Acromyotonia -

The affected area can feel like a solid, immovable piece, similar to a spasm. It is often a symptom of underlying neuromuscular disorders rather than a disease on its own.

Based on your request, (sometimes referenced as acromyotonus) is a medical term for a type of myotonia (muscle spasm or inability to relax) that specifically affects the muscles of the extremities (hands and feet), often leading to a temporary "solid," stiff, or rigid state after contraction . Key Aspects of Acromyotonia acromyotonia

It should not be confused with the (part of the shoulder) or acromegaly (a growth hormone disorder). The affected area can feel like a solid,