GIMME SOME SKIN, YOU BASTERD!

I'VE GOT YOU...

Skin has a number of layers to it. In most areas of the body it is thick and tough. Here's a slide of the epidermis (top layer), dermis, and hypodermis (aka superficial fascia), which contains a lot of round fat cells. Collagen fibers from the dermis run down through the hypodermis to anchore the skin onto deeper structures of muscle or bone. The epidermis is purple in this picture because these cells have been stained with a special dye.

Skin

Pinch the skin on your forearm and roll it around between your fingers. Now pinch the skin on your forehead and do the same. Now, just for laughs, roll the forearm and forehead skin of a friend of the opposite sex between you fingers. Notice anything?

You probably noticed that there is more tissue thickness between your fingers when you lift the forearm skin. Believe it or not, the skin on your forearm is thinner than on your forehead. But the forearm skin and underlying connective tissue will seem bulkier because there's more fat there. You will also likely have more play in movement with the forearm skin, as opposed to the forehead skin, which is strapped on to your skull very tightly.

When you were pinching your skin, you also probably felt the tug pulling on the muscles and bones below. This demonstrates how hard it is to remove one's skin, on a whim.

Yes, this is a picture of back skin, but I couldn't find a picture of pincer palpation to the forehead. There are many types of massage techniques that address scarring and binding of the hypodermis.

Why pinch the skin of

an opposite sex person? Because according to the experts, men have 13% thicker forehead skin

than women(1).

You can't argue with a graph. It proves that Brad Pitt and Quentin Tarantino are more thick headed than Melanie Laurent.

Whether your skin is male or female, it's pretty tough. It takes a lot of abuse without breaking or tearing, thanks to those tough collagen fibers. It's also waterproof because of a protein called keratin. Let's take a moment to consider what life would be like if skin dissolved when you took a shower... it's worse than a water allergy(2)!

Angelena's dress, Brad's shoes... cow skin (probably not forehead).

It's tough when it's dead, and tougher when it's alive.

THICK SKINNED

Why the sudden lesson about the toughness of skin? Because the other night I went on a date with my cartoonist husband to see Quentin Tarantino's brilliant film, Inglourious Basterds. What do the Basterds do with their dead Nazi victims? Scalp them, of course. What do they do with the Nazis who survive their encounter with the Basterds? Carve a swastika on their forehead.

I have never scalped anybody, but I have dissected a cadaver. For some people, cutting the skin off the body is the worst part of the dissection. For me, getting through the connective tissue and fat of the hypodermis/superficial fascia was my biggest gross-out challenge. (Mostly because of the fatty smell and texture.) Cutting though those layers and manually breaking through that tissue(3) was a lot of work.

The special effect Geniouses got the tissue thickness pretty well during the scalping scenes. They could have used a little more blood and fibrous mess to add fullness. Even if the scalpee was dead, he wasn't dry, and hydration and blood add volume. But hey... exceptional job! I was appreciative in the moment.

Langer's lines

See these lines on the scalp? They're called Langer's lines. they indicate lines of least tension in the connective tissue of the scalp. "Elliptical excisions achieve greatest width of tissue removal when made parallel to (Langer's) lines of minimum tension(4)." Those oval-shaped scalp prosthetics in the film demonstrated the most efficient cut to get the most tissue.

Eli Roth as Sgt. Donny Donowitz and Brad Pitt as Lt. Aldo Raine, contemplate their handiwork.

Spoiler alert! At the end of the film a certain someone gets a swastika carved into his forehead. Again, the effects are effective! They got the skin thickness right and the bleeding was profuse, too. Bravo! But did you notice how loose the skin was? At a certain point a flap lifts up and is caught on the blade of the knife. If that were really forehead skin, there wouldn't be a flap. It would be anchored by the connective tissue beneath.

Now... go eat one of my favorite snacks - pork rinds.

1. Sex- and site-dependent variations in the thickness and mechanical properties of human skin, by S. Diridollou, et. al. International Journal of Cosmetic Science, 22 421-435 (2000).

