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

Assessing the Accuracy of Common Clinical Tests for Detecting Palmaris Longus: A Prospective Study in a Tertiary Center

Background  Palmaris longus (PL) is a short-bellied muscle with a long tendon that merges with the palmar aponeurosis. It is supplied by the median nerve and acts as a tensor of the palmar aponeurosis and flexes the wrist. This tendon is commonly used for tendon transfers and as a donor for tendon graft. There are numerous clinical tests to detect the presence of PL like Schaeffer's test, Thompson's test, Mishra's test I, Mishra's test II, Pushpakumar's "two-finger sign" method, and AIIMS test. The principle of all these tests is to make the tendon prominent by eliciting its flexor action and then its identification by inspection and palpation. Objectives  The tests that are consistently easy to perform with good understandability would be easy to explain to the general population (patients). The aim of our study is to find out the accuracy and easy comprehensibility of various tests using compulsive postures for detecting PL tendon clinically. Materials and Methods  This is a prospective study on 137 participants. All the patients were subjected to six clinical tests to detect the presence or absence of PL tendon. The results were recorded for both hands by a single observer. Results  Of the 137 participants, 75 were males (54.74%) and 62 were females (45.26%). The mean age was 21 years. The AIIMS test showed the maximum number of tendons, that is, 113 (82.4%) in the right hand and 108 (78.8%) in the left hand. In view of the ability to comprehend the tests, 119 (86.9%) subjects understood Schaeffer's test very easily. Conclusion  According to this study, the AIIMS test best demonstrates the PL tendon, and Schaeffer's test was the test most easily understood by the subjects.

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.

Detection of the palmaris longus tendon: physical examination versus sonography

This study investigated the sensitivity, specificity, and accuracy of physical examination compared with high resolution sonography for the detection of the palmaris longus tendon in 136 wrists. The incidence of tendon absence was 10% by sonography and 14% by physical examination. The sensitivity of the physical examination was 94% and the specificity 86% compared with sonography as the reference standard. Accurate identification of the palmaris longus tendon through physical examination was not influenced by body mass index or wrist circumference. Upon review of the sonography images, none of the palmaris longus tendons missed on physical examination were considered to be adequate for grafting based on expert opinion. While physical exam was 93% accurate for detection of the palmaris longus tendon compared with ultrasound, our study suggests that it is sufficient for detection of those tendons that can be used as donors clinically.

Musculus Palmaris Longus: Influence on Playing Capability of Keyboard Musicians - Preliminary Report

Musculus Palmaris Longus (PL) is one of the most variable anatomical structures in the human body. Despite being biomechanically active, it is vastly considered to have no impact on the functionality of the upper extremity in the general population. The aim of this study is to examine the relation between playing capability of young musicians and morphology of Musculus PL and to compare it with the relation between manual capability of non-musicians and morphology of their Musculus PL. 42 forearms of 21 healthy individuals (11 musicians and 10 non-musicians) were subjected to Shaeffer's test and ultrasound imaging and tested by dynamometer for hand grip strength and the first and fifth finger opposition before and after exertion. No difference in morphology pattern was observed between the groups. In the musicians, a substantial loss of a hand grip strength of the left hand compared to the right hand after exertion, regardless of lateralization, was observed. A disproportion in exhaustion of the musician's hands with unilateral absence of PL was observed - the difference in grip strength between the dominant and non-dominant hand before and after exertion increased over eight times more than in the musicians with bilateral presence. There is no difference in PL morphology between either the musicians or non-musicians. Regardless of lateralization, the musician's left hand in musicians seems weaker and therefore more prone to misuse related injuries. PL may play a role in musicians in balancing muscular exhaustion.

Interobserver and intraobserver reliability of different methods of examination for presence of palmaris longus and examination of fifth superficial flexor function

The palmaris longus is harvested as a tendon graft in various surgical procedures. Several tests are used to assess the presence of palmaris longus tendon. In the present study, we attempted to assess the interobserver and intraobserver reliability of five of the most famous methods and also the examination of fifth superficial flexor function. Two observers, who had been trained on the tests and had practiced them, examined 105 volunteers on two separate occasions and in 1-month interval the results were recorded. The reliability of each method was assessed with Kappa measurement. Kappa ranged from 0.541 (moderate reliability) to 0.813 (almost complete agreement) for palmaris. The highest interobserver and intraobserver reliability and also the best agreement with other tests were of Schaeffer. The lowest kappa was for Thompson and the others have good to excellent reliability. Kappa for interobserver and intraobserver reliability for the fifth flexor were 0.415 and 0.500 (moderate reliability), respectively. The tests that were assessed have good reliability except for Thompson that has a moderate one. It seems that the standard test (Schaeffer) is the best method for the assessment of the absence or presence of palmaris longus. The method used for the evaluation of fifth superficial flexor variations assessment has a moderate interobserver and intraobserver reliability.

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.

