Question

Can you explain in detail how a hand, wrist, and arm work together to left an object on a table from point A to point B. Such as the anatomy and Mechanics of the human hand. Example would be grabbing coke can and moving it to a different spot on table. (Talk about Wrist, Carpus, Metacarpus, Fingers, Muscles, Power grip, Connective tissue and tendons, etc.) Thank you and in paragraph form.

Answer 1

The human hand is made up of total 27 bones:

8 carpal bones,5 metacarpals and 14 phalanges which are connected by joints and ligaments.

The hand can be divided into 3 different areas based on joints:

A.carpus- wrist

B.metacarpus

C.fingers

In the limbs, flexion decreases the angle between the bones while extension increases the angle and straightens the joint.

The abductor pollicis stabilizes an object against the palm. This is also known as power grip.

Three arches balance stability and mobility in the hand.

The proximal transverse arch is rigid,but other two are flexible and are maintained by hand's extrinsic muscles.

The palm is protected by a strong pad of tendons { aponeurosis } , enabling a powerful grip.

There are 30 muscles working in complex way in the hand. Movements are started by the muscles in forearm

The ulnar nerves moves the muscles of the hypothenar eminence. Median nerve responsible for the movement of the thenar eminence muscles and rest of the lumbricals.

Radial nerves activate the extensors and muscles in wrist that are responsible for extending the hand.

The collective use of these enables a hand to lift an object.