2. Yes, it's true! Some people have a water "allergy" and break out in hives when they're in the shower.

3. Yup! My instructor had been trained as a Rolfer and since many of us were massage therapists, he asked us to use our hands (gloved, of course!) to separate tissues as much as we could. Wild!

4. Scalp Surgery: Anatomic and Biomechanical Considerations, by Gerard E. Seery, MD. Dermatologic Surgery 27.9 (2001)

FANCY FEAST

I weary of cyborgs! They are ruining my sleep. I could go on and on about implanted mechanical devices for a long long time. Enough! (For now.) Let us speak of other things -

Like what? Like what's with the cat food? That's what!

Wikus van de Merwe evicting aliens from District 9

In District 9 the aliens love canned cat food, as does our human protagonist making the transition to alien. It seems a little gimmicky to put the cat food thing in the script, but while watching this refreshing and brilliant movie, I found myself questioning what could be in cat food that a crustacean would crave? I'm sure you wondered the same thing.

The cat food obviously wasn't making the aliens high, so it couldn't be a drug-like substance. Sure, I could have assumed it was a flavor thing, like some people have for chocolate, but then I wouldn't be able to blog about it.

Fancy Feast cat food. Yum.

It's got the taste aliens crave.

I compared ingredients in seafood Fancy Feast cat food with Wardley Shrimp Pellets, to see if there were any similar ingredients. Wardleys is recommended for feeding your pet freshwater crustacean. I figured the aliens in District 9 might be closer to crawdads than lobsters, even though they are called "prawns", since they hang out on land and don't seem to require a lot of salt(1). Plus, I couldn't easily find the ingredients for prawn food or lobster food online. There are plenty of recipes for cooking prawn/lobster, but none for cooking FOR prawn or lobster.

Wardley Shrimp Pellets

Yum.

Here are the ingredients shared by Fancy Feast and Wardley Shrimp Pellets: shrimp(2); meat meal/by-products; vitamins B-12, D-3, and A; ferrous sulfate; thiamine mononitrate; various forms of calcium; various forms of pantothenate; zinc; manganese; copper sulfate; riboflavin; pyridoxine hydrochloride; folic acid(3); and biotin.

Wardley's also include poultry meal. If I had scrutinized Fancy Feast chicken dinner, we might have had some additional crossover.

Wow! Who knew that cats and crawdads have so much in common? Wait a minute... people need a lot of that stuff too! I wonder if there's more folic acid in beer... or scotch? I will research.

1. Although I wanted to be a marine biologist when I was very young, I know nothing about crustacean essentials. But I did catch a lot of crawdads when I was a kid.

2. Aren't shrimp prawns? Ugh! It's like feeding cattle meat by-products.

3. Wait... isn't folic acid vitamin B-9 or something? Why don't they just say that?

SMORGASBORG #7: Endoskeletons part B

What do Sam Worthington, Peter Weller, and Will Smith have in common? They're all dreamy, and they all play characters in movies who have devices implanted into their bodies. In their films the only issues they seem to have with their artificial parts are emotional ones, but putting a foreign object into a human body without adverse physical effects is actually pretty hard to do.

Marcus.

Note the chiseled endoskeletal cheekbones.

Marcus (Worthington) in Terminator Salvation, is apparently the lone humanoid organism to have survived Skynet's experimentation to build a cyborg with a metallic endoskeleton. Why would this be so hard? (Other than the fact that a machine dominated society using humans as lab rats wouldn't really care that much if there were a lot of casualties.) Living tissue and many types of metals have problems getting along together.

YOU PUT WHAT, WHERE?

Metals for making cyborgs, or hip or knee replacements, have to be corrosion resistant and biocompatible. If you have an allergy to nickel, you sure don't want a nickel implant, or a nickel belt buckle, or a phone with nickel in it.

The consequences of nickel allergies.

