)

• Wikipedia articles incorporating text from the 20th edition of Gray's Anatomy (1918)
• Bones of the pelvis
• Ischium

• Use American English from January 2019
• All Wikipedia articles written in American English
• Articles with short description
• Short description matches Wikidata
• Use mdy dates from January 2019