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    Related Topics

    From Musculoskeletal System

    Skull
    Bony structure of the head that encases the brain.
    Temporal Bones
    Bones forming the lower sides of the skull and housing the ears.
    Hinge Joints
    e.g., elbow, knee
    Metatarsals (5 bones)
    5 bones forming the mid-foot.
    Gluteus Maximus
    Largest muscle in the buttocks responsible for hip extension.
    Cervical Vertebrae (C1 - C7)
    Vertebrae in the neck region (C1-C7).
    Saddle Joints
    e.g., thumb joint
    Coccyx
    Tailbone, the remnant of the tail in humans.
    Latissimus Dorsi
    Back muscle responsible for arm adduction and extension.
    Buccinator
    Muscle that helps with chewing and blowing air out.
    Deltoid
    Shoulder muscle responsible for arm abduction.
    Gliding (Plane) Joints
    e.g., between carpals
    Patellar Tendon
    Tendon connecting the patella to the tibia.
    Mandible
    Lower jawbone that houses the teeth.
    Soleus
    Calf muscle responsible for plantarflexion of the foot.
    Temporalis
    Muscle involved in closing the jaw.
    Interspinous Ligament
    Spinal ligament between adjacent vertebral spinous processes.
    Ethmoid Bone
    Bone forming part of the nasal cavity and the orbit.
    Diaphragm
    Primary muscle for breathing.
    Palatine Bones
    Bones forming part of the hard palate and nasal cavity.
    Tibia
    Shin bone, the larger bone in the lower leg.
    Pectoralis Major
    Chest muscle responsible for shoulder movement.
    Sesamoid Bones
    e.g., patella, some found in hands/feet.
    Clavicle
    Collarbone connecting the arm to the body.
    Adductors
    Muscles that bring the thighs toward the midline.

    Rotator Cuff Tendons

    Reviewed by our medical team

    Tendons of the rotator cuff muscles.

    1. Overview

    The rotator cuff tendons are the tendinous extensions of the four rotator cuff muscles—supraspinatus, infraspinatus, teres minor, and subscapularis. These tendons insert on the humeral head and work together to stabilize the glenohumeral (shoulder) joint. They form a continuous sheath over the shoulder joint capsule and play a vital role in dynamic shoulder stability and motion.

    2. Location

    The rotator cuff tendons are located around the proximal humerus and encapsulate the shoulder joint:

    • Supraspinatus tendon: Passes under the acromion and inserts on the superior facet of the greater tubercle of the humerus.

    • Infraspinatus tendon: Inserts on the middle facet of the greater tubercle.

    • Teres minor tendon: Inserts on the inferior facet of the greater tubercle.

    • Subscapularis tendon: Inserts on the lesser tubercle of the humerus (anteriorly).

    3. Structure

    Rotator cuff tendons are composed of dense regular connective tissue primarily made up of Type I collagen fibers:

    • Collagen alignment: Fibers are oriented along the direction of pull to withstand tensile loads.

    • Insertion zones: Tendons transition through four zones—tendon, unmineralized fibrocartilage, mineralized fibrocartilage, and bone—to create a strong, gradual attachment.

    • Vascular supply: Relatively poor, especially in the supraspinatus tendon (notably in the “critical zone”), which makes it prone to degeneration and tears.

    • Synovial sheath: Tendons are surrounded by a synovial layer to reduce friction during motion.

    4. Function

    The rotator cuff tendons transmit force from the muscle bellies to the humeral head and:

    • Stabilize the shoulder: Anchor the humeral head into the glenoid fossa during shoulder movement.

    • Coordinate movement: Work synergistically with deltoid and scapular muscles to guide shoulder elevation and rotation.

    • Control joint mechanics: Prevent superior migration of the humeral head during arm elevation.

    5. Physiological role(s)

    Rotator cuff tendons contribute to upper limb mechanics and coordination:

    • Enable complex motions: Facilitate overhead activities, throwing, reaching, and lifting.

    • Proprioception: Contain sensory receptors that relay information about joint position and muscle tension.

    • Load distribution: Help spread mechanical stress across the shoulder capsule and joint surfaces.

    6. Clinical Significance

    Rotator cuff tendons are prone to injury due to their anatomical location, limited vascularity, and frequent use:

    • Tendon tears:

      • Partial thickness: Damage to some tendon fibers; often seen in overhead athletes and laborers.

      • Full-thickness (complete): Complete detachment of tendon from bone, most commonly affecting the supraspinatus.

    • Tendinopathy:

      • Chronic overuse can lead to tendon degeneration, thickening, and fibrosis—often referred to as rotator cuff tendinosis.

    • Impingement syndrome:

      • Compression of the rotator cuff tendons (especially supraspinatus) beneath the acromion, leading to inflammation and pain.

    • Calcific tendinitis:

      • Calcium deposits form within the tendon, typically the supraspinatus, causing severe pain and reduced mobility.

    • Rotator cuff arthropathy:

      • Chronic tears may lead to glenohumeral joint instability, arthritis, and superior migration of the humeral head.

    • Repair and rehabilitation:

      • Tendon repair (open or arthroscopic) may be required for full-thickness tears, followed by extensive physiotherapy.

    Did you know? The femur is the longest and strongest bone in the human body.