Underneath the layers of fatty tissue there is a network of muscles connecting to bone, tendons and fat.
Most of the time, bodies aren't defined enough to see these individual muscle groups so we have to research our anatomy from pictures and photos. Look at the anatomy books and look at the illustrations and try to understand which muscles connect to which bones. Then you will start to grasp how they move and what they look like when they move.
When it comes to breasts, we usually can't see what's going on muscularly. The pectoralis major muscle, shown here in orange (sternal portion) and red (clavicular portion) connect to the sternum and the clavicle, running out from center to meet the deltoid and biceps, fixed to the humerus (arm).
Note (under the arm):
when the arm is down - the sternal portion (orange) is running underneath the clavicular portion (red) to the humerus (under the arm).
when the arm is raised - the sternal portion slides over the the clavicular portion, so the sternal portion is now above and the clavicular portion runs underneath.
Nathan Aardvark
2016-02-09 22:53:29 +0000 UTCOppai Inc
2016-02-09 22:39:03 +0000 UTC