Welcome!

Hello everyone --I'll be posting yoga and anatomy information here!  I'll start with a little article I wrote about drishti:

Introduction:

The Embodyoga® system is one that can be described as yoga that emphasizes alignment from the inside-out.  We use what we call the “quiet spine principal” as one of our main emphases in teaching, whereby no shearing lines of force are taken across the spine no matter how deeply into a pose one attempts to go.  As the spine is the house of sushumna nadi, it is of supreme importance that we not allow these “breaks” in the spine to occur, as that would obviously be counter-productive in yoga practice, where we are ultimately trying to allow Prana to flow unimpeded along sushumna.

I became intrigued with the idea of drishti as more than simply a focus- or gazing-point in the practice of Ashtanga Vinyasa, while delving into some of the deeper backbends of the second, third, and fourth series.  I discovered that when practicing the deeper backbends:  specifically dwi pada viparita dandasana, raja kapotasana, chakra bandhasana, kapotasana, etc. (especially those poses where the feet touch the head) if I held the postures for longer than the prescribed 5-10 breaths, and, if I did not have my gaze down the tip of my nose, I would finish the practice with an excruciating headache. That led me to investigate the various Ashtanga texts that described the gaze point, or drishti, in the backbends, where I found that with the exception of lagu vajrasana, the gaze is described as past the tip of the nose.  (David Swenson, Lino Miele, Matthew Sweeney) I began to bring more of my attention to the drishti in my practice and emphasize it in my teaching.  I found that my headaches disappeared completely, and also found that my students had much less tendency to “break” in the cervical spine when bringing the gaze down the end of the nose at the apex of the pose.

Drishti--

Traditionally, drishti is defined as gazing point in asana practice --specifically in the Ashtanga vinyasa system as taught by Sri K. Patthabi Jois.  Though it is commonly thought of as simply a way to focus the gaze and keep the mind from wandering, it is really much more than that.  The drishti has deep implications for creating and maintaining the body-mind connections forged in asana practice.   It does serve to focus the gaze and the mind; however, there are many other levels on which it functions to create and hold what we call Yoga, or union within the body-mind. 

On the physical level, the drishti functions to help keep the body in alignment from head-to-tail, so there are no shearing lines of force taken across the spine.  It accomplishes this by setting the stage for the body to fall into its natural state of balance and alignment.  When coming into any backbend, in the ashtanga vinyasa system, the gaze point or drishti is at or past the tip of the nose.  This is especially important in the deeper backbends such as kapotasana and ustrasana, but equally important in urdva mukha svanasana, and bhujangasana as well.  Let’s look at the physical relationship of the eyes to the spine first.  The common tendon of the eye muscles that move them around in their sockets originates along the tendinous ring surrounding the optic canal, encasing the optic nerve, with some attaching on the sphenoid bone (plate 517 Clemente).  The muscles that depress the eye (looking down) are the superior oblique and inferior rectus.  The superior oblique attaches to the sphenoid bone of the skull via the occipital bone; and the inferior rectus to the tendinous ring.  Thus, as we drop the gaze, the sphenoid bone is drawn up slightly, stabilized by the inferior rectus.  The sphenoid bone is indirectly connected to the posterior surface of dens of the atlas via the alar and apical ligaments (pl 420, 549, Clemente).  Thus, as we drop the gaze, we move the dens forward and up slightly, which has enormous implications for the health and safety of the spinal cord.  If we take the head back without moving the dens forward, due to the orientation of the dens itself, we risk impinging the spinal cord.  (The dens of C2 sits anteriorly to the spinal cord, acting as the body of C1).  If we allow the dens to collapse back, which happens when students try to take their heads back without support, then there is a visible break in the cervical spine, and a subsequent impingement of the spinal cord, which I think most of us would agree is not wise practice.  By dropping the gaze down the end of the nose, we provide ourselves with some of the support needed to keep the spine in a nice, long arc, opening up the central channel, which is sushuma nadi.  There are many different ways to support the spine properly in extension, this is simply another way to affect subtle support in the backbend postures.

Other subtle supports for the spine and sushumna nadi are found in the glandular system, particularly those of the head.  The pituitary gland is situated in the cellae tursica directly above the sphenoid sinuses (pl 490, 522, Clemente).  The mammillary bodies are situated posterior and superior to the pituitary gland, adjacent to the optic nerve.  Some neuroanatomists believe them to be a part of the hypothalmus, which acts to link the endocrine system to the nervous system via the pituitary. (Innerbody.com: http://www.innerbody.com/image/endoov.html).  It can be argued that when we take the gaze down, we also slightly lift the pituitary and mammillary bodies and shift them forward and down.  (pl 495, Clemente) In fact, the pituitary sits just below the optic chiasm (Netters, pl.100), which connects directly to the corpus collosum via the anterior commisure and the lamina terminalis.  The pineal gland sits just below the base of the corpus collosum, surrounded by the great cerebral vein and below the choroid plexus (artery).  (Netters, pl 100).  Thus, as the gaze drops, the corpus collosum  moves slightly down and forward, which creates space for the pituitary, mammillary bodies, and the pineal gland, and ultimately provides more space for the flow of blood to the entire brain.  When bringing the spine into extension, and taking the gaze downward, we bring the pineal gland up and forward, which brings us more into the parasympathetic nervous system, calming the sympathetic nervous system and bringing space to the area where the glands are housed.  Simply by the nature of the backbending postures, we stimulate the sympathetic nervous system, thus it would seem logical that the nervous system would come into balance when we drop the gaze while placing the spine in extension, rolling around the axis of the mamillary bodies.  We are stabilizing the glands of the head by bringing the gaze down, taking us more into the parasymapthetic nervous system and balancing the inherent sympathetic nervous system activity of the backbending process. 

In both teaching and practice, what I have found is that though the initiation of the backbend may be one where the eyes lift, at the fullest expression of the posture, the natural drishti should be at or past the tip of the nose.  Though this has been by no means a full or scientific study of the effects of dristhi in backbends, I have found from my own experience and that of many of my students, that it is immensely calming to the nervous system to take the gaze down.  Though it really isn’t necessary to find explanations for the ancient wisdom of drishti, it is useful when working therapeutically with students to know what the effects of the more subtle aspects of the yoga practice are, and how we can help our students to come to a place of quiet and calm in their yoga practices.

Sources:

Clementes Anatomy

Netter’s Anatomy

Innerbody.com Human Anatomy Atlas

Miele, Lino; Ashtanga

Swenson, David; Ashtanga Yoga

Sweeney, Matthew;   Ashtanga Yoga As It Is