Metals shed ions. In order for the body to tolerate the metal well, it can't leach too much into the surrounding tissue. Although your body uses some metals for metabolism (copper, iron, magnesium, etc.), too much can cause toxicity. You don't want that metal plate in your head shedding too much of anything near your brain(1).

So you can imagine that corrosion resistant types of metals, plastics, or ceramics, would be a good idea. Using incompatible metals could interfere with normal tissue growth near the implant(2). Blood acidity and ph balance can have a corrosive effect on metals. If metals shed into the bloodstream, your whole body may have a (systemic) reaction. Organs that filter blood, like the liver and kidneys may accumulate unhealthy amounts of metal ions, which is bad. And don't forget cancer! You have to be careful that whatever you're implanting isn't carcinogenic 20 years after you've implanted it.

Cobalt-chromium alloys, stainless steel, and titanium have been reported to have minimal tissue reactions in rabbits, dogs, and people. If Terminator Salvation was going to be really accurate, we should have seen some rabbit cyborgs hopping around killing humans.

Kelli Doyle's Cyborg-Bunny puppet

Although there are always many things to consider, many people enjoy their artificial joints (made of plastics and metals) or eye lenses (plastics), or boobs (silicone) and never have any problems. 300,000 women per year receiving breast implants can't be all wrong, can they(3)?

Lens implant

CYBORG FATIGUE

Once you find biocompatible materials to implant in the body, you also want them to last. Fatigue resistance is important. You don't want parts to break or bend like a lug nut on an airplane wing.

If we're talking about hip replacements, "... chrome is favoured if tensile and fatigue strength are required, titanium is favoured if load sharing with adjacent bone (uncemented prostheses) is required (titanium has a similar modulus to cortical bone)(4)." So it really depends on what you're going to do with that hip and whether you glue the prosthetic, or just jam it in there really tight.

Bo Jackson, cute enough to be a cyborg, and a super-human athlete.

The metal and the bone it's embedded in, making up the structure of an artificial joint, are able to withstand normal physical stresses. Professional athletes with joint replacements often end up with complications because they put super-human stress on their bodies. The metal may bend, the bone holding it may break, or the prosthetic starts to work its way lose. For this reason, RoboCop with his combination of exoskeleton and implanted sensory parts, Spooner and his entirely prosthetic limb, and Marcus with a full body endoskeleton are the creme de la creme of the Hollywood Cyborgs.

1. Which is why they use titanium or niobium in the skull.

2. This can lead to chronic inflammation and scarring in the area.

3. Women with breast implants do not qualify as cyborgs.

4. Page 394 from Imaging of the Hip and Bony Pelvis: techniques and applications, by Arthur Mark Davies, Karl J.Hohnson, Richard Wihehouse. Read it on Google books, otherwise it costs over $200!

SMORGASBORG #6: Endoskeletons part A

A NEW WORD

Before we get started on the cyborg thing, I'd like to introduce a new term I coined last week due to a wicked cold (or maybe it was H1N1...). What is this term? Boughing. Cough so hard you try to barf, and there you have it. It's practical and combines two signs(1) of illness into one convenient word.

RoboCop isn't smiling because he's sensitive about his teeth

Might RoboCop bough? Certainly. He has a digestive system(2), such as it is, and a respiratory system. Just because he is mostly metal exoskeleton doesn't mean he can't catch a cold.

Might the Terminator bough? No. He has no respiratory system that involves lungs, and no digestive system providing an esophagus for vomit. Come to think of it, he doesn't eat food, and therefore has no vomit. Come to think of it, we don't know that he even has a functional transversus abdominis(3), the muscle that does most of the work during forced exhalation, like coughing.

Transversus abdominis is the deepest (and most petulant)

of the muscles at the waist.

YOU KNOW THIS ALREADY

Exo- means "without" or "external" while endo- means "within" or "internal." Marcus (Terminator Salvation) and the Terminator (from the great state of California) are excellent examples of cyborgs with endoskeletons.

