Surgical neck of the humerus the skin over a small part of the lateral shoulder. Surgical neck of the humerus The surgical neck of the humerus is a constriction below the tubercles of the greater tubercle and lesser tubercle, and above the Deltoid Tuberosity. It is much more frequently fractured than the anatomical neck of the humerus. A fracture in this area is most likely to cause damage to the axillary nerve and posterior circumflex humeral artery. Damage to the axillary nerve affects function of the teres minor and deltoid muscles, resulting in loss of abduction of arm (from 15-90 degrees), weak flexion, extension, and
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