Muscle spasm and Writer's cramp

Muscle spasm noun - A painful and involuntary muscular contraction.

Writer's cramp and muscle spasm are semantically related. In some cases you can replace phrase "Writer's cramp" with "Muscle spasm", this phrases are similar.

Writer's cramp noun - Muscular spasms of thumb and forefinger while writing with a pen or pencil.

Muscle spasm and writer's cramp are semantically related. You can use "Muscle spasm" instead a noun phrase "Writer's cramp".