a. Adducts the arm at the shoulder (glenohumeral) joint. b. Medially rotates the arm at the shoulder (glenohumeral) joint. c. Extends the arm at the shoulder (glenohumeral) joint. - See more at: http://www.getbodysmart.com/ap/muscularsystem/armmuscles/anteriormuscles/latissimus/tutorial.html#sthash.QrSitzCE.dpuf