Upper extremity nerve involvement in Swedish female machine milkers

Abstract

Entrapment of the median nerve in the proximal forearm, the so‐called pronator syndrome, is considered a rather rare condition but it is four times more common in women than in men. In this study, 23 of 30 female machine milkers with symptoms in the forearm and hand were clinically diagnosed as having the pronator syndrome. The diagnosis of median nerve involvement was based on the clinical history and on physical examination by a hand surgeon. All 23 milkers complained of aching in the volar part of the forearm and had a sensation of numbness, tingling, and decreased muscle strength in their hands, mostly in the hands which usually were statically loaded with heavy equipment. Objectively, all had an experience of tenderness over the pronator teres muscle. Furthermore, they showed reduced muscle strength, especially in the following muscles: pronator teres (PT), flexor carpi radialis (FCR), flexor pollicis longus (FPL), and flexor digitorum profundus II (FDP II). To validate the manual muscle testing, Mannerfeldt's intrinsicmeter was used to quantify the clinically observed weakness. Eight of the 23 milkers with pronator syndrome were surgically released from neuropathy and were almost symptom‐free at follow‐up after six months. One patient had a slight sensation of numbness and had to be given surgical carpal tunnel release later on. The external exposure of the arm during the application of the milking cluster probably causes muscle and fascial tensions that induce compression of the nerve. Further studies are needed to establish the level of the internal exposure. Am. J. Ind. Med. 33:551–559, 1998. © 1998 Wiley‐Liss, Inc.

Neurological Examination of the Upper Limb: A Study of Construct Validity

“…This finding is supported by reports of others of non-nociceptive and potentially neuropathic pain conditions secondary to the compression, tightening, and traction of the upper limb nerves [14,16,41,42] in a substantial proportion of patients with unclassifiable (“non-specific”) refractory cervicobrachial pain conditions occurring in an occupational context [11,15,26,43,44]. Abnormalities suggesting neural dysfunction include elevated vibratory thresholds [43], pathologic upper limb tension tests [15], axonal flare responses [45], hyperalgesia [18], and allodynic responses to supra-threshold vibratory stimulation [43].…”

“…This is a characteristic feature of, e.g. median neuropathy at elbow level [26] and brachial plexopathy [27]. …”

Can testing of six individual muscles represent a screening approach to upper limb neuropathic conditions?

“…Werner [34] and Hagert et al [35] reported rotational loads of the forearm causing radial tunnel syndrome rather than epicondylitis, and Stål et al described pronator syndrome in a high proportion of female milkers [36]. Recent epidemiological evidence supports that upper limb neuropathy can be work-related as has been shown for, e.g.…”

Work-Related Upper Limb Pain and Its Diagnosis: Contribution from the Neurological Examination

“…Werner [22] and Hagert et al [20] have reported on rotational load of the forearm causing radial tunnel syndrome rather than epicondylitis. Stål et al has described pronator syndrome in a high proportion of female milkers [23]. Other researchers have also dealt with the work-relatedness of ulnar neuropathy [24], carpal tunnel syndrome [25,26], and brachial plexopathy, [13,27], of which the latter in particular was prevalent in our studies [8,10,11,17].…”