Skip to content
English
Sign in
Contact us
  • There are no suggestions because the search field is empty.

What Is the Skeletal System? Structure, Functions, and Key Terms

Learn what the skeletal system is, what structures it includes, how it supports and protects the body, and the key terms used to describe bones, joints, cartilage, and movement.

Skeletal System: Structure, Function, and Key Terms

The skeletal system is the body’s framework. It is made up of bones, cartilage, ligaments, joints, and tendons, all of which work together to provide structure, support, protection, and movement. In addition to shaping the body and enabling mobility, the skeletal system also plays an essential role in blood cell production and mineral and fat storage.

The skeletal system is divided into two main parts: the axial skeleton and the appendicular skeleton. Together, these structures support overall body function, protect vital organs, and allow the body to move efficiently.

What Does the Skeletal System Do?

The skeletal system performs several important functions that are necessary for health and survival.

Support and Shape

The skeleton gives the body its structure, helps maintain posture, and holds organs in place.

Protection

Bones protect delicate internal organs. For example, the skull protects the brain, while the rib cage helps shield the heart and lungs.

Movement

Bones work with muscles to create movement. They act as levers, while joints allow motion and tendons connect muscles to bones.

Blood Cell Production

Certain bones contain red bone marrow, which produces red blood cells, white blood cells, and platelets. This process is called hematopoiesis.

Mineral and Fat Storage

Bones store important minerals such as calcium and phosphorus. They also store fat in bone marrow.

Main Components of the Skeletal System

The skeletal system includes several key structures.

Bones

Bones are living organs made of cells, protein fibers, and minerals. An adult human body typically has 206 bones.

Cartilage

Cartilage is a smooth, flexible connective tissue that cushions joints and reduces friction between bones.

Ligaments

Ligaments are strong fibrous tissues that connect bones to other bones and help stabilize joints.

Joints

Joints are the places where two or more bones meet. They allow movement and flexibility in areas such as the knees, elbows, and shoulders.

Tendons

Tendons are fibrous connective tissues that connect muscles to bones, helping the body move.

Divisions of the Skeletal System

The skeleton is organized into two major divisions.

Axial Skeleton

The axial skeleton includes the:

  • Skull
  • Vertebral column (spine)
  • Rib cage

This division forms the central axis of the body and contains 80 bones.

Appendicular Skeleton

The appendicular skeleton includes the:

  • Arms and legs
  • Pectoral girdle (shoulder region)
  • Pelvic girdle

This division supports movement and contains 126 bones.

Types of Bones

Bones are classified by their shape and function.

Long Bones

Bones that are longer than they are wide, such as the femur and humerus.

Short Bones

Bones that are about equal in length and width, such as the carpals and tarsals.

Flat Bones

Thin, flat bones that help protect organs, such as the skull and ribs.

Irregular Bones

Bones with complex shapes, such as the vertebrae and pelvis.

Sesamoid Bones

Bones embedded within a tendon, such as the patella.

Important Skeletal System Terms

Understanding these key terms can make the skeletal system easier to study.

  • Bone: A rigid organ that forms part of the skeleton
  • Cartilage: Flexible connective tissue found in joints and other parts of the body
  • Ligament: Fibrous connective tissue that connects bones to other bones
  • Joint: The location where two or more bones meet
  • Tendon: Fibrous connective tissue that connects muscles to bones
Common Prefixes and Suffixes

Medical terminology related to the skeletal system often includes specific prefixes and suffixes.

Prefixes

  • Osteo-: Relating to bone
  • Chondro-: Relating to cartilage
  • Arthro-: Relating to joints
  • Myelo-: Relating to bone marrow or the spinal cord

Suffixes

  • -itis: Inflammation
  • -oma: Tumor
  • -clast: To break
  • -cyte: Cell
Why the Skeletal System Matters

The skeletal system is essential because it provides the body with strength, form, and stability while also protecting organs and making movement possible. It does much more than hold the body upright—it also supports critical internal functions such as blood cell production and mineral storage.

A clear understanding of the skeletal system helps explain how the body is supported, protected, and able to move throughout daily life.