Clinical assessment of absence of the palmaris longus and its association with other anatomical anomalies – a chinese population study

Palmaris Longus—Sandeep J Sebastin et al

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Original Article

Clinical Assessment of Absence of the Palmaris Longus and its Association With Other Anatomical Anomalies – A Chinese Population Study
Sandeep J Sebastin,1MCh (Plastic), Aymeric YT Lim,1FRCS (Glas), Hwee-Bee Wong,2MSc

Abstract
Introduction: Ethnic variations in the prevalence of absence of the palmaris longus (PL) arewell known. Many techniques for clinically determining the presence of the PL have been described. Studies have also attempted to correlate its absence with other anatomical anomalies. However, most studies have been done in Caucasian populations. Materials and Methods: The presence of the PL was clinically determined in 329 normal Chinese men and women using the standard technique. In subjects withan absent PL, 4 other tests were performed to confirm absence and an Allen’s test was done to assess the palmar arches. All subjects were examined for the presence of the flexor digitorum superficialis (FDS) to the little finger. Results: The overall prevalence of absence of the PL was 4.6%. All techniques were equally effective in determining the absence of the PL. There was no significantdifference in its absence with regard to the body side or sex. Absolute deficiency of FDS to the little finger was seen in 6.4%. No correlation could be detected between the absence of the PL and FDS of the little finger. Conclusions: The prevalence of absence of the PL and absence of FDS to the little finger in a Chinese population is much lower compared to previous reports in the literature. There isno association between absence of the PL and absence of the FDS to the little finger. Although all techniques of examining for the absence of the PL are equally effective, the method suggested by Mishra seems the best as it was easily understood by subjects and can be used even when thumb abduction is not possible. Ann Acad Med Singapore 2006;35:249-53 Key words: Chinese, Palmaris longus, Tendonanomalies

Introduction The prevalence of absence of the palmaris longus (PL) has been extensively studied following the first report of its absence in 1559 by Colombos in De Re Anatomica Libri.1-9 It is well known that there is a wide variation in the reported prevalence of PL absence in different ethnic groups.4,6 However, only one report has documented the prevalence of its absence in aChinese population.6 Some authors suggest that apart from its ethnic variations, its absence is more common in women, bilateral absence is more common, and that unilateral absence occurs more frequently on the left side.3,5 Others have attempted to correlate the absence of the PL with other anatomical anomalies, like an anomalous superficial palmar arch, an absence of the plantaris, etc.2,10-14 Aclinical study has even
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attempted to explore the relationship between the functional absence of the flexor digitorum superficialis (FDS) to the little finger and the absence of the PL.15 Most papers attempting to correlate the relationship of the PL with other anatomic structures have been carried out in Caucasian subjects (or cadavers). Many techniques for clinically determining the presence ofthe PL have been described in the literature.3,4,16,17 In this study, we examined 329 people of Chinese descent (658 upper limbs) to address the above issues and see if they applied to a Chinese population. We studied the prevalence of absence and correlated it with other anatomic variations. In subjects with an absent PL, we reconfirmed the absence using 4 additional clinical tests and determinedthe best technique to assess absence of the PL.

Department of Hand and Reconstructive Microsurgery National University Hospital, Singapore 2 Clinical Trials and Epidemiology Research Unit, Singapore Address for Reprints: Dr Aymeric Lim, Department of Hand and Reconstructive Microsurgery, Level III, Main Building, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074. Email:...