The retroesophageal aberrant right subclavian artery (ARSA) is a variation of the aortic arch that occurs asymptomatically in most patients. However, when symptomatic, it is most commonly associated with dysphagia. ARSA has also been noted as a location of potentially severe aneurysms in some patients, as well as posing a risk during surgical interventions in the esophageal region. This case study analyzes two individuals with ARSA morphology in comparison to a normal sample in order to gain a better anatomical understanding of this anomaly, potentially leading to better risk assessment of ARSA patients going forward. The diameter of the ARSA vessel was found to be substantially larger than both the right subclavian artery and brachiocephalic trunk of the subjects with classic aortic arch anatomy. As many ARSA individuals are asymptomatic, we hypothesize that the relative size of the ARSA may dictate its contribution to the presence and/or severity of associated symptomatology.

The snow leopard (Panthera uncia) is currently considered vulnerable by the IUCN, with approximately 5,000 individuals left in the wild with a 20% decline in their population in the last two decades. The hyoid apparatus of this felid has been documented, but the musculature of this region has not. The hyoid region of snow leopards is of interest because they have an incompletely ossified hyoid apparatus and they produce distinctive vocalizations among the Felidae. Similar to other pantherines, the snow leopard can elongate the vocal tract by moving the larynx away from the oral cavity to produce lower‐pitched sounds. In this study, we dissected, documented in detail, and imaged the hyoid apparatus and musculature in two adult P. uncia specimens (1M/1F). Our results indicate that the occipitohyoideus, found in numerous carnivorans and felids, is not present in the snow leopard, instead it may be fused with the stylohyoideus. In lions, the sternohyoideus and sternothyroideus both take origin from the second sternebra, however in P. uncia, these muscles take origin from the second sternebra and the first and second rib. The omohyoideus is absent in the snow leopard, not unlike the condition seen in other feliformes. The geniohyoideus is not fused in the midline, which is similar to the condition seen in the tiger. The stylohyoideus inserts on the stylohyoideum via a fascial band, similar to the tiger and the serval. Our initial results suggest that the hyoid musculature of the snow leopard displays unique features, which may shed light on its unique vocalizations.

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