Prevalence of the palmaris longus through clinical evaluation

Prevalence of Absence of Palmaris Longus Tendon in a Population Sample from a Multiethnic Brazilian City

Objective  The objective of the study was to determine the prevalence of absence of palmaris longus tendon in a population sample from a multiethnic Brazilian city. Methods  A cross-sectional observational study was carried out between October 2017 and April 2018. We included male and female volunteers aged 18 years or older. The absence of palmaris longus tendon was determined by asking the volunteers to perform the Schaeffer test bilaterally. Results  We prospectively collected data on 1,008 volunteers, 531 male and 477 female, with age between 18 and 74 years (mean 38.4 years). The absence of palmaris longus tendon was observed in 264 (26.2%) volunteers. Bilateral absence was detected in 123 volunteers (12.2%), 60 female (48.8%) and 63 male (51.2%). Unilateral absence was found in 141 patients (14.0%), 54 female (38.2%) and 87 male (61.8%) ( p  < 0.05). Conclusion  The prevalence of absence of palmaris longus tendon in our study was 26.2%. There was no statistically significant difference between gender and bilaterally. The absence of palmaris longus tendon was predominant on unilateral right side in males.

A Cadaveric Case of Palmaris Longus Agenesis and Reversal

The palmaris longus frequently exhibits anatomical variations with palmaris longus agenesis and reversal being the most prevalent. These variations are relevant clinically, as the muscle is often used during plastic surgeries for grafting tendons. They are also relevant in pathology, as hypertrophy of the reversed muscle is related to median nerve compression. In this report, we describe an unusual case in which a male cadaver-donor exhibited a right-sided palmaris longus reversal and left-sided palmaris longus agenesis. Review of the literature documents no previous co-occurrence of these anomalies. Since the muscle has relevance in a variety of contexts within medicine and surgery, reporting on a variation like this carries significant educational and clinical value.

Anatomical variations of the superficial palmar arch in human fetuses

The superficial palmar arch is an important anatomical structure that contributes to the arterial supply of the palmar side of the hand in the upper extremity. However, there is limited information on the embryological morphological structure of the superficial palmar arch in the literature. We studied the types of the superficial palmar arch and determined their variations by dissecting 80 upper extremities of 40 formalin-fixed human fetuses (19 males, 21 females) 18-37 weeks of age. The types and variations of the superficial palmar arch were examined, and the median artery was imaged. The superficial palmar arch type was complete in 58 hands (72.5%) and incomplete in 22 hands (27.5%). The complete group consisted of type A (47.5%), type B (16.25%), type C (3.75%), type D (1.25%), and type E (3.75%). On the other hand, the incomplete group consisted of type F (15%), type G (8.75%), type H (2.5%), and type I (1.25%). A median artery that originated from the ulnar artery and passed through the carpal tunnel during its course was detected in two hands (2.5%). Knowledge of the superficial palmar arch variations will contribute to hand microsurgery particularly in vascular graft and free flap application interventions for arterial bleeding in the palmar region.

The Palmaris Longus and Its Association with Carpal Tunnel Syndrome

Background  The palmaris tendon inserts into the palmar fascia and is positioned in close association with the transverse carpal ligament. Loading of this tendon has been demonstrated to increase carpal tunnel pressures. Purpose  The purpose of this study was to determine if a relationship exists between the palmaris tendon, carpal tunnel syndrome (CTS), and handedness. The sensitivity, specificity, positive predictive value, and negative predictive value for Schaeffer's test were calculated. Methods  A retrospective review of patient charts undergoing endoscopic carpal tunnel release was performed. Rates of palmaris longus agenesis (PLA) were compared to a population matched data set. Statistical analysis was performed using a one-proportion z -test. Schaeffer's test for the palmaris longus tendon was performed on all patients and compared to intraoperative confirmation. Results  A total of 520 carpal tunnel releases were performed in 389 consecutive patients. The frequency of PLA in this surgical cohort was significantly lower compared to the population matched dataset. No correlation between handedness and laterality of CTS or PLA was found. Schaeffer's test was evaluated to yield sensitivity (93.6%), specificity (100%), positive predictive value (100%), and negative predictive value (50.8%). Conclusion  The palmaris tendon was more prevalent in a population of patients undergoing carpal tunnel release. These findings can be used to provide further insight into the pathophysiology of CTS. While Schaeffer's test was accurate in detecting the palmaris longus tendon, a negative test was frequently incorrect. Further imaging is recommended in patients with a negative Schaeffer's test when the palmaris longus is desired for surgical utilization. Level of Evidence  This is a Level III, prognostic study.

