Glenohumeral Joint

• Glenohumeral Joint - Stability

  some stability is provided by the rotator cuff mucles, long head brachii + extracapsular ligaments

  
• Glenoid Cavity

  the large hemispherical head of the humerus fits in the small, shallow glenoid cavity of the scapula

  altho the glenoid caivty is slightly deepened by a rim of fibrocartilage, the glenoid labrum, it is only approx 1/3 the size of the humeral head + contributes lil to joint stability

  
• Articular Capsule of the Glenohumeral Joint Cavity

  the articular capsule enclosing the joint cavity from the margin of the glenoid cavity to the neck of the humerus) is v thin + loose, qualities that contribute to this joint's freedom of movement
• Reinforcing Ligaments - Coracohumeral Ligament

  located on the superior, anterior aspect of the humerus

  provides the only strong thickening of the capsule + helps support the weight of the upper limb
• Musce Tendon Superstabiliser

  muscle tendons that cross the shoulder joint contribute most to this joint's stability

  the superstabiliser is the tendon of the long head of the biceps brachii this tendon attaches to the superior margin of the glenoid labrum, travels thru the joint cavity + then runs w in the intertubercular sulcus of the humerus

  it secures the head of the humerus against the glenoid cavity

  
• Rotator Cuff - Muscle Tendons

  4 other tendons (and the associated muscle) makes up the rotator cuff

  this cuff encircles the shoulder joint + blends w the articular capsule

  the 4 muscles of the rotator cuff - subscapularis, supraspinatus, infraspinatus + teres minor

  
• Joint Classification of Glenohumeral Joint

  ball + socket joint

  diarthroses - freely moveable joint, w wide range of movements
• Movements of the Glenohumeral Joint

  flexion/extension

  abd/add

  horizontal abd/add

  internal/medial rotation

  external/lateral rotation

  elevation

  circumduction
• Muscles of GH Joint - Pectoralis Major (Action)

  adducts + medially rotates humerus

  
• Muscles of GH Joint - Latissimus Dorsi

  origin - T7-T12 via thoracolumbar fascia to L1-5 + iliac crest

  insertion - bicipital groove of humerus

  
• Muscles of GH Joint - Latissimus Dorsi (Action)

  protact + laterally rotate GHJ

  
• Muscles of GHJ - Deltoid

  origin - lateral 3rd of anterior asect of clavicle, acromion + spine of scapula (posterior)

  insertion - deltoid tuberosity of humerus