Extremities

The hand


The lowest section of the human arms is formed by the hands as a gripping organ. They are connected to the forearm via the wrist and are extremely flexible thanks to their special bone structure. From the forearm downwards, the proximal (scaphoid, moon, triangle, pea) and distal carpal bones (large polygonal, small polygonal, scalp, hookbone) form the beginning of the hand. The five metacarpal bones follow and then the finger bones. The fingers are made up of three bones each, except for the thumb, while the thumb only has two bones. Another specialty of the human hand is the freedom of movement of the thumb, which enables finely controlled gripping with two fingertips. In total there are 27 bones in the hand area and the fingers alone have 14 finger joints.

In order to enable the countless different movements of the hands or fingers, there are more than thirty muscles in the hand, but the muscles in the forearm also make a significant contribution to the movement of the hands and fingers. The hands are essentially connected to the nervous system via the ulnar nerve, the median nerve and the radial nerve. The blood supply takes place via the arteries or the spokes and ulna artery, the blood drainage mainly via the vena basilica and the vena cephalica. Symptoms in the hand area are often due to impairment in the upper arm sections, but can also have their origin in the hand area. For example, ulnar gutter syndrome is associated with tingling and numbness in the little finger, in the ring finger and on the corresponding outside of the palm. Carpal tunnel syndrome can also be accompanied by sensations and pain that extends from the hand to the forearm.

The hands are almost constantly moving in everyday life and sometimes exposed to considerable stress. Here, signs of wear on the joints are not uncommon. The finger joints can also be affected by a so-called Heberden arthrosis (finger end joints) or Bouchard arthrosis (finger middle joints), the cause of which is suspected on a genetic and hormonal level. If the thumb saddle joint is affected by osteoarthritis, this is called rhizarthrosis. Rheumatoid arthritis also increasingly affects the finger joints, whereby joint pain, swelling, redness and warming in the joint area are the main symptoms. Furthermore, the joint capsules of the finger joints are relatively easily vulnerable to external force - a so-called capsule tear is a typical consequence here. In addition, there are fractures of the finger, metacarpal and carpal bones as well as ruptures of the various ligaments as possible consequences of external forces such as in the context of an accident or fall. Overall, hands are the most important human tools and they also perform essential functions in communication, but the high loads also come at a price and so symptoms in the hand area are not uncommon. (fp)

Hand

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