Hypertrophied reversed palmaris longus muscle (pseudotumor) of the forearm causing median nerve compression: a case report

Background

The palmaris longus muscle is considered one of the most anatomically variable muscles in the human body. Localized swelling of the forearm due to hypertrophy of the palmaris longus muscle is rare.

Case presentation

Here, we report a rare case of a 24-year-old Arab man who presented with a painful mass on his forearm with symptoms of median nerve compression. A full radiological assessment was performed, and he was treated conservatively.

Conclusion

This case confirmed that a hypertrophied palmaris longus muscle can be the cause of swelling on the forearm and should always be considered in the differential diagnosis. With this report, we aimed to increase awareness regarding the unusual variations of palmaris longus muscle and the importance of using radiological investigations to establish a diagnosis.

Clinical Assessment of Existence of Palmaris Longus Muscle among South Indian Population

Background: Palmaris longus tendon is often used as a donor tendon by surgeons in tendon grafts. It is one of the flexor muscles of the forearm and documented well for its variations in both morphology and number of tendons. Prevalence of absence of this muscle varies among the individuals of same population and individuals of various ethnic groups. The aim of this study was to assess the existence of Palmaris longus muscle within a group of students and its association with side of the limb and gender of the individual. Methods: Three hundred medical students of 150 males and 150 females with age group of 18-21 years were clinically assessed. The standard Schaffer's test was used for the assessment of PL tendon. If the tendon was not found in this test, the confirmation was done by other four tests. Results: Results of this study shows that an overall absence of palmaris longus muscle in both sexes was found to be 32%, out of which 21% absence was found in males and 43% absence found in females. Among the males, the unilateral agenesis was seen in 16% and bilateral agenesis in 4% and in females the unilateral agenesis was seen in 29% and bilateral agenesis seen in 14%. Conclusions: To conclude; in the present study, prevalence of Palmaris longus muscle agenesis was found to be more in female subjects on their left side. Surgeons who plan for tendon reconstructive procedures should know variations of Palmaris longus muscle and its clinical assessment.

Bilateral reversed palmaris longus muscle: a case report and systematic literature review

PURPOSE

We present a case of a bilateral reversed palmaris longus muscle and a systematic review of the literature on this anatomical variation.

METHODS

Routine dissection of a 90-year-old male cadaver revealed a rare bilateral reversed palmaris longus. This was documented photographically, and length and relation to anatomical landmarks were recorded. This finding stimulated a systematic review of the literature on the reversed palmaris longus variation, from which measurements were collated and statistical analysis performed to determine the prevalence, average length, relationship to side and sex, and to discuss its clinical and evolutionary implications.

RESULTS

The average length of the muscle belly and tendon of reversed palmaris longus was 135 mm and 126 mm, respectively. Statistical analysis revealed no disparity in presentation due to sex and side; however, bilateral reversed palmaris longus has only been reported in males. A high proportion (70.8%) of reversed palmaris longus were discovered in the right upper limb compared to the left.

CONCLUSION

Variations in palmaris longus are purported to be as a result of phylogenetic regression. Clinically, patients with this variant may present with pain or swelling of the distal forearm, often as a result of intense physical exertion related to occupation or sport. Clinicians should be aware of this muscle variant as its presence could lead to confusion during tendon allograft harvesting procedures in reconstructive and tendon grafting surgery.

