Review Sheet 11 Articulations And Body Movements

Review Sheet: 11 Articulations and Body Movements

Understanding the intricacies of human movement requires a firm grasp of the various articulations, or joints, and the types of movements they facilitate. This comprehensive review sheet delves into eleven key articulations and their associated movements, providing a detailed overview for students of anatomy, kinesiology, and related fields. We'll explore the structure, function, and specific movements possible at each joint, emphasizing the interconnectedness of these structures in overall body mechanics.

1. Fibrous Joints: Sutures of the Skull

Type: Synarthrosis (immovable joint)

Structure: Fibrous connective tissue directly unites the bones. The sutures of the skull are classic examples, interlocking edges providing immense strength and protection for the brain.

Movements: Minimal to no movement. Slight expansion during childbirth accommodates the passage of the infant's head. Sutures fuse completely in adulthood, resulting in synostosis (complete fusion).

Clinical Significance: Premature fusion of sutures (craniosynostosis) can lead to abnormal skull shape and potential neurological issues.

2. Cartilaginous Joints: Intervertebral Discs

Type: Amphiarthrosis (slightly movable joint)

Structure: Hyaline cartilage or fibrocartilage connects the bones. Intervertebral discs, composed of an annulus fibrosus (outer layer) and nucleus pulposus (inner core), are exemplary cartilaginous joints.

Movements: Limited movement, primarily flexion, extension, lateral flexion, and rotation of the vertebral column. The discs act as shock absorbers and allow for flexibility.

Clinical Significance: Degeneration of intervertebral discs (e.g., herniated discs) can lead to pain, nerve compression, and reduced mobility.

3. Synovial Joints: Hinge Joint (Elbow)

Type: Diarthrosis (freely movable joint)

Structure: Characterized by a synovial cavity filled with synovial fluid, articular cartilage covering the bone ends, a joint capsule, and often accessory structures like ligaments and menisci. The elbow is a classic hinge joint.

Movements: Primarily flexion (bending) and extension (straightening) along a single plane. Slight rotation is possible in some individuals.

Clinical Significance: Injuries to the elbow joint, such as sprains, dislocations, and fractures, are common, particularly in contact sports.

4. Synovial Joints: Pivot Joint (Atlantoaxial Joint)

Type: Diarthrosis (freely movable joint)

Structure: One bone rotates around another. The atlantoaxial joint, between the atlas (C1) and axis (C2) vertebrae, is a prime example. The dens (odontoid process) of the axis acts as a pivot.

Movements: Rotation of the head (side-to-side movement).

Clinical Significance: Injuries to this joint can result in instability and compromise head movement.

5. Synovial Joints: Saddle Joint (Carpometacarpal Joint of the Thumb)

Type: Diarthrosis (freely movable joint)

Structure: Articular surfaces are saddle-shaped, allowing for movement in two planes. The carpometacarpal joint of the thumb is a classic example.

Movements: Flexion, extension, abduction, adduction, and opposition (touching the thumb to other fingers). This unique joint allows for the dexterity of the thumb.

Clinical Significance: Osteoarthritis is relatively common in this joint, leading to decreased thumb mobility and pain.

6. Synovial Joints: Condyloid Joint (Wrist Joint)

Type: Diarthrosis (freely movable joint)

Structure: Oval-shaped condyle of one bone articulates with an elliptical cavity of another bone. The radiocarpal joint (wrist) is a typical example.

Movements: Flexion, extension, abduction, and adduction. Circumduction (a combination of movements) is also possible.

Clinical Significance: Fractures of the wrist bones (scaphoid, radius) are common injuries.

7. Synovial Joints: Ball-and-Socket Joint (Shoulder)

Type: Diarthrosis (freely movable joint)

Structure: A spherical head of one bone fits into a cup-shaped cavity of another. The glenohumeral joint (shoulder) is the most mobile ball-and-socket joint.

Movements: Flexion, extension, abduction, adduction, medial and lateral rotation, and circumduction. Its high degree of freedom allows for a wide range of motion.

Clinical Significance: Shoulder dislocations are relatively common due to the joint's shallow socket. Rotator cuff injuries are also frequent.

8. Synovial Joints: Ball-and-Socket Joint (Hip)

Type: Diarthrosis (freely movable joint)

Structure: Similar to the shoulder joint, but the hip's acetabulum (socket) is deeper, providing greater stability.

Movements: Flexion, extension, abduction, adduction, medial and lateral rotation, and circumduction. The range of motion is slightly less than the shoulder due to increased stability.

Clinical Significance: Hip dislocations are less common than shoulder dislocations due to the deeper socket. Osteoarthritis is a common degenerative condition affecting the hip joint.

9. Gliding Joints: Intercarpal Joints

Type: Diarthrosis (freely movable joint)

Structure: Articular surfaces are relatively flat, allowing for gliding movements. The intercarpal joints (between carpal bones of the wrist) are classic examples.

Movements: Gliding movements in various directions, contributing to the wrist's overall flexibility.

Clinical Significance: These joints are susceptible to sprains and dislocations.

10. Synovial Joints: Plane Joint (Intertarsal Joints)

Type: Diarthrosis (freely movable joint)

Structure: Similar to gliding joints, the articular surfaces are relatively flat, allowing for sliding and gliding movements. Intertarsal joints are found between the tarsal bones of the foot.

Movements: Gliding movements, contributing to the foot's adaptability to uneven surfaces.

Clinical Significance: Sprains and fractures are potential injuries to these joints.

11. Synovial Joints: Bicondylar Joint (Knee)

Type: Diarthrosis (freely movable joint)

Structure: A modified hinge joint involving two condyles (rounded articular projections) of the femur articulating with the tibia. The patella (kneecap) also plays a crucial role. The menisci act as shock absorbers and enhance stability.

Movements: Primarily flexion and extension. Slight medial and lateral rotation is possible when the knee is flexed.

Clinical Significance: The knee is the largest and most complex joint in the body, making it prone to numerous injuries, including ligament sprains (ACL, MCL, LCL, PCL), meniscus tears, and cartilage damage. Osteoarthritis is a common degenerative condition affecting the knee.

Understanding Articulations: Key Considerations

This review sheet provides a foundation for understanding the diverse articulations and body movements. Remember these crucial points:

• Joint Classification: Joints are classified structurally (fibrous, cartilaginous, synovial) and functionally (synarthrosis, amphiarthrosis, diarthrosis).

• Range of Motion: The range of motion at a joint is determined by its structure, ligaments, and surrounding muscles.

• Interdependence: Individual joint movements are interconnected. Movement in one joint often influences movement in adjacent joints.

• Clinical Relevance: Understanding joint structure and function is essential for diagnosing and treating musculoskeletal injuries and disorders.

This comprehensive overview provides a solid base for further exploration of the human musculoskeletal system. Further study using anatomical models, imaging techniques, and practical exercises will solidify your understanding of these vital articulations and their associated movements. Remember to consult additional resources and seek professional guidance for a deeper understanding of the intricate mechanics of the human body.