The pelvis, or pelvic girdle is formed by 2 hip bones (coxal bones). They come together in front and in back, they attach to the sacrum of the backbone. Each coxal bone is actually made up of 3 fused bones (ilium, ischium and pubis). On the outside of each coxal bone is a deep socket, called the acetabulum, where the head the leg bones (the femur) sits. The pelvis supports and protects internal organs, attaches the lower limb to the body and with the lower limb supports the weight of the whole upper body. The hip joint is very important for leg movement and is supported by strong muscles and ligaments. Though it is a ball and socket joint like the shoulder, it is more stable and less moveable than that joint.
LS1.A: Structure and Function
• All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular). (MS-LS1-1)
• Within cells, special structures are responsible for particular functions, and the cell membrane forms the boundary that controls what enters and leaves the cell. (MS-LS1-2)
• In multicellular organisms, the body is a system of multiple interacting subsystems. These subsystems are groups of cells that work together to form tissues and organs that are specialized for particular body functions. (MS-LS1-3)