The infraspinatus and teres minor rotate the head of the humerus outward (external, or lateral, rotation)
The primary motion of the infraspinatus is to externally rotate your humerus.

So more room in the thoracic outlet.

http://en.wikipedia.org/wiki/Infraspinatus_muscle
http://en.wikipedia.org/wiki/Teres_minor_muscle
http://www.ncpad.org/exercise/fact_s...6&section=2336
http://www.askthetrainer.com/rotator...exercises.html

Infraspinatus muscle atrophy in professional Baseball players (they got TOS sometimes)

http://cat.inist.fr/?aModele=afficheN&cpsidt=15523935



Do we need to strenghten these muscles ?