The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones,[1] or as a pair the sitting bones,[2] is a large posterior bony protruberance on the superior ramus of the ischium. It marks the lateral boundary of the pelvic outlet.
Ischial tuberosity | |
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Details | |
Identifiers | |
Latin | tuber ischiadicum, tuberositas ischiadica |
TA98 | A02.5.01.204 |
TA2 | 1342 |
FMA | 17010 |
Anatomical terms of bone [edit on Wikidata] |
When sitting, the weight is frequently placed upon the ischial tuberosity.[3] The gluteus maximus provides cover in the upright posture, but leaves it free in the seated position.[4] The distance between a cyclist's ischial tuberosities is one of the factors in the choice of a bicycle saddle.
The tuberosity is divided into two portions: a lower, rough, somewhat triangular part, and an upper, smooth, quadrilateral portion.
This article incorporates text in the public domain from page 235 of the 20th edition of Gray's Anatomy (1918)