Who We Are > Medical Education > Anatomy and Physiology > Hand anatomy
What Makes Up Your Hand?
Firstly, it's very important to understand the many tissue types that make up the hands (which are pretty much the same as any other part of the body).
- Epithelium: This includes the many layers of dermis, the epidermis being the outermost layer. Epithelial tissue is not at all vascular, this means that there aren't any blood vessels running directly through it. Additionally, epithelium contains few to no nerves. These are all in the next layer, past the basement membrane, which binds epithelium with connective tissue.
- Connective tissue: Connective tissue, being highly vascular and nerve dense, especially in the finger tips, is the more worrisome part of self surgery. There are no large blood vessels in the pads of the fingers (most common for neodymium implants), but blood vessels become larger and larger for the most part as you head to the proximal end of most structures. A simple way to know where significant areas are that you don't want to hit would be to shine a light through your hand. This is fairly effective in most parts, but you should always be careful.
- Bone: It is very important to know where bone is before cutting towards it. There is more detail on that later on. Bottom line is, don't hit it. Bone takes a long time to heal, and depending on where you snick it and how deep, it can cause problems.
Basic Hand Anatomy
First off, this is a good site to go to for a 3D visual of all of the things here: https://human.biodigital.com/index.html
Here's a basic look at the anatomy of the hand (structures are listed proximal to distal).
- Tendons and muscles (20): These all start in the forearm, and there are twenty in total. you can get a basic idea of what forearm muscles do what by simply moving your fingers one at a time. Take a look at a few diagrams of these particular muscles and/or the link above to get an idea of where they are before you start making any cuts. There are many of them and they can be quite thin at points (especially as they start to reach the wrist).
- Carpals (8): This set of bones is located on the distal end of the hand and are numbered one to eight. There is a small muscle that moves the thumb's tip from one side of the hand across to the other. Aside from this muscle tissue, the surface of the skin is fairly close to the bone in this area.
- Metacarpals (5): Metacarpals comprise the base structure for the palm of the hand. They run from the carpals to the proximal ends of the phalanges. there is connective tissue between each of them.
- Phalanges (14): the proximal, middle, and distal phalanges comprise the phalanges or fingers. blood vessels and nerves are more dense on the sides of the fingers until they reach the finger tips. Once again, this is an important area to shine a light through to get an idea of where not to cut during surgery.
Specific Areas And Precautions
Obviously, before making any cuts, it is extremely important to understand what is right below where you are cutting. Extremely vascular and nerve dense areas to precaution yourself on before cutting would be:
- The back of the hand: This area is very thin, very close to bone, and has many large blood vessels running through it, though the most worrisome ones can be seen just by looking for them.
- Webs between fingers: Trust me, it hurts getting cut here. Use anesthetics if making any openings here.
- Finger tips: Yes, this is the most common area to cut a hole in, because of neodymium implants needing to be placed in an area of high nerve density to work best. Use anesthetics, ice, or anything possible during surgery. If you don't have anesthetics or live in a country where they are illegal, find a friend, ice everything, put a wet towel in between your teeth, and enjoy.
- Bone: Unless you are a professional (ex. anchoring a prosthetic), DO NOT cut, drill, or otherwise damage any bone anywhere. This should be obvious.
- Knuckles and other joints: Joints are extremely complicated structures, and they take a lot of stress on a daily basis. damaging a joint can easily result in more serious problems down the road. In short, you need joints to move things, don't screw them up.