We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Bone Marrow?

By S. Mithra
Updated Mar 03, 2024
Our promise to you
The Health Board is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At The Health Board, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Bone marrow is a distinctive class of tissue that fills the cores of larger bones in humans and other animals. Unlike the hard, or compact, tissue that forms the outer shells of bones, the marrow has a malleable, sponge-like texture. It serves an active function in the body by producing all three types of blood cells, as well as lymphocytes, which support the immune system. Transplants are frequently performed in patients whose own marrow has become diseased. Additionally, marrow is a major source of stem cells, which can be harvested for certain medical treatments. Rich in nutrients, bone marrow even makes a highly desirable food source for animals as well as for humans in numerous cultures.

Bones that Contain Marrow

In humans, marrow is found in the interior of most major bones of the body. These include flat bones such as the sternum, skull, and pelvis, as well as most long bones, such as the humerus and the femur. Other smaller bones, by contrast, like those in the spine and lower jaw, contain little or no marrow. Marrow is referred to as a spongy bone. It's infused with blood vessels that supply oxygen and carry away newly created cells.

Types of Marrow

There are two categories of bone marrow: yellow and red. The yellow type mostly contains fat, and serves to provide sustenance and maintain the correct environment for the bone to function. It tends to be located in the center-most cavities of long bones, and is generally surrounded by a layer of red marrow. Red marrow is directly involved in cell production. As a body ages, the quantity of red marrow tends to shrink while the amount of yellow marrow increases, but it tends to have the strongest concentrations in flat bones such as the sternum or ilium.


Immature stem cells, along with extra iron, can be found inside bone marrow. These stem cells wait until weak, unhealthy, or damaged cells need to be replaced, and then differentiate, or become specialized. An undifferentiated stem cell can, for example, turn into a red or white blood cell or a platelet. Likewise, lymphocytes, part of the lymphatic system, are formed in this way. This is how such cells get replaced to keep the body healthy, making healthy bone marrow tissue crucial in fighting pathogens like fungi, bacteria, and viruses.

A number of diseases, often incurable, pose a threat to bone marrow. Put simply, they prevent it from turning stem cells into essential cells. Leukemia, Hodgkin's Disease, and other lymphoma cancers are known to damage the marrow's productive ability and destroy stem cells.

Bone Marrow Transplants and Stem Cell Harvesting

The leading treatment for conditions that threaten the marrow's ability to function is a bone marrow transplant. This procedure typically begins with chemotherapy to eliminate the compromised marrow. A matching donor must then be found; in most cases, this is a close family member. A needle is usually used to extract the donor's red marrow, often from one of the pelvic bones. The red marrow is then injected into the patient's bloodstream. With luck, the donation will "take," and make its way into the central shaft of larger bones to restore stem cell function.

Through a similar procedure, stem cells themselves can be harvested for certain cancer treatments, as well as for ongoing medical research into other potential medical uses. Stem cells may either be directly extracted, in the same way as they are for bone marrow transplants, or medication can be given that stimulates the marrow to release the cells into the bloodstream. In the latter case, after blood is drawn from the donor, the stem cells are then filtered out.

As a Food Source

The high concentration of fat, as well as minerals including iron, make bone marrow an eagerly sought food source. Many species of animals chew on large bones of their prey, even after the meat is gone, in order to crack them open and gain access to the treat held within. Likewise, it is considered a delicacy in a variety of human cultures around the world, ranging from parts of Europe to Asia and the Americas.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Link to Sources

Discussion Comments

By anon975048 — On Oct 23, 2014

@anon942777: People who have a bone marrow transplant and the donors for the one who is getting the BMT are not paralyzed. The donor is sore for a few days to a week, but that is it. The only reason why I know this is because I had a bone marrow transplant for ALL. This is a type of leukemia called Acute Lymphocytic Leukemia.

By anon942777 — On Mar 29, 2014

After a bone marrow transplant, is the donor paralyzed?

By anon158373 — On Mar 07, 2011

bone marrow cancer is not something any one should joke about. i take it very personally! my mother got sick with it at the age of 32 and died at the age of 37 with it. people should have a little more respect for things!

By anon68412 — On Mar 02, 2010

That's so wrong even to joke about. What if someone was dumb enough to actually try that? Does this relate to bone marrow?

By anon63894 — On Feb 04, 2010

Bone marrow is harmful more than cancer and its treatment is as expensive as transplant. the other treatment is given through injections but that is not reliable.

By anon62791 — On Jan 28, 2010

"4: Try it from a high building, Einstein - anon22431"

That's so wrong even to joke about. What if someone was dumb enough to actually try that?

By anon62251 — On Jan 25, 2010

now it is true that you can levitate or fly by magnetizing the iron in you nervous system. i've tried it.

By anon38923 — On Jul 29, 2009

Well anon1741 if you could levitate or fly by magnetizing the iron in your nervous system without destoying the nervous system itself you could, quite possibly, and with a powerful enough magnitized force, be able to fly. But those are all pretty big if's.

By anon27670 — On Mar 04, 2009

The bone marrow is the red blood cells, the fatty part, and stem cells, right? But what part of a bone marrow transplant is used from the marrow? The fat, the blood and/or only the stem cells?

By anon22431 — On Dec 03, 2008

Try it from a high building, Einstein

By anon1741 — On Jun 13, 2007

I was wondering how much iron can be stored in bones. i'm a physicist and a runner. i discovered some equations that say you can condense all the laws of physics into 8 words. If copper is high, molybdenum is low, iron. i was wondering if i had a strong enough electrical current because of my nervous system if i could magnetize all the stores of iron in my bones. if i can control the nervous current with my brain could one produce enough force to levitate or fly?

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.

The Health Board, in your inbox

Our latest articles, guides, and more, delivered daily.