Supracondylar process of the humerus Supracondylar process of the humerus The supracondylar process of the humerus (also known as an "avian spur") is a bony projection on the anteromedial aspect of the upper arm bone (humerus), about 5 cm above the medial epicondyle. It is directed downward, forward and medially pointing to the medial epicondyle. It is an anatomical variation which occurs in about one percent of all people. A fibrous band, Struthers ligament, may connect this process to the medial epicondyle. Supracondylar processes are usually asymptomatic, but may be palpable as a mass on the upper arm. They are most commonly found as an
Bone marrow the umbilical cord. The earliest fossilised evidence of bone marrow was discovered in 2014 in "Eusthenopteron", a lobe-finned fish which lived during the Devonian period approximately 370 million years ago. Scientists from Uppsala University and the European Synchrotron Radiation Facility used X-ray synchrotron microtomography to study the fossilised interior of the skeleton's humerus, finding organised tubular structures akin to modern vertebrate bone marrow. "Eusthenopteron" is closely related to the early tetrapods, which ultimately evolved into the land-dwelling mammals and lizards of the present day. Bone marrow Bone marrow is a semi-solid tissue which may be found within the spongy or