A variety of Terminator endoskeletons

It seems that the Borg don't necessarily have to have endoskeletons per se(4). Some of them appear mostly organic with a new eye and exoskeletal structures. The Queen, however, has an endoskeletal cranium and vertebral column mounted in a machine structure with other fleshy parts. She's hard to figure out.

The remains of the Borg Queen

The implantation of fabricated devices into the cyborg is what interests me about the whole endoskeleton thing. Even Pearl from Cyborg(5) has this type of physiological intimacy with technology. This is really where the metal hits the meat.

Pearl

WHAT TYPES OF MATERIALS CAN YOU PUT IN A LIVING PERSON?

For decades, people have been walking (and running and dancing) around with all sorts of artificial devices imbedded in their bodies. The list runs from simple screws to hold broken bones together, to artificial joints, to cochlear implants, to artificial corneas... and don't forget the occasional misplaced hemostat!

Here is the most adorable "cyborg" ever!

Why would some people say he was a cyborg? Because he has a cochlear implant.

Scissors in a patient, from an interesting blog called The Sterile Eye

As long as surgeons have been implanting devices (accidentally and on purpose) they have also been taking copious notes about the substances those devices are made of. It turns out that finding the right material to do the job is harder than you'd think.

Next time we look a different physiological reactions to implants.

1. Remember, signs are objective, observable, data like coughing or vomiting. Symptoms are subjective, like a sore throat or nausea.

2. It just occurred to me. RoboCop/Murphy has teeth but eats the equivalent of babyfood. If he doesn't chew and exercise his teeth, they will get soft and weak. Do they give him dentures in RoboCop 2?

3. The transversus abdominis, along with two other muscles at the waist, the external and internal obliques, are commonly known as bacon in our porcine friends. Hey... it's a theme! H1N1 is swine flu, and now I've mentioned bacon!)

4. If anyone proficient in Borg lore wishes to comment and educate me, please do!

5. What a bad movie that was.

SMORGASBORG #5: Exoskeletons part D

PRACTICAL APPLICATIONS FOR EXOSKELETON TECHNOLOGY

considering the devastating nature of brain and nerve injury, it is no surprise that people are very excited about research in the areas of biomechatronics, robotics, and other areas exploring ways to support and/or rehabilitate people with weakened or paralyzed bodies(1). Here are some examples of exoskeletal technology put to better purpose than superhuman strength and killing people. According to my constructed definition of a cyborg in SMORGASBORG #1, these thing wouldn't qualify one to be a cyborg because they lack an information exchange between the machinery and the body wearing it. But what the heck...

ReWalk

There's a video ad of the suit at this link, but a better version is on YouTube.

A company called Argo Medical Technologies is developing an exoskeletal system for the legs. The exoskeleton, called ReWalk, doesn't provide an exchange of information between it and the wearer. You have to cue actions individually. The suit doesn't know if you want to go up one stair, or five(2). But who cares? It's so cool! There's a control panel that you can strap to your wrist. You cue ReWalk by pushing a command button that says something like "stand up." Then you cue the suit that you're ready to stand by tipping yourself forward, and the suit stands you up. Crutches have to be used to help maintain balance. It looks a little cumbersome, but trying to get a wheel chair up even one step can be really hard.

HAL suit from Cyberdyne

(If I have to listen to one more Western newscaster say

"Domo arigato, Mr. Roboto" one more time - I'm going to SCREAM!)

Above is a link to a video about a Japanese company called Cyberdyne! Argh! Can you believe it? They have been doing research, and have now started marketing a robotic suit called HAL. Argh! Can you believe it? I assume this isn't a hoax. If it is, I suspect the technology is very nearly there for this kind of thing. These suits(3) interpret nerve impulses that are trying to stimulate muscular contraction. The suit will then move the wearer's limb the way the person is trying to move it. It can give extra-human strength to a normal person, or produce normal strength for a weakened individual. It essentially anticipates and performs the movements of the wearer. In the video, they show elderly people who have suffered strokes using a half suit, and care-givers using the full body suit to carry a patient.

