Ontogenetic development of the shoulder joint muscles in frogs (Amphibia: Anura) assessed by digital dissection with implications for interspecific muscle homologies and nomenclature

Abstract

Previous myological studies show inconsistencies with regard to the identification and naming of the shoulder joint muscles in frogs and toads (Amphibia: Anura). Those inconsistencies were revealed and resolved by assessing the ontogenetic development, innervation, and adult morphology of selected anuran species representing ancient lineages and two major neobatrachian groups. To do so, digital dissections of volumes acquired by histological serial sectioning, episcopic microtomy, and contrast-enhanced micro-computed tomography scanning were performed and three-dimensional reconstructions were derived. Muscle units crossing the shoulder joint were defined, their ontogenetic development was described, their homology across species was established, and a consistent nomenclature was suggested. The mm. anconaeus, dorsalis scapulae, latissimus dorsi, and the group of scapulohumeralis muscles were ontogenetically derived from the dorsal pre-muscle mass present in all tetrapods. The ventral pre-muscle mass gave rise to the mm. cleidohumeralis, episternohumeralis, supracoracoideus, coracoradialis, subcoracoscapularis, coracobrachialis, and pectoralis. The results indicate that the mm. anconaeus, dorsalis scapulae, latissimus dorsi, coracoradialis, and the portionis sternalis and abdominalis of the m. pectoralis have consistently been recognized and denoted in previous studies, whereas the names for the muscle units commonly denoted as m. coraco-brachialis longus and as parts of the m. deltoideus are misleading with regard to the ontogenetic origin of these muscles. The mm. scapulohumeralis profundus anterior and posterior, although present, have been overlooked in some studies. The mm. cleidohumeralis, supracoracoideus, and coracobrachialis are present with two parts or portions in some species, these portions have previously not always been recognized and assigned correctly.

[Retracted] Application of Ultrasound‐Guided Upper Trunk Brachial Plexus Block in Observation of Lower Shoulder Surgery

“…After intravenous midazolam sedation, the contralateral radial artery was punctured and catheterized to monitor blood pressure. The blood pressure and heart rate measured after resting and 5 minutes were the blood pressure and heart rate at T0, and then nerve block was performed [ 17 ].…”

Treefrog Diversity in the Neotropics: Phylogenetic Relationships of Scinaxini (Anura: Hylidae: Hylinae)

“…The terminology employed follows Duellman (1970a) for adult external morphology, Trueb (1973, 1993) for cranial and postcranial osteology, Fabrezi (1992, 1993) for carpal and tarsal osteology, Trewavas (1933) for laryngeal morphology, Jurgens (1971) for nasal cartilage morphology, Blotto et al (2020) for hand and foot myology, Tyler (1971), Trewavas (1933), Horton (1982), and Elias-Costa et al (2021) for submandibular myology, Diogo et al (2008) for neck and head myology, Engelkes et al (2021) for shoulder joint myology, Gaupp (1896) and Duellman and Trueb (1986) for abdominal myology, Luna et al (2018) for nuptial pad morphology, Altig and McDiarmid (1999) for larval external morphology, and Wassersug (1976) for larval internal oral morphology. Throughout the text, hand digits were numbered II–V following Fabrezi and Alberch (1996); following Altig and McDiarmid (1999) the labial tooth rows are considered A (anterior) and P (posterior).…”

Diversity and function of the fused anuran radioulna

“…The completely split model (Figure 4d ) was sculpted from the portions of the radius and ulna of the original model using the morphology of juvenile frogs (Figure 1b ; Púgener & Maglia, 1997 ; Maglia & Púgener, 1998 ; Hanken et al, 2001 ) and adult salamanders (Figure 1c ) as a reference. The semi‐split model design was informed both by patterns of radioulna development in juvenile frogs (Engelkes et al, 2021 ; Hanken et al, 2001 ; Maglia & Púgener, 1998 ; Púgener & Maglia, 1997 ) and the fusion patterns we observed in the tibiale and fibulare of species in our sample.…”

“…Thus, we estimated this position on our models which lacked an obvious CR scar (Figure S3 c–d,g–j). We estimated the direction of the vector by referring to the position of the CR scar in our specimen and illustrations of the coracoradialis tendon from existing contrast‐enhanced CT datasets (Engelkes et al, 2021 ; Keeffe & Blackburn, 2020 ). The vector used is listed in Table S4 (which has a 56.19° angle with the x axis, 133.44° angle with the y axis, and a 62.20° angle with the z axis).…”