yläjäsenen

Yläraaja is the Finnish term for the upper limb of the human body. It encompasses all the structures from the shoulder to the fingertips. This includes the clavicle (collarbone) and scapula (shoulder blade), which form the shoulder girdle and connect the upper limb to the axial skeleton.

The main bone of the upper arm is the humerus. This long bone articulates with the scapula at the shoulder joint and with the radius and ulna at the elbow. The forearm contains two bones, the radius and the ulna, which run parallel to each other. These bones allow for pronation and supination, movements that rotate the forearm.

The wrist, or carpus, is composed of eight small carpal bones arranged in two rows. These bones provide flexibility and allow for a wide range of wrist movements. The hand, or manus, consists of the metacarpal bones and the phalanges, which form the fingers and thumb. The intricate structure of the hand, with its opposable thumb, is crucial for grasping and manipulating objects.

The muscles, nerves, and blood vessels of the upper limb are highly specialized to facilitate its extensive range of motion and sensory functions. These components work in coordination to enable actions such as lifting, carrying, writing, and complex fine motor skills. The upper limb's primary role is to interact with the external environment, making it a vital part of human interaction and activity.