Vol.:(0123456789) 1 3 Surgical and Radiologic Anatomy (2019) 41:1307–1314 https://doi.org/10.1007/s00276-019-02265-0 ORIGINAL ARTICLE Prevalence of the Linburg–Comstock variation through clinical evaluation Mirela Erić 1  · Kaissar Yammine 2,3  · Vipin Gosh 4  · Georg Feigl 5  · Dušica Marić 1 Received: 23 March 2019 / Accepted: 23 May 2019 / Published online: 30 May 2019 © Springer-Verlag France SAS, part of Springer Nature 2019 Abstract Introduction Linburg–Comstock variation, the tendinous interconnection between fexor pollicis longus and fexor digitorum profundus, is known to have a wide frequency range. Its prevalence is reported with a range of 13–66%. The aim of the study was to assess this variation in general population and to correlate it with gender and side. Material and methods This prospective study included 215 subjects (82 males and 133 females). Two clinical tests were conducted to diagnose the variation and to detect any related symptomatology. The primary outcome was set to be the preva- lence of Linburg–Comstock variation. Secondary outcomes were defned as gender-based prevalence, side-based prevalence, and Linburg–Comstock variation prevalence association with gender and side. Results Linburg–Comstock variation was clinically diagnosed in 130 (60.47%) participants. Unilateral and bilateral preva- lence were of 17.21% and 43.26%, respectively, yielding a statistically signifcant diference. Right-sided and left-sided presence were calculated at 7.44% and 9.77%. Bilateral prevalence was statistically more common in females. Right-sided variation was found to be more frequent in males while left-sided variation was more prevalent in females. The index fnger was the most commonly involved with prevalence of 91.03%. Symmetry was noted in 67.74% of subjects. Conclusion The results of our study demonstrated a relatively high prevalence of the Linburg–Comstock variation in Serbian population. We noted a few unusual cases and this fnding point to the existence of the broader spectrum of Linburg–Com- stock variation, and complexity of the fexor apparatus of the hand, so, further investigations about this topic are needed to improve our knowledge. Due to the possibility of false-positive result during clinical testing we suggest to use expanded clinical method. Keywords Linburg–Comstock variation · Flexor pollicis longus · Flexor digitorum profundus · Hand Introduction The presence of an anomalous interconnection between fexor pollicis longus (FPL) and fexor digitorum profundus (FDP) tendons was described during the second half of the nineteenth century [7, 12, 20, 23–25]. Linburg and Com- stock were the frst to report clinical and cadaveric frequency of this variation in humans [9]. It represents an anomalous connection between FPL and mostly FDP of the index fnger but rarely, FDP tendons of the other long fngers, or in some sporadic cases the frst lumbrical muscle, have been reported to be involved. The tendinous interconnection is most often based proximally originating from the FPL and extending obliquely downward to the FDP. Therefore, during the active thumb fexion, contraction of the FPL will pull the tendinous connection upward which results in simultaneous fexion of the involved digit(s) while an independent active fexion of * Mirela Erić mirela.eric@mf.uns.ac.rs; mirela.eric@gmail.com 1 Department of Anatomy, Faculty of Medicine, University of Novi Sad, Hajduk Veljkova 3, 21000, Novi Sad, Serbia 2 Department of Orthopedics, Lebanese American University Medical Center-Rizk Hospital, Lebanese American University School of Medicine, Beirut, Lebanon 3 The Center for Evidence-Based Anatomy, Sport and Orthopedic Research, Beirut, Lebanon 4 Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia 5 Institute of Macroscopic and Clinical Anatomy, Medical University of Graz, Graz, Austria