Halasana (plow pose) is one of the more common yoga inversions that move the neck into deep forward flexion. With the forward flexion of the neck, the movement of the chin towards the neck creates an energetic lock (bandha) or connection with the Vishuddha Chakra – the main energy center situated on the level of the throat and the nerve plexus of the pharynx region. This energetic connection invites balanced energy into this center leading to creative expression, constructive communication, positive self-expression, and conscious listening as well as the feeling of being centered and content.
This deep forward flexion can have its challenges, though, for many yoga participants, especially beginner yoga students. Most people have limited flexibility in the posterior tissues of the neck (especially if one has excess tension due to poor posture or work ergonomics).
One main tissue creating this limited flexibility is the Nuchal Ligament (ligamentum nuchae). The Nuchal Ligament is a fibrous membrane that starts from the external occipital protuberance (boney process on the very back of the skull) and the median nuchal line (a boney line that runs from the occipital protuberance down and inwards toward the middle of the skull). It travels from these attachment points down the back of the vertebrae to the spinous process of the 7th cervical vertebrae.
(Click here to view the occipital protuberance and medial nuchal line. Note: this image is viewing the skull from underneath.) The Nuchal Ligament limits the forward flexion of the cervical vertebrae and aids the posterior neck muscles in retaining a natural arch to the back of the neck. With this natural arch and posture, the weight of the skull can be effectively balanced over the vertebral column.