Humerus true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons. The word "humerus" is derived from meaning upper arm, shoulder, and is linguistically related to Gothic "ams" shoulder and Greek "ōmos". At the shoulder, the head of the humerus articulates with the glenoid fossa of the scapula. More distally, at the elbow, the capitulum of the humerus articulates with the head of the radius, and the trochlea of the humerus articulates with the trochlear notch of
Bone marrow Bone marrow Bone marrow is a semi-solid tissue which may be found within the spongy or cancellous portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production or hematopoiesis. It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adult humans, bone marrow is primarily located in the ribs, vertebrae, sternum, and bones of the pelvis. On average, bone marrow constitutes 4% of the total body mass of humans; in an adult having 65 kilograms of mass (143 lb), bone marrow typically accounts for approximately . Human marrow