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.

Symptoms are often worsened by cold temperatures or repetitive movement, leading to a "locked" or "solid" feel in the hands. acromyotonia

It is associated with disorders involving muscle stiffness, such as paramyotonia congenita or types of dystrophic myotonia . The affected area can feel like a solid,

It should not be confused with the (part of the shoulder) or acromegaly (a growth hormone disorder). acromyotonia