Editing Trabecula (section)

=== Trabecula in other organisms ===
{{unreferenced section|date=March 2018}}
The larger the animal, the higher the load forces on its bones. Trabecular bone increases stiffness by increasing the amount of bone per unit volume or by altering the geometry and arrangement of individual trabeculae as body size and bone loading increases. Trabecular bone scales [[Allometry|allometrically]], reorganizing the bones' internal structure to increase the ability of the [[skeleton]] to sustain loads experienced by the trabeculae.  Furthermore, scaling of trabecular geometry can moderate trabecular strain. Load acts as a [[Stimulus (physiology)|stimulus]] to the trabecular, changing its geometry so as to sustain or mitigate strain loads. By using finite element modelling, a study tested four different species under an equal apparent stress (σapp) to show that trabecular scaling in animals alters the strain within the trabecular. It was observed that the strain within trabeculae from each species varied with the geometry of the trabeculae. From a scale of tens of micrometers, which is approximately the size of [[osteocyte]]s, the figure below shows that thicker trabeculae exhibited less strain. The relative frequency distributions of element strain experienced by each species shows a higher [[Elastic modulus|elastic moduli]] of the trabeculae as the species size increases.

Additionally, trabeculae in larger animals are thicker, further apart, and less densely connected than those in smaller animals. Intra-trabecular [[osteon]] can commonly be found in thick trabeculae of larger animals, as well as thinner trabeculae of smaller animals such as [[cheetah]] and [[lemur]]s. The osteons play a role in the diffusion of nutrients and waste products of osteocytes by regulating the distance between osteocytes and bone surface to approximately 230 μm.

Due to an increased reduction of blood oxygen saturation, animals with high metabolic demands tend to have a lower trabecular thickness (Tb.Th) because they require increased vascular [[perfusion]] of trabeculae. The [[vascularization]] by tunneling osteons changes the trabecular geometry from solid to tube-like, increasing bending stiffness for individual trabeculae and sustaining blood supply to deep tissue osteocytes.

Bone volume fraction (BV/TV) was found to be relatively constant for the variety of animal sizes tested. Larger animals did not show a significantly larger mass per unit volume of trabecular bone. This may be due to an [[adaptation]] which reduces the physiological cost of producing, maintaining, and moving tissue. However, BV/TV showed significant positive scaling in avian [[Condyle (anatomy)|femoral condyle]]s. Larger birds present decreased flight habits due to avian BV/TV allometry. The flightless kiwi, weighing only 1–2&nbsp;kg, had the greatest BV/TV of the birds tested in the study. This shows that trabecular bone geometry is related to ‘prevailing mechanical conditions’, so the differences in trabecular geometry in the femoral head and condyle could be attributed to different loading environments of [[Hip joint|coxofemoral]] and [[Knee|femorotibial joints]].

The [[woodpecker]]'s ability to resist repetitive head impact is correlated with its unique micro/nano-hierarchical [[Composite material|composite]] structures.<ref name="ReferenceC"/> [[Microstructure]] and [[nanostructure]] of the woodpecker's [[skull]] consists of an uneven distribution of [[Bone#Trabeculae|spongy bone]], the organizational shape of individual trabeculae. This affects the woodpecker's mechanical properties, allowing the [[Skull|cranial bone]] to withstand a high [[ultimate strength]] (σu). Compared to the cranial bone of the [[lark]], the woodpecker's cranial bone is denser and less spongy, having a more plate-like structure rather than the more rod-like structure observed in larks. Furthermore, the woodpecker's cranial bone is thicker and more individual trabeculae. Relative to the trabeculae in lark, the woodpecker's trabecular is more closely spaced and more plate-like. [19] These properties result in higher ultimate strength in the cranial bone of the woodpecker.