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    Related Topics

    From Musculoskeletal System

    Ligamentum Flavum
    Spinal ligament connecting the laminae of adjacent vertebrae.
    Skull
    Bony structure of the head that encases the brain.
    Rotator Cuff Muscles
    Supraspinatus, Infraspinatus, Teres Minor, Subscapularis.
    Zygomatic Bones
    Cheekbones that form part of the orbit.
    Fibula
    Smaller bone in the lower leg, located alongside the tibia.
    Obliques (External and Internal)
    Muscles responsible for torso rotation.
    Ilium
    Uppermost and largest part of the hip bone.
    Extensor Tendons
    Tendons that help extend the fingers and toes.
    Zygomaticus
    Muscle that raises the corners of the mouth.
    Biceps Brachii
    Muscle responsible for elbow flexion.
    Temporal Bones
    Bones forming the lower sides of the skull and housing the ears.
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Wormian Bones
    Sutural bones in the skull.
    Rotator Cuff Tendons
    Tendons of the rotator cuff muscles.
    Thoracic Vertebrae (T1 - T12)
    Vertebrae in the upper and mid-back (T1-T12).
    Tarsals (7 bones)
    7 ankle bones.
    Sternum
    Breastbone located in the center of the chest.
    Achilles Tendon
    Tendon connecting the calf muscle to the heel bone.
    Sutures (in the skull)
    Fibrous joints between skull bones.
    Sphenoid Bone
    Bone forming part of the base of the skull and sides of the orbits.
    Vertebral Column
    Spinal column consisting of vertebrae.
    Interspinous Ligament
    Spinal ligament between adjacent vertebral spinous processes.
    Parietal Bones
    Bones forming the sides and roof of the skull.
    Glenohumeral Ligaments
    Shoulder ligaments that stabilize the shoulder joint.
    Posterior Longitudinal Ligament
    Spinal ligament running along the back of the vertebral column.

    Medial Collateral Ligament (MCL)

    Reviewed by our medical team

    Knee ligament that stabilizes the inner knee.

    1. Overview

    The medial collateral ligament (MCL) is a broad, flat band of connective tissue located on the inner side of the knee. It is one of the four major ligaments that stabilize the knee joint, alongside the ACL, PCL, and LCL. The MCL is particularly responsible for resisting valgus stress (forces that push the knee inward) and plays a critical role in maintaining medial knee stability during movement and weight-bearing.

    2. Location

    The MCL is found on the medial (inner) aspect of the knee:

    • Proximal attachment: Medial epicondyle of the femur.

    • Distal attachment: Medial surface of the tibia, approximately 5–7 cm below the joint line.

    • Medially: Lies deep to the sartorius muscle and over the pes anserinus tendons.

    • Adjacent structures: Lies superficial to the joint capsule and medial meniscus, with deeper fibers merging with both.

    3. Structure

    The MCL is a flat, broad, and layered ligament with two distinct parts:

    • Superficial MCL:

      • Primary stabilizer against valgus stress.

      • Runs from the medial femoral epicondyle to the medial tibia.

    • Deep MCL:

      • Shorter and thicker, located deep to the superficial layer.

      • Firmly attached to the medial meniscus and joint capsule.

    The ligament is composed of densely packed collagen fibers aligned parallel to resist tensile forces, with limited elasticity.

    4. Function

    The medial collateral ligament plays a key role in knee stability and biomechanics:

    • Resists valgus stress: Prevents the knee from collapsing inward, especially when the foot is planted and a lateral force is applied.

    • Limits external rotation: Helps stabilize the knee during twisting motions.

    • Stabilizes medial joint line: Supports the integrity of the joint during walking, running, and side-to-side movements.

    • Assists in controlling knee flexion-extension motion: Acts in concert with other ligaments and muscles.

    5. Physiological role(s)

    The MCL contributes to several physiological and functional processes:

    • Proprioception: Contains sensory receptors that provide feedback on joint position and motion, aiding balance and coordination.

    • Force distribution: Helps dissipate forces across the knee joint, especially during high-load activities.

    • Joint capsule reinforcement: The deep fibers of the MCL blend with the joint capsule, contributing to passive stabilization.

    • Protection of medial meniscus: Prevents excessive gapping that could injure the meniscus.

    6. Clinical Significance

    The MCL is commonly injured, particularly in athletes and during contact sports:

    • MCL sprain:

      • Occurs when the knee is subjected to valgus stress; classified into grades:

        • Grade I: Mild sprain with no instability.

        • Grade II: Partial tear with some laxity.

        • Grade III: Complete rupture, often with joint instability.

    • Mechanism of injury:

      • Usually from a blow to the lateral knee or sudden directional changes.

    • Symptoms:

      • Medial knee pain, swelling, bruising, tenderness along the inner knee, and instability during walking or pivoting.

    • Diagnosis:

      • Clinical valgus stress test, MRI for detailed grading and assessment of associated injuries (e.g., medial meniscus or ACL).

    • Treatment:

      • Most MCL injuries (Grades I–II) are treated non-surgically with rest, bracing, physical therapy.

      • Grade III tears may require surgical repair, especially if combined with ACL injury.

    • Rehabilitation:

      • Includes strengthening, proprioception exercises, and progressive return to activity.

    Did you know? Each human hand has 27 bones.