Skeleton | Skeletal System Overview

Author: Scott A. Sheffield MS

Last update:


The adult human skeleton is a framework of 206 bones and is anatomically divided into two parts, the axial skeleton, and the appendicular skeleton.

Axial Skeleton:

The axial skeleton is the core of the skeleton, it consists of the following 80 bones:

image descriptionSkull: 22 bones
image descriptionHyoid: 1 bone
image descriptionVertebrae: 32 bones
image descriptionRibs: 24 bones
image descriptionSternum: 1 bone

Anterior view on the axial skeleton.
anterior view of the skeleton with the hyoid bone magnified and labeled.

How well do you know all 206 bones in the body? Start learning with free skeleton diagrams, bone labeling exercises and skeletal system quizzes.

Appendicular Skeleton:

The appendicular skeleton is attached to the axial skeleton. It consists of 126 bones.

image descriptionPectoral girdle: 4 bones (Scapula and clavicle).
image descriptionArms and forearms:: 6 bonesĀ  (Humerus, ulna, and radius).
image descriptionWrists and hands:: 54 bones (Carpals, metacarpals, and phalanges).


Bony Pelvis: 2 bones (Os coxae).

image descriptionThighs and legs: 8 bones (Femur, patella, tibia, and fibula).
image descriptionAnkles and feet: 52 bones (Tarsals, metatarsals, and phalanges).

Anterior view of the leg bones with the foot magnified and the phalanges, metatarsals and tarsals labeled.

Functionally, the bones primarily give support to the appendages and protect the fragile organs of the body such as the brain, spinal cord, heart, and lungs.
They also store calcium and phosphorus in the hard bone matrix, which can be released when needed elsewhere.
The bumps, ridges, and grooves on the surface of bones provide attachment sites for the skeletal muscles.
Additionally, many bones contain a soft tissue called marrow that produces new blood cells and stores fat.