Final answer:
Hand signals and gestures involve the intentional use of arm movements and positions to convey specific messages, backed by an understanding of anatomy such as the carrying angle and muscle contractions.
Step-by-step explanation:
The subject at hand involves understanding how the arm is used to give hand signals, relating closely to health and anatomy. In this context, the focus is on the physical movements and gestures that communicate specific messages or commands, especially within a military or performance setting.
Quintilian's Institutes of Oratory emphasizes the deliberate use of gestures to convey meaning, which is an art requiring control and understanding of one's body language. The description of the arm's extension and the carrying angle highlights the anatomical considerations underpinning gestures. Arm wresting, as an illustration of muscle contraction and physical force, is also related to the use of arms in signaling. These principles are not just relevant to oratory but extend to physical disciplines and performance arts where arm gestures play a crucial role.