WEBVTT

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Bone marrow examination
is useful in establishing

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the diagnosis of a variety
of hematological disorders

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and other systemic diseases.

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In adult patients, the body of the sternum
opposite the second interspace

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is the site of choice
for bone marrow aspiration.

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Although the ilium and vertebral
processes may be used,

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the patient should be lying
as straight as possible.

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The site is first swabbed with a suitable

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disinfectant such as Merthiolate.

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During this time,
the procedure may be explained

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and the patient appraised to the fact
that there may be some discomfort

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or pain and reassured.

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The area surrounding the site
is draped with sterile towels.

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A local anesthetic such as 1% propane

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is administered
to the site of the puncture.

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The midline of the sternum

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between the second and third
ribs is located,

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and the skin and periosteum
are infiltrated with one

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or two milliliters of the anesthetic.

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A small incision is made through the skin

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with a sharp pointed knife to facilitate

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penetration by the bone marrow
needle while the propane is taking effect,

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the external marrow needle
is assembled by inserting the stylet.

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Also, the syringe is checked
for adequate suction.

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A plain tip syringe is preferable.

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The marrow needle
is forced through the upper cortex

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only by gentle pressure.

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In some individuals,
penetration is difficult.

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In others, elderly women, for instance,
the needle penetrates easily.

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Great care must be taken
not to penetrate both courtesies

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since the great vessels lie directly
beneath the sternum at this point.

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Note that the fingers
of the left hand are held

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against the needle collar
to restrict the depth of penetration.

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When the needle is felt
to enter the marrow,

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the stylet is withdrawn
and the syringe attached.

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Two tens or three-tens milliliters

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of marrow are withdrawn
into the dry syringe.

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Smears are quickly prepared
before clotting occurs.

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Slides or coverslips may be used
in the preparation of smears.

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To produce smears of proper density,
some practice is required.

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At least 10 smears are prepared
from the sample of marrow.

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These are stained with right stain
and other special stains as indicated.

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The remaining marrow
is allowed to clot in the syringe

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and transferred
to a container of 10% formula

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or other appropriate
fixatives for histologic sections,

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H&D, and iron stains
are usually routinely performed.

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Peripheral blood smears
are prepared from a finger puncture

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for comparative evaluation
with the bone marrow material.