PALMARIS LONGUS ABSENT IN ONE IDENTICAL TWIN: A CASE REPORT

SUMMARY – Palmaris longus is a very variable muscle in the human body, but it is often used as an applicable tendon graft. We report on differences between one pair of identical twins regarding the existence of the palmaris longus, which were detected accidentally during examination of the presence/absence of this muscle in Caucasian population. In one of the twins, the palmaris longus was present at both forearms, while the other twin was lacking this muscle at both forearms. On search of the available literature, we found no articles about distinctions in the presence or absence of the palmaris longus in twins.

Prevalence of Absence of Palmaris Longus and Its Association with Gender, Hand Dominance and Absence of FDS Tendon to Little Finger Among Malay Population

BACKGROUND

Palmaris Longus is being widely used in reconstructive, plastic and cosmetic surgeries due to its long tendon. It is the most readily available source for tendon grafting. The objective of this study was to determine the prevalence of absence of Palmaris Longus and its association with gender, hand dominance and absence of FDS (flexor digitorum superficialis) tendon to little finger among Malay population.

METHODS

An analytical cross sectional study design was used and a self-administered proforma was distributed for data collection. 1239 Malay secondary school children in Putrajaya were tested for absence of Palmaris Longus using Schaffer's test. 4 additional tests namely Thompson's test, Mishra's test I, Mishra's test II and Pushpakumar's 'two-finger sign' method were used to confirm its absence in respondents with negative Schaffer's test. Function of Flexor Digitorum Superficialis tendon to little finger was determined by flexing PIP of little finger while hyperextend the other fingers.

RESULTS

The prevalence of absence of Palmaris Longus was 11.7%. Left side absence of Palmaris Longus was much common. There was a significant association between absence of Palmaris Longus with gender in which female had higher prevalence of absence of Palmaris Longus than male.

CONCLUSIONS

In conclusion, the prevalence of absence of Palmaris Longus in Malay population was lower than Indian but higher than Chinese population. Females had higher prevalence of absence of Palmaris Longus and no association can be found with hand dominance and absence of Flexor Digitorum Superficialis tendon to little finger.

Congenital absence of the palmaris longus muscle: A meta-analysis comparing cadaveric and functional studies

The aim of our paper was to provide comprehensive data on the prevalence of absence of palmaris longus muscle (PLM) and its anatomical characteristics and conduct two separate meta-analyses comparing cadaveric and functional studies while identifying variation among different ethnic groups. An extensive search was conducted through the major electronic databases to identify eligible articles. Data extracted included prevalence of absence of PLM among subjects, ethnicity, laterality, side, and gender. Our main findings revealed that the absence of PLM is more frequently reported in functional studies. Moreover, functional tests likely overestimated the absence of PLM and recommend future studies to assess the validity of functional tests and use an imaging assessment prior to excluding the use of a palmaris longus tendon graft in patients in whom a function test identified the absence of PLM.

That Tendon is the Median Nerve: Perils of a Palmaris Longus Deficient Wrist

BACKGROUND

To document the course of the median nerve in the distal forearm in palmaris longus (PL) deficient forearms and elucidate features that help distinguish it from the PL.

METHODS

In the cadaveric study, 56 cadaveric forearms were dissected and the location and course of the median nerve were documented. In the clinical study, 20 healthy subjects with absent PL were examined with provocative tests to elucidate the PL (Schaeffer's test and Thompson's test), and modified Durkan's and Phalen's tests. In the imaging study, one subject with a clearly visible and palpable median nerve was further evaluated with MRI with a superficial fiducial marker.

RESULTS

Cadaveric dissection revealed that the median nerve was deep to the antebrachial fascia and superficial to the FDS tendons in the distal forearm. In 9 specimens without a PL, the median nerve was the most superficial structure deep and lay draped over the FDS tendons. In the clinical study, PL absence was bilateral in 4 subjects and unilateral in 16. The nerve was visible and palpable in 4 forearms and palpable but not visible in 20 forearms. In all 24 forearms, the nerve was palpable as a lax, mobile, cord-like structure that could be rolled over the taut FDS tendons. Tinel's and Durkan's signs were positive in 11 subjects. In the imaging study, MRI confirmed that the palpable structure was the median nerve.

