The arms are readily visible and thus relatively easy to understand from an anatomical point of view.
There are three bones in the arm – the humerus, the radius and the ulna.
The Humerus Bone of the Arm
The humerus, the large bone of the upper arm, is the largest bone in the arm. Its ball socket sits in the scapula of the shoulder. In a drawing, the viewer cannot see the bone, but the effects of the joints are evident in the artist’s portrayal of the arm, the shoulder, the wrist and the hands.
The Ulna and the Radius
The ulna bone is the next largest bone in the arm; it is wide at both its top and at the bottom near the pinky finger. The ulna fits into the elbow socket. The elbow is at the end of the ulna bone. The coronoid process forms the triangle at the elbow by projecting forth from the ulna bone. The elbow joint itself is formed like a spool of thread sitting on its side.
The radius bone is wide at the wrist but narrows at the elbow. The wrist itself is rectangular in shape.
These two bones – the ulna and the radius – twist to allow the twisting flexibility in the lower arm. In a normal pose with arms hanging down at rest, the ulna and radius are twisted. When the arm is supenated (with the palms facing outward toward the viewer) the ulna and radius are parallel. Being aware of the twisting motion of the two bones of the lower arms gives artists the knowledge to realistically display the arms of figures in their paintings. If an artist does not possess this understanding of the nature of the bones and muscles of the arms, the muscles may look distorted.
The shoulder joint is composed of a ball socket that allows almost 360 degree mobility.
The Muscles of the Arm
There are strong and very easily visible and inter-connected muscles in the shoulder, arm and chest. The muscles work together in basic groups, contracting and relaxing to perform various movements like picking up objects or writing. Lower arm muscles extend the hands, the fingers, and the palm. Muscles of the arm are flexed when they bring the hands and fingers toward the body. Flexor muscles attached to the ulnar bone create a drumstick shape and form a hard line down the outside of the forearm. The muscles are extended when they move these body parts away from the body. Extensor muscles form the softer inside of the forearm.
The deltoid muscle of the shoulder is large and tear-drop shaped. The tricep muscle starts out large at the top of the arm and is mostly tendon as it gets close to the elbow. The bicep looks like a Twinkie.
A flexed muscle contracts and gets smaller and rounder. Separations between the various muscles will form bumps or ridges visible on the surface of the arm.
Muscles in Paintings
In a painting, a flexed muscle appears more compact and shorter; knowledge of the nature of a flexed muscle helps an artist’s portrayal especially when a figure is foreshortened. A forearm that is turned will appear as a spiral or twisted series of muscles.
Doing preliminary sketches of three-dimensional spheres, rectangles, cones, and rods helps the artist know how best to compose an understandable and realistic figure as a compilation of these basic forms.
Looking at how artists handle the musculature and bone structure of the arms, elbow, and shoulder is quite enlightening. For example, Leonardo is especially noted for his beautiful exploratory sketches of the body and its muscles. The knowledge he gained from this deep understanding of the body translated into the exquisite paintings of his that museum-goers enjoy today. Viewers can see Leonardo's beautiful Virgin and Child with Saint Anne (1519) as an example of experimentation with figure composition and an inspirational depiction of the arm.
Sources
- Sam Lacombe anatomy drawing lecture presented at Towson University, Towson, Maryland, in November, 2010.
- “Grove Dictionary of Art.” Oxford University Press, 2010.
Suzanne Hill - Suzanne Moniea Hill studied art history and studio art and has been passionate about art all her life. She believes that people should ...
Join the Conversation