W9 (OIA’s) All Muscles of Back & Shoulder

Deltoideus (origin)

Clavicle, acromion, and spine of scapula

Deltoideus (insertion)

Deltoid tuberosity of humerus

Deltoideus (Action)

Flexion, abduction, extension of arm

Trapezius (origin)

Occipital bone, spinous processes of the cervical and thoracic vertebrae

Trapezius (Insertion)

Clavicle, acromion & spine of scapula

Trapezius (Action)

Fixates scapula; elevates, adducts, rotates scapula

Latissimus dorsi (origin)

Spinous processes of T6-L5 & iliac crest

Latissimus dorsi (Insertion)

Medial lip of intertubercular groove of humerus

Latissimus dorsi (Action)

Extension & Adduction of arm; medial rotation of arm

Serratus anterior (origin)

Ribs 1-9

Serratus anterior (Insertion)

Vertebral border of the scapula

Serratus anterior (Action)

Abducts & fixates scapula; elevates ribs

Levator scapulae (origin)

C1-C4 transverse processes

Levator scapulae (Insertion)

Vertebral border of the scapula (at the superior angle)

Levator scapulae (Action)

Elevates scapula

Rhomboideus major (origin)

Spinous processes of T2-T5

Rhomboideus major (Insertion)

Vertebral border of the scapula (below spine of scapula)

Rhomboideus major (Action)

Adducts, rotates, & fixates scapula

Rhomboideus minor (origin)

Spinous processes of C7-T1

Rhomboideus minor (insertion)

Vertebral border of the scapula (above spine of scapula)

Rhomboideus minor (action)

Adducts, rotates, & fixates scapula

Teres major (origin)

Axillary border of scapula

Teres major (insertion)

Medial lip of intertubercular groove of humerus

Teres major (action)

Extension and adduction of arm

Teres minor (origin)

Axillary border of scapula

Teres minor (insertion)

Greater tubercle of humerus

Teres minor (action)

External (lateral) rotation of arm

Infraspinatus (origin)

Infraspinous fossa of scapula

Infraspinatus (Insertion)

Greater tubercle of humerus

Infraspinatus (Action)

External (lateral) rotation of arm

Supraspinatus (origin)

Supraspinous fossa of scapula

Supraspinatus (Insertion)

Greater tubercle of humerus

Supraspinatus (Action)

Abduction of arm

Subscapularis (origin)

Subscapular fossa of scapula

Subscapularis (Insertion)

Lesser tubercle of humerus

Subscapularis (action)

Internal (medial) rotation of arm

Erector spinae (action - only)

Extension and lateral flexion of back

Transversospinalis (action - only)

Various movements of the vertebral column