Femoral bone perfusion through the nutrient foramen during growth and locomotor development of western grey kangaroos Macropus fuliginosus

Abstract

The nutrient artery passes through the nutrient foramen on the shaft of the femur and supplies more than half of the total blood flow to the bone. Assuming that the size of the nutrient foramen correlates with the size of the nutrient artery, an index of blood flow rate () can be calculated from nutrient foramen dimensions. Interspecific is proportional to locomotor activity levels in adult mammals, birds and reptiles. However, no studies have yet estimated intraspecific to test for the effects of growth and locomotor development on bone blood flow requirements. In this study, we used micro-CT and medical CT scanning to measure femoral dimensions and foramen radius to calculate femoral during the in-pouch and post-pouch life stages of western grey kangaroos () weighing 5.7 g to 70.5 kg and representing a 12,350-fold range in body mass. A biphasic scaling relationship between and body mass was observed (breakpoint at ca. 1-5 kg body mass right before permanent pouch exit), with a steep exponent of 0.96±0.09 (95% CI) during the in-pouch life stage and a statistically independent exponent of -0.59±0.90 during the post-pouch life stage. In-pouch joeys showed values that were 50-100 times higher than those of adult diprotodont marsupials of the same body mass, but gradually converged with them as post-pouch adults. Bone modelling during growth appears to be the main determinant of femoral bone blood flow during in-pouch development, whereas bone remodelling for micro-fracture repair due to locomotion gradually becomes the main determinant when kangaroos leave the pouch and become more active.

Regional femoral bone blood flow rates in laying and non-laying chickens estimated with fluorescent microspheres

“…Long bones of younger mammals have a higher relative blood flow rate than those in older ones, consistent with higher metabolic rates during growth ( Nakano et al, 1986 ; Pasternak et al, 1966 ; Whiteside et al, 1977 ). Femoral nutrient foramen sizes of in-pouch kangaroo joeys are severalfold larger than in adult marsupial species of similar body mass ( Hu et al, 2018 ). All chickens in our study were still growing to some extent, so they may have been influenced by elevated bone perfusion for growth.…”

“…The mean was 1.50×10 −4 mm 3 , which is higher than the 95% confidence bands for adult birds in general. This probably relates to the fact that our chickens were actually still growing, because bone growth is associated with relatively larger nutrient foramina ( Hu et al, 2018 ). At present, the best correlation between bone shaft blood flow rate ( , ml min −1 ) and nutrient foramen radius ( r , mm) is / r =1.07 ml min −1 mm −1 ( Fig.…”

“…Femoral bone blood flow index ( ) was calculated using an equation derived from Poiseuille's law: = r 4 / L , where r (mm) is the foramen radius and L (mm) is an arbitrary length, measured as femur length ( Allan et al, 2014 ; Hu et al, 2018 ; Seymour et al, 2012 ). It was assumed that the arbitrary units of (mm 3 ) are proportional to absolute blood flow rate.…”

“…This ‘foramen technique’ relies on a theory that foramen size is proportional to the size of the occupying vessels. This technique has been developed to evaluate the blood supply to femora through nutrient foramina ( Allan et al, 2014 ; Hu et al, 2018 ; Schwartz et al, 2018 ; Seymour et al, 2012 ) and to brains through carotid foramina ( Boyer and Harrington, 2018 , 2019 ; Seymour et al, 2015 , 2016 , 2019 ). Blood flow rates estimated from human, rat and mouse carotid foramina match direct blood flow measurements ( Seymour et al, 2015 ), suggesting this technique can provide accurate regional perfusion values in some cases by simply measuring the size of foramina.…”

Sample specific sex estimation method using parameters around dominant nutrient foramina in unknown femur bones collection of contemporary Egyptians

“…Despite lack of conclusive evidence with respect to the number of nutrient foramina of femur, the fixed location of femoral dominant nutrient foramina on the posterior and medial aspects in the mid‐third of femur is presumably related to the requirements for continuous blood supply to the group of thigh muscles involved in the upright posture and bipedal gait, which are inserted in this region (Kizilkanat, Boyan, Ozsahin, Soames, & Oguz, 2007; Polguj, Bliźniewska, Jędrzejewski, Majos, & Topol, 2013; Santolini et al, 2014; Sołtysiak, 2015; Theodorou, Theodorou, & Resnick, 2006). More blood supply is critical to repair microfractures that are caused by the mechanical loading factors (Hu, Nelson, Snelling, & Seymour, 2018). The principal source of nourishment is via large calibre nutrient arteries originating from the perforating branches of the profunda femoris artery that passes through the nutrient foramen (Kawasaki, Kinose, Kato, Sakai, & Ichimura, 2019).…”