Trapezius (Upper fibers)O: base of skull, occipital protuberance, posterior ligaments of neckI: posterior aspect of lateral 1/3 of clavicleA: elevation of scapula, extension and rotation of head at the neck

Trapezius (Middle fibers)O: spinous processes of 7th cervical and upper three thoracic vertebraeI: medial border of acromion process and upper border of scapular spineA: elevation, upward rotation, and adduction (retraction) of scapula

Trapezius (Lower fibers)O: spinous process of 4th through 12th thoracic vertebraeI: triangular space at the base of scapular spineA: depression, adduction (retraction), and upward rotation of scapula

Levator scapulaeO: Transverse processes of upper four cervical vertebraeI: Medial border of scapula above base of scapular spineA: Elevates the medial margin of scapula, weak downward rotation and weak adduction

Rhomboid minor and majorO: Spinous processes of last cervical and first five thoracic vertebraeI: Medial border of scapula below the spineA: Acting together: adduction (retraction) of scapula, rotation downward from upward rotated position, and elevation

Serratus anteriorO: Surface of upper nine ribs at side of chestI: Anterior aspect of whole length of medial border of scapulaA: Abduction (protraction) and rotation upward of scapula

Pectoralis minorO: Anterior surfaces of 3rd to 5th ribsI: Coracoid process of scapulaA: Abduction (protraction) of scapula, downward rotation of scapula, and depression of scapula from elevated position

SubclaviusO: Superior aspect of 1st rib at its junction with its costal cartilageI: Inferior groove in the midportion of clavicleA: Stabilization and protection of sternoclavicular joint, depression and abduction of scapula

Joints of the Shoulder

• Glenohumeral Joint

• Acromioclavicular Joint

• Coracoclavicular joint

• Sternoclavicular joint

• Coracoacromial joint

Ligaments of the Shoulder

• Coracohumeral ligament – stabilizes the superior part of glenohumeral joint

• Glenohumeral ligament (superior, middle, inferior) – stabilizes the anterior part of the glenohumeral joint

• Transverse humeral ligament – stabilizes the biceps brachii tendon (long head)

• Coracoacromial ligament (coracoacromial arch) – stabilizes the superior part of glenohumeral joint

• Acromioclavicular ligament - stabilizes the acromioclavicular joint (AC joint)

Coracohumeral and Glenohumeral Ligaments (superior, middle, inferior)

Transverse humeral ligament

Coracoacromial Arch (acromion, coracoid process, coracoacromial

ligament)

Acromioclavicular Ligament