Elbows: Definition, Characteristics and Causes of the Appearance of This Type of Cell

They are red blood cells that resemble a shooting target with a bullseye.

Under the light microscope, these cells appear to have a dark center (a central hemoglobinized area) surrounded by a white ring (a measurement of ​​relative pallor), followed by a second dark outer (peripheral) ring that contains a band of hemoglobin.

The mean corpuscular hemoglobin volume and mean corpuscular hemoglobin concentration of the elbows are always low. Elbow cells can be viewed as cells whose envelope is too large for their hemoglobin content.

Consequently, its resistance to hypotonic saline increases and lysis is resolved only when the cell membrane is stretched to the maximum.

Elbow cells could be considered the antithesis of spherocytes, which have tiny membranes for their volume and therefore increase susceptibility to lysis or increase “osmotic fragility.”

In other words, on a film of blood, these cells appear thinner than usual, mainly due to their paleness, so the thickness is judged by microscopy.

These cells are characterized by a disproportionate increase in the ratio of membrane surface area to volume. This gives cells a decrease in osmotic fragility, allowing them to take in more water for a given amount of osmotic stress.


The elbows are abnormally resistant to saline.

Other names for elbows

They are also known as:

  • Diana cells.
  • Target cells.
  • Cells Mexican hats.

Essential characteristics of the elbows and their association with a target or objective

They are associated with a target or objective since it is observed:

  • Central staining.
  • Ring of paleness.
  • The outer edge of staining.

Causes of the appearance of elbows

Causes include:

  • Obstructive liver disease.
  • Thalassemia.
  • Hemoglobin C and D disease.
  • Sickle cell disease
  • Iron deficiency anemia (small amounts can be seen).
  • After splenectomy.

Brief description of some diseases in which elbows appear

  • Liver disease: Lecithin-cholesterol acyltransferase (LCAT) activity may decrease obstructive liver disease. The decrease in enzyme activity increases the cholesterol to phospholipid ratio, producing an absolute increase in the surface area of ​​the red blood cell membranes.
  • Iron deficiency: the decrease in hemoglobin content about the surface area is probably the reason for the appearance of target cells. This is also seen in thalassemias, hemoglobin C disease, etc.
  • Alpha-thalassemia and beta-thalassemia (hemoglobinopathy).
  • Hemoglobin C and D disease.
  • Post-splenectomy: A significant function of the spleen is the removal of opsonized, deformed, and damaged erythrocytes by splenic macrophages. If splenic macrophage function is abnormal or absent due to splenectomy, the altered red blood cells will not be removed from the circulation efficiently. Therefore, a more significant number of target cells can be observed.
  • Autosplenectomy is caused by sickle cell anemia.

Uses of the term target cells according to specialists

Immunologists use the term “target cell” to refer to a cell in the body that has been infected with a virus or damaged somehow, triggering the production of abnormal proteins that do not belong in the body.

The cell presents antigens that act as alert signals for helper T cells, which can alert the immune system to a problem and destroy the target cells. The body destroys cells to prevent the spread of a virus or abnormality.

For endocrinologists, the term refers to cells with receptors for specific hormones. Many cells in the body act as target cells for particular hormones, and some are receptors for multiple hormones.

The body uses hormones to trigger various events, from dropping milk after delivery to sending signals between cells.

In some types of cancer, tests can be done to see what type of cell may be involved, such as in breast cancer, where surgeons look for compartments with estrogen receptors to determine what type of treatment would be most appropriate for the patient’s condition. Patient.

If a doctor suspects that a patient has a target cell-related condition of particular concern, tests may be ordered to determine whether or not they are present.

Blood and tissue samples can be analyzed for the presence of target cells to gather the information that could be used to diagnose and treat a patient.

It is important to remember that this article is informative. Go to specialized personnel for your medical care.