Axial Skeleton System: Definition, Bones, Function, Description, Characteristics

What Is An Axial Skeleton?

The axial skeleton is one of the essential constituents of the human skeletal system, comprising 80 bones that form the central axis of the body. This includes the skull, vertebral column, and rib cage; these structures are protective for the brain, spinal cord, and thoracic organs such as the heart and lungs.

It maintains the posture of the body, supports the head, and provides anchorage to the muscles, which aid in locomotion. Its rigid structure protects vital organs of the body from physical injury. Moreover, it forms the base to which the appendicular skeleton is attached and serves to provide stability and balance within the human anatomy.

Components Of The Axial Skeleton

The components are explained below-

Skull

The skull is a complicated structure comprising 22 bones which protect the brain and form the framework of the face.

Cranial bones

There are 8 cranial bones---coronal, parietal, temporal, occipital, sphenoid, ethmoid---which act as a protective covering for the brain.

Facial bones

Facial bones--there are a total of 14. These include the mandible, maxilla, nasal, and zygomatic bones. Such bones form the face and anchor the facial muscles.

Vertebral Column

The vertebral column or spine is a flexible, segmented structure comprising 33 vertebrae that support the body while protecting the spinal cord.

Different regions

• Cervical: 7 vertebrae; Supports the head and allows neck movements

• Thoracic: 12 vertebrae; Attached to the ribs anchoring the thoracic cage

• Lumbar: 5 vertebrae; Supports the weight of the body, gives flexibility and movement

• Sacral: 5 fused vertebrae; Form the back part of the pelvis.

• Coccygeal (4 fused vertebrae): Also known as the tailbone, it supports one while sitting.

Thoracic Cage

A thoracic cage is a bony structure made of ribs and a sternum. It serves to protect the heart and lungs, providing support for breathing.

Ribs and sternum

• Ribs (12 pairs): These are curved bones extending from thoracic vertebrae toward the front portion of the body. They protect against injury to thoracic organs.

• Sternum: This is a flat bone in the middle of the chest to which ribs are attached with the help of costal cartilage.

Functions Of The Axial Skeleton

The functions are explained below-

Protection

The axial skeleton serves to protect the body's vital organs. It encases and protects the brain within the skull, shelters the spinal cord within the vertebral column, and has the thoracic cage ′ protecting the heart and lungs from physical damage

Support

The axial skeleton offers structure and framework support for the overall structure of the body. It supports posture and stability which allows the upright standing and weight endurant of the human body.

Movement

The axial skeleton acts as a framework over which many muscles get attached. Then, the attachment of muscles to these bones provides motion in the form of bending, twisting, or balancing.

Hematopoiesis

The bones, mainly in the axial skeleton, contain red bone marrow. These include the vertebrae, sternum, and ribs. It is the site of hematopoiesis—the production of blood cells, among them oxygen-carrying red blood cells, various types of immune function-performing white blood cells, and platelets needed for blood clotting.