Which four bones make up the pelvis?

• A. Left and right innominate bones, sacrum, coccyx
• B. Left and right femurs, sacrum, coccyx
• C. Left and right innominate bones, lumbar vertebrae, coccyx
• D. Ischium, ilium, pubis, sacrum

Answer: (A)

The pelvis is structurally composed of the left and right innominate bones, along with the sacrum and coccyx. The innominate bones, which are also known as the hip bones, consist of three fused parts: the ilium, ischium, and pubis. These bones form the sides of the pelvis. The sacrum is a triangular bone located at the base of the spine, connecting the pelvis to the vertebral column, while the coccyx, commonly referred to as the tailbone, is situated at the very bottom of the vertebral column. Together, these four bones create a sturdy structure that supports the body, anchors muscles, and enables movement.

The other choices contain components that either do not belong to the pelvis or are incorrectly grouped. For instance, the femurs are long bones of the thigh and not part of the pelvis, while lumbar vertebrae are part of the spine and do not constitute the pelvic structure.