In what region of the arm would you find the ulna?

The ulna is one of the two long bones in the forearm, the other being the radius. It is located on the opposite side of the thumb, running parallel to the radius. The forearm consists of both the ulna and radius and is the area between the elbow and the wrist, allowing for various movements of the hand and wrist. Understanding the anatomy of the arm is essential for any practice in manicuring, as it helps in understanding clients' needs and how to position their arms and hands comfortably during treatments.

The other regions listed, such as the upper arm, hand, and wrist, do not contain the ulna. The upper arm is comprised of the humerus bone, while the hand consists of numerous small bones, and the wrist is made up of carpal bones. Hence, the ulna's specific location in the forearm makes this the correct answer.