actions of these muscles
Muscle                                   
  
origin                       
                 
insertion                           
action
Latissimus dorsi
Spinous processes of T7 thru L5, lower 3 ribs, iliac crest
Rhomboids
Spinous processes of C7 thru T5
Diaphram
External intercostals
Internal Intercoatals
Triceps brachii
Long head: inferior margin of glenoid cavity
Lateral head: posterior humerus
Medial head: distal radial groove of post. humerus
Biceps brachii
Short head: coracoid process
Long head: supra-glenoid tubercle
Brachioradialis
Flexor Digitorum Longus