Bone marrow transplants are used to treat leukemia.
heart's core; depths of one's heart
Figurative use for the innermost feelings or essence of a person.
Those words penetrated to the core of his being.
main point; vital part
Obsolete sense for the essential or most important part of something.
In old texts, one finds the expression 'to strike at the marrow of an argument'.
They transplanted bone marrow to treat the leukemia.
He registered with the bone marrow bank and became a donor.
Many people donate bone marrow to save patients.
medullary cavity
bone marrow suppression; myelosuppression