The Variation in the Absence of the Palmaris Longus in a Multiethnic Population of the United States: An Epidemiological Study

Abstract

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.

The Impact of Palmaris Longus Muscle on Function in Sports: An Explorative Study in Elite Tennis Players and Recreational Athletes

“…The prevalence of agenesis was found to be significantly more common on the left side [3,34]. This corresponds to our study, in which four subjects had a unilateral PLM on the right side while only two subjects showed a unilateral PLM on the left side.…”

“…Thompson et al reported that men were more prone to have a bilateral and unilateral absence of the PLM, but this was not statistically significant [27]; other authors reported the incidence of agenesis to be higher in women [1,26,34].…”

“…Finally Soltani et al found that bilateral presence of the PLM occurred the most, followed by unilaterally absence of the PLM while bilaterally absence of the PLM occurred less [34].…”

Clinical prevalence of palmaris longus agenesis: A systematic review and meta‐analysis

“…Seven studies reported the overall PLA rate in Africans (Kayode et al, ; Gangata, ; Mbaka et al, ; Ndou et al, ; Kigera and Mukwaya, ; Soltani et al, ; Venter et al, 2013) with a total of 3,907 subjects. The pooled proportion of the random effects distribution for studies of PLA was 11.3% (95% CI = 0.037–0.222) with Q = 499.52, df = 6, P < 0.0001, I 2 = 98.8%.…”

Agenesis of the Medial Gastrocnemius and Plantar Muscle: Case Presentation

“…Muscle agenesis is a rare anomaly, being the agenesis of palmar longus the most frequently reported in the literature, with an overall incidence of 15 % (Htwe et al, 2012) (Sankar et al, 2011) and 13.1 % in the Hispanic population (Soltani et al, 2012). As for the absence of the Medial Gastrocnemius Muscle (MGM), there is not sufficient evidence of its incidence and only have been described case reports, while Plantar Muscle (PM), is estimated to be 7-20 % (Aragão et al, 2010& Kwinter et al, 2010.…”