CONCLUSIONS

Unlike the PL, the nerve is non-contractile and remains flaccid on provocative testing. It is usually palpable and may also be visible in thin forearms. Careful scrutiny may reveal it to be distinct from, and draped over underlying FDS tendons. These findings may help avoid inadvertent median nerve harvest in place of a PL tendon graft.

The angular course of the median nerve in the distal forearm and its anatomical importance in preventing nerve injury in a modern era of carpal tunnel release

OBJECTIVE A thorough understanding of anatomy is critical for successful carpal tunnel release. Several texts depict the median nerve (MN) as taking a course parallel to the long axis of the forearm (LAF). The authors report on their attempt to formally assess the course of the MN as it travels to the carpal tunnel in the distal wrist and discuss its potential clinical significance. METHODS The width of the wrist, the distance from the radial wrist to the MN, and the distance from the distal volar wrist crease to the point where the MN emerges between the flexor carpi radialis (FCR) tendon and the flexor digitorum superficialis (FDS) tendons were recorded during cadaveric dissection of 76 wrist specimens. The presence or absence of palmaris longus was documented. Finally, the angles between the MN and FCR tendon and between the MN and the LAF were measured using ImageJ. RESULTS The relative position of the MN at the distal wrist crease, as determined by the ratio of the distance from the MN to the radial wrist divided by wrist width, revealed a mean value of 0.48, indicating that the nerve was usually located just radial to midline. The mean distance between the distal wrist crease and the MN's emergence was 34.6 mm. The mean angle between the MN and the FCR tendon was 14.1°. The angle between the MN and the LAF had a mean value of 8.8° (range 0.0°-32.2°). The nerve was parallel to the LAF in only 10.7% of the studied wrists. Palmaris longus was absent in 14 (18.4%) of the 76 wrists. CONCLUSIONS The MN takes an angular approach to the carpal tunnel in the distal wrist in the vast majority of cases. This newly described finding will be useful to both clinicians and anatomists.

The Prevalence of Absence of the Palmaris Longus Muscle Tendon in the North of Iran: A Comparative Study

BACKGROUND

The palmaris longus is a degenerating weak flexor muscle in the anterior of the forearm. Many techniques for clinically determining the presence of the palmaris longus have been described. Ethnic variations in the prevalence of the absence of the palmaris longus are well known.

OBJECTIVES

This study considered the prevalence of absence of the palmaris longus muscle tendon in the north of Iran.

PATIENTS AND METHODS

The presence of the palmaris longus was clinically determined in 562 men and women from the Guilan population, using the standard technique (Schaeffer's test). In subjects with an absent palmaris longus, three other tests (Thompson, Pushpakumar and Mishra tests) were performed to confirm the absence.

RESULTS

The overall prevalence of right, left, bilateral and total absence of the palmaris longus were 4.1%, 5.2%, 3.9% and 13.2%, respectively. There was no significant difference in its absence with regard to the body side or gender (P > 0.05).

CONCLUSIONS

This study demonstrated that the presence of the palmaris longus muscle tendon in the Guilan population was considerably higher than the absence of the palmaris longus tendon. The overall prevalence of right, left, bilateral and total absence of the palmaris longus was not significantly different between men and women. The prevalence of the left-absent palmaris longus was more common in the present study.

Palmaris Longus Muscle's Prevalence in Different Nations and Interesting Anatomical Variations: Review of the Literature

The prevalence of the palmaris longus (PL) muscle varies more than any other muscle in the human body. Its absence across the world ranges between 1.5% and 63.9%. It presents with many different anomalies, discovered either clinically, intraoperatively or after anatomical examination of cadavers. This paper includes recent studies and reports about the presence and variations of the PL muscle, thereby illustrating the differences between ethnic groups, as well as emphasizing the different ways of finding it, during daily clinical and surgical practice.

