Aberrant lumbrical muscles causing carpal tunnel syndrome

Area of Science:

• Orthopedic Surgery
• Anatomy
• Neurology

Background:

• Carpal tunnel syndrome (CTS) is a common condition often caused by median nerve compression in the wrist.
• Anatomical variations, though less common, can contribute to CTS.
• The lumbrical muscles originate from the flexor digitorum profundus tendons and insert onto the radial side of the extensor hood.

Discussion:

• This study presents two unique cases of CTS attributed to an abnormally proximal origin of the lumbrical muscles.
• The proximal origin of these muscles may lead to increased pressure within the carpal tunnel.
• Surgical intervention involved division of the transverse carpal ligament and neurolysis of the median nerve.

Key Insights:

• Anomalous lumbrical muscle origins are a potential, albeit rare, cause of carpal tunnel syndrome.
• Transverse carpal ligament release and median nerve neurolysis provided complete symptom relief.
• Resection of the anomalous lumbrical muscle bellies was not necessary for successful treatment.

Outlook:

• Further anatomical studies are warranted to determine the prevalence of proximal lumbrical muscle origins.
• This case series highlights the importance of considering atypical anatomical factors in refractory CTS cases.
• Understanding these variations can refine surgical approaches for complex carpal tunnel syndrome presentations.