The skeletal system

The Skeleton: An Overview

The skeletal system is made up of 206 bones in an adult human, these are divided into two main parts: the axial skeleton and the appendicular skeleton.
The axial skeleton consists of the skull, spine, ribs, and sternum.
The appendicular skeleton includes the shoulder girdle, arms, pelvic girdle, and legs.
Functions of the skeletal system: protection for vital organs, movement through muscle attachment, mineral storage (such as calcium), and blood cell production in the bone marrow.

Long bones: these are mainly found in the limbs and include the femur and humerus. They are crucial for movement and support.
Short bones: examples include the carpals and tarsals. These aid fine motor skills and movement.
Flat bones: such as the cranium and scapula, these are primarily protective but also provide attachment for muscles.
Irregular bones: examples are the vertebrae and the pelvis. These often have a specialised function.

At birth, human beings have approximately 270 bones, many of which fuse together by adulthood to form the 206 bones of the adult skeleton.
Growth plates: thin layers of cartilage located between the diaphysis and each epiphysis at the end of long bones. This is where bone growth in children and adolescents occurs.
Bones grow in length until early adulthood, during this time they also increase in density.

Joints are the points at which bones meet, they enable movement and provide mechanical support.
Fibrous joints: immobile or allow limited movement, they include sutures in the skull.
Cartilaginous joints: allow limited movement, examples include the intervertebral discs.
Synovial joints: freely movable joints such as the knee or elbow, they have a synovial cavity filled with synovial fluid for lubrication.

Bones are susceptible to fractures, which can be categorised as open, closed, transverse, oblique, and more.
Common joint injuries include sprains, strains, dislocation, and more.
Osteoporosis is a condition in which the bones become weak and brittle, commonly affecting older people but can also be a consequence of inappropriate nutrition and exercise.