Palmaris brevis spasm syndrome: The treatable hypothenar dimpling

Abstract Palmaris brevis spasm syndrome is a rare disorder, mostly reported with occupational overuse of a computer keyboard, mouse, pipette, and vibratory tools or after the use of arm braces. Rarely, it can be spontaneous. It is clinically characterized by spontaneous contraction of the palmaris brevis muscle over the hypothenar eminence. Here, we report a patient with long-standing, spontaneous, and bilateral palmaris brevis spasm syndrome without any occupational exposure who demonstrated excellent response to botulinum toxin therapy. Clinicians should be aware of this rare but treatable entity in patients presenting with hypothenar spasms.