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Overview of the Hip Joint

• Acetabular Labrum:

  • Extends the depth of the hip socket, enhancing stability.

  • Composed of fibrocartilage, allowing better flexibility compared to a bony socket.

• Joint Characteristics:

  • Capsule around the hip joint is thick, contributing to its strength.

  • The hip joint is stronger than the shoulder joint due to deeper socket and sturdier ligaments.

Comparison of Joint Stability

• Muscle Support:

  • More muscle mass around the hip joint, especially in the gluteal and thigh regions.

  • Results in greater stability of the hip joint compared to the shoulder joint.

• Injury Likelihood:

  • The hip joint is less likely to be injured than the shoulder, though it still remains susceptible to injuries due to its mobility.

Comparison of Glenohumeral and Coxal Joints

• Mobility vs. Stability:

  • Glenohumeral Joint (Shoulder): More mobile.

  • Coxal Joint (Hip): More stable.

Structure of the Knee Joint

• Knee Joint Composition:

  • Features a hinge joint between the femur and tibia, with movement primarily from these two bones.

  • Includes a plane joint between the patella and femur, allowing smooth gliding motion.

• Articular Components:

  • Articular Cartilage: Hyaline cartilage covering the ends of femur and tibia.

  • Meniscus: Fibrocartilage structure aiding pressure absorption and stability, comprises medial and lateral menisci.

Patella and Supporting Structures

• Patella's Role:

  • Held in place by the quadriceps tendon and connects to the tibia via the patellar ligament.

  • Described as a sesamoid bone due to its role in enhancing leverage in leg movement.

• Infrapatellar Fat Pad:

  • Cushioning structure located beneath the patella, aiding in reducing friction during knee movement.

Ligaments in the Knee

• Types of Ligaments:

  • Fibular Collateral Ligament (LCL):

    • Located on the lateral side of the knee; prevents abnormal inward bending (hyperadduction).

  • Tibial Collateral Ligament (MCL):

    • Positioned on the medial side; connecting the tibia to the femur, helps stabilize against sideways movement.

• ACL and PCL:

  • Anterior Cruciate Ligament (ACL): Vulnerable to injury from hyperextension, often torn in contact sports.

  • Posterior Cruciate Ligament (PCL): More robust, attached to the posterior tibia and anterior femur, less prone to hyperextension injuries.

Common Knee Injuries

• ACL Injuries: Common from hyperextension or sudden movements during physical activities.

• Meniscus Injuries: Often undetected initially, can lead to long-term joint problems.

• Overuse Injuries: Like tendinitis and bursitis, resulting from repetitive motions.

Introduction to Muscle Tissue

• Function of Muscle:

  • Enables movement (e.g., walking, maintaining posture).

  • Supports and protects organs, especially abdominal structures.

• Muscle Structure:

  • Composed of bundles called fascicles.

  • Individual cells referred to as muscle fibers (muscle fibers are the basic unit of muscle tissue).

Conclusion

• Relevance of Muscle:

  • Essential for daily activities and sustaining body postures without necessarily being in motion (e.g., holding the head up).

  • Importance of muscle endurance highlighted through continuous contraction during daily activities.