- long head: infraglenoid tubercle of scapula to olecranon process. functions in joint stability (shunt muscle) - medial head: dorsal surface of humerus to olecranon process.most active of the head in all three positions.- lateral head: dorsal surface of humerus to olecranon process.Strongest, but only active against resistance.unctions in joint stability (shunt muscle) - medial head: dorsal surface of humerus to olecranon process. most active of the head in all three positions. - lateral head: dorsal surface of humerus to olecranon process. Strongest, but only active against resistance.
The ES 500 is a great little backup unit. Easy to use, long battery life (about 25 min. with a desktop PC plugged in; 2 hrs. with a notebook PC plugged into it). It includes full surge protector capabilities, so you won't need to buy another one of those.
This is highly dependant on your usage, and the way in which you maintain your battery. Apple expects your battery to retain approximately 80% of its charge after about 300 full cycles. In newer MacBooks and MacBook pros (2009 and later), Apple claim that the battery can be used for around 1000 cycles (5 years of typical use).