Computing muscle, ligament, and osseous contributions to the elbow varus moment during baseball pitching

Baseball pitching imposes a dangerous valgus load on the elbow that puts the joint at severe risk for injury. The goal of this study was to develop a musculoskeletal modeling approach to enable evaluation of muscle-tendon contributions to mitigating elbow injury risk in pitching. We implemented a forward dynamic simulation framework that used a scaled biomechanical model to reproduce a pitching motion recorded from a high school pitcher. The medial elbow muscles generated substantial, protective, varus elbow moments in our simulations. For our subject, the triceps generated large varus moments at the time of peak valgus loading; varus moments generated by the flexor digitorum superficialis were larger, but occurred later in the motion. Increasing muscle-tendon force output, either by augmenting parameters associated with strength and power or by increasing activation levels, decreased the load on the ulnar collateral ligament. Published methods have not previously quantified the biomechanics of elbow muscles during pitching. This simulation study represents a critical advancement in the study of baseball pitching and highlights the utility of simulation techniques in the study of this difficult problem.

Hypotheses for ongoing evolution of muscles of the upper extremity

There are organs and muscles in the human body that may be considered rudimentary in that they have insignificant or undetermined function. Several such muscles are found in the upper extremity. In this review, four muscles that appear to be undergoing evolutionary changes are discussed: flexor digitorum superficialis to the fifth finger, anconeus, palmaris longus, and anconeus epitrochlearis. The present study synthesizes, advances and extends previously described work about these muscles and extends the hypotheses and concludes that: (a) the flexor digitorum superficialis to the fifth finger is currently under adaptive evolution, (b) the anconeus has currently stabilized its evolution and is serving as a transient stability augmenter during a short portion of the human lifespan, and (c) the entire distal upper extremity is currently in the process of undergoing evolutionary change. Understanding of these muscles and their evolutionary context is important for understanding of impact on function, dysfunction, treatment and future research.

Use of the tendon of the palmaris longus muscle in surgical procedures: study on cadavers

Objective

Demonstrate that the tendon of palmar long can be estimated in relation to its length and width before using it as a graft in surgical procedure.

Methods

There were examined 60 forearms of 30 corpses of black ethnicity; measure the length and width of the tendon of the palmaris longus muscle and compared the length of the forearm.

Results

There are notes their absence unilateral right in two female corpses. The medium length and width were more or less respectively 11.9, 15.2 mm and 4.1 + 1.5 mm. The total average forearm length of 275.4 was more or less 17.9 mm.

Conclusion

There is a significant relationship between the length of the tendon and the length of the forearm; so we can evaluate the size of the tendon of the palmaris longus muscle when it is necessary to use it for grafts. Levels of Evidence IV, Case series.

Clinical prevalence of palmaris longus agenesis: a systematic review and meta-analysis

We report a systematic review and a proportion meta-analysis of prevalence studies evaluating the prevalence of palmaris longus agenesis (PLA) in the literature. The overall PLA rate was defined to be the primary outcome. Secondary outcomes were rates of PLA in relation to ethnicity, laterality, side, gender, age, and hand dominance. We identified 26 articles which met the inclusion criteria. Meta-analyses showed an overall PLA pooled rate of 20.25%, higher than the commonly reported overall rate of 15%. Our results also showed significantly lower pooled rates in Africans (11.3%) and East Asians (4.5%) when compared to Arab Middle Eastern population (41.7%). A subgroup analysis of the African group showed a pooled rate of 2.71%, the lowest, in the East and South East African population. The pooled rate was 26.3% among Caucasians, 26.16% among South and Southeast Asians and 34.13% among Turkish. In discordance with the literature, PLA was statistically more predominant on the right side. No significant differences in PLA rates were found for laterality, gender, the combination of gender and side or the combination of gender and laterality. The lowest rate of PLA found in East and South East African populations might be indicative of the subsequent phylogenetic degeneration of the palmaris longus muscle in modern humans after the "Out of Africa" migration.

