A great source for Yoga Postures by Mark Giubarelli.

YOGA POSTURES ASANA YOGA POSES YOGA POSITIONS
Tadasana Downward Dog Cobra pose Headstand Shoulderstand Warrior 1 pose Warrior 2 pose Triangle pose Half Moon pose child pose Cat Pose

Yoganidrasana

Translation: Yogic Sleep Pose 

Lying on the back in a supine position bring the knees to the chest. Open them and cross the feet over one and other. Hold the feet in the middle or beside the toes so that you can get a little more leverage. Roll back a little and draw the feet towards the top of the head. Try to bring them over the top of the head so that the hook behind the head.

Try to take the shoulders through the legs also if this posture can be done with ease.

Breathing is hard due to the decreased volume in the lungs and restricted diaphragm movement. When the posture is held without force breathing becomes
easier.

Tips
Once sufficient flexibility in the legs and hips has been gained try bringing the shoulders through the opened legs as well.

Benefits
This is one of the few stretches that really stretches the deep muscles in the spine. These  muscles run along the vertebrae. (The bones in the spine) Some of these are the multifidus which extend and laterally bend the trunk and neck and rotate it. The erector spinae muscles that run the length of the vertebral column. Little muscles and ligaments in the neck below the skull are stretched. Some of these are the rotatores cervicis which are little muscles that attach each bone in the neck and are involved with neck rotation and spinalis capitis and semispinalis capitis and the rectus capitis major and minor. Hip flexors are
also stretched.

Vinyasa Yoga Sequencing and Flowing

Vinyasa Yoga postures to transition from and to:

Urdhva Mukha Paschimottasana,
Sarvangasana, Navasana, Setubandhasana, Eka Pada Setubandhasana, Eka Pada Salamba Sarvangasana, Halasana, Supta Konasana, Matsyasana, Baddha Konasana, Upavistha Konasana

Yoga Teacher Tips
Offer students an easy pose where the feet are taken towards the chest
without coming over the head. In time with practice help them get the head
through the legs.