Articulations And Body Movements Review Sheet

Articulations and Body Movements: A Comprehensive Review Sheet

Understanding articulations (joints) and body movements is fundamental to comprehending human anatomy, physiology, and biomechanics. This comprehensive review sheet will cover the classification of joints, types of movement, common joint pathologies, and practical applications for healthcare professionals and students.

I. Classification of Articulations (Joints)

Joints, or articulations, are the points where two or more bones meet. Their classification is based on both structural and functional characteristics.

A. Structural Classification:

This classification focuses on the connective tissue that binds the bones together:

• Fibrous Joints: These joints have bones connected by fibrous connective tissue, offering little to no movement (synarthroses). Examples include:

  • Sutures: Found in the skull, these joints are interlocking and immovable.
  • Syndesmoses: Bones are connected by ligaments, allowing slight movement. The distal tibiofibular joint is an example.
  • Gomphoses: A peg-in-socket fibrous joint, such as a tooth in its alveolar socket.

• Cartilaginous Joints: These joints have bones connected by cartilage, allowing limited movement (amphiarthroses). Examples include:

  • Synchondroses: Bones are united by hyaline cartilage, such as the epiphyseal plates in growing bones (temporary) and the first sternocostal joint (permanent).
  • Symphyses: Bones are connected by fibrocartilage, providing strength and flexibility. The intervertebral discs and the pubic symphysis are examples.

• Synovial Joints: These are the most common type of joint, characterized by a fluid-filled joint cavity that allows for free movement (diarthroses). Key features include:

  • Articular Cartilage: Hyaline cartilage covering the ends of bones, providing a smooth, low-friction surface.
  • Synovial Fluid: Lubricates the joint and nourishes the articular cartilage.
  • Joint Capsule: A fibrous sac enclosing the joint, providing stability.
  • Synovial Membrane: Lines the joint capsule and produces synovial fluid.
  • Ligaments: Connect bones to bones, reinforcing the joint and limiting movement.
  • Bursae: Fluid-filled sacs that cushion the joint and reduce friction. These are often located between tendons and bones.
  • Menisci: Fibrocartilaginous pads that improve the fit between bones and distribute forces. Found in the knee joint.

B. Functional Classification:

This classification is based on the degree of movement allowed:

• Synarthroses: Immovable joints, such as sutures in the skull.
• Amphiarthroses: Slightly movable joints, such as intervertebral discs.
• Diarthroses: Freely movable joints, such as the knee and shoulder joints. These are all synovial joints.

II. Types of Body Movements

Synovial joints allow for a wide range of movements. These movements can be described in several ways:

A. Basic Movements:

• Flexion: Decreasing the angle between two bones. Example: Bending the elbow.
• Extension: Increasing the angle between two bones. Example: Straightening the elbow.
• Hyperextension: Extending a joint beyond its normal range of motion. Example: Tilting the head backward excessively.
• Abduction: Moving a limb away from the midline of the body. Example: Raising the arm to the side.
• Adduction: Moving a limb toward the midline of the body. Example: Lowering the arm to the side.
• Rotation: Turning a bone around its own long axis. Example: Turning the head from side to side.
• Circumduction: Moving a limb in a circular motion. Example: Tracing a circle with your finger.

B. Special Movements:

Certain joints have unique movements not found in others:

• Inversion: Turning the sole of the foot inward.
• Eversion: Turning the sole of the foot outward.
• Dorsiflexion: Bending the foot upward at the ankle.
• Plantarflexion: Bending the foot downward at the ankle.
• Protraction: Moving a body part forward. Example: Protruding the jaw.
• Retraction: Moving a body part backward. Example: Retracting the jaw.
• Elevation: Lifting a body part superiorly. Example: Shrugging the shoulders.
• Depression: Moving a body part inferiorly. Example: Dropping the shoulders.
• Opposition: Bringing the thumb to touch the fingertips.

