The clinical surface anatomy anomalies of the palmaris longus muscle in the Black African population of Zimbabwe and a proposed new testing technique

Abstract

The presence of the palmaris longus muscle (PLM) is highly variable. Rates of absence vary from 0.6% in the Korean population to as high as 63.9% in the Turkish population. The tendon of PLM may be absent on one or both forearms, may have duplicated tendons on one forearm or may be laterally shifted to the extent that the tendon of the PLM lies superficial to that of flexor carpi radialis muscle. Among Black American populations, in which there is usually mixed ancestry, rates of absence are 3.5%. Only two studies have been performed on Black African populations: in Republic of Congo and Uganda, and each showed widely differing rates of absence of 3.0% and 14.6%, respectively. In this study, a total of 890 Black Zimbabwean subjects in Harare aged between 8 and 13 years, were examined for clinical surface anatomy anomalies of the tendon of PLM. The results showed that the tendon of the PLM was absent unilaterally in 0.9% of the population, and bilaterally absent in 0.6% with an overall rate of absence of 1.5%. Other variations noted were a laterally shifted PLM in 1.1% of subjects and duplicated tendons on one forearm, which was the least prevalent anomaly, in 0.2% of subjects. The author proposes a new technique to test the tendon of PLM, which combines resisted thumb abduction and resisted wrist flexion. The proposed technique capitalizes on the role of the PLM as an important abductor of the thumb.

Study on Palmaris Longus Muscle Tendon Agenesis Among First Year Filipino Medical Students

“…Studies of Ahn in 2000 in Korea (0.9%), Gangata in 2009 in Zimbabwe (1.5%) and Igbigbiet et al in 1998 in Uganda (1.02%) have reported lower incidence rates of agenesis compared to the present study 1,7,9 .…”

Hypertrophy of palmaris longus muscle, a rare anatomic aberration

“…1). During a more detailed visual examination and palpation done while the patient was performing the Thompson [7] and Hiz-Ediz et al [9] tests, it was established that the patient had hypertrophy of the PLM. The muscle appeared as a strong protrusion under the skin of the left forearm.…”

Prevalence of the Palmaris Longus Muscle and its Relationship with Grip and Pinch Strength: A Study in a Turkish Pediatric Population

“…It has also been used for a wide variety of procedures including lip augmentation, ptosis correction, and in the management of facial paralysis [13]. Another important attribute of the tendon of the palmaris longus muscle is its somewhat superficial protective role over the median nerve [4].…”