Joints

JOINTS  

Fibrous Joints: These joints are held together by dense connective tissue and have little to no movement. 

• Example: Sutures in the skull, Syndesmoses (between tibia and fibula). 

• Cartilaginous Joints: These joints are connected by cartilage and allow limited movement. 

• Example: Pubic symphysis, Intervertebral discs. 

• Synovial Joints: These joints are characterized by a synovial cavity, surrounded by a joint capsule. These joints allow for a wide range of movement. 

• Example: Shoulder, Knee, Hip. 

Functional Classification: 

• Synarthrosis: Immovable joints ( sutures in the skull). 

• Amphiarthrosis: Slightly movable joints (pubic symphysis). 

• Diarthrosis: Freely movable joints (synovial joints like the knee, elbow) 

Types of Synovial Joints Based on Axes of Movement and Examples: 

1. Uniaxial Joints (Move in one axis): 

1. Hinge Joints: Movement occurs around one axis (flexion and extension). 

Example: Elbow, Knee, Interphalangeal joints. 

2. Pivot Joints: Rotation around a single axis. 

Example: Atlantoaxial joint (between C1 and C2 vertebrae), Radioulnar joint. 

2. Biaxial Joints (Move in two axes): 

1. Condyloid (Ellipsoidal) Joints: Allows movement in two planes, typically flexion/extension and abduction/adduction. 

Example: Wrist joint, Metacarpophalangeal joints (knuckles). 

2. Saddle Joints: Allows movement in two directions but with more freedom than condyloid joints. 

Example: Carpometacarpal joint of the thumb. 

3. Multiaxial Joints (Move in three axes): 

1. Ball-and-Socket Joints: The most mobile joints in the body; allows movement in multiple planes (flexion/extension, abduction/adduction, rotation). 

Example: Shoulder (glenohumeral joint), Hip joint. 

2. Plane (Gliding) Joints: Flat or slightly curved surfaces allow sliding or gliding movements. 

Example: Intercarpal joints (wrist), Intertarsal joints (foot). 

Synovial Joints Details: 

1. Shoulder Joint (Glenohumeral Joint): 

• Bones/Bony Landmarks: Head of the humerus and glenoid cavity of the scapula. 

• Ligaments: 

• Intraarticular: Glenoid labrum. 

• Extraarticular: Glenohumeral ligaments, Coracohumeral ligament, and the acromioclavicular ligament. 

• Range of Motion: 

• Flexion, extension, abduction, adduction, internal/external rotation, circumduction. 

• Unique Characteristics: Highly mobile joint, but prone to dislocation due to its shallow socket. 

2. Elbow Joint: 

• Bones/Bony Landmarks: Humerus, ulna, and radius. 

• Ligaments: 

• Intraarticular: N/A. 

• Extraarticular: Ulnar collateral ligament (UCL), Radial collateral ligament (RCL), Annular ligament (surrounds the radius). 

• Range of Motion: 

• Flexion and extension (hinge movement). 

• Unique Characteristics: Primarily a hinge joint, but allows for limited rotation at the radioulnar joint. 

3. Knee Joint: 

• Bones/Bony Landmarks: Femur, tibia, and patella. 

• Ligaments: 

• Intraarticular: Anterior cruciate ligament (ACL), Posterior cruciate ligament (PCL). 

• Extraarticular: Medial collateral ligament (MCL), Lateral collateral ligament (LCL). 

• Range of Motion: 

• Flexion and extension, limited rotation when flexed. 

• Unique Characteristics: Largest and most complex synovial joint, highly stable due to ligaments, but prone to injury. 

4. Hip Joint (Coxal Joint): 

• Bones/Bony Landmarks: Acetabulum of the pelvis and head of the femur. 

• Ligaments: 

• Intraarticular: Ligamentum teres. 

• Extraarticular: Iliofemoral ligament, Pubofemoral ligament, Ischiofemoral ligament. 

• Range of Motion: 

• Flexion, extension, abduction, adduction, internal/external rotation, circumduction. 

• Unique Characteristics: Strong joint due to deep socket; allows for a wide range of motion while maintaining stability. 

5. Temporomandibular Joint (TMJ): 

• Bones/Bony Landmarks: Mandibular condyle and the temporal bone's mandibular fossa. 

• Ligaments: 

• Intraarticular: Articular disc (fibrocartilage). 

• Extraarticular: Lateral ligament, Stylomandibular ligament, Sphenomandibular ligament. 

• Range of Motion: 

• Elevation/depression (opening/closing of mouth), Protrusion/retraction, Lateral movement. 

• Unique Characteristics: Allows for complex movements like chewing, speaking; has both hinge and gliding action. 

6. Ankle Joint (Talocrural Joint): 

• Bones/Bony Landmarks: Tibia, fibula, and talus. 

• Ligaments: 

• Intraarticular: N/A. 

• Extraarticular: Deltoid ligament, Lateral ligament complex (anterior talofibular ligament, calcaneofibular ligament). 

• Range of Motion: 

• Dorsiflexion and plantarflexion (flexion and extension of foot). 

• Unique Characteristics: Primarily a hinge joint, responsible for walking and running. 

Range of Motion (ROM) and Examples: 

1. Flexion: Decreasing the angle between two body parts. 

1. Example: Bending your elbow. 

2. Extension: Increasing the angle between two body parts. 

1. Example: Straightening your knee. 

3. Abduction: Moving a limb away from the midline of the body. 

1. Example: Raising your arms sideways. 

4. Adduction: Moving a limb toward the midline of the body. 

1. Example: Lowering your arms back to your sides. 

5. Rotation: Turning a body part around its axis. 

1. Example: Turning your head left or right. 

6. Circumduction: Circular movement of a limb, combining flexion, extension, abduction, and adduction. 

1. Example: Making circles with your arms. 

7. Pronation: Turning the palm down. 

1. Example: Turning your hand so the palm faces downward. 

8. Supination: Turning the palm up. 

1. Example: Turning your hand so the palm faces upward.