Abduction vs. Adduction- Medical Terminology

A few standard terms that are easily confused come up on exams now and again. Among them are the terms abduction, adduction, and similarly absorbent and adsorbent. New EMT’s and even veterans might mix these terms up. Let’s quickly learn the terms abduction vs. adduction.

Both pairs of words share more than the first three letters. Their meanings can be tied together for easy memorization and ease of use on an EMT, AEMT, or Paramedic exam.

These terms come up early when learning about the direction and movement of bones at the joint during an anatomy and physiology course or lecture. Let’s dive in to drill these into our memory. These tools can also aid in the names of muscles involved in abduction vs. adduction movements, like adductor magnus or adductor longus, and abductor minimi digiti.

Abduction

The term abduction might make you think of aliens taking people away to probe in the bum, and that is an excellent memory tool to use. To abduct is to take away. The movement of abduction is to move away from the center of the body. Imagine your legs held close together along their inside edge. Abducting the left leg would be to rotate it away from the midline, where the right and left leg were touching and outward. Kids from the 80’s and 90’s may remember Suzanne Sommer’s Thighmaster. To use the ThighMaster, you would employ abduction for one half of the movement.

Adduction

Adduction is the opposite movement. To adduct is to take that left leg that we had previously abducted and move it toward the midline, toward which the left and right legs were previously touching. This is the opposite of the last movement and added the left leg to the right leg at the midline. In another example, if you started with your arms outstretched along the side of your body, you would add your arms to the sides of your body, moving from the outstretched position back to your sides, or toward the midline. We added the arms to the torso, so we adducted

Simple, right?

Adsorption and absorption can be memorized in a similar fashion. Absorption is the most common term of the four. It’s likely that you use a paper towel known for its absorptive properties. If you spill a liquid on your textbook cover, use the paper towel to remove the fluid from the shiny cover and transfer it to the paper towel. In essence, you abducted the liquid from the surface of your textbook and put it in your paper towel space ship so you could… throw it away. Toilet paper is also absorbent. 

Absorption vs. Adsorption

Adsorption is the opposite property. Most commonly in EMS we find the term in the drug activated charcoal. Activated charcoal is as it sounds: a very finely ground mixture of charcoal that has a tendency to be passed from the stomach to the toilet without being absorbed through your intestines in the process. Food is absorbed, charcoal is not. Charcoal’s property of passing through the gastrointestinal tract is good if we want other things in the stomach to also pass through the GI tract and not absorbed into the body, like a large, fatal dose of some medications. In this case, the charcoal will bind to the drug and help prevent digestion by coating the pill and taking it to the toilet with the charcoal. The charcoal does not absorb it, the medication rather has charcoal added to it. So we have adsorption occurring by not absorbing the medication, but adding the charcoal to the medication.

There we have it. Adduction is to add to the body, adsorption is to add charcoal to medication. Abduction is to abduct away from the body’s midline, and absorption is to take up something.