Arcuate line of ilium
Linea arcuata ossis ilium
- Related terms: Arcuate line
Definition
The arcuate line of ilium is an oblique bony ridge located on its inner or medial surface. it connects antero-inferiorly with the pectineal line (a.k.a. pecten pubis), which is the sharp border of the superior ramus of the pubis. Postero-superiorly, it extends to the ala and promontory of the sacrum. Together they form the linea terminalis, contributing to the pelvic inlet or pelvic brim.
The arcuate line of ilium (or linea terminalis or pelvic inlet) divides the inner aspect of the ilium into anterosuperior and posteroinferior regions:
The anterosuperior region is a concave area called the iliac fossa, which is part of the false pelvis as it lies above the pelvic inlet.
The posteroinferior region is known as the sacropelvic surface and consists of three sub-parts: 1) an upper thickened iliac tuberosity, 2) an auricular surface located anterior and inferior to the iliac tuberosity (which articulates with the sacrum at the sacroiliac joint), and 3) a pelvic surface. It is important to note that the anterosuperior region (iliac fossa) and the iliac tuberosity and auricular surfaces form part of the ala of the ilium, while the pelvic surface, which is part of the true pelvis, corresponds to the body of the ilium.
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Text written by Muhammad A. Javaid, MD, PhD © 2023 IMAIOS.
Drake, R.L., Vogl, A.W. and Mitchell, A.W.M. (2009). ‘Chapter 5: Pelvis and Perineum’ in Gray’s anatomy for Students. (2nd ed.) Philadelphia PA 19103-2899: Elsevier, pp.421-424.
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. 1339-1344.
