Practical Hematology
Dec 16, 2015
Bone Marrow (BM)
•BM is the soft, flexible, spongy tissue inside bones that helps form
blood cells.
Types of Bone Marrow
1. Red BM: Which consists mainly of hematopoietic tissues.
2. Yellow BM: Which consists mainly of fat tissues.
•At birth, all bone marrow is red. With age, more of it is
converted to the yellow type.
•Only around half of adult bone marrow is red.
•Red marrow is found mainly in the flat bones
(pelvis, sternum, ribs, scapulae) and in
the cancellous (spongy) material at the epiphyseal ends
of long bones (femur and humerus).
•Yellow marrow is found in the medullary cavity, the hollow
interior of the middle portion of long bones.
•In cases of severe blood loss, the body can convert yellow
marrow back to red marrow to increase blood cell
production.
•BM Composition (Anatomy)
1. Stroma (Network of connective tissues).
3. Sinusoidal capillaries.
4. Stem cells.
5. Adipose tissues.
•BM Cellular Components
1. Mesenchymal stem cell (Multipotent): which differentiate into
osteoblasts, chondrocytes, myocytes, adipocytes and beta-
pancreatic islets cells.
2. Hematopoietic stem cell (Pluripotent): which differentiate into
RBC, WBC and platelets.
BM Aspiration
•It is the removal of a small amount of BM in semi-liquid form for
examination.
•BM biopsy removes a small amount of bone and a small amount of
fluid and cells from inside the bone.
Procedure
1. Make the animal to be relax (using calmative).
2. Clean and sterilize the skin (shave if necessary).
3. A special needle with a tube attached to it that creates suction
should be used.
4. An aspirate needle is inserted through the skin using manual
pressure and force until the bone.
5. Once the needle is in the marrow cavity, a syringe is attached and
used to aspirate semi-liquid bone marrow.
6. Remove the needle, press the area and then a bandage should
apply to the skin.
7. The sample should be directly processed.
8. If several samples are taken, the needle should be changed
between the samples to avoid contamination.
9. simple analgesics can be used to ease soreness, which is
common for 2–3 days after the procedure.
10. Any worsening pain, redness, fever, bleeding or
swelling may suggest a complication and contamination.
11. Avoid washing or wetting of the procedure site for at
least 24 hours after the procedure is highly advised.
Sites for BM Aspiration
a. Human
1. Posterior iliac crest.
2. Sternum (breastbone).
3. Tibial plateu.
Cautions Should be Considered During BM Aspiration
1. Allergic to any medications.
2. Pregnancy cases.
3. Bleeding problems.
4. Medications you are taking.
When the Test is Needed?
1. Look for the cause of problems with RBC, WBC, or platelets in
those who have conditions such as thrombocytopenia, anaemia,
or an abnormal WBC count.
2. Find blood disorders, such as leukemia, and multiple myeloma.
3. To find out if the cancer has spread and how much it has spread
to the bone marrow such as Hodgkin's lymphoma or non-
Hodgkin's lymphoma.
4. Disseminated bacterial or fungal infection.
5. Genetic or chromosome problem.
6. Suspicion of BM Toxicity.
7. Clinical trial of some drug and natural products.
8. Collect a sample of bone marrow for medical procedures, such as
stem cell transplantation or chromosomal analysis.
9. To get more information about hematopoiesis.
The Risks of BM Aspiration
1. Allergic reaction to anaesthesia.
2. There may be excessive bleeding at the puncture site.
3. Contamination and infection, which are very rare.
4. Long lasting discomfort.
•These risks are most oftenly associated with conditions that cause a
weakened immune system or low platelet count.