Hip flexor musculature was instrumental in the evolution of hominin bipedal gait and in endurance running for hunting in the genus Homo. The iliacus and psoas major muscles were historically considered to have separate tendons with different insertions on the lesser trochanter. However, in the early 20th century, it became "common knowledge" that the two muscles insert together on the lesser trochanter as the "iliopsoas" tendon.
View Article and Find Full Text PDFA new species of tyrannosaurid from the upper Two Medicine Formation of Montana supports the presence of a Laramidian anagenetic (ancestor-descendant) lineage of Late Cretaceous tyrannosaurids. In concert with other anagenetic lineages of dinosaurs from the same time and place, this suggests that anagenesis could have been a widespread mechanism generating species diversity amongst dinosaurs, and perhaps beyond. We studied the excellent fossil record of the tyrannosaurid to test that hypothesis.
View Article and Find Full Text PDFExtant crocodilians are a highly apomorphic archosaur clade that is ectothermic, yet often achieve large body sizes that can be subject to higher heat loads. Therefore, the anatomical and physiological roles that blood vessels play in crocodilian thermoregulation need further investigation to better understand how crocodilians establish and maintain cephalic temperatures and regulate neurosensory tissue temperatures during basking and normal activities. The cephalic vascular anatomy of extant crocodilians, particularly American alligator (Alligator mississippiensis) was investigated using a differential-contrast, dual-vascular injection technique and high resolution X-ray micro-computed tomography (μCT).
View Article and Find Full Text PDFExtinct archosaurs, including many non-avian dinosaurs, exhibit relatively simply shaped condylar regions in their appendicular bones, suggesting potentially large amounts of unpreserved epiphyseal (articular) cartilage. This "lost anatomy" is often underappreciated such that the ends of bones are typically considered to be the joint surfaces, potentially having a major impact on functional interpretation. Extant alligators and birds were used to establish an objective basis for inferences about cartilaginous articular structures in such extinct archosaur clades as non-avian dinosaurs.
View Article and Find Full Text PDFObjectives: Surgical excision of the submandibular gland (SMG) is commonly indicated in patients with neoplasms, and non-neoplastic conditions such as chronic sialadenitis, sialolithiasis, ranula and drooling. Traditional SMG surgery involves a direct transcervical approach. In the recent past, alternative approaches to SMG excision have been described in effort to offer minimally invasive options or better cosmetic results.
View Article and Find Full Text PDFThe structure of the temporalis muscle was examined in detail from cadaveric specimens (32 specimens from 16 subjects: 5 males, average age 80.6 years; 11 females, average age 88.6 years) and Computerized Tomography (CT) and T1-weighted Magnetic Resonance (MR) images from normal clinical patients (10 females: average age 45.
View Article and Find Full Text PDFDuring routine anatomical dissection, a bilateral variation of the muscle subclavius was discovered with additional morphological features consistent with the muscle subclavius posticus. Attached medially to the first rib by tendon and to the clavicle by fibrous bands, the long triangular shaped muscle ran dorsal-laterally to attach onto the transverse scapular ligament and the coracoid process. The scapular insertion of the omohyoid muscle was just medial to this muscle, with some intermingling of fibers close to their insertions.
View Article and Find Full Text PDFData on vascular anatomy traditionally have been derived from time-consuming gross dissection and histology, which has prevented the assembly of large sample sizes. Vascular injection of radiopaque medium (angiography) is a rapid technique, but, as typically performed, it has limitations (e.g.
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