Ooops!! Your PLL is showing!
In our anatomy segment this week, let’s take a closer look at my favorite ligament, the PLL (Posterior Longitudinal Ligament) and why you should take responsibility for it’s integrity before major spinal problems arise.
I see an interesting array of posture in my profession. I also hear interesting stories of people who work from home..on their Laptops, in bed, slumped and propped with pillows for 10 hours a day.
In the above image, we are looking at you from the front. The posterior longitudinal ligament is situated inside the vertebral canal, and runs along the entire posterior surfaces of the bodies(the chunky part) of the vertebræ, from the body of C2 (axis), where it is continuous with the membrana tectoria, all the way down to the sacrum. In the lumbar spine, it gets nice and thick and broadens just behind each intervertebral disc.
When you flex your spine to touch your toes, the nucleus of the intervertebral disc acts like the bubble in your Leveler tool. It moves posteriorly and hopefully bumps into a nice, healthy, broad PLL. The PLL acts as a block to the posteriorly moving nucleus of that disc and you get to get up the next day!
Let’s consider the integrity of Mr. Couch Potato’s PLL (above) or that of the dude working from bed or slumped at his desk. That PLL is no longer nice and broad and taught. It’s overstretched and slack! Maybe our poor example is the weekend warrior at the gym rushing through hamstring stretches like these:
In each of these examples, the only thing being over stretched is the PLL! Add to these above positions the unnatural effort of bearing down and holding the breath and…well…just call the EMTs because that disc is going to blow right through the slack PLL and into the spinal canal or laterally into the nerve root. Maybe you actually make it home from the gym and later just reach across the table for something. That’s usually the story I hear, “I don’t know what I did! I just reached for my Coke!” If our postural habits and lack of good Wellness Education (WE) continue long enough, eventually we tip the scale. The absolute key here is prevention and education. Once that PLL is overstretched, we have a problem and 23 discs to protect!
It is vital that you keep your spine erect and long in all forward bends. As PTs, Pilates and Yoga Teachers and Yoga Therapists, we must insist.
When you stretch the hamstrings with this in mind, you probably won’t go anywhere near as far as you are used to…and that’s wonderful!
Most of us will never enjoy this full expression of Janushirshasana in our bodies, however between sitting at your desk and the above posture is a whole range of exploration! All of the forward bends in Yoga can be fully adapted by your Yoga Therapist to meet your needs. It is not even a requirement to be able to get down on the floor! The forward bends facilitate introspection. In addition you are stretching all the musculature in the posterior leg and spine (gastrocnemius, hamstrings, gluteus maximus, erector spinae, quadratus lumborum and latisimus dorsi). Far from a passive event, you will be strengthening the quadriceps, the abdominals, lower and middle trapezius as well as the erector spinae to hold the proper alignment.
Janushirshasana with Props (blanket under hips and small bolster under knee). The Bolster creates slack in the hamstrings, allowing me to elongate the spine. The blanket tips my pelvis forward a bit taking out any slump. The strap helps me engage my middle and lower trapezius to further elongate tailbone to crown with an open chest.
Janushirshasana without props:
If it is your regular practice to push through an overly flexed spine in Janushirshasana or Paschimotanasana, try backing off a bit and use the props to help you go deeper into reflection instead of deeper into pain and resistance.
Preserve the integrity of the PLL and of your intervertebral discs. They will thank you for many years and you won’t have to walk around with your PLL showing!