It occured to me that today is Saturday and since my brain is not working well enough to absorb school work I figured I could pick up on the Saturday Matinee. Or just tell you about the Retroflexed Odontoid and all the problems from it and from EDS.
Retroflexed Odontoid (RO)
What is the odontoid? The spine is made of vertebrae and cartilage discs in between those vertebrae. At the top, cervical (neck) vertebrae number 2 has a portion of bone that points upward. This "bony prominance" is called the odontoid process and it sits inside the first cervical vertebrae, which is more of a ringed structure than the other vertebrae. That joint between C1 and C2 is called the atlanto-axial joint. The head sits very nicely on top of C1 and this joint is what allows the head to shake yes and no, look side to side. It's a pretty important joint in the body, and usually doesn't cause many problems except in some disorders. But, as you could imagine, a joint with the spinal cord and so close to the brain could really cause issues...
So first, a retroflexed or retroverted odontoid process is one that does not stand nice and straight, but rather presses backwards. RO can cause the cerebral spinal fluid (CSF) to be blocked, or can press into the brain stem, which is where the spinal cord connects with the brain.
The odontoid is held in place by a ligament called the transverse ligament. In Ehlers-Danlos Syndrome the ligaments and tendons tend to be lax from missing collagen in connnective tissue. You can imagine where this might cause a problem.
Basilar Invagination is when the skull has "settled" from loose ligaments farther onto the spine than it is supposed to and the result is the odontoid process pushes up into the "foramen magnum". The foramen magnum is the hole at the base of the skull where the spine travels.
By extending up into that hole the odontoid further presses on the brainstem, and causes serious blocking of the CSF.
A pannus build up is the result of the odontoid process being more mobile than it was designed to be. It rubs and wears on the surrounding tissue and creates a build up.
I guess in essence it would be like trying to balance a bowling ball on a rubber stick. There's not enough support for the weight of the head with loose joints. The ligaments holding the head to the spine are lax, which means the head settles.
Symptoms-- headache, neck pain, visual disturbances...... etc etc etc. My gosh, it's near the brain, every symptom starts out in the brain...
Keep in mind that I am NOT a doctor, this is purely for information for those who are curious, and with as much research as I have done, I still run the risk of being wrong! hahaha. =)