The full body suit's structure will hold your joints in alignment to prevent injury from forces they can't handle. The half suit doesn't seem to offer much support around the pelvis, so it might be uncomfortable if you don't have the strength to hold yourself erect for any period of time. That would limit who could use it and how it could be used.

Exoskeletal devices such as these would help someone confined to a wheelchair feel more normal and independent. Stairs could be negotiable without a ramp. You wouldn't always have to be looking up at people as they stood over you. For many people with flaccid paralysis or paresis, these types of devices wouldn't be a cure, but would provide a form of exercise(4) and potentially improve posture, which would improve health.

Luke and Yoda

The Force Trainer

The kid is using his hand for show. The sensors go on your head.

USE THE FORCE, LUKE!

Here is a trivial step on the road to great things. A toy called The Force Trainer teaches you to control a fan with your mind. Yes... a fan... yes... your mind. The fan in turn blows a ping-pong ball into the air, in a clear plastic tube, to levitate it. I can't decide if this toy is cool, or lame. Eventually, I assume that people with spinal cord injury may be able to use a brain wave sensing device that either helps them move their body, or control a robot that can more things for them, which sounds more interesting.

NeuroBoy

BETTER THAN A PING-PONG BALL...

"What is it like to mentally float an object and then hurl it far into the distance? The Adventures of NeuroBoy fulfills this classic dream by demonstrating the experience of superpowers." You can also blow things up. You wear a headset and manipulate an animated game with your mind. I'm sure it's not nearly as disappointing as it looks online.

The new Ilimb

SPEAKING OF LUKE SKYWALKER

Look at this! A "bionic hand controlled by a patient's mind and muscles." It's expensive, but probably worth it.

Enough with exoskeletons. Next time we will look at some of the factors involved in implanting devices into living tissue. It turns out that building an army of human killing cybernetic organisms is trickier than you'd think.

1. Some new devices may be able to "retrain" someone's nervous system. Some devices will not help with recovery from injury, but will facilitate more physical independence. It all depends on what caused a person's paralysis in the first place.

2. Oh! I can see the madcap Adam Sandler comedy already!

3. HAL is a lower body model. They will have a full body model out soon.

4. "Exercise" is a relative term meaning any activity that will physically challenge a particular body.

SMORGASBORG #4: Exoskeletons part C

GI JOE: THE RISE OF COBRA

A MOMENT FOR GI JOE: THE RISE OF COBRA

Only a moment? Yes, that's it. Otherwise I'll go on and on about Stephen Sommers and how much I love The Mummy and Van Helsing. (I know three people who are going to stop visiting this blog after reading that sentence, but there it is: I love Sommers for his mind.)

And what a mind! That guy never fails to put at least two kinesthetically satisfying action sequences in his films. Watching GI Joe as a choreographer, I respond to the way the action is timed, plotted, and filmed. As a pathology teacher, and as someone who watches a doctor on TV, I can appreciate the way the Parisian chase scene would be physically impossible to survive, even with those exoskeletal suits the Joes were wearing. Does this ruin my enjoyment of the film? Absolutely not! I don't watch Stephen Sommers films for their realism.

The exoskeletal suits

Why couldn't the Joes endure an action-packed high speed romp through Paris in those suits? Well, I'm going to put this as specifically as possible while trying to stay sensitive to readers who want to enjoy this very enjoyable sequence in theaters near them. Those exoskeletal suits encase one head to toe, are reinforced everywhere, give the wearer supplemental visual interface with their environment, and enhance physical speed, power, and coordination. Plus they have guns build into the sleeves! The wearer of such a suit is one kick-ass cyborgian lobster.

But no matter how tough the suit is, the contents of the suit (meaning the person inside) are comparatively delicate. Even though a skull is pretty tough, the brain inside it is liquidy and fragile. It can slosh. When it does, the connective tissue holding your brain and its blood vessels in place can tear. That causes intracranial bleeding and injury. It's kind of like having a stroke. This type of injury is called a contrecoup injury.(1) Perfectly named if aquired during a ballistic Parisian chase scene.

