Lesson 02 / Axial Skeleton

Axial Skeleton

Explore the skull, vertebral column, and thoracic cage that form the body's protective central axis.

The body's central axis

The axial skeleton forms the central axis of the body. It includes the skull, the vertebral column, and the thoracic cage, and its main job is to protect the brain, spinal cord, and organs of the chest.

Diagram of the axial skeleton highlighted on the human body

The axial skeleton, highlighted

The axial skeleton includes 80 bones: the skull, the hyoid bone, the vertebral column, and the thoracic cage.

01 / SKULL

Cranium and face

The skull is made up of cranial bones that enclose the brain and facial bones that shape the face.

02 / VERTEBRAL COLUMN

The spine

A stack of 33 vertebrae surrounds and protects the spinal cord while supporting the body's weight.

03 / THORACIC CAGE

Ribs and sternum

The ribs and sternum form a protective cage around the heart and lungs.

04 / HYOID

A floating bone

The U-shaped hyoid bone in the neck is unique because it does not directly connect to any other bone.

Following the spine

The vertebral column is organized into five regions, each with a different number and shape of vertebrae suited to its role.

Cervical
Thoracic
Lumbar
Sacral
Coccygeal

Why the axial skeleton matters

Because the axial skeleton surrounds the central nervous system and the organs of the chest, injuries to it can be especially serious, which is part of why it is built from some of the body's sturdiest bone structures.

REMEMBER

Protection is the axial skeleton's primary role.

While the appendicular skeleton is built for movement, the axial skeleton is built first and foremost to protect the structures it surrounds.

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