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Epifascial accessory palmaris longus muscle
Cesare Tiengo1, Veronica Macchi, Carla Stecco
1Institute of Plastic Surgery, University of Padova, Padova, Italy.
Clinical Anatomy (New York, N.Y.)
|August 19, 2006
Summary
An accessory palmaris longus muscle, an unusual anatomical variation, can cause median nerve compression and present as a volar mass. This rare finding in hand surgery requires consideration for accurate diagnosis and treatment.
Area of Science:
- Anatomy
- Surgical Pathology
- Morphogenesis
Background:
- The palmaris longus muscle is a common donor site in reconstructive hand surgery.
- Anatomical variations of the palmaris longus can lead to median nerve compression.
Observation:
- A case report of a 40-year-old woman with 5 months of hand numbness and paresthesias, exacerbated by typing.
- Imaging revealed a subcutaneous mass in the distal forearm; biopsy confirmed striated muscle fibers.
Findings:
- Surgery identified an accessory palmaris longus muscle in the epifascial plane, originating from subcutaneous septa and inserting onto the palmar aponeurosis.
- Histology confirmed unremarkable striated muscle fibers within a connective sheath.
- Standard palmaris longus tendon and other flexor tendons showed normal anatomy.
Implications:
- Accessory palmaris longus is a rare but important differential diagnosis for volar forearm masses.
- This anatomical anomaly can cause median nerve compression, mimicking carpal tunnel syndrome.
- Awareness of accessory palmaris longus is crucial for hand surgeons to avoid misdiagnosis and ensure proper treatment.
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