Why Are Different Injections Given in Your Arm, Rear, or Elsewhere?

Medical professionals give us shots in different body parts based on how much medicine we need and what the medicine needs to do. Learn more in this episode of BrainStuff, based on this article: https://health.howstuffworks.com/medicine/medication/shots-in-arm-bum.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of iHeart Radio. Hey
brain Stuff, Lauren Vogel Bomb Here. When you walk into
a doctor's office to get a shot, as sometimes it's
a surprise. Most of the time you can count on
getting an injection in your arm, but occasionally they'll pitch
you a curveball and injected into your rear end or

(00:22):
even your belly. So why is this? It generally has
to do with the type of medicine being injected, the
volume of the dose, and how quickly or slowly the
medicine needs to be absorbed into the body. So today
let's talk about the four basic types of medical injections.
And if you don't like hearing about needles, but you've

(00:44):
made it this far, now might be a good time
to stop or skip to the next episode. Okay, okay.
The first category we're talking about is intravenous injections. These
go directly into the vein and deliver medicine really quickly.
They're normally delivered in the back of the hand or
the front of the elbow. Next up, intramuscular shots. These

(01:07):
are injected directly into a muscle where the medicine is
absorbed a little more slowly by blood vessels. The most
common locations for these are the deltoid muscle of the
shoulder that's the meaty bit above the bicep, and the
gluteous medius of the bum, which is the meaty bit
at the upper outer quadrant of each buttock. In young

(01:28):
children who may not have developed these muscles yet, the
thigh muscle might be used instead. Then we've got subcutaneous injections.
These are given into fatty tissue where there's less blood
supply and therefore the medicine is taken up by the
body more slowly. These are generally injected into the abdominal fold.
And finally, there are intradermal injections. These target the middle

(01:52):
layer of the skin and are absorbed the most slowly
of all. Common injection sites for these include the inner
surface of the forearm and the upper back under the
shoulder blade for the article of this episode is based
on how stuff Work. Spoke with Libby Richards, a faculty
associate at the Perdue University School of Nursing. She explained

(02:12):
the injection site is driven by how the medication is absorbed.
Some medications, like insulin, need to be absorbed slowly, so
fatty tissue without much blood flow works better. Medications injected
into the muscles are absorbed faster than fatty tissues, but
slower than intravenous. For example, it's coming for antibiotics and
diuretics to be administered intravenous LYE, whereas many vaccines, hormone shots,

(02:37):
and allergy medications are injected intramuscular LYE. Vaccines are often
injected into muscles because muscles contain more immune cells than
other injection sites. These immune cells will immediately recognize the
stuff that makes the vaccine work, uh the weakened or
non operational or otherwise non infectious bits of virus material
that the vaccine contains, so those cells will quickly start

(03:01):
to prepare your body to fight the real thing should
it invade. In addition to the type of medicine, doctors
and nurses need to think about how much medicine needs
to be injected and whether a specific muscle is large
enough to hold that much medication. Richard said, a muscle
tissue can generally hold more volume than fatty or subcutaneous tissue,

(03:23):
so that's another consideration when choosing an injection site. When
the volume of medication is a consideration. A larger muscles
such as the buttocks or thigh may be used instead
of the arm. Plus some medications can cause irritation to
delicate blood vessels. In this case, muscle is preferred as well.
And even with all of these considerations, you can still

(03:46):
ask your doctor if they can give you an injection
in your preferred location, Richard said, Sometimes it comes down
to patient preference and convenience. The arm is often easier
to access and preferred by patients. M Today's episode is
based on the article why are some shots given on
the arm and some in the bum? On how stuff

(04:07):
works dot com written by Jocelyn Shields. Brain Stuff is
production of by Heart Radio in partnership with how stuff
works dot Com and it's produced by Tyler Clang. Four
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