Affiliations: [a] Department of Physical Medicine and Rehabilitation, Faculty of Medicine, University of Usak, Usak, Turkey | [b] Department of Radiology, Training and Research Hospital of Konya, Konya, Turkey | [c] Department of Anatomy, Faculty of Medicine of Necmettin Erbakan University, Konya, Turkey | [d] Department of Physical Medicine and Rehabilitation, State Hospital of Cumra, Konya, Turkey | [e] Department of Physical Medicine and Rehabilitation, Training and Research Hospital of Usak, Usak, Turkey | [f] Department of Physical Medicine and Rehabilitation, Training and Research Hospital of Derince-Kocaeli, Kocaeli, Turkey
Corresponding author: Ali Yavuz Karahan, Department of Physical Medicine and Rehabilitation, Faculty of Medicine, University of Usak, Usak, Turkey. Mobile: +90 5386921934; E-mail: [email protected]
Abstract: BACKGROUND: The palmaris longus (PLM) is a fusiform-shaped muscle that appears in the superficial flexor compartment of the forearm. It has been suggested that PLM is a phylogenetically degenerate metacarpophalangeal joint flexor. OBJECTIVE: The aim of this study was to compare the strength of wrist flexion and extension in healthy volunteers with and without the PLM. METHODS: Sixty-four healthy subjects, 30 men and 34 women, 18–22 years old were enrolled in this study. The database consisted of 128 wrist tests. The inclusion criteria were as follows: sedentary lifestyle, unknown musculoskeletal disorders and right-handedness. Musculoskeletal ultrasound imaging was used for assessing the presence of PLM. A hand-held digital dynamometer was used to assess the peak force of wrist extension and flexion. Data were analyzed separately for women and men RESULTS: The existence of right-sided PLM was 73.3% in male subjects and 55.9% in female subjects. For men, the strength of wrist flexion was 36.03 ± 13.92 N and 34.24 ± 12.23 N for the right and left side, respectively. For women, the respective strengths were 16.20 ± 7.29 N and 15.26 ± 6.79 N. For both sexes, there was no statistically significant difference between those with and without a PLM (p> 0.05). There was also no significant difference in the agonist/antagonist (flexion/extension) ratio of the wrist between those with and without a PLM in both sexes and sides. CONCLUSIONS: The existence or absence of PLM plays no role in the strength of either the flexors or extensors of the wrist.