Natalie Keough

Scoring of Decomposition: A Proposed Amendment to the Method When Using a Pig Model for Human Studies†

Decomposition studies often use pigs as proxies for human cadavers. However, differences in decomposition sequences/rates relative to humans have not been scientifically examined. Descriptions of five main decomposition stages (humans) were developed and refined by Galloway and later by Megyesi. However, whether these changes/processes are alike in pigs is unclear. Any differences can have significant effects when pig models are used for human PMI estimation. This study compared human decomposition models to the changes observed in pigs. Twenty pigs (50–90 kg) were decomposed over five months and decompositional features recorded. Total body scores (TBS) were calculated. Significant differences were observed during early decomposition between pigs and humans. An amended scoring system to be used in future studies was developed. Standards for PMI estimation derived from porcine models may not directly apply to humans and may need adjustment. Porcine models, however, remain valuable to study variables influencing decomposition.

The thoracic surface anatomy of adult black South Africans

Surface landmarks or planes taught in anatomy curricula derive from standard anatomical textbooks. Although many surface landmarks are valid, clear age, sex, and population differences exist. We reappraise the thoracic surface anatomy of black South Africans. We analyzed 76 (female = 42; male = 34) thoracoabdominal CT‐scans. Patients were placed in a supine position with arms abducted. We analyzed the surface anatomy of the sternal angle, tracheal, and pulmonary trunk bifurcation, azygos vein termination, central veins, heart apex, diaphragm, xiphisternal joint, and subcostal plane using standardized definitions. Surface anatomy landmarks were mostly within the normal variation limits described in previous studies. Variation was observed where the esophagus (T9) and inferior vena cava (IVC) (T8/T9/T10) passed through the diaphragm. The bifurcations of the trachea and pulmonary trunk were inferior to the sternal angle. The subcostal plane level was positioned at L1/L2. The origin of inferior mesenteric artery was mostly inferior to the subcostal plane. Sex differences were noted for the plane of the xiphisternal joint (P = 0.0082), with males (36%) intersecting at T10 and females (36%) intersecting at T9. We provide further evidence for population variations in surface anatomy. The clinical relevance of surface anatomical landmarks depends on descriptions of normal variation. Accurate descriptions of population, sex, age, and body type differences are essential. Clin. Anat. 29:1018–1024, 2016.

The thoracic surface anatomy of adult black South Africans: A Reappraisal From CT Scans.

Surface landmarks or planes taught in anatomy curricula derive from standard anatomical textbooks. Although many surface landmarks are valid, clear age, sex, and population differences exist. We reappraise the thoracic surface anatomy of black South Africans. We analyzed 76 (female = 42; male = 34) thoracoabdominal CT‐scans. Patients were placed in a supine position with arms abducted. We analyzed the surface anatomy of the sternal angle, tracheal, and pulmonary trunk bifurcation, azygos vein termination, central veins, heart apex, diaphragm, xiphisternal joint, and subcostal plane using standardized definitions. Surface anatomy landmarks were mostly within the normal variation limits described in previous studies. Variation was observed where the esophagus (T9) and inferior vena cava (IVC) (T8/T9/T10) passed through the diaphragm. The bifurcations of the trachea and pulmonary trunk were inferior to the sternal angle. The subcostal plane level was positioned at L1/L2. The origin of inferior mesenteric artery was mostly inferior to the subcostal plane. Sex differences were noted for the plane of the xiphisternal joint (P = 0.0082), with males (36%) intersecting at T10 and females (36%) intersecting at T9. We provide further evidence for population variations in surface anatomy. The clinical relevance of surface anatomical landmarks depends on descriptions of normal variation. Accurate descriptions of population, sex, age, and body type differences are essential. Clin. Anat. 29:1018–1024, 2016.

Inter- and intraclass correlations for three standard foot radiographic measurements for plantar surface angles. Which measure is most reliable?

BACKGROUND The purpose of this study was to evaluate the reliability and reproducibility of three commonly used radiographic measures for plantar surface angles. METHODS The calcaneal angle (CA), calcaneal pitch angle (CPA), and length-height index (LHI) was measured by three independent examiners on two occasions on lateral foot radiographs. Intra- and inter-rater correlations were calculated using a general linear estimate model and post-hoc tests for repeated measures. Bland-Altmans plots with limits of agreement were used for observer differences in scores. RESULTS The intra-class correlations for the CA ranged from 0.91 to 0.94, for the CPA from 0.93 to 0.98, and for the LHI from 0.96 to 0.97. The inter-class correlations were 0.80 for CA, 0.83 for CPA and 0.93 for LHI. CONCLUSIONS The results of this study strongly suggest that the length-height index was the most consistent and reliable measure for arch height. LEVEL OF EVIDENCE Diagnostic Level II, validity.

The mechanical properties of fresh versus fresh/frozen and preserved (Thiel and Formalin) long head of biceps tendons: A cadaveric investigation

Human cadaveric specimens commonly serve as mechanical models and as biological tissue donors in basic biomechanical research. Although these models are used to explain both in vitro and in vivo behavior, the question still remains whether the specimens employed reflect the normal in vivo situation. The mechanical properties of fresh-frozen or preserved cadavers may differ, and whether they can be used to reliably investigate pathology could be debated. The purpose of this study was to therefore examine the mechanical properties of cadaveric long biceps tendons, comparing fresh (n=7) with fresh-frozen (n=8), formalin embalmed (n=15), and Thiel-preserved (n=6) specimens using a Universal Testing Machine. The modulus of elasticity and the ultimate tensile strength to failure was recorded. Tensile failure occurred at an average of 12N/mm2 in the fresh group, increasing to 40.1N/mm2 in the fresh-frozen group, 50.3N/mm2 in the formalin group, and 52N/mm2 in the Thiel group. The modulus of elasticity/stiffness of the tendon increased from fresh (25.6MPa), to fresh-frozen (55.3MPa), to Thiel (82.5MPa), with the stiffest being formalin (510.6MPa). Thiel-preserved and formalin-embalmed long head of biceps tendons and fresh-frozen tendons have a similar load to failure. Either the Thiel or formalin preserved tendon could therefore be considered as alternatives for load to failure studies. However, the Youngs modulus of embalmed tendons were significantly stiffer than fresh or fresh frozen specimens, and these methods might be less suitable alternatives when viscoelastic properties are being investigated.