Definition
"Os longum" is the Latin term for "long bone." It describes a bone whose length exceeds its width. These bones are essential for movement and support. They make up much of your appendicular skeleton (limbs). Think of the femur (thigh bone) or the humerus (upper arm bone). Unlike *ossa brevia* (short bones), *ossa longa* have a diaphysis (shaft) and epiphyses (ends). These bones contain bone marrow, vital for hematopoiesis (blood cell production).