Prevalence of the palmaris longus muscle and its relationship with grip and pinch strength: a study in a Turkish pediatric population

Clinical studies generally reveal a trend of variation in the reported prevalence of the palmaris longus (PL) muscle absence. The aim of this study was to find an answer to the question of whether the congenital absence of tendon would affect hand functions or not. A total of 585 subjects, comprised of 305 males and 280 females, were included in our study. Mean age was 8.9 ± 1.4 standard deviation within a range of 6-11. For both sexes, the groups were divided further into three subgroups including 6-7, 8-9, and 10-11 years of age ranges. The grip strength of each hand and pinch strength of all fingers of each subject were measured separately. The absence of PL tendon in the right hand was 35.4 % in females, 25.9 % in males, and 30.4 % in overall average. The distribution of absence of the palmaris longus muscle between both genders was statistically significant. The p value for the right hand was 0.013. The absence of PL tendon in the left hand was 37.5 % in females, 27.9 % in males, and an overall average of 32.5 %. The p value for the left hand was 0.017. In terms of grip strength, a comparison between females and males did not reveal a significant difference. The pinch strength of the second fingers of both hands did not show any difference in both sexes. Pinch strength of the third finger of the right hand was different only in girls of subgroup 6-7 ages (p = 0.024). In girls, the pinch strength of the fourth finger of the right hand of subgroups 6-7 and 10-11 ages showed difference (p = 0.009 and p = 0.026, respectively). In boys, the fourth finger in subgroup of 8-9 ages showed significant difference in both hands (p = 0.011). The fifth fingers of both hands were found different in males for only subgroup of 8-9 ages (p = 0.001). Pinch strength of the fifth finger of the right hand was different in females for only subgroups of 6-7 and 10-11 ages (p = 0.023 and p = 0.047, respectively). While grip strength of the hand was not affected in the case of absence of the palmaris longus, in both sexes, pinch strength of the fourth and fifth fingers of both hands decreased.

Frequency of palmaris longus absence and its association with other anatomical variations in the Egyptian population

The palmaris longus (PL) is one of the most variable muscles in the human body. Racial differences in its variation have been documented. Several studies have attempted to correlate PL absence with other anatomical variations. This study was conducted to determine the prevalence of absence of PL, correlate it with gender and body side and to determine its association with other anatomical variations in the Egyptian population. The presence of PL was clinically determined in 386 Egyptians using the standard technique. All subjects were examined for the presence of the flexor digitorum superficialis (FDS) to the fifth finger. Allen's test was done to assess the completeness of the superficial palmar arch (SPA). The overall prevalence of absence of the PL in Egyptian subjects was 50.8%. There was no significant difference in PL absence with regard to the body side but a significant difference was seen as regards gender and when bilateral absence of PL was compared to its unilateral absence. Absence of FDS tendon to the fifth finger was seen in 1.3% subjects. There was no association between the absence of the FDS tendon to the fifth finger and either presence or absence of PL and also between the absence of PL and the incompleteness of SPA in both genders. In conclusion, the prevalence of absence of PL in the Egyptian population represents one of the highest rates of absence to be reported for this muscle, which is significantly different from that in other ethnic groups.

Long-term results after ulnar collateral ligament reconstruction of the elbow in European athletes with interference screw technique and triceps fascia autograft

BACKGROUND

In the last decade, there has been increasing interest in medial ulnar collateral ligament (MUCL) reconstruction techniques for MUCL insufficiency of the elbow. All case series are based on American and Asian Athletes and use primarily a palmaris longus tendon or gracilis tendon as an autograft in reconstructions. A new technique is the interference screw fixation. Evidence that supports the use of this technique is mainly from controlled laboratory studies. The purpose was to evaluate the interference screw technique for MUCL reconstructions in a European, clinical setting, with a triceps tendon fascia autograft.

