Origin/Insertion of Muscles - Back - Latissimus Dorsi

Latissimus Dorsi
Origin: Spinous processes of lower 6 thoracic vertebrae, ribs and lumber vertebrae
Insertion: Intertubercular groove of humerus
Action: Extension, adduction and medial rotation at shoulder; extends arm at shoulder, adducts arm at shoulder, medially rotates arm at shoulder

Latissimus Dorsi

Spinous Processes

Intertubercular Groove of Humerus

Origin/Insertion of Muscles - Back - Trapezius

Trapezius
Origin: Medial superior nuchal line and external protuberance of occipital bone and spinous processes of C7-T12
Insertion: Lateral clavicle and scapula (acromion and scapular spine)
Action: Upper Fibres: elevate and upwardly rotate scapula; extend neck
             Middle Fibres: adducts (retracts) scapula
             Lower Fibres: depress and help upper fibres upwardly rotate scapula



Superior Nuchal Line

 


External Protuberance of Occipital bone

Spinous Processes

Acromion and Scapula Spine