Analysis of M. Palmaris Longus Tendons' presence frequency with clinical examination and imaging techniques

The palmaris longus muscle is the most variable muscle of the human body and quantitatively and structurely the incidance of these variations has reported to differ between ethnicities. It becomes more important to detect the presence of the palmaris longus tendon used as an otogen renovation tissue in reconstructive surgery. There are many tendon examination techniques described for determining the presence of the palmaris longus tendon but additional tests may required to confirm prevailing methods. There isn't any referance revealing the incidance of its presence verified by radiological evaluation except the articles about the relationship between the tendon & palmar aponeurosis and some case reports. In this prospective study, Schaeffer's test which is accepted as a standart and defines the presence or absence of the palmaris longus tendon via inspection and palpation is used to examine this tendon in 300 volunteers ages differ between 17-81, consisting of 123 female and 177 male, without any history of upper extremity complaints and any sign of reduced range of motion and randomly choosen outpatients, hospital stuff and medical students in Yeditepe University Hospital, Department of Plastic, Aesthetic and Reconstructive Surgery. In case of absence of the tendon evaluated by Schaeffer's test, forearm ultrasound is used as an additional test for confirmation without any information given to the radiologist and the patient. In order to comparing the statistical results of the palmaris longus side absence either in this study itself or between the other studies; age, sex, hometown data and body mass index of all volenteers are recorded as well. Schaeffer's test results show that within 44 cases (14.7%) the absence of palmaris longus tendon examined there is 31 cases (10.3%) with bilateral absence and 13 cases (4.3%) with unilateral absence. The affected hand is the right one in 8 cases (2.7%) and the left one in 5 cases (1.7%). There is PLA shown in 5% (15 person) of male subjects with bilaterally 3.3% and the sum of 0.7% of left and 1% right that totally equal to 1.7% of unilaterally. There is PLA shown in 9.7% (29 person) of female subjects with bilaterally 7% and the sum of 1% of left and 1.7% right that totally equal to 2.7% of unilaterally. All 44 Turkish volenteers examined as having an agenesis bilaterally or unilaterally evaluated via ultrasonography without informing any Schaeffer's test result. The number of subjects after performing ultrasound decreased to 41. The change is not just the number of affected persons, it reflected the variability of side and laterality in persons with PLA. Bilateral absence result decreased from 31 to 25 after performing ultrasound. 3 of these 6 cases are all females and the result of Schaeffer's test which was bilateral absence is changed with the ultrasound examination to bilateral presence. Cases with right or left unilateral PLA shown with Schaeffer's test came with no changes but ultrasound reveals that 1 of the other 3 cases with bilateral absence has PL tendon on the right and 2 of them has PL tendon on the left side. So, the number of the cases with right unilateral PLA and absence of PL tendon examined via Schaeffer's test increases from 5 to 6, the number of the cases with left unilateral PLA and absence of PL tendon examined via Schaeffer's test increases from 8 to 10. The combined results show that the absence of palmaris longus tendon found in 41 (13.67%) within 300 persons. The tendon was bilaterally absent in 25 cases (8.33%) and unilaterally absent in 16 cases (5.33%) cosisting of 10 (3.3%) right, 6 (2%) left unilaterality. There is PLA shown in 4.67% of male subjects with bilaterally 2.33% and the sum of 0.67% of left and 1.66% right that totally equal to 2.33% of unilaterally. There is PLA shown in 9% of female subjects with bilaterally 6% and the sum of 1.33% of left and 1.66% right that totally equal to 3% of unilaterally. Schaeffer's test results show that the incidance of PLA among Turkish people without regarding sex is 14.7% but there is a female dominance. The incidance of bilateral PLA for both males and females is higher than unilateral PLA. The combined results show that the incidance of PLA among Turkish people without regarding sex is 13.7% that is 1% less than the Schaeffer's test results. Female dominance of PLA insidance is stable but the relationship between laterality and sex is slightly changed. No difference noted between the frequency of bilateral and unilateral PLA presence but female dominance is shown among bilateral PLA presences and there isn't a significant difference in male cases. But ultimaltely, there isn't any relationship shown between laterality and sex. In this study with combined results of Schaeffer's test and ultrasound examination, incidance data of Turkey is much more lesser than other matching studies and shows similarity to the global incidance data. This combined results of both Schaeffer's test and ultrasound examination evantually directs us to evaluate the wrong results of slight percentages merging with the huge number of humans worldwide. Also, the last results with ultrasonography findings about the relationship between laterality and sex can not be neglected. Although it's technically hard to use for wide prevelance studies, ultrasonography should be done in order to detect the agenesis of the palmaris longus before the surgical procedures involving palmaris longus muscle.