What does ilia mean?
The ilia are the two large bones that form the upper part of the human pelvis. Each ilium has a broad, curved upper surface and joins the sacrum behind, while its lower part contains the acetabulum, the deep socket that receives the head of the femur at the hip joint. Together, the ilia support and protect the pelvic organs, provide attachment sites for major muscles of the torso and legs, and help transfer the body's weight from the spine to the lower limbs. The word is almost always used as a plural anatomical term: one bone is an ilium, while the two bones are the ilia. It is especially common in anatomy, medicine, radiology, and physical education. Although the name may initially suggest something connected with the small intestine because of its similarity to ileum, the ilia are bones of the pelvis rather than parts of the digestive system.
plural nounThe plural of ilium: the two large, paired bones that form the upper part of the pelvis and articulate with the sacrum. Each ilium bears the acetabulum, the socket in which the head of the femur fits.
- Either of the two large bones forming the upper portion of the pelvis.
- The bones of the pelvis considered collectively.
"The ilia support the upper body and transmit its weight through the pelvis to the lower limbs."
"The radiograph showed a fracture through the right ilium."
"The ilia are joined to the sacrum at the sacroiliac joints."
"Damage to one ilium can alter the alignment of the pelvis and the lower limb."
Ilia is already plural; the corresponding singular is ilium.
"The ilia are the paired bones of the upper pelvis."
Two bones named ilia support your entire upper body and provide the hip sockets that let you walk, run, and dance.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ilia
The singular ilium comes from Latin ilium, meaning “flank” or “hip,” and ilia is its regular Latin plural. English anatomical usage developed the same plural form. The root is also reflected in iliac, iliofemoral, and iliosacral, all terms describing structures associated with the hip, pelvis, or the junction between the ilium and adjacent bones.
Related word forms
How ilia is actually used
In anatomical usage, ilia is normally plural. The singular ilium refers to one side of the pelvis, while ilia generally refers to the pair.
Easily confused with ilia
The ilia are the paired pelvic bones, whereas the ileum is the final section of the small intestine.