Anatomic description of the palmaris longus muscle and report of variant nerve supply in the white‐footed tamarin (Saguinus leucopus Günther, 1876)

Abstract

The gross anatomy of the palmaris longus muscle in 12 specimens of Saguinus leucopus was studied by dissection. This muscle was constant and unipennate, originated in the medial epicondyle of the humerus; inserted onto flexor retinaculum and palmar aponeurosis; and innerved by the median nerve, and in one case, together with the ulnar nerve. This is the first report of double innervation for this muscle in primates.

Gross anatomical adaptations of the craniolateral forearm muscles in Tamandua mexicana (Xenarthra: Myrmecophagidae): development of accessory muscles and rete mirabile for its arterial supply

“…According to the anatomical disposition of the m. brachioradialis in T. mexicana , it should act as an elbow flexor and a supinator of the forearm and the hand, which are functions reinforced by the m. brachioradialis accessorium, agreeing with Taylor (1978), however, the insertion onto flexor retinaculum of the latter muscle must generate tension into this retinaculum and at the same time increase the space of the carpal canal to allow a better sliding of the tendon of the m. flexor digitorum profundus and also to avoid the compression of the median nerve and artery, similar to the proposed function of the m. palmaris longus in primates (Vélez-García et al., 2018). In sloths, the brachioradialis muscle is large (Diniz et al., 2018; Olson et al., 2018), it even represents a great weight among the thoracic limb musculature, therefore it has been indicated as a strong elbow flexor (Olson et al., 2018), being different to T. mexicana , where it is a simple complementary muscle to the elbow flexion.…”

Evolutionary and terminological analysis of the flexor digitorum superficialis, interflexorii and palmaris longus muscles in kinkajou (Potos flavus) and crab‐eating racoon (Procyon cancrivorus)

“…interflexorii’ (IF) has been established because these muscles are positioned between the FDS and the FDP, but despite this, several studies of carnivorans have referred to them as FDS or flexor digitorum sublimis (due to its homologous position with that of humans), despite the fact that they observed tendons for the digits (Table 1). These studies become confusing for terminology, since the PL gets its name because it is inserted into the palmar fascia and does not form tendons for the digits as do those established in primates (Aversi‐Ferreira et al., 2014; Cribillero et al., 2009; Michilsens et al., 2009; Diogo & Wood, 2012; Standring, 2016; Vélez‐García, ,Duque‐Parra, et al., 2018; Vanhoof et al., 2020). In some primates, the PL may be absent as an intraspecific anatomical variation, such as might occur in H. sapiens (Standring, 2016), G. gorilla and P. troglodytes (Testut & Latarjet, 1984; Diogo & Wood, 2012).…”

Gross anatomy of the shoulder and arm intrinsic muscles in the white‐footed tamarin (Saguinus leucopus – Günther, 1876): Inter‐ and intraspecific anatomical variations

“…Since morphological characteristics are adapted to the environment, there is wide diversity of types of arboreal locomotion related to the variety and irregularity of substrates in arboreal environments . In S leucopus, there have been intraspecific variants reported in the forearm muscles ; therefore, the main objective of this study is to characterize the gross anatomy of the shoulder and arm intrinsic muscles and report their anatomical variants.…”