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.

Palmaris longus absence in six largest Indonesian ethnicities and its relationship with gender, ethnicity, and hand dominance

Background: Palmaris longus (PL) tendon is often used as graft in tendon or ligament reconstruction. PL absence is a normal variation in human body. Its prevalence was different in various population. Serbian population had an absence rate of 42.4%, but in the Korean population it was only 4.0%. This study aimed to determine the prevalence of PL absence in various ethnic of Indonesian population and its relationship with gender and side of hand dominance. Methods: We conducted a cross-sectional study in 1230 people from six ethnicities in Indonesia. The absence of PL was determined by Schaeffer test and confirmed with Mishra and Thompson test. Data collection was performed by a single examiner in various cities in Indonesia. The relationship between PL absence with ethnicity, gender, and hand dominance were determined by Chi-square test. Results: Prevalence of PL absence in overall Indonesian population was 10.4% (bilateral 37.5% and unilateral 62.5%). The highest were in Batak and Madura ethnicities (15.5%), followed by Sunda (11.8%), Java (10.0%), Betawi (6.0%), and the lowest was Minang ethnicity (4.1%) (p = 0.008). Prevalence of PL absence in female and male were 10.7% 10.2%, respectively, p > 0.05).Conclusion: Compared to range of prevalence in other countries in the world, prevalence of PL absence in Indonesian population was moderate (10.4%). There was significant difference found between ethnicity, but not in gender. Surgeon should consider this data when planning for reconstruction procedures using PL graft in Indonesian population.

Morphometric and statistical analysis of the palmaris longus muscle in human and non-human primates

The palmaris longus is considered a phylogenetic degenerate metacarpophalangeal joint flexor muscle in humans, a small vestigial forearm muscle; it is the most variable muscle in humans, showing variation in position, duplication, slips and could be reverted. It is frequently studied in papers about human anatomical variations in cadavers and in vivo, its variation has importance in medical clinic, surgery, radiological analysis, in studies about high-performance athletes, in genetics and anthropologic studies. Most studies about palmaris longus in humans are associated to frequency or case studies, but comparative anatomy in primates and comparative morphometry were not found in scientific literature. Comparative anatomy associated to morphometry of palmaris longus could explain the degeneration observed in this muscle in two of three of the great apes. Hypothetically, the comparison of the relative length of tendons and belly could indicate the pathway of the degeneration of this muscle, that is, the degeneration could be associated to increased tendon length and decreased belly from more primitive primates to those most derivate, that is, great apes to modern humans. In conclusion, in primates, the tendon of the palmaris longus increase from Lemuriformes to modern humans, that is, from arboreal to terrestrial primates and the muscle became weaker and tending to be missing.

Prevalence of bifid median nerves and persistent median arteries and their association with carpal tunnel syndrome in a sample of Latino poultry processors and other manual workers

INTRODUCTION

The prevalence of bifid median nerves and persistent median arteries, their co-occurrence, and their relationship to carpal tunnel syndrome (CTS) are only understood partially.

METHODS

We screened 1026 wrists of 513 Latino manual laborers in North Carolina for bifid median nerves and persistent median arteries using electrodiagnosis and ultrasound.

RESULTS

A total of 8.6% of wrists had a bifid median nerve, and 3.7% of wrists had a persistent median artery independent of subgroup ethnicity, age, gender, or type of work. An association with definite carpal tunnel syndrome was not found. The presence of either anatomic variant was associated with a high likelihood of co-occurrence of another variant in the same or the contralateral wrist.

CONCLUSIONS

The occurrence of median anatomic variants can be determined in field studies using ultrasound. Persistent median arteries and bifid median nerves tend to co-occur but do not put manual laborers at additional risk of developing CTS.

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.

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.

The variation in the absence of the palmaris longus in a multiethnic population of the United States: an epidemiological study

The absence of the palmaris longus (PL) has been shown to vary based on body side, gender, and ethnicity. In prior studies, homogenous ethnic populations have been shown to have differences in rates of absence. However, no study thus far has analyzed the differences in palmaris longus prevalence in a multiethnic population. We prospectively collected data on 516 patients visiting the outpatient hand clinics at LAC+USC Medical Center and Keck Medical Center. Analysis of the data was then performed for variables including ethnicity, laterality, and gender. There were no differences in the absence of the PL based on laterality or gender. Ethnically, there was no difference between white (non-Hispanic) and white (Hispanic) patients, with prevalence of 14.9% and 13.1%, respectively. However, African American (4.5%) and Asian (2.9%) patients had significantly fewer absences of the PL than the Caucasian, Hispanic reference group (P = 0.005 and P = 0.008, resp.). African Americans and Asians have a decreased prevalence of an absent PL. The Caucasian population has a relatively greater prevalence of an absence of the PL. This epidemiological study demonstrates the anatomic variation in this tendon and may be taken into account when planning an operation using tendon grafts.