★How to draw the arm
　The movement of the arm muscle

■Structure of the arm from the shoulder to the wrist

Arm is a complex dynamic motion.
However, to draw once you understand the distinctive part is not very difficult.
Let's check the movement of the parts while observing his own arm.


＠Ulnar
＠Brachioradialis muscle
　※extensor carpi radialis longus muscle
＠Biceps brachii
＠Triceps brachii

Ulnar has led to the little finger side of wrist from the elbow.
Brachioradialis muscle is connected around the thumb side from the outside of the upper arm.
Muscles of the arm to create a "Well-developed biceps" biceps brachii.
Triceps muscle of the back of the arm.

Ulna is very important.
Please confirm by touching the arm.

Brachioradialis muscle is used primarily with the rotation of the forearm.
It is also used to bend the elbow also.



The above figure represents the positional relationship between them.

On the back of the brachioradialis has a radius.
Radius and ulna are crossed as "X".

To draw a manga character, please remember these four.


The movement of the arm, rotation

＠Ulnar
＠Brachioradialis muscle
　※extensor carpi radialis longus muscle
＠Biceps brachii
＠Triceps brachii

The upper arm will rotate 90+α degrees, and the lower arm will rotate 180 degrees.
Wrist can be rotated nearly 360 degrees.



Photo of the arm rotation.



＠短橈側手根伸筋
　Extensor carpi radialis brevis muscle

＠腕橈骨筋
　brachioradialis muscle

＠長橈側手根伸筋
　extensor carpi radialis longus muscle

＠指伸筋
　extensor digitorum muscle

＠尺側手根伸筋
　extensor carpi ulnaris muscle