Classification Of Joints And Muscles

1. Classification of Joints

Joints are the structures where two or more bones meet, allowing movement and providing support. Joints can be classified based on structure and function.

A. Structural Classification of Joints

1. Fibrous Joints (Immovable Joints)
   • Bones are connected by dense connective tissue.
   • No movement occurs at these joints.
   • Examples: Sutures of the skull, Syndesmosis (between tibia and fibula).
2. Cartilaginous Joints (Partially Movable Joints)
   • Bones are joined by cartilage, allowing limited movement.
   • Examples:
     • Synchondrosis – Growth plates in children (temporary joints).
     • Symphysis – Intervertebral discs, Pubic symphysis.
3. Synovial Joints (Freely Movable Joints)
   • Most common type of joint, containing synovial fluid for smooth movement.
   • Highly mobile.
   • Examples: Shoulder joint, knee joint, elbow joint.

B. Functional Classification of Joints

1. Synarthrosis (Immovable Joints) – Skull sutures, Teeth joints.
2. Amphiarthrosis (Slightly Movable Joints) – Intervertebral discs, Pubic symphysis.
3. Diarthrosis (Freely Movable Joints) – Shoulder, Hip, Knee joints.

C. Types of Synovial Joints (Based on Movement)

1. Ball and Socket Joint – Shoulder and Hip (360° movement).
2. Hinge Joint – Knee and Elbow (Back-and-forth movement).
3. Pivot Joint – Neck (Rotational movement).
4. Gliding Joint – Wrist and Ankle (Sliding movement).
5. Saddle Joint – Thumb joint (Movement in different directions).
6. Condyloid Joint – Wrist joint (Up-down and side-to-side movement).

2. Classification of Muscles

Muscles are responsible for movement, posture, and body support. They are classified based on structure and function.

A. Structural Classification of Muscles

1. Skeletal Muscles (Voluntary Muscles)
   • Attached to bones via tendons.
   • Striated (striped) appearance.
   • Under conscious control.
   • Example: Biceps, Triceps, Quadriceps.
2. Smooth Muscles (Involuntary Muscles)
   • Found in internal organs (stomach, intestines, blood vessels).
   • Non-striated and involuntary.
   • Example: Muscles of digestive tract, Bladder muscles.
3. Cardiac Muscles (Heart Muscles)
   • Found only in the heart.
   • Striated but involuntary.
   • Example: Myocardium (heart muscle).

B. Functional Classification of Muscles

1. Agonist (Prime Mover) – Muscle responsible for main movement (e.g., Biceps in elbow flexion).
2. Antagonist – Opposes the agonist (e.g., Triceps opposes Biceps).
3. Synergist – Assists the prime mover (e.g., Brachialis assists Biceps).
4. Fixator – Stabilizes the origin of the prime mover (e.g., Muscles around the shoulder).

Conclusion

• Joints are classified based on structure (Fibrous, Cartilaginous, Synovial) and function (Immovable, Slightly Movable, Freely Movable).
• Muscles are classified as Skeletal (Voluntary), Smooth (Involuntary), and Cardiac (Heart Muscle).
• Both joints and muscles work together to provide movement and stability to the human body.