The Skeletal System: Bones and Functions

The Framework of Movement

The human skeleton is a living structure made of 206 bones that provides the framework for every movement you make in sport. Without it, muscles would have nothing to pull against. The skeleton works in partnership with the muscular system: muscles contract and pull on bones, which act as levers, creating movement at joints. Understanding which bones are where — and what they do — underpins everything else in PE.

Bones of the Skeleton: Head to Toe

Working from the top of the body downwards, the cranium sits at the very top of the head, curving down around the brain. Below it, the vertebrae form a column of 33 bones running from the base of the skull to the pelvis — protecting the spinal cord and giving the trunk both stability and a controlled range of movement. At the front of the chest, the sternum (breastbone) and the ribs form the ribcage, encasing the heart and lungs. The clavicle (collarbone) connects the sternum to the shoulder on each side, and the flat, triangular scapula (shoulder blade) lies across the upper back.

The humerus is the long bone of the upper arm, running from the shoulder joint down to the elbow. Together, the scapula and humerus form the shoulder joint — a ball-and-socket joint that allows the greatest range of movement in the body. At the elbow, three bones meet: the humerus, the radius (which runs along the thumb side of the forearm) and the ulna (which runs along the little-finger side). In the wrist and hand, the carpals form the wrist, the metacarpals form the palm, and the phalanges are the finger bones. These hand bones are named explicitly in the OCR specification and are examined directly — learn all three.

Moving to the lower body, the pelvis is a large basin-shaped structure at the base of the spine. It forms the hip joint with the head of the femur — a ball-and-socket joint allowing the greatest range of movement in the lower limb. At the knee, the femur articulates with the tibia (the large shin bone), forming a hinge joint. The patella sits in front of the knee joint. The fibula runs alongside the tibia on the outer side of the lower leg. At the foot, the tarsals form the ankle and heel, the metatarsals form the arch of the foot, and the phalanges are the toe bones — mirroring the hand structure.

The Six Functions of the Skeleton

The skeleton does far more than hold the body upright. It serves six distinct functions, each of which can be applied directly to sport and physical activity.

Support — the skeleton holds the body upright against gravity. A sprinter’s lower limbs support their entire body weight as they drive off the blocks. Without a rigid skeletal frame, the muscular system would have nothing to act on.

Posture — the vertebral column and pelvis maintain the upright alignment of the body. Good posture keeps the skeleton in correct mechanical alignment, reducing injury risk and allowing muscles to work most efficiently. A rower must maintain an upright spine throughout the drive phase; poor posture transfers force inefficiently and risks back injury. OCR lists posture as a distinct function, separate from support — always treat them as two separate marks.

Protection — flat bones protect vital organs. The cranium shields the brain; the ribs and sternum form a cage around the heart and lungs. In contact sports such as rugby, the ribcage absorbs impact forces that would otherwise damage the heart and lungs directly.

Movement — bones act as levers. When the biceps contracts during a bicep curl, the forearm bones (radius and ulna) pivot at the elbow to lift the load. In kicking a football, the femur swings at the hip and the tibia swings at the knee, producing explosive leg extension.

Blood cell production — red bone marrow inside flat and irregular bones produces red blood cells, white blood cells and platelets. Red blood cells carry oxygen to the working muscles during exercise via haemoglobin. This function links directly to cardiovascular performance: a well-functioning skeletal system supports oxygen delivery to muscles.

Storage of minerals — bones store calcium and phosphorus. These minerals are released into the bloodstream when the body needs them, and weight-bearing exercise stimulates the bones to increase their mineral density, making them stronger over time.