Of note, pre-operatively he had a very tight FPL and wrist flexors but also incidentally a severe flexion deformity of his ring little and fingers which resembled a claw hand.
During surgical exploration and release of the muscles, an anomalous fusiform muscle was found originating from the tendon of the FPL, heading to the ring finger and flexing the distal interphalangeal joint.
The patient’s right hand was gripping the steering wheel when he was involved in a low velocity head on collision.
Shortly afterwards he noticed a swelling in his right palm over the first web space which increased in size with finger flexion.
Introduction: Anatomical variations of the flexor pollicis longus(FPL) muscle are well described, the common two being an accessory head of FPL also known as Gantzer’s muscle described in 1813 and the anomalous tendon slips from the FPL to the flexor digitorum profundus(FDP) of the index and more rarely middle finger described by Linburg and Comstock in 1979.
We present an anomaly not previously described in the literature where the FDP to the ring finger was found to originate from the FPL tendon, causing tight flexion contracture of both due to underlying muscle spasticity.
Anomalous and accessory muscles in the palm are anatomical curiosities until they become symptomatic.
A tendon ran proximally from this accessory muscle belly into the forearm.The PA analysis and MRA findings for the detection of medial facets of the lunate were compatible in 119 of the 150 patients (79.3%).Twenty-eight (90.3%) of a total of 31 incompatible wrists had a medial facet on the lunate on MRA (Type II), which was undetected on the PA analysis (Type I).On the CTD analysis, 76 (50.7%) of the total wrists were classified into the intermediate group; excluding them, 27 of 29 Type II lunates (93.1%) and 39 of 45 Type I lunates (86.7%) were compatible with the MRA findings.Conclusions: Both systems had moderate inter-observer and intra-observer reliabilities.However, significant functional problems have been reported in conjunction with these anatomical variations, including pain, compression neuropathy, digital triggering and stiffness.Because of their rarity, their diagnosis is often delayed or initially missed.Methods: Plain radiographs of a total of 150 wrists were reviewed by three observers.The lunate types were independently evaluated twice using both PA analysis (Lunate Types I and II) and CTD analysis (Lunate Types I, CTD≤2mm; II, CTD≥4 mm; Intermediate, Others).While most anomalous muscles are asymptomatic, ours was causing symptoms particularly due to underlying muscle spasticity.The other clinical relevance of this is that the ring finger FDP usually supplied by the ulnar nerve was in this instance supplied by the median nerve.