Studying Anatomy from Historical Drawings: Arms (Patreon)

The arms, whilst seemingly quite simple in their 3D structure, are immensely complex in the finer details of their anatomy. When drawing arms, it is important to have a good awareness of how the forms change through the limb.

The arm divides into three major sections; the shoulder, the upper arm and the lower arm. The shoulder attaches the arm to the torso, linking it to the chest and back muscles, whilst the elbow hinges the upper and lower arm.

Main image: Albrecht Dürer - Studies for 'Adam and Eve'

Gesture 

Whilst the arms are placed across the body from each other, it can still be worth thinking about the paired gesture of both arms across the shoulder.

George Bellows - 'Dempsey through the Ropes'

George Bellows - 'George Bellows - Counted Out No.01'

These dynamic drawings by Bellows show that flow across the shoulders really well. These figures look fluid because their underlying rhythm lines are simple, clarifying the gesture. By just focusing on the arms, we can see that the gesture of many pairs can reduce to simple C and S curves. 

Jean Baptiste Greuze -'A Seated Female Nude' Here I have indicated a flow of gestural rhythm down the arm. 

The asymmetric forms of the arm are key to it functioning, as well as leading the eye through its action. Here we can see that the muscles of the arm do not create a symmetrical contour, like a vase, but are instead staggered down the arm. Their curvature is also different - in this pose the muscles of the back of the arm are longer and stretched whilst the ones of the inside are shorter and more compressed. When the arm is bent, the muscles on the inside are flexing as they hold that pose. This switches when the arm is held straight, and the muscles on the back are working.

Bones of the Arm

There are 3 bones in the arm, the humerus in the upper arm, and the ulna and radius in the lower arm. The ulna and radius can twist about the elbow, rotating the hand.

Peter Paul Rubens - 'Two Studies of an Outstretched Right Arm'

1.  Ulna

2.  Radius

3.  Humerus

Here we can see how the bones create some of the distinctive bumps in the arm. The elbow is created by the ulna slotting into the humerus, the ulna creating the bump on the back of the elbow whilst the humerus is largely responsible for the sides. 

At the wrist, the ulna and radius are visible, as there are no muscles to cover them. The ulna can be seen running along the back of the forearm (top) with just a thin layer of muscle over it, and ending with a round bump of the wrist. Look out for the bumps on the inside of the wrist that relate to the radius.

Forms of the Arm

The most simple version of the arm is to use two cylinders. This is a handy way to reduce complexity and help with foreshortening, but does not show the true story of the forms as the arm changes as we travel down its length.

Jacopo da Pontormo - 'Right Arm of a Man, Raised to his Ear'

In this drawing, Pontormo may not have started with cylinders, but it is clear from his hatching marks that this kind of structure was in mind. Look at how the shading marks wrap around the arm. They describe anatomy by following the surface direction, but are also mindful of orientation. The raised forearm shows downwards-curving hatching lines, indicating its upwards-pointing orientation. The same technique is done for the upper arm as it points to the left.

A cylinder is a poor fit for the end of the forearm and wrist. We can see here how the edge of the ulna starts to create a firmer shadow edge and a more square-like cross section.

Annibale Carracci - 'Temple of Apelles'

1.  Upper Arm

2.  Elbow

3.  Forearm (upper)

4.  Forearm (lower)

As we travel down the length of this arm, the contour, hatching and shadow patterns describe its changing cross section.  The key take away here is how forms alternate between soft/rounded and hard/squared.

The first cross section of the upper arm shows a rounded form, created by the muscles of the upper arm. At the elbow, muscles turn to tendons and contribute less to the volume, leaving us with the blockier cross section of the bones. Again we encounter a round, fleshy cross section in the upper arm, thanks to the layers of muscles required to articulate the hand. At the end of the arm, the cross section becomes noticeably squarer as we reach the end of the ulna and radius. In particular, pay attention to the cross section on the farther arm, underneath the thumb, as the end of the radius creates a little flat surface on the inside of the wrist.

These forms will change as the arm moves into different positions, causing the muscles to flex. It is a good idea to study the limbs of the body in lots of different poses to see how artists express this.

Over to You

The arm's anatomy is very complex, so I recommend looking at how gesture works, and getting familiar with the major forms first. 

Understanding the volumes of the arm, and its cross sections, is generally more productive at first, as in many life drawing settings, the muscles are not easy to discern, or even hidden almost entirely. A common issue with arms is that the forms become generic and flat, so a good understanding of volumes is key.

In these sketchbook studies I have broken the arm down into simple volumes, to understand orientation, as well as creating copies to look at cross sections at different points in the arms – these are just a couple of approaches.

In these examples, try to break the arm down first into simple volumes, such as the cylinders from the Pontormo drawing, or similar. Think carefully about their orientation; which way is the end facing? Once you are confident about this, start to go into detail with the cross sections. This can be done by taking 'slices', such as in the Carracci drawing or just by placing some surface lines that hug the forms onto your copy of the drawing.

Dean Cornwell - 'Study of a Boy, for Water Mural'

Eugène Delacroix - 'Torso of a Man Seen from Behind'

Peter Paul Rubens – 'Study of a River God'

Annibale Carracci -  'Crawling Male Figure'

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This is the fifth  blog post in Lancelot's 'Studying anatomy from historical drawings' series, commissioned using money raised here on the Draw Patreon. 

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