III. Types of Synovial Joints:

Synovial joints are further classified based on their shape and the types of movements they allow:

• Plane (Gliding) Joints: Flat articular surfaces that allow for gliding movements. Examples: Intercarpal and intertarsal joints.
• Hinge Joints: Allow movement in one plane (flexion and extension). Examples: Elbow and knee joints (primarily).
• Pivot Joints: Allow rotation around a single axis. Examples: Atlantoaxial joint (head rotation), radioulnar joint (pronation and supination).
• Condyloid (Ellipsoid) Joints: Allow movement in two planes (flexion/extension and abduction/adduction). Examples: Radiocarpal joint (wrist).
• Saddle Joints: Allow movement in two planes, with a greater range of motion than condyloid joints. Example: Carpometacarpal joint of the thumb.
• Ball-and-Socket Joints: Allow movement in all three planes (flexion/extension, abduction/adduction, and rotation). Examples: Shoulder and hip joints.

IV. Common Joint Pathologies

Many conditions can affect the structure and function of joints. Some common examples include:

• Osteoarthritis (OA): A degenerative joint disease characterized by the breakdown of articular cartilage. Symptoms include pain, stiffness, and limited range of motion.
• Rheumatoid Arthritis (RA): An autoimmune disease causing inflammation of the synovial membrane, leading to joint damage and pain.
• Gout: A form of inflammatory arthritis caused by the buildup of uric acid crystals in the joints.
• Bursitis: Inflammation of the bursae, causing pain and swelling.
• Tendinitis: Inflammation of tendons, often due to overuse or injury.
• Sprains: Injuries to ligaments caused by overstretching or tearing.
• Dislocations: Displacement of bones from their normal position within a joint.
• Carpal Tunnel Syndrome: Compression of the median nerve in the wrist, causing pain, numbness, and tingling.

V. Practical Applications

Understanding articulations and body movements is crucial in various fields:

• Physical Therapy: Therapists use this knowledge to assess patients, develop treatment plans, and rehabilitate injured joints. They focus on restoring range of motion, strength, and function.
• Occupational Therapy: OTs adapt activities and environments to promote independence and participation in daily living for individuals with joint limitations.
• Athletic Training: Trainers use this knowledge to prevent injuries, treat injuries, and design rehabilitation programs for athletes.
• Chiropractic Medicine: Chiropractors focus on the diagnosis, treatment, and prevention of musculoskeletal disorders, particularly those affecting the spine and other joints.
• Orthopedic Surgery: Surgeons utilize this knowledge to repair and replace damaged joints through surgical interventions like arthroscopy, joint replacement, and ligament reconstruction.
• Medical Imaging: Radiologists and other imaging professionals utilize this knowledge to interpret medical images of joints, such as X-rays, CT scans, and MRIs, to detect pathologies.

VI. Assessment and Examination Techniques

Clinical assessment of joints involves several techniques:

• Inspection: Visual examination of the joint for swelling, deformity, redness, or bruising.
• Palpation: Feeling the joint for tenderness, warmth, crepitus (grating sensation), or abnormal masses.
• Range of Motion (ROM): Assessing the extent of movement at the joint using goniometry (measurement of angles). This helps determine the presence and severity of joint limitations.
• Muscle Strength Testing: Evaluating the strength of muscles that act on the joint. Weakness can indicate underlying pathology.
• Special Tests: Specific maneuvers designed to assess particular joint structures or identify specific injuries (e.g., Lachman test for ACL injury in the knee).

VII. Conclusion

This review sheet provides a comprehensive overview of articulations and body movements. Mastering this knowledge is essential for healthcare professionals and students alike. Further exploration of specific joints and pathologies will enhance your understanding and clinical application of this vital information. Remember to consult reliable anatomical resources and clinical guidelines for in-depth study and accurate diagnosis. Continuing education and practical experience are key to honing your skills in assessing and managing musculoskeletal conditions. The human body is a complex and fascinating system, and understanding its intricate workings is crucial for effective healthcare.