Analysis on the ways Dazai and Fyodor injected poison (BSD Chapter 97 Spoilers)
Disclaimer: All of the medical information below is merely from the Internet so it maybe false information. I am not absolutely certain about what I found. I might edit this post when I have collected more necessary information.
Heavily inspired by this post by @tortolette. In each part, I'll provide you with some medical theory first. Then, I'll compare this panel to it so you can easily grasp what the panel is conveying.
I. 4 types & angles of administration of injection
There are 4 types of injections. To quote from Drugs.com:
"Intramuscular (IM) injections. IM injections are given deep into a muscle where the medication is then absorbed quickly by surrounding blood vessels.
Subcutaneous (SC) injections. SC injections are injected into the innermost layer of the skin called the subcutis or hypodermis, which is made up of a network of fat and collagen cells. SC injections are also known as ‘subcut’ or ‘SQ’ injections. These injections work more slowly than an IV or IM injection because the area does not have such a rich blood supply.
Intravenous (IV) injections. An IV injection is the fastest way to inject a medication and involves using a syringe to inject a medication directly into a vein. When people talk about receiving medication via IV, however, they are usually talking about an IV infusion or drip, which involves using a pump or gravity to infuse the medication into a vein, rather than a syringe. IV infusions allow a set amount of medication to be administered in a controlled manner over a period of time.
Intradermal (ID) injections. ID injections are given directly into the middle layer of the skin called the dermis. This type of injection is absorbed more slowly again than IV, IM or SC injections."
"Muscle", "Subcutaneous tissue", "Vein", "Dermis", "Epidermis"
According to PubMed.gov, "intramuscular injections administered at a comfortable angle between 72 degrees and 90 degrees."
Dazai and Fyodor were injecting the poison at 72-90 degree-angle, which might be SC or IM injections.
II. Injection sites and techniques
According to Children's Hospital of the King's Daughters, "the most common areas for SC injections are:
the upper outer area of the arm
the front and outer sides of the thighs
the abdomen, except for a 2 inch area around the navel
the upper outer area of the buttocks
because these are away from joints, nerves and large blood vessels."
According to this site, common SC injection sites and common IM injection sites are:
while common ID injection sites are:
and according to Victorian Agency for Health Information, the preferred sites for IV cannulation are:
Cubital fossa. Median antecubital, cephalic and basilic veins.
Scalp. Scalp veins should only be used once other alternatives are exhausted
In this panel, Dazai and Fyodor did not pinched their skin (as they needn't, I think).
Based on the angles of injection, I think they did IM or SC injections in ID and IV injection sites but I'm not quite sure about this because the needle hubs were quite far away from their skin when they were injecting the poison:
This is quite confusing but let’s say Dazai and Fyodor intentionally gave injections in the wrong sites. This is what may happen:
According to Tom Shimabukuro, deputy director of the Centers for Disease Control and Prevention’s immunization safety office, “if you were to receive an injection too high – in the wrong place – you could get pain, swelling and reduced range of motion in that area”. When that happens, he adds, “an acute process can become chronic.”
According to National Post, a 2010 study suggested “that in some of our cases, the injury may have been the result of improper injection technique", causing pain and limited range of motion. A third of the patients who were given injections with improper techniques needed surgery, some of them twice.
I cannot figure out why they had done this despite the risks.
I also wondered why they chose the 90-degree angle instead of the 45-degree angle if they intentionally did this and this is what I found: According to Journal of the American Academy of Dermatology, there is “no difference in pain between 45- and 90-degree angles of injection, but that the energy required to inject was lower with insertion at 90 degrees. Lower injection energy may lead to less tissue distension and thus less pain. In addition, 90-degree angle insertion may result in less direct transection of nerve endings than 45-degree angle insertion.” To cut a long story short, it gives them less pain.
They may not have chosen IV injections because "IV injection is the introduction of a medication into the veins using a needle, and it is used when rapid absorption is called for, when fluid cannot be taken by mouth, or when the medication to be administered is too irritating to be injected into the skin or muscles", according to US National Library of Medicine. However, I have no idea why they did not choose ID injections even though "this type of injection is absorbed more slowly again than IV, IM or SC injections", according to Drugs.com.
Anyways, there are three more analyses that I know, I will put the links here if you want to continue reading about this subject.
1. This one by @tortolette
2. This one by @infjsnightmare
3. This one (about the poison) by @overtainted
I apologise in advance for any inaccuracies and please feel free to correct me in the comment section. Thank you for reading my ramblings :'>