Bilateral Congenital Absence of Flexor Pollicis Brevis and Abductor Pollicis Brevis Muscles with Bilateral Thenar Atrophy: A Case Report

Abstract

In this paper, we report a case of a 23-year-old male patient with bilateral absence of the flexor pollicis brevis and abductor pollicis brevis muscles with an intact functioning opponens pollicis and flexor pollicis longus muscles with bilateral thenar atrophy due to its rarity. All physical, neurological, ultrasonographic, direct radiographic, electromyographic and MRI studies were used to confirm and document this congenital anomaly.

Bilateral Congenital Absence of the Opponens Pollicis Muscle: A Case Report

“…We found no embryological basis for the isolated absence of these muscles. Previously reported anomalies include isolated absence of the thenar muscles innervated by the median nerve, isolated unilateral absence of the abductor pollicis brevis and flexor pollicis brevis muscles, bilateral congenital absence of the abductor pollicis brevis and flexor pollicis brevis muscles, and bilateral congenital absence of the opponens and abductor pollicis brevis muscles [4,6,8,11]. To the best of our knowledge, isolated bilateral absence of the opponens pollicis muscle has not previously been reported.…”

“…Corrective surgery is recommended for types 1, 2, and 3A anomalies, and pollicization is recommended for types 3B, 4, and 5 anomalies [5]. Although thenar muscle anomalies and thumb hypoplasia may be isolated defects, as in Cavanagh's syndrome [5], they are commonly associated with syndromes such as Holt–Oram syndrome (with associated cardiac disorders), Okihiro syndrome (with associated eye disorders), thrombocytopenia-absent radius syndrome, Fanconi's pancytopenia, the VACTERL association (vertebral abnormalities, anal atresia, cardiac abnormalities, tracheoesophageal fistula, esophageal atresia, renal defects, radial dysplasia, and lower limb abnormalities), radial bone anomalies, and hand anomalies such as Haas's malformation [8, 10, 12].…”

Diagnosing Carpal Tunnel Syndrome in Cavanagh Syndrome: A Literature Review and Proposed Electro Physiologic Protocol

“…Three of these articles did not report detailed findings. Two reported only that the median nerve was intact [11,12], and 1 reported only that stimulation of the median nerve did not cause thumb movement.…”

Hand Intrinsic Muscles

“…Absence of the FPB and APB can cause problems with thumb opposition and pinching (Koca et al 2012). These muscles may be variably absent in the hypoplastic thumb, which result in functional deficits.…”