METHODS

Twenty consecutive athletes with diagnosed MUCL insufficiency who underwent a MUCL reconstruction using the interference screw technique were reviewed retrospectively. Indications for reconstruction were medial elbow pain and/or instability caused by insufficiency of the MUCL that prevented the athlete from sport activity after a minimum of 3 months of conservative treatment.

RESULTS

At a mean follow-up of 55 months (range, 36-94), the mean Mayo Elbow Performance Index (MEPI) score improved from 82 to 91 points (range, 80-100); P < .001. In the end, 6 patients (30%) quit the sport activities they were preoperatively participating in, all because of reasons unrelated to the MUCL reconstruction. There were excellent results on the Conway scale in 18 patients.

CONCLUSION

Good results are reported based on the postoperative MEPI and Conway scores with clinically stable MUCL reconstructions without signs of break-out or fractures on radiographic follow-up. However, the dropout, even after successful reconstruction in European athletes, is high.

Physical examination of the athlete's elbow

Elbow injury is encountered less frequently than are other joint conditions. The bony architecture, muscle, ligament, and nerve anatomy are complex, and the forces leading to injury in the athlete's elbow are unique. Appreciating the pathomechanics leading to injury and a detailed knowledge of elbow anatomy are the foundation for conducting a directed history and physical examination that achieves an accurate diagnosis. Recent advances in physical examination have improved our ability to accurately diagnose and treat athletic elbow disorders. This article reviews general and focused physical examination maneuvers of the elbow in a systematic anatomic fashion.

Frequency of agenesis Palmaris longus through clinical examination--an East African study

Introduction

The Palmaris longus, one of the most variable muscles in the body both flexes the wrist and tenses the palmar fascia. It is used by surgeons as a source of tendon graft and racial differences in its variation have been documented. We sought to determine the frequency of the absence of the Palmaris longus in an East African population.

Methods

A prospective study was conducted using ten common clinical tests among patients and students in a large teaching hospital in East Africa to determine the presence of a Palmaris longus.

Results

The overall rate of absence was 4.4% with unilateral absence at 3.3% and bilateral absence at 1.1%. The overall difference between males and females was not statistically significant (p = 0.605). Participants were more likely to have absence in their non dominant hand.

Discussion

Our findings though in contrast to many studies worldwide, it concurs with most studies done in the African setting. These differences may be due to the higher levels of manual labour and the more use of the right hand in these activities. The frequency of the absence of Palmaris longus in East Africa has been determined. Surgeons should acquaint themselves with prevalence in their areas of practice.

Prevalence of the palmaris longus in relation to the hand dominance

PURPOSE

The incidence of left-handedness in the general population is between 8 and 15%. There is a presumption that the prevalence of palmaris longus muscle differ between right-handed and left-handed people. This prospective study was conducted to determine the prevalence of the palmaris longus in relation to the hand dominance.

METHODS

The study included 542 subjects (216 male and 326 female). They were initially tested to hand dominance and after that they were asked to do the standard test (Schaeffer's test) for the assessment of the palmaris longus tendon. If the tendon was not visualized or palpable, four additional tests (Thompson's test, Mishra's tests I and II, Pushpakumar's "two-finger sign" method) were done to confirm its absence.

RESULTS

Right hand dominance was recorded in 452 (83.4%) subjects while the left hand dominance was recorded in 90 (16.6%) subjects. In right-handed subjects, palmaris longus tendon was absent on the right side in 24 (5.3%) and on the left side in 50 (11.1%) cases. In left-handed subjects, it was absent on the right side in 18 (20%) and on the left side in 2 (2.2%) cases. These differences were statistically significant. Bilateral absence of palmaris longus tendon was similar in both examined groups (25.1% in the overall series, 24.3% in right-handed subjects, 28.9% in left-handed subjects).

CONCLUSIONS

The results of our study show that a right-sided absence was more common in left-handed persons while the left-sided absence was more common in right-handed persons. Unilateral tendon absence was more common on the non-dominant hand.