Related Experiment Video
Updated: Jan 2, 2026
Dissection, MicroCT Scanning and Morphometric Analyses of the Baculum
Published on: March 19, 2017
Variations and morphometrics of palmaris longus in fetuses: a meta-analysis of cadaveric studies
Kaissar Yammine1,2,3, Mirela Erić4, Chahine Assi5,6,7
1Department of Orthopedics, Lebanese American University Medical Center-Rizk Hospital, P.O. Box 11-3288, Achrafieh, Beirut, Lebanon. cesaryam@gmail.com.
Insights
The palmaris longus (PL) muscle is highly variable, with fetal prevalence similar to adults. However, fetal variations appear more common than in adults, with significant population differences observed.
Area of Science:
- Anatomy
- Developmental Biology
- Human Morphology
Background:
- The palmaris longus (PL) muscle is known for its high variability in adults.
- Fetal development and variations of the PL muscle are less understood.
- Understanding PL muscle development is crucial for anatomical and clinical studies.
Purpose of the Study:
- To synthesize existing evidence on palmaris longus (PL) muscle variations and agenesis during fetal development.
- To determine the prevalence of PL agenesis and morphological variations in fetuses.
- To compare fetal PL prevalence and variations with adult populations.
Main Methods:
- A meta-analysis was conducted on seven studies.
- Data from 497 fetuses (1027 limbs) were analyzed.
- Weighted prevalence rates for agenesis and morphological variations were calculated.
Main Results:
- The overall fetal PL prevalence was high (81.2% true, 77% crude).
- Bilateral and unilateral prevalence were 62.2% and 15%, respectively.
- Common variations included digastric muscle (5.1%), bifid tendon (2%), inverted PL muscle (1.9%), and muscle duplication (1.36%).
- Significant population differences in prevalence were noted, with Japanese populations showing the highest rates and Turkish the lowest.
- Fetal PL prevalence was similar to adults, but variations appeared more frequent.
Conclusions:
- Fetal palmaris longus (PL) muscle presence and agenesis rates are comparable to adult populations.
- Morphological variations of the PL muscle may be more prevalent in fetuses than in adults.
- Significant ethnic variations in PL prevalence exist, necessitating further research into genetic and environmental factors.
Abstract:
The palmaris longus muscle, and its tendon, is one of the most variable muscles in humans. Though it has been extensively researched in the adult population, its variations and development in the fetal period were rarely investigated. The aim of this meta-analysis is to conduct an evidence synthesis on PL variations and the prevalence of its agenesis during intrauterine development. Seven studies met the inclusion criteria comprising 497 fetuses and 1027 fetal limbs. The true and crude weighted prevalence rates were of 81.2% and 77%, respectively. The bilateral and unilateral prevalence estimates were of 62.2% and 15%, respectively. No significant differences were found for side-based and gender-based prevalence values. There were significant frequency differences between the studied populations (p < 0.0001).The Japanese population had the highest prevalence, the Turkish had the lowest and the European value was in between. Out of 494 studied muscles, 67 (13.5%) variations were noted. The weighted proportions of the commonest morphological variations were as follows: (a) bifid tendon in 10 (2%) cases, (b) inverted PL muscle in 9 (1.9%), muscle duplication in 6 (1.36%), and digastric muscle in 25 (5.1%). Prevalence values of the fetal PL were similar to those reported in adults; however, variations seem to be higher than in older populations. The true, crude, and ancestry-based prevalence presence rates of PL in fetuses were found to be similar to those of the adult population.
Related Concept Videos
01:17Muscles of the Forearm that Move the Hand and Fingers
Anterior Compartment
The anterior compartment muscles originate from the humerus. They primarily function as flexors and are also known as flexor muscles. They typically insert on the carpals, metacarpals, and phalanges. The superficial layer includes the flexor carpi...
01:09Changes in the Appendicular Skeleton with Age
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:09Bones of the Upper Limb: Radius
The radius has a nail-shaped head, and a...