The skeletal system is the framework of the human body. It gives shape, provides protection, supports movement, and works with muscles to help us perform everyday activities—from walking and running to sitting and writing. The adult human body contains 206 bones, all arranged in a precise and functional manner.
This article explains the skeletal system in a clear, easy-to-understand, student-friendly way with diagrams, bone lists, types of bones, and practical examples.
Introduction: What Is the Skeletal System?
The skeletal system consists of:
1. BonesTogether, they form the internal framework that protects vital organs, stores minerals, and enables movement with the help of muscles.
Major Divisions of the Skeleton
The human skeleton has two major parts:
1. Axial Skeleton (80 bones)
Forms the central axis of the body.
- Skull
- Vertebral column
- Ribs
- Sternum
2. Appendicular Skeleton (126 bones)
Includes limbs and girdles.
- Shoulder girdle
- Arms
- Hands
- Pelvic girdle
- Legs
- Feet
Bones of the Human Skeleton (From Head to Toe)
Below is a detailed explanation of the major bones labelled in your provided diagram.
1 Bones of the Skull
The skull protects the brain and forms facial structure.
Major Skull Bones
- Frontal bone – forehead
- Maxilla – upper jaw
- Mandible – lower jaw (only movable skull bone)
- Zygomatic bone – cheekbone
2 Bones of the Shoulder and Upper Limb
Clavicle (Collarbone)
- Connects arm to body
- One of the most commonly fractured bones
Scapula (Shoulder Blade)
(Not labelled in image but part of the system)
Humerus
Upper arm boneRadius & Ulna
- Forearm bones
- Radius = thumb side
- Ulna = little finger side
Carpal Bones
Wrist bones (8 small bones)Metacarpal Bones
Bones of the palmPhalanges
Bones of fingers (3 in each finger, 2 in the thumb)3 Thorax (Chest Region)
Sternum
Flat bone in center of chestRibs
- 12 pairs
- Protect lungs and heart
Costal Cartilage
Flexible cartilage connecting ribs to sternum4 Vertebral Column (Spine)
The spine is divided into 5 regions:
1. Cervical Vertebrae (7)
- Neck region
- Supports head
2. Thoracic Vertebrae (12)
- Attached to ribs
3. Lumbar Vertebrae (5)
- Lower back
- Strongest vertebrae
4. Sacrum
- 5 fused vertebrae
5. Coccyx (Tailbone)
- 4 fused vertebrae
- Vestigial structure
5 Pelvic Bones
Ilium
- Upper broad part of pelvis
Sacrum & Coccyx
- Form back part of pelvic cage
6 Bones of the Lower Limb
Femur
- Thigh bone
- Longest and strongest bone in the body
Patella (Kneecap)
- Small triangular bone protecting the knee joint
Tibia & Fibula
- Leg bones
- Tibia = shin bone (larger)
- Fibula = thinner bone on the outer side
Tarsal Bones
- Ankle bones
Metatarsal Bones
- Bones of the foot
- Memory Trick: MetaTarsal = Middle of Toes
Phalanges
- Bones of toes
Types of Bones by Shape
1. Long Bones
- Femur, humerus, tibia
2. Short Bones
- Carpals, tarsals
3. Flat Bones
- Skull bones, ribs, sternum
4. Irregular Bones
- Vertebrae, mandible
- Patella
Bone Structure (Microscopic and Macroscopic)
Macroscopic Structure
- Diaphysis – shaft
- Epiphysis – ends of long bone
- Medullary cavity – bone marrow
- Periosteum – outer covering
Microscopic Structure
- Compact bone – strong, dense
- Spongy bone – light, contains red marrow
Functions of the Skeletal System
The skeleton performs six major functions:
1. Support
Provides shape and framework.
2. Protection
Protects vital organs:
- Skull → brain
- Ribs → heart, lungs
- Vertebrae → spinal cord
3. Movement
Works with muscles to allow motion.
4. Mineral Storage
Stores calcium and phosphorus.
5. Blood Cell Formation
Bone marrow produces RBCs, WBCs, platelets.
6. Fat Storage
Yellow marrow stores lipids.
Joints of the Human Body
Joints connect bones and enable movement.
Types of Joints
- Ball-and-socket – shoulder, hip
- Hinge – knee, elbow
- Pivot – neck
- Gliding – wrist
- Saddle – thumb
- Fixed joints – skull
Common Disorders of the Skeletal System
1. Fractures
Breaks in bone.
2. Osteoporosis
Weak, brittle bones due to calcium loss.
3. Arthritis
Inflammation of joints (osteoarthritis, rheumatoid arthritis).
4. Scoliosis
Abnormal curvature of spine.
5. Rickets
Vitamin D deficiency in children.
6. Sprains
Injury to ligaments.
7. Dislocation
Bone displaced from normal position.
How to Keep Bones Healthy
- Eat calcium-rich foods (milk, leafy greens).
- Get vitamin D from sunlight.
- Exercise regularly (especially weight-bearing activities).
- Maintain correct posture.
- Avoid smoking & excessive alcohol.
- Prevent falls by strengthening muscles.
The skeletal system provides the foundation on which the human body is built. With 206 bones, it ensures stability, enables movement, protects vital organs, and stores essential minerals. Understanding the skeleton helps students appreciate human anatomy, movement science, and health.
This system works closely with muscles (muscular system), joints, and nervous system to maintain posture and movement.
FAQs on the Skeletal System
1. How many bones are in an adult human skeleton?
206 bones.
2. Which is the longest bone in the body?
Femur.
3. What are the two major divisions of the skeleton?
Axial and appendicular skeleton.
4. What is bone marrow?
Soft tissue inside bones that produces blood cells.
5. Which bone protects the brain?
The skull.
6. What is the function of the patella?
Protects the knee and improves leverage of thigh muscles.
7. What is the function of cartilage?
Provides cushioning and reduces friction between bones.
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