Ischial tuberosity

Tuber ischiadicum

Definition

The lower portion of the ischium thickens to create a bony structure known as the ischial tuberosity.

Structurally, the ischial tuberosity is marked by a transverse ridge, which divides it into upper and lower sections. The upper half is further divided by an oblique ridge into superolateral and inferomedial parts, while the lower half is subdivided by a longitudinal ridge into outer and inner regions.

The hamstring muscles originate from the ischial tuberosity, with the semimembranosus arising from the superolateral area (above the oblique ridge), the semitendinosus and long head of biceps femoris from the inferomedial area (below the oblique ridge), and the adductor magnus from the outer lower area (lateral to the longitudinal ridge).

The inner lower area (medial to the longitudinal ridge) is covered by fibrofatty tissue, providing support when sitting. Additionally, the sacrotuberous and ischiofemoral ligaments arise from the medial and lateral margins of the ischial tuberosity, respectively.

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Text written by Muhammad A. Javaid, MD, PhD © 2023 IMAIOS.

  • Standring, S. and Gray, H. (2016). ‘Chapter 80: Pelvic girdle, gluteal region and thigh’ in Gray’s anatomy The anatomical Basis of Clinical Practice. (41st ed.) New York: Elsevier, pp. 1341-1345.


Comparative anatomy in animals

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