I can breath better when I extend my neck backward to its full length. What is the reason?

hello,

greetings of the day.

Your analysis of neck backwards is right. During neck extension there is opening up of the trachea which will allow more air to pass through the passage. Also during the extension of the neck the spine will regain its normal anatomical position and the line of gravity and centre of gravity will change the position of their imaginary position. due to which the stress and strain applied on the muscle will deviate and allow the spinal vertebrae weight to reduce on each vertebrae upto the sacrum and so the hip is relaxed. there is ofcourse a benefit of breathing in this position. And can be achieved while sleeping.

But while studying the head is in flexion and the same benefits cannot be attained as the trachea is compresses by the muscles of the neck. But a regular practice of the correction of posture can help with benefits. I cannot draw over here any diagram to explain you more in detail or else i would have helped you understand better. But i think i have tried my best to explain you better and the query is answered to a certain extent. thank you