Bone marrow


Medulla ossium


The bone marrow fills the inside of the bone and is the main place of blood formation in humans.
Many diseases result from an imbalance in cell formation in the bone marrow. For example, leukemia and anemia (anemia), which can occur as part of many underlying diseases.

Illustration bone structure with bone marrow

Figure Structure of the long bones of an adult (A) and a child (B)

a - epiphysis
(Bone end)
b - metaphysis
(active growth zone)
c - diaphysis
(Bone shaft)

  1. Sponge-like built
    Bone with red
    Bone marrow -
    Spongiosa substantia
    Medulla ossium rubra
  2. Epiphyseal line -
    Epiphysial line
  3. Dense (compact) bone -
    Substantia compacta
  4. Medullary cavity with yellow
    Bone marrow -
    Cavitas medullaris
    + Medulla ossium flava
  5. Bony artery -
    Nutrician artery
  6. Periosteum -
  7. Osteon (basic functional unit) -
  8. Spaces filled with bone marrow
    between the trabeculae -
    Medulla ossium
  9. Growth plate -
    Lamina epiphysialis

You can find an overview of all Dr-Gumpert images at: medical illustrations


The Bone marrow lies at the core of the human bone and does about 2500 grams of body weight. It is divided into yellow and red Bone marrow.
The red bone marrow is the place of blood formation, the yellow, however, not, it is called fat marrow. In the newborn, the red bone marrow makes up the main part, but in the course of development it largely changes to yellow, so that in an adult red - blood-forming - bone marrow is only found in certain bones.
These include the bones of the trunk, as among other things Rib bones, Sternum, Vertebral bones, Pelvic bones and Collarbones, such as Skull bones and the end up (Epiphyses) the long tubular bones of the arm and leg.

Before the birth, play next to the Bone marrow Yet other organs play an important role in blood formation. The main places of blood formation between the 2nd and 7th month of the fetus are above all those liver and the spleen.

In addition to blood formation, the bone marrow has another important function. It's part of the Immune system. A population of white blood cells - the B lymphocytes - that are essential for the immune system.


Blood formation begins in the bone marrow from so-called multipotent stem cells. This means that these cells can develop into any cell.
In the case of the Blood formation there are two possibilities as there are two large cell populations here.

  1. The myeloid cell line and the lymphatic cell line. The lymphatic cell series includes the cells of the immune system, the lymphocytes, which belong to the white blood cells.
  2. Of the myeloid series include the red blood cells (Erythrocytes), and the Platelets (Platelets) on. The red blood cells are used to transport oxygen in the body, the blood platelets are an important part of blood clotting. These finished blood cells develop in the Bone marrow through many progenitor cells and are ultimately - when they are mature enough - released into the blood.

Diseases of the bone marrow

An important disease of the bone marrow is the leukemia.
There are different forms of leukemia depending on whether it develops quickly or slowly and which cell lines are affected. However, they often have one thing in common:

  • In the bone marrow become en masse white blood cells (Lymphocytes) produced. This suppresses the production of the other cells. So there is a lack of Erythrocytes and platelets. This leads to Anemia (anemia) and blood clotting disorders. It is true that a large number of lymphocytes are produced, but these are "mutants" and therefore not able to carry out their normal tasks - namely the immune system.
    Therefore, leukemias usually also lead to a pronounced susceptibility to infections.

So a patient with leukemia can stand out paleness (anemia), increased bruises and bleeding from the skin that occur even with minor trauma (lack of platelets) and frequent infections (lack of functional lymphocytes).

Another disease of the bone marrow is the Osteomyelitis, an inflammation that usually occurs through bacteria is conditional.

The bone marrow in diagnostics

A so-called Bone marrow puncture, i.e. taking a sample from the bone marrow, can be an important step in the diagnosis of various diseases.
Among other things, if some types of leukemia are suspected and in some cases Hodgkin's disease and Non-Hodkin lymphoma and other diseases of the hematopoietic system (multiple myeloma, myelodysplastic syndrome).

Even when looking for Metastases (that is, the colonization of tumor cells) among others at Breast cancer (Breast cancer) and Lung cancer (Bronchial carcinoma) a bone marrow aspiration may be necessary.
Even if one of the rows of cells in the blood is increased or decreased (as is often the case with leukemia), this can be an indication for a bone marrow puncture.
The puncture is usually carried out on the iliac crest after prior anesthesia. A distinction is made between the type of bone marrow removal aspiration and a biopsy.

  • In the aspiration aspirates a small sample, this method is used when a single cell examination is sufficient.
  • A biopsy, i.e. punching out a small section of tissue, is done when the bone marrow has to be viewed as a whole.

The bone marrow in therapy

It can be therapeutically very valuable to transplant certain blood cells, i.e. to supply them to a person.
These blood cells are stem cells that have the ability to develop into a wide variety of blood cells. One can do that transplantation with cells from the peripheral blood, similar to a blood donation (peripheral stem cell transplant) or using cells from the bone marrow.

The former sits opposite the Bone marrow donation always on through. A distinction is also made as to whether a patient's own cells are removed and re-administered (autologous stem cell transplant) or whether cells are taken from a compatible donor and then given to the recipient (allogeneic stem cell transplant).
In such a procedure, the ability to fit is essential (compatibility) of donors and recipients in relation to certain tissue characteristics, the so-called HLA molecules.

Only with the most accurate fit is there a good chance that the recipient's body will not reject the donor's cells.
The greatest likelihood of compatibility is with siblings, and nowadays there are also extensive databases in which the HLA characteristics numerous voluntary donors are stored.

A Stem cell transplant can be used therapeutically for some Forms of leukemia, Hodgkin-Lymphoma and Non-Hodgkin-Lymphoma, Immunodeficiency, hematological Diseases like Thalassemia and others.