SUMMARY:The anatomy of mammal's lung air space constitutes the bronchial tree which disposition is associated to air flux dynamics. Casts obtained from human, pig and rat lungs were studied to analyze possible differences of the bronchial tree architecture in mammals with diverse dimensions and posture. Air spaces were filled with polymers through trachea followed by acid corrosion. Tracheal and main bronchial division's diameters were measured to relate with body mass using allometry. The results revealed a dichotomic bronchial branching pattern in the human casts and a monopodial pattern in animals. In allometric relationship trachea was larger in rats, then pigs and lastly in humans, differences were statistically significant, the same occurs in right bronchus, as in the left bronchus there was no difference between rat and pig. The linear relationship between the human tracheal diameters was 1.2 times larger than the pig and 6.7 times larger than the rat; the pig tracheal diameter was 5.6 times larger than the rat. Quadruped position of the pig and rat is linked to a horizontal air way while the erect position, biped in human, correspond to a vertical air way. A big mammal shows less respiratory frequency than small mammals. Mammals with small, medium and high body mass allied to diverse posture and habits was compared revealing morphological differences in the bronchial trees as different allometric correlations between quadruped animals and human biped.

showed a predominance of such findings at regions proximal to the navicular tubercle, towards the midline of the foot. After dissections of four cadaveric specimens, they suggested that the proximity of the abductor hallucis (AH), flexor hallucis brevis (FHB), and flexor digitorum brevis (FDB) muscles would possibly explain such findings, although they commented that the compound action potential (CNAP) of the medial plantar nerve could also contribute.We recently had the opportunity to dissect 30 feet from 15 previously fixed cadavers, which allowed us to measured the entry point of the motor nerves to the AH, FDB, and FHB muscles from a common reference point (the tip of the calcaneus). These measurements are directly related to the length of these motor nerves in relation to the main trunk of the parent nerve. Values from right and left feet did not differ significantly (t-test for paired data). Values from the different motor nerves of the right feet were statistically compared through a repeated measure ANOVA followed by the Tukey-Kramer multiple comparison test. We found that the distance from the reference point to the nerve entry point for the three muscles differed significantly (Table 1; F 2,28 = 69.78, P < 0.0001); the entry point to the AH muscle was shorter than that for the FDB (P < 0.05), and both were shorter than that to the FHB (P < 0.001).The present findings support the hypothesis that the proximity of the muscles and the interaction of their M waves in the volume conductor are responsible for the emergence of false motor points. An important assumption of this hypothesis is that the other muscles should be activated at different times, and our findings also support this assumption. In fact, our findings suggest that, in studying the M waves around the navicular tubercle, the smaller difference in length of the motor nerves to the AH and FDB muscles is responsible for the predominance of false motor points at the posterior and medial regions, as found previously.1 The length of the FHB motor nerve in relation to that of the other muscles, particularly the AH, makes the presence of false motor points anterior to the navicular tubercle less frequent, as has also been found.

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