Sunday, January 10, 2010

AVATAR #1: Paraplegia

Sigourney and Sam

A miracle has occurred! I get to blog about characters played by two of my favorite actors! Sigourney Weaver and Sam Worthington! Both in Avatar! Yippee! Although there are some disturbing racial themes to this film(1), there's also dramatization of the forces behind aboriginal genocides, great action, and a decent story that ends "happily" (but doesn't really.)

Jake Sully (Sam Worthington) is a paraplegic ex-marine, replacing his dead twin brother on a mission to a moon called Pandora, orbiting a planet called Polyphemus. Jake sustained a spinal cord injury in combat. Symptoms and signs of spinal cord injury will vary with the amount of damage to the cord (complete or partial) and the location of the damage.

Generally speaking, nervous function will remain above the level of the cord lesion. Function below the injury will be absent or diminished. It's hard for me(2) to tell from the movie, how much control Jake has over his hip muscles.

A variety of deep and superficial flexors of the hip, from an old copy of Gray's Anatomy, 1918.
Don't worry, muscles haven't changed that much in the last ninety-two years.

It is easy to see that Jake clearly has no control over knee or foot movement. If we use the chart below, which I lifted from the Merck Manual online, we can assume that Jake's injury is at the spinal cord, between the 11th and 12th thoracic nerves. This is an area between the lower thoracic vertebrae, where the floating ribs attach(3).

Effects of spinal cord injury on the body, from the Merck manual online.
I love the Merck as a resource.

Grouping #2 in this illustration shows the thoracic nerves.
The lowest of these are T11 and T12.

We see in the film that Jake does not have the use of his legs, which have atrophied due to lack of use. I understand that James Cameron's production crew cast prosthetic legs for Jake from a paraplegic man who was of Worthington's build. I thought they did a really great job of making Jake's atrophied legs blend with Worthington's body. I have no idea how they did that.

If you want to watch a film that will educate you about different types of disability, spinal cord injury and the variables of paralysis, I highly recommend Murderball. This documentary is about exactly the types of character Jake Sully represents: young, competitive, loaded with testosterone, and male. It humanizes victims of spinal cord trauma in a way I've never seen before. It made me cry(4). I show it to my pathology classes.

Athletes playing wheelchair rugby, a.k.a. murderball, from the movie.

Where does Sigourney Weaver come in to all this? Wait for my next post about Avatar....

1. There is a very strong message that it takes a white guy to "go native" and save an indigenous population that clearly can't save itself.
2. It doesn't look like he has control over any of the gluteals, adductors, tensor fascia latae, etc. The way he moves his body in relationship to his legs, it appears that he has psoas function, but I'm not a doctor (I just watch one on TV.)
3. See the 12/30/09 post for more on floating ribs.
4. What can I say? I cry at the movies unless they're stupid.


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