Guess where that head is going

How do you slosh your brain? Get your body flying around the streets of Paris at the speed of traffic, and then stop suddenly. If you don't have access to an exoskeletal suit, get in a car and put on your seatbelt, or get on a motorcycle and put on your helmet. Kick up some speed, and drive right into a brick wall. It works practically every time(2).

Okay, I got sidetracked. Next time we'll do practical applications of the suit for paralysis.

1. Remember Terminator Salvation: Spoiler Alert #2? I also write about contrecoup there, if your curious.

2. Coup and contrecoup injuries can happen from a blow to the head, or through sudden deceleration. Either way, compressive forces act on one side of the brain, while shearing forces act on the other. Sometimes these injuries can be mild, but they can also cause coma, or death. For an excellent resource about traumatic brain injury, visit emedicine.medscape.com.

SMORGASBORG #3: Exoskeletons part B

RoboCop

MAN AND/OR MACHINE?

Biomechatronic(1) feedback and motor systems could be used for prosthetic devices that replace limbs, or for exoskeletal structures that support and enhance function of an intact body.

External devices that interface intimately with human internal anatomy are represented in RoboCop, as Murphy's (Peter Weller) shattered corpse is resuscitated, amputated, and implanted into an exoskeleton that also serves as a prosthetic(2). The bullets from the men who murder him, and the surgeries of the people who "save" him, leave Murphy very little that can be physically recognized as the man he was. Once he is implanted within his carapace, and once additional devices are implanted within what's left of his body, he becomes even less recognizable as a man. Murphy is deliberately brainwashed in this cyborging process. He is rendered less than human by the people who re-make him. This movie is an engrossing investigation of our corporeal attachment to human identity(3). It's also a kick-ass action film.

Del Spooner (Will Smith) defending himself against an evil robot.

In I, Robot, Del Spooner has lost his arm as the result of a car accident. The arm has been replaced by a prosthetic. To Spooner's mind it is a robotic prosthetic, and Spooner hates robots. Although Isaac Asimov is light years away from this film, the amputee who hates his life-like robotic prosthetic (and himself, by extension) makes for good drama, I guess.

But in this film, Spooner remains a human and a man. Although he is conflicted about his acceptance of a prosthetic arm, he is unquestioningly human to all who know and see him. He retains his personality. He works out. He is a guy with a motorcyle. Unlike RoboCop, he is sexually attractive and has his 'nads(4).

Spooner's prosthetic upper extremity includes all of his shoulder and a number of ribs. This type of device probably has a surgically implanted interface, since there would have to be a design element that allowed the prosthetic rib replacement to maintain a vacuum between the lung and chest wall. I bet the prosthetic ribs even act and react to Del's rib movement and breath rate. This would require some kind of invasive interface with the nervous system. To support my logic, we see that the inside of the fake arm is all lit up and sparkly. It just screams fancy technology capable of anything. I rest my case.

WHAT ELSE CAN YOU DO WITH THAT?

Discussion of biomechatronics and the developments in prosthetics and exoskeletons brings us to what they could (and probably should) be used for, beyond killing and superhuman strength, I mean. What is that use? To restore normal function to a body that is missing a part, or that has been weakened, paralyzed, or otherwise damaged.

A VERY SIMPLISTIC INTRODUCTION TO PARALYSIS; MAKING BROAD STATEMENTS AND LACKING IN SUBTLETY

Some bodies are intact but unable to respond voluntarily to the will of the brain. This is the result of damage to the nervous system. Damage from injury or disease can happen in a number of different ways, and cause a variety of symptoms. Insult to a nerve may cause a complete flaccid paralysis(5) or a partial paralysis(6) to the part of the body the nerve served. Injury to the spinal cord can lead to paralysis or paresis of one or more limbs.

