Muscle You didn’t know you have

Muscles, some are big, some are small, and some are fake, including both skeletal and smooth muscle. They make up about 82 percent of your body weight. Skeletal muscle, the muscle that you actually see on the human body, allows us to move by exacting forces on our bones. Smooth muscle, the ones you don’t see, act as pumps and tubing within our body. The human body has over 800 different muscles, and I’m willing to bet you can only name about five or six.
Let me guess: biceps, pecs, traps, abs, quads, and maybe calves. Congratulations, you know nothing about the human muscular system, but you’re not alone; most people don’t know much about their own muscles except that they can make them swole. For example, most people think that this is a tendon, and some may even think it’s a bone. It’s neither; it’s a muscle called the sternocleidomastoid.
It’s attached at the sternum, the clavicle, and the mastoid process, hence the name sternocleidomastoid. The sternocleidomastoid allows you to rotate your head and flex your neck; otherwise, your roughly 10-pound head would not stay up straight at all. What about this muscle on your forearm? This is the extensor digitorum communis; its function is to extend your fingers, case in point. But in case you notice, the muscle is way over here, and the fingers are extending over here. There is muscle in the forearm for sure, but the wrists and palm are pretty flat and have nowhere near as much muscle.

That’s because right here in the back of your hand are long stringy tendons called the extensor digitorum tendons. When the extensor digitorum communis muscle contracts, it pulls the tendons back and extends the fingers. If you ever got into an accident where the tendons in the back of your hand are damaged or even severed, your fingers will not be able to move at all. How about your lungs? Nearly everyone assumes that when you breathe, it’s because your lungs are sucking in air Your lungs are not a muscle; they do nothing; they’re just elastic sacs that inflate when air fills them.
The way you breathe is not through your lungs but rather your diaphragm. The diaphragm is a muscle that sits at the bottom of your chest cavity and allows you to breathe by changing the pressure inside your lungs. When you exhale, the diaphragm moves upward, putting pressure on your lungs and forcing air out, similar to squeezing a balloon; air cannot go into the balloon because air is being forced out. In contrast, when you breathe in, your diaphragm moves downward, allowing the lungs to expand, thereby reducing pressure.
Now the air pressure is higher outside your body, and air can flow into your lungs where the pressure is now lower. That sensation you think you feel of inhaling air is not real; you think it’s real, but it’s just a pressure differential acting on your body. Okay, here’s an easy one: what’s the longest muscle in the body? Hint: it’s below the waist, and I just walked into that one, but it’s not that muscle. Okay, guys, the longest muscle in the body is the sartorius muscle, a relatively obscure muscle. It measures nearly 20 inches in length, almost 2 feet long, or 3 and 1/3 hot dogs. It connects at the interior iliac spine, wraps around your quads, and ends at the upper tibia below your knee. Oh, but what does it do? Just flexes your hips and knees; that’s pretty much it, but it is the longest muscle in the body.
Finally, do you know how urination works? Well, I hate to tell you, but the bladder is not a muscle; it’s just an elastic reservoir that holds liquid waste. Instead, urine is expelled by way of the detrusor muscle, a smooth muscle that surrounds the bladder. Upon activation of the pelvic nerve, the detrusor muscle contracts around the bladder, pushing urine into the urethra and out of the body.
While we’re on the subject of anatomy, did you know that there’s a bone literally floating in your throat? Yeah, it’s called the hyoid bone, and there’s no other bone connected to it; it’s just sitting there. Form your fingers like you’re holding a small matchbox and place them where your jaw meets your throat, right above your trachea. Once you find it, you can actually wiggle it back and forth; yeah, it’s pretty gross. Sorry if I ruined your day, but uh, hey.