The Skeletal System
Introduction

the framework of bones and cartilage that protects our organs and allows us to move is called
the skeletal system.

the specialised branch of medicine that deals with the preservation and restoration of the
skeletal system, articulations (joints), and associated structures is called orthopaedics.
The skeletal system performs the following functions:
 support
 protection (for internal organs)
 movement
 mineral storage
 storage of blood cell-producing cells
 storage of energy
Types of Bones

there are five principal types of bones based on shape
1.
Long bones (e.g. thighs, legs, toes, arms, forearms, and fingers)
 greater length than width
 consist of a shaft and extremities (ends)
 slightly curved for strength
 consist mostly of compact bone (dense bone with few spaces) but also contain
considerable amounts of spongy bone (bone with large spaces)
2.
Short bones (e.g. wrist, ankle bones)
 somewhat cube-shaped and nearly equal in length and width
 spongy except at the surface where there is a thin layer of compact bone
3.
Flat bones
(e.g. cranial bones, sternum,. ribs, scapulas)
 generally thin and composed of two more or less parallel plates of compact bone
enclosing a layer of spongy bone
 flat bones afford considerable protection and provide extensive areas for muscle
attachment
4.
Irregular bones
(e.g. vertebrae, and certain facial bones)
 have complex shapes and cannot be grouped into any of the other three categories
 they vary in the amount of spongy and compact bone
5.
Sesamoid bones
 are small bones in tendons where considerable pressure develops, for instance, the
wrist
 their number varies greatly from person to person
 all people have at least two sesamoid bones: the patella (kneecap)