"Wrist drop" a.k.a. radial nerve palsy.

This painter suffered lead poisoning and lost the use of the muscles that extend the wrist.

Damage to the brain can lead to spasticity, rigidity, tremors(7) etc., anywhere in the body, depending on what part of the brain is damaged. A person with any of these conditions may have partial control over the limb, or no control at all. It depends on the extent of the damage to the nervous system.

Josh Blue

A really funny comedian (with cerebral palsy).

What could damage, alter, traumatize, or injure the nervous system? Direct trauma(8), poisoning(9), or diseases(10) are the usual culprits.

Paralysis Resource Center

ENVISION A LIFE WITH PARALYSIS

Imagine, if you can, what it would be like to never stand up again. Imagine how your day would change if you could use your shoulder and elbow, but not use your hand, or what would it be like to walk with a foot that doesn't respond. Think about how your body would change if you could no longer contract muscles in your arms or legs. If a muscle stops contracting it shrinks (atrophies), just as it will grow in size if you exercise it. How would you feel about your physical appearance if your limbs were atrophied and much smaller than those of a more physically active person?(11)

This young man in New Delhi contracted polio myelitus.

Polio is caused by a virus that attacks motor nerves, leading to flaccid paralysis.

As a massage therapist, I have thought about these questions a lot. When you are touching a disabled body, and you develop a relationship with the body and the person, it forces you to think really hard. I have an intellectual understanding of the causes of many of these conditions, and the basics of various therapies one can undergo to recover from nerve and/or brain damage. I can appreciate the heroic efforts of my patients, even when they are at their pissy worst. But frankly, that knowledge doesn't help much. I know I've been lucky so far, and that my luck could change. I don't know how I would react to being struck by any disease or debilitating injury, until it happens.

As you would expect, my massage patients have all viewed their conditions differently. From observation, I have concluded that descriptive terms like "the worst thing imaginable," "pain in the ass," and "extremely frustrating," don't begin to describe the impact of losing physical function has on someone's life.

Yes, we are ending on a downer. Next time, exoskeleton technology applications for persons with paralysis.

1. See SMORGASBORG #2 for more on biomechatronics.

2. What is a prosthetic? An artificial substitute or replacement for a part of the body (eye, leg, breast, tooth) or a replacement for a joint (hip, knee). A prosthesis can be used for functional or cosmetic purposes, or both. You can go to Medterms.com for a more in depth definition.

3. Sorry for that last sentence, folks! I'm reading too much academic writing and it's causing me to "act out."

4. We assume Spooner's testicles and penis weren't harmed in the accident. With Murphy in RoboCop, the corporation orders the amputation of his viable leg. Through that act, it is implied that any other unneeded parts are also removed. He doesn't eat normal food. Digestion and excretion have been altered to fit his new being. Murphy wouldn't need a functional reproductive system, either.

5. Paralysis where there is a loss of tone, loss of reflexes, and atrophy (shrinkage) and degeneration of affected muscles.

6. Partial paralysis is called paresis. Partial flaccid paralysis may manifest as weakness in the body part.

7. Spasticity and rigidity are produced by excessive uncontrolled muscular contraction and are due to brain (as opposed to nerve or spinal cord) injury. Tremors can have a variety of causes, and like spasticity and rigidity, cannot be willed to stop.

8. Car accident, birth trauma, gunshot, stabbing, etc.

9. Lead, mercury, etc.

10. Multiple sclerosis, amyotrophic lateral sclerosis (ALS or Lou Gherig's disease), Parkinson's etc.

11. I teach lessons on massage for different deformities, and I'm used to using clinically descriptive language to describe these conditions. Terms like "valgus" or varus", etc. If I'm massaging a patient with a deformity, we're talking about their body, the state of the tissues, anatomical structures, goals for the session, etc. Or we're talking about movies, our pets, or food. I'm not current on the acceptable social language used to describe atrophy or other conditions. I'm not even sure that there are socially acceptable non-clinical adjectives out there. Any comments?