Kinesiology - Shoulder Girdle Muscles and Motion

Osteo: Scapular Abduction (Protraction)

Artho: Lateral Slide (scapula slides out to the side when protracted)

Osteo: Scapular Adduction (retraction)

Arthro: Medial slide (scapula slides together inside)

Osteo: Elevation of scapula

Arthro: Superior slide/glide of scpaula

Osteo: Depression of scapula

Arthro: Inferior slide/glide of scapula

Osteo: Upward rotation (tracks inferior point on scapula, it gets higher angle when you move your arm up)

Arthro: Slides in the same direction that we see the scapula moving

Osteo: Downward rotaiton

Arthro: Slides in the same direction that we see the scapula moving

The shoulder girdle muscles primarily innervated by

Cervical plexus (C1-C4) and brachial plexus (C5-C8)

Long thoracic nerve innervates

Serratus anterior

Trapezius muscle action

Upper fibers: elevation of scapula, extension and rotation of head

Middle fibers: elevation, upward rotation and adduction

Lower fibers: depression, adduction and upward rotation

Trapezius muscle origin and insertion

Origin: base of skull, cervical ligaments, spinous process C7-C12 and all thoracic vertebrae

Insertion: clavicle, acromion process, and spine of scapula

Levator Scapulae muscle action

Elevates the medial margin of hte scapula

Levator Scapulae muscle origin and insertion

Origin: Transverse process of C1-C4 (lateral protrusions)

Insertion: Medial boarder of scapula from superior angle of scapula

Rhomboid muscle action

Adduction, downward rotation, and elevation

Rhomboid muscle origin and insertion

Origin: Spinous process of C7-T5

Insertion: Medial border of scapula

Serratus anterior muscle action

Abduction and upward rotation

Serratus anterior muscle origin and insertion

Origin: Surfaces of upper nine ribs on side of chest

Insertion: Anterior aspect of whole length of medial border of scapula

Pectoralis minor muscle action

Abduction, downward rotation, and depression

Pectoralis minor muscle origin and insertion

Origin: Anterior surfaces of third to fifth ribs

Insertion: Coracoid process of scapula (anterior protruding process)

Subclavius muscle action

Depression, abduction

Subclavius muscle origin and insertion

Origin: Superior aspect of first rib at its junction with its costal cartilage

Insertion: Inferior groove in the midportion of the clavicle