<b>Gross anatomy of the intrinsic muscles of the scapular and humeral joint regions in crab-eating fox (<i>Cerdocyon thous</i>, Linnaeus 1776)

Abstract

The crab-eating fox (Cerdocyon thous) is a wild canid with a wide distribution in South America that is susceptible to traumas due to road kills-an event in which some specimens can survive. Therefore, anatomical studies in their thoracic limbs may be a base for rehabilitation. Six dead specimens were donated by Wildlife Rescue Centre of CORPOCALDAS (Environmental Authority of the Department of Caldas in Colombia), which were then filled with silicone rubber via the common carotid artery, and later fixed with formaldehyde through the external jugular vein. One male was dissected in fresh, and after a week, the others were dissected on the scapular and humeral joint regions. The intrinsic muscles of these regions in the crab-eating fox were homologous to domestic dog, with similar characteristics in terms of shape, origin, insertion, innervation and arterial blood supply. However, the crab-eating fox did have some differences, such as its supraspinatus muscle being conformed by two bellies and attached into the articular capsule of the humeral joint in same manner as the subscapularis muscle, thus conferring greater stability to the humeral. However, the clinical and surgical approaches that must be performed in this region may be homologous to the domestic dog.

Functional and phylogenetic interpretation of the forelimb myology of two South American carnivorans, the ring‐tailed coati (Nasua nasua) and crab‐eating raccoon (Procyon cancrivorus)

“…The most distinctive difference between both procyonids was the broad insertion of pars cervicis in P. cancrivorus. This feature is observed in other carnivorans with terrestrial and running habits, such as some herpestids (Taylor, 1974) and canids (De Souza Junior et al, 2018;Evans & De Lahunta, 2013;Velez-Garcia et al, 2018). The particularly expanded insertion and better differentiation of the bundles of the m. serratus ventralis pars cervicis, and greater development of the whole m. serratus ventralis in P. cancrivorus (Table 2), may reflect the importance of stabilization of the scapula and weight bearing (Sharir et al, 2006).…”

Evolutionary derivation inferences of the intrinsic shoulder and brachial muscles in crab-eating raccoon (Procyon cancrivorus, Caniformia, Carnivora) based on the topology, innervation, and anatomical variants

“…Besides, the presence of an intermuscular septum between the supraspinatus and subscapularis muscles in carnivorans has been related to a more force to extend and stabilize the shoulder since the bands of both muscles are disposed cranially to the scapula. This arrangement has been associated in species with locomotion mainly cursorial as canids (Vélez-García et al 2018b) and as occurs in P. cancrivorus. The m. biceps brachii is another muscle that supports cranially the shoulder joint and extends it since its tendon of origin crosses internally the joint capsule of the shoulder.…”

“…Some anatomical variants found in P. cancrivorus may be present in other species within the order Carnivora. The presence of two bellies in the m. supraspinatus has been reported in the canid Cerdocyon thous (Vélez-García et al 2018b), the felid Panthera leo (Barone 1963), and the viverrid Civettictis civetta (Macalister 1873b). While in the mustelid Galictis cuja, it has three bellies (Ercoli et al 2015).…”

Looking back over the shoulder: New insights on the unique scapular anatomy of the tapir (Perissodactyla: Tapiridae)

“…The limb musculature literature available for perissodactyls (and non‐veterinary ungulates in general) is not particularly extensive by comparison to that of feeding systems or for other mammalian groups (e.g., primates and carnivorans; Deutsch et al, 2020; Fabre et al, 2018; Hartstone‐Rose et al, 2012, 2022; Law et al, 2022; Marchi et al, 2018; Vélez‐García et al, 2018, etc.). The absence of detailed comparative limb muscle studies for large herbivore groups is not surprising, given the logistics and time constraints on performing such experiments (e.g., Böhmer et al, 2020; Etienne et al, 2021; MacLaren & McHorse, 2020), and especially if those dissections are to involve measuring quantitative muscular architecture.…”