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    Triceps Brachii
    Muscle responsible for elbow extension.
    Hyoid Bone
    U-shaped bone in the neck that supports the tongue.
    Fibula
    Smaller bone in the lower leg, located alongside the tibia.
    Inferior Nasal Conchae
    Bones inside the nasal cavity that filter and humidify air.
    Femur
    Thigh bone, the longest and strongest bone in the body.
    Acromioclavicular Joint
    The acromioclavicular joint connects the clavicle and scapula at the top of the shoulder, enabling smooth scapular motion and stability during arm movements.
    Temporal Bones
    Bones forming the lower sides of the skull and housing the ears.
    Gluteus Maximus
    Largest muscle in the buttocks responsible for hip extension.
    Gastrocnemius
    Calf muscle responsible for plantarflexion of the foot.
    Nasal Bones
    Bones forming the bridge of the nose.
    Lacrimal Bones
    Bones forming part of the eye socket and housing the tear ducts.
    Sphenoid Bone
    Bone forming part of the base of the skull and sides of the orbits.
    Ribs (12 Pairs)
    12 pairs of bones that form the sides of the thoracic cage.
    Skull
    Bony structure of the head that encases the brain.
    Parietal Bones
    Bones forming the sides and roof of the skull.
    Diaphragm
    Primary muscle for breathing.
    Mandible
    Lower jawbone that houses the teeth.
    Hinge Joints
    e.g., elbow, knee
    Acromioclavicular Ligament
    Ligament that connects the acromion to the clavicle.
    Pectoralis Major
    Chest muscle responsible for shoulder movement.
    Zygomatic Bones
    Cheekbones that form part of the orbit.
    Lateral Collateral Ligament (LCL)
    Knee ligament that stabilizes the outer knee.
    Latissimus Dorsi
    Back muscle responsible for arm adduction and extension.
    Thoracic Cage
    Ribs and sternum forming the protective cage for the heart and lungs.
    Masseter
    Muscle that elevates the mandible.

    Coracoacromial Ligament

    Reviewed by our medical team

    Ligament that connects the acromion to the coracoid process.

    1. Overview

    The coracoacromial ligament is a strong, triangular band of connective tissue located in the shoulder. It connects the coracoid process to the acromion, both of which are projections of the scapula. This ligament forms part of the coracoacromial arch, a protective arch over the head of the humerus, preventing its upward displacement. Although it does not directly stabilize the glenohumeral joint, it plays a crucial role in maintaining the structural integrity of the shoulder and preventing impingement.

    2. Location

    The coracoacromial ligament is found in the superior aspect of the shoulder, forming a roof over the glenohumeral joint:

    • Proximally: Attaches to the lateral border of the coracoid process.

    • Distally: Inserts onto the medial border of the acromion process.

    • Orientation: Extends obliquely over the head of the humerus, forming a protective arch along with the acromion and coracoid process.

    3. Structure

    The coracoacromial ligament is composed of dense regular connective tissue and has the following structural characteristics:

    • Shape: Flat and triangular, with a broad base at the acromion and an apex at the coracoid process.

    • Fibers: Run obliquely, blending with the deep fascia of the shoulder and sometimes with the deltoid or trapezius muscle fascia.

    • Coracoacromial arch: Along with the acromion and coracoid process, it forms a bony-ligamentous arch over the humeral head.

    4. Function

    The coracoacromial ligament serves important mechanical and protective functions:

    • Prevents superior dislocation: Acts as a barrier to upward displacement of the humeral head during shoulder movements.

    • Supports the coracoacromial arch: Maintains the integrity of the arch, which protects the rotator cuff and glenohumeral joint from direct trauma.

    • Limits excessive motion: Assists in restricting superior translation of the humerus.

    5. Physiological role(s)

    Though not a dynamic stabilizer, the coracoacromial ligament has several physiological roles:

    • Passive restraint: Provides a static check-rein to upward movement of the humeral head, especially during deltoid contraction.

    • Force redirection: Helps distribute forces exerted by surrounding muscles and tendons over the superior shoulder.

    • Anatomical roof: Forms a part of the shoulder's subacromial space, influencing the biomechanics of the rotator cuff tendons and bursa.

    6. Clinical Significance

    The coracoacromial ligament is implicated in various shoulder pathologies, particularly in impingement syndromes:

    • Subacromial impingement syndrome:

      • The coracoacromial arch can impinge on the supraspinatus tendon or subacromial bursa during arm elevation, causing pain and reduced mobility.

      • Thickening or ossification of the ligament may contribute to narrowing of the subacromial space.

    • Rotator cuff tears:

      • Chronic impingement against the ligament can cause wear and eventual tearing of the supraspinatus tendon.

    • Coracoacromial ligament release:

      • In severe or recurrent impingement cases, partial resection of the ligament may be performed surgically to decompress the subacromial space.

    • Shoulder instability evaluation:

      • Though it does not directly stabilize the glenohumeral joint, an intact coracoacromial arch is a secondary restraint to superior translation in the event of rotator cuff failure.

    Did you know? Bones are constantly producing new cells in the bone marrow.