UPPER EXTREMITY NERVE INVOLVEMENT IN SWEDISH FEMALE MACHINE MILKERS

Entrapment of the median nerve in the proximal forearm, the so-called pronator syndrome, is considered a rather rare condition but it is fou r times more common in women than in men. In this study, 23 of 30 fema le machine milkers with symptoms in the forearm and hand were clinical ly diagnosed as having the pronator syndrome. The diagnosis of median nerve involvement was based on the clinical history and on physical ex amination by a hand surgeon. All 23 milkers complained of aching in th e volar part of the forearm and had a sensation of numbness, tingling, and decreased muscle strength in their hands, mostly ir? the hands wh ich usually were statically loaned with heavy equipment. Objectively, all had an experience of tenderness over the pronator teres muscle, Fu rthermore, they showed reduced muscle strength, especially in the foll owing muscles: pronator teres (PT), flexor carpi radialis (FCR), flexo r pollicis longus (FPL), and flexor digitorum profundus II (FDP II). T o validate the manual muscle testing, Mannerfeldt's intrinsicmeter was used to quantify the clinically observed weakness. Eight of the 23 mi lkers with pronator syndrome were surgically released from neuropathy and were almost symptom-free at follow-up after six months. One patien t had a slight sensation of numbness and had to be given surgical carp al tunnel release later on. The external exposure of the arm during th e application of the milking cluster probably causes muscle and fascia l tensions that induce compression of the nerve. Further studies are n eeded to establish the level of the internal exposure. (C) 1998 Wiley- Liss, Inc.