Hypothenar Dimpling. A peripheral equivalent of Hemifacial Spasm?

Area of Science:

• Neurology
• Clinical Electrophysiology

Background:

• Idiopathic intermittent dimpling of the hypothenar eminence is a rare phenomenon.
• Understanding the underlying neuromuscular mechanisms is crucial for diagnosis and management.

Observation:

• Two patients presented with spontaneous, irregular, dimpling contractions of the skin overlying both hypothenar eminences.
• The dimpling was observed to be benign and intermittent.

Findings:

• Electrophysiological studies revealed spontaneous discharge of motor units in the palmaris brevis muscle as the cause.
• The origin of the discharge was localized to the ulnar nerve, potentially at the wrist.
• No clinical or physiological evidence of neuropathy or nerve compression was found.

Implications:

• Hypothenar dimpling may represent a peripheral manifestation analogous to central nervous system disorders like hemifacial spasm.
• Further research into similar neuromuscular excitability disorders is warranted.
• This finding expands the differential diagnosis for involuntary movements in the hand.