Iliace

Iliace is an English term historically used as an adjective referring to structures pertaining to the ilium, the uppermost bone of the pelvis. In contemporary anatomy, the preferred term is iliac, and iliace appears mainly in older texts or discussions of historical nomenclature. The noun form is extremely rare and largely obsolete.

Etymology and usage notes: The word is derived from Latin ilia/ilium with an archaic English suffix -ace, a formation found in some early medical vocabularies. It is related to but distinct from ileac, a variant spelling that sometimes appeared in older literature; modern writing generally avoids this form. For references to the intestine, the standard terms are ileal (adjective) and ileum (noun).

Modern context and examples: When describing the pelvic region in current practice, iliac is the accepted adjective, as in the iliac crest, iliac fossa, or external/internal iliac arteries. If iliace appears in a text, it is typically historical or a trace of earlier spelling conventions rather than a standard term in contemporary anatomy. In modern usage, care should be taken to distinguish iliac (relating to the ilium) from ileal and ileum, which pertain to the intestinal region.