The adult human body contains 22 internal organs, 206 bones, 600 muscles and more.
It could do with less.
While even the most heartless of us require an actual heart, we all possess body parts whose function, if not existence, is now dubious. Herewith, 12 pieces of you, you no longer need or didn’t even know you had.
Fragments of this third eyelid linger next to the tear ducts of the eyes. The plica semilunaris helps ensure tear drainage and flushing of debris, but it’s not actually needed for vision or survival.
Darwin’s Point or Skin Fold on Ear
This top fold of skin on the upper ear, also known as Darwin’s tubercle, is pointless. Only 10 percent of people boast it. Scientists think it might originally have been associated with a joint that allowed the ear to swivel up and down. See auricular muscles below.
This group of muscles surrounding the fleshy outer ear (called the auricle or pinna) are used by some animals to swivel their ears in the direction of sound. Humans have them too, but they’re largely non-functional and serve no purpose, except as an amusement for folks who can still wiggle their ears.
Hair on the head still retains some functional value as insulation, vision protection (eyebrows help keep sweat and dust away) and male facial hair might play a role in sexual attraction. But body hair, well, not so much. Interestingly, we still have just as much body hair as our primate cousins. It’s just finer and lighter – and harder to see. Also see erector pili.
Erector pili are tiny muscles attached to each of our hair follicles. When they contract, they cause hair to stand on end. For hairier creatures, the result can improve insulation and warmth. For humans, it’s just a case of goose bumps.
Among amphibians, reptiles and many other mammals, the vomeronasal organ (sometimes called Jacobson’s organ) is quite useful. Part of the olfactory system, it detects chemical stimuli, such as pheromones. The human vomeronasal organ persists, but the genes that are essential to its functioning in other animals are non-functional in people.
In bygone days, like back when our ancestors chomped on coarse, rough, uncooked foods, a third set of molars was important. They added chewing power and resistance to wear and tear. Nowadays, they’re more likely to be a literally painful reminder that evolution moves on. Today, roughly one-third of people don’t even develop wisdom teeth. Talk about being wise.
Otherwise known as the tailbone, this is a vestigial bit of vertebrae from when our ancestors were high-tailing around.
The appendix is located between the small intestine and large intestine, but plays no major role in digestion. It’s been suggested that the appendix was more vital when humans primarily ate plants. Now appendixes are largely ignored until they become inflamed, burst and require surgical removal. But don’t get rid of it just yet. There is some evidence that appendixes produce and harbor beneficial probiotic bacteria useful to the digestive system.
The P Muscles
These are muscles that performed various duties in our distant past. The palmaris muscle, which extends from the elbow to the wrist, may once have been important for climbing and hanging. Now, 11 percent of modern humans lack it and surgeons sometimes harvest it for reconstructive surgery elsewhere. The plantaris muscle performed a similar function in the legs. Other primates still use it to help grasp things with their feet. The pyramidalis muscle is a tiny, triangular patch of tissue attached to the pubic bone. One in five people these days don’t even have the muscle. It could be a remnant of our distant relations to pouched marsupials.
Chimpanzees have ribs by the baker’s dozen. Most humans have just 12, though 8 percent of adults still possess an extra set to monkey around with. (I know, chimps aren’t monkeys.)
OK, we couldn’t ignore the obvious. Male lactation is not unheard of, but generally speaking, male nipples are merely decorative. They are another example of nature sticking with a basic design. Males and females begin with the same blueprint, with subsequent tweaking according to gender. Males don’t need functional nipples. They have them because females have them.