The palmaris longus muscle and its relations with the antebrachial fascia and the palmar aponeurosis

Abstract

The palmaris longus (PL) is a muscle of the forearm with a long distal tendon that is continuous with the palmar aponeurosis (PA). It is generally assumed that the muscle lies deep to the antebrachial fascia from origin to termination, but a detailed description is lacking. The relationship of the PL tendon with the antebrachial fascia was studied in 30 dissections. The PL was completely absent in six specimens (20%), whereas the PA was identified in all. Average length of the forearm was 25.5 cm (SD: 2.1 cm, range 22-29 cm), overall length of the PL muscle 26.9 cm (SD: 2.6 cm, range 22.5-31.5 cm), muscular belly 13.8 cm (SD: 3.4 cm, range 9.5-23 cm), tendon 13.1 cm (SD: 3.3 cm, range 8-15.5 cm). Proximally, the PL was situated deep to the antebrachial fascia, then in the lower third of the forearm its tendon perforated the antebrachial fascia (at 4.7 +/- 1.7 cm from the bistyloid line) moving to a suprafascial plane, inserting in the PA. The PA could be divided into two layers: the superficial one formed by longitudinal fibers and adherent to the skin, the deep one formed by transverse fibers continuous laterally with the deep fascia of the hand. The PL tendon was found to be in continuity only with the longitudinal fibers of the PA. Based on the anatomical findings, it may be suggested that the superficial part of the PA is situated in the subcutaneous planes of the palm, and that the muscle should be considered as a tensor of the superficial fascial system of the subcutaneous tissue.

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

“…It is located in the most superficial layer of the anterior compartment of the forearm, between the radial and the ulnar flexors of the wrist [4]. In most cases, the distal tendon of the PLM shows a lateral slip that attaches to the superficial surface of the abductor pollicis brevis muscle that may contribute to thumb abduction [5].…”

“…In most cases, the distal tendon of the PLM shows a lateral slip that attaches to the superficial surface of the abductor pollicis brevis muscle that may contribute to thumb abduction [5]. In the proximal part of the forearm, the PLM is situated deep to the antebrachial fascia, while in the lower third of the forearm its tendon perforated the antebrachial fascia [4]. The origin of the PLM is at the epicondylus medialis of the humerus and the insertion is on the aponeurosis Palmaris [6].…”

“…The origin of the PLM is at the epicondylus medialis of the humerus and the insertion is on the aponeurosis Palmaris [6]. The PLM shares its origin with different muscles such as the flexor digitorum superficialis muscle, the flexor carpi radialis muscle, and the flexor carpi ulnaris muscle [4]. such as the flexor digitorum superficialis muscle, the flexor carpi radialis muscle, and the flexor carpi ulnaris muscle [4].…”

Morphometric analysis of the palmaris longus muscle: a fetal study

“…[24] Ito et al reported palmaris longus length 124.6±17 mm and width 4.5±0.7 in male, and 108.3±16.4 mm and width 4±0.7 in female. [25] Kopuz reported bilateral absence in 40.4% and unilateral absence in 8.5% and palmaris longus length 41.1 mm and width 1.7 mm in fetuses.…”

Morphology and Morphometry of the Tendons of the Palmaris Longus and Radial Carpal Extensor Muscles in Humans

“…It continues with its tendon, which is long and flat, at the middle third level of the forearm. At this level, the PL muscle tendon is superficial at the retinaculum of the flexor muscles and is inserted in its anterior part, in the thenar eminence and in the palmar aponeurosis, with which it is continuous (Stecco et al, 2009). The extensor carpi radialis longus (ECRL) is fusiform and originates in the lateral supracondylar crest of the humerus (Lippert, 2006;Moore et al, 2010) and in the lateral intermuscular septum of the arm (Testut & Latarjet).…”