Bone Marrow Biopsy

The bone marrow aspiration and biopsy is a notoriously feared procedure from a patient standpoint.   Does it really hurt? Unfortunately it can hurt (and the pain is variable depending on the patient), but with good technique (which only comes with practice), us docs can TRY to keep the pain at a minimum. In general, patients over the age of ~70 will have less problems with this procedure than younger patients, due to the fact that their bones are softer.

So what is bone marrow?  Bone is composed of an outer hard shell (the cortex) and an inner gooey matrix (the marrow).  The bone marrow is essentially a factory for your white cells, red cells, and platelets. It contains stem cells from which all three of these cell lines are derived.  when on of us does a bone marrow on you, we need to to go through skin, fatty tissue, and the outer cortex of your bone to access the bone marrow.

This is a drawing of bone cortex (upper left) and marrow (lower right, arrow)


A low power view under the microscope of what bone marrow looks like

Why is this procedure done? For diagnostic purposes in the world of hematology, whether it is to definitively diagnose a patient’s cause of anemia, or to diagnose leukemia or lymphoma, or as a follow-up in certain diseases to observe the status of the disease. Simply put, the bone marrow examination is oftentimes a diagnostic procedure that just can’t be replaced by a less invasive procedure.

The anatomic location of the procedure is in the posterior iliac crest ( see diagram at this website: ).  In English, rather than a medical Latin, the procedure is done slightly above where your buttocks are.  Either side of the body may be used.  You are usually lying flat down on your stomach or on your side when the procedure is done.

Your skin is then prepped with an iodine scrubbing to ensure sterility, followed by at least one injection of Novocaine/Lidocaine under the skin, and one injection right on top of the bone. Unfortunately, the bone itself cannot usually be numbed up, so there is always at least a sense of pressure when the cortex of the bone is entered by the bone marrow needle.

Once the needle enters the bone marrow, the hard part from a patient’s perspective takes place. This is the aspiration, or, in English, this is when we attach a small syringe to the bone marrow needle and pull back. What we get when we pull back looks like blood to the naked eye, but is actually bone marrow stem cells that will be examined with a variety of techniques. I usually call the aspiration the 15 seconds of the most intense pain during the procedure. Women have told me that it resembles a very bad menstrual cramp, and guys have told me that it resembles a bad charlie horse.  Nevertheless, we try to get this over with pretty quickly.

After the aspiration, we will often though not always do a bone marrow biopsy, where we will get a pencil lead size in diameter (1-2 cm in length) piece of bone marrow out.  From our perspective, this requires a bit more concentration to get a good specimen.  From a patient standpoint, this is usually much less intense than the aspiration, but you will likely feel at least a strange sensation of pressure.

How much pain afterwards? The vast majority of my patients will take Tylenol for any pelvic aches which usually either do not occur or subside within ~3 days. Occasionally a patient will need narcotic pain medication after the procedure to cope (so don’t be afraid to ask!). Some patients will also want to take narcotic pain medication before the procedure to dull their senses (they must have someone drive them back and forth then, since we don’t want patients “driving under the influence”).

Is the procedure safe? The vast majority of the time, yes. Other than a varying degree of pain and minor amounts of bleeding during the procedure, most bone marrows are uneventful. Of course, poking a needle in this area stirs up patient fears of becoming paralyzed or the needle going too far through the bone, but I can’t say I’ve even heard of such complications occurring.

There are numerous videos on the procedure on YouTube, but please note that the discomfort experienced is tremendously variable, and that during the procedure, patients do not see a whole lot of what is being done since they are lying on their stomach.   One particularly decent video (if you really want to watch this) is at


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