Sonographic Evidence for the Absence of Abductor Pollicis Longus, Extensor Pollicis Longus, and Brevis

Complete absence or variations of extensor pollicis brevis and abductor pollicis longus; absence of the extrinsic extensors, abductor pollicis longus, thenar muscles along with congenital hypoplasia of the thumb; absence of flexor pollicis brevis and abductor pollicis brevis; and bilateral absence of extensor pollicis have been reported previously. Those cases mainly comprised absence/variations of the first extensor compartment either with or without thumb anomalies. This article presents a case of a patient in which the constituents of the first and third compartments (extensor pollicis brevis, abductor pollicis longus and extensor pollicis longus) were absent unilaterally. Herewith, we also highlight the role of static/dynamic sonography for prompt imaging in this regard. A 24-year-old man presented with difficulty using the left thumb. He reported no trauma and had not used the affected thumb since childhood. On physical examination, the left thumb was observed to be in flexion and opposition. He was unable to perform active extension and abduction but passive motion was free. Neurological examination of the left upper extremity was unremarkable. No organ anomaly was present on systemic examination. Radiographs of the left hand revealed no joint problems or hypoplasia. Ultrasonographic evaluation was consistent with absence of the first and third extensor compartment tendons. Tendon transfer was recommended but the patient refused surgery.