Ilium

A large, flat bone on each side of the pelvic region, playing a crucial role in supporting the body's structure.

The ilium is one of the three bones that fused together to form the pelvic bone, specifically the largest and most superior part of the hip bone. Each ilium is a broad, wing-like structure that helps anchor various muscles and ligaments. This bone provides a surface for the attachment of muscles and supports the weight of the upper body when sitting and standing.

Terminologia Anatomica

ilia

System

Skeletal system

Function

The ilium serves several essential functions in the human body. Primarily, it is instrumental in forming the pelvic girdle, which connects the spine to the lower limbs. This connection is vital for mobility and balance. Moreover, the ilium acts as an attachment site for muscles involved in movements of the hip and thigh, such as walking, running, and climbing. The stability provided by the ilium allows for the distribution of weight during various activities, preventing injuries. In addition to its structural role, the ilium also encompasses the iliac fossa, which houses muscles that assist in hip flexion and contribute to core stability, crucial for overall movement.

Location

The ilium is located in the lower part of the torso, forming the upper section of the hip bones. Each ilium is positioned laterally, giving the pelvis its characteristic broad shape. The bone extends from the iliac crest, a prominent ridge that can be felt along the top of the pelvis, down to the auricular surface, where it articulates with the sacrum, forming the sacroiliac joint. This joint plays a significant role in connecting the spine to the lower extremities, allowing for efficient movement and weight transfer. The ilium's expansive sides and smooth interior allow for the attachment of ligaments and muscles critical for the function of the hips and legs.

Did You Know?

The term 'ilium' derives from the Latin word for 'groin' or 'flank', emphasizing its location in the body.
The iliac crest can be easily palpated on the human body and is often used as a landmark by medical professionals.
The iliac fossa, found on the anterior side of the ilium, is where the iliacus muscle originates, which plays a critical role in hip flexion.
The ilium is involved in the formation of the greater sciatic notch, allowing for the passage of nerves and blood vessels from the pelvis to the lower limb.