myel

Myel is a combining form used in medical terminology. It derives from the Greek myelos, meaning marrow, and is used in reference to two related but distinct anatomical regions: bone marrow and the spinal cord. In hematology and pathology, the myel form appears in terms describing bone marrow–related processes and cells, such as myeloma (a plasma cell tumor of the bone marrow), myelogenous (originating in bone marrow), myeloblast (an immature bone marrow cell), and myelopoiesis (the formation of bone marrow–derived cells). The form may appear as myelo- or myel-, depending on the word.

In neurology and anatomy, the same root is used for terms referring to the spinal cord. Here the form is often written as myelo- or myel-, as in myelopathy (disease of the spinal cord), myelitis (inflammation of the spinal cord), and myelography (imaging of the spinal cord and vertebral canal). The noun myelon is used in anatomical terminology to denote the spinal cord itself. The bone marrow and spinal cord senses are distinguished by context and surrounding terminology.

Related terms include myelin, the insulating sheath around many nerve fibers, which is etymologically connected to the same root but denotes a different structure. Other related forms include myelocyte (a later-stage bone marrow cell) and various myelo- terms describing spinal cord and bone marrow conditions. Note that myel is not a disease by itself but a linguistic element used to form numerous medical terms.