Final answer:
The forearm is the part of the upper limb between the elbow and wrist, containing the bones ulna and radius. The upper limb is segmented into three regions with a total of 30 bones, including the humerus in the upper arm.
Step-by-step explanation:
The forearm is the region of the upper limb that is located between the elbow and wrist joints. It contains two bones: the ulna, which is situated medially (towards the body), and the radius, which is located on the lateral side (thumb side). The ulna has a trochlear notch that articulates with the trochlea of the humerus at the elbow joint, allowing for the bending and extending motions of the arm. Additionally, the head of the radius articulates with the radial notch of the ulna. The upper arm contains the humerus, which is the largest and longest bone of the upper limb. It forms joints with the shoulder at the top and with the ulna and radius at the elbow. This configuration allows for a wide range of movements and supports the complex function of the upper limbs. Each upper limb is divided into three regions: the arm, the forearm, and the hand. In total, there are 30 bones in each upper limb, which includes the humerus in the arm, the radius and ulna in the forearm, and the carpal, metacarpal, and phalanges in the hand.