This weekend I had the privilege of attending a cadaver dissection with Thomas Meyers (author of Anatomy Trains) and Todd Garcia, founder of Laboratories of Anatomical Enlightenment. I’m writing this in my hotel room the night of the class so as to keep everything that happened fresh in my head.
We were a class of about twenty students split between four cadavers. Unlike the cadavers traditionally used in Medical Schools these were “un-treated”. This means that they retained much of their original range of motion, and potentially more without neurological inhibitors functioning.
Most of us in this class were more on the “movement” side versus the “medical” side. In general we were trainers, massage therapists, physical therapists, etc. For our purposes, being able to properly articulate the joints and see what effect is produced on attached muscles, etc. is important. This is why having cadavers with as close to normal tissue types is essential.
Muscles, in general, are much thinner than you would expect. Granted, these cadavers were in an advanced stage of life, but the pectoralis muscles, lats, biceps, etc. are very thin sheaths.
The calcaneal tendon (commonly known as the achilles tendon) while being incredibly strong is also not as dense as you might imagine. In addition it does not have the “stiffness” (for lack of a better word) that you might expect, even in a fully stretched position. It is very supple and “rubbery”. This is particularly interesting when you consider that this tendon can handle a force load 7.7 times your bodyweight when running, yet somehow we still manage to rupture it…
The tissue quality in areas of restricted movement is very poor. Our cadaver had a right shoulder that was very restricted in flexion. While working on the posterior, as we attempted to go superficial to deep, we found that removing one layer from atop another was next to impossible. It seemed that the individual muscles had literally become one piece of tissue. The left side did not have this problem and we were easily able to separate the trapezius from the deep layers. The obvious question is: If she were still alive, would this be reversible with enough time and effort? It’s hard to say. At an earlier time in her life, perhaps. In the state she was in (bear in mind this cadaver was untreated) highly unlikely.
I was looking directly over Tom Myers’ shoulder as he removed the brain from his cadaver. As someone with a neurological bias this was the highlight. The brain in an untreated state was FAR more liquid than I ever would have thought. It was much more liquid than it was solid, and I watched as Tom literally poured it out of the cranium. Once this was done I was able to see that the brain was noticeablly larger on one side than the other, and this was reflected in the dimensions of the cranium. We were also able to see the optic nerves and other interesting features of the cranium. How did I get such a great vantage point for this? Interestingly, not many people were very keen on watching this close up. 😛
I was honored to be asked to break down for the class the line of dysfunction that I had observed early on in our cadaver. I had noticed that her left ankle was in negative dorsiflexion (effectively locked in plantarflexion) while the right ankle moved more normally. The left leg was also noticeably larger than the right, which seemed to indicate she was getting away from the right leg. This was further compounded by an abdominal scar that was creating drag on the right shoulder when manually moved into flexion. We could see that when we put the right shoulder into flexion it caused the head to tilt to the left, the ribs to flare and created a line of pull directly to the abdominal scar. As we began the actual dissection we found many areas of compromised tissue quality along these lines. I removed the dermal and fascial layers superficial to the rectus on the left side and some on the right. It was as if they were from different bodies. While I observe these types of movement problems often with clients, it was invaluable to have my theories as to what is going at an anatomical level validated.
The sciatic nerve is HUGE. It is at least the size of your index finger, and has a lot of flexibility and glide to it. It is not a surprise that this often causes so many problems. It has been reported that in 25% of the population the sciatic nerve passes directly through the piriformis, which is why relaxing this muscle often improves sciatic nerve pain. This was not the case in my cadaver. Bummer.
There is a high degree of variability in anatomic structure, both at a skeletal and musculoskeletal level. I already knew this, but seeing it is different. This gives us additional insight as to why a “one size fits all” approach to addressing dysfunction is a decidedly bad idea.