Human skeleton

Lore & Background

The human skeleton performs six major functions: support, movement, protection, production of blood cells, storage of minerals, and endocrine regulation. The axial skeleton, consisting of the vertebral column, rib cage, skull, and associated bones, maintains upright posture and transmits weight from the head and trunk to the lower extremities. The appendicular skeleton, including the pectoral and pelvic girdles and limb bones, enables locomotion and protects organs of digestion, excretion, and reproduction.

Reader's Guide

The human skeleton is not as sexually dimorphic as that of many other primate species, but subtle differences exist in the skull, dentition, long bones, and pelvis. Female skeletal elements tend to be smaller and less robust, and the female pelvis is adapted for childbirth. The skeleton stores calcium and iron, and bone cells release osteocalcin, which regulates blood sugar and fat deposition. Common disorders include osteoporosis, characterized by reduced bone mineral density and increased fracture risk, and scoliosis, a side-to-side spinal curve most common in adolescent females. Arthritis involves joint inflammation and cartilage degradation, with osteoarthritis affecting both large and small joints. The skeleton's role in haematopoiesis shifts from long bones in children to the pelvis, cranium, vertebrae, and sternum in adults.

Did You Know?

• Bone mass makes up about 14% of total body weight, reaching maximum between ages 25 and 30.
• The axial skeleton includes the skull, spinal column, and rib cage, while the appendicular skeleton includes limb bones and girdles.
• The human female pelvis is wider than the male pelvis to facilitate childbirth.