The cervical and thoracic spine are fully extended in Matsyasana. The chest is lifted and and the rib cage expands to allow for deep breathing. The pectoralis and anterior deltoids are stretched as the spinal extensors and rectus abdominus engage in tandem to lift and support the spine. The psoas and quadriceps contract to flex the hips and pull the rim of the pelvis foward while the soleus muscles of the lower legs point the feet.
Enter Matsyasana by lying down on your back. Bring the legs together, engage the thighs and point the toes. Bring the palms flat beneath the soft part of the buttocks and walk the elbows tightly into your waist. Take an inhale as you lift your chest and head to look at your toes, then exhale as you drop only the head back, maintaining the lift of the chest, and lightly touch the crown of your head to the floor. Keep the elbows as close together as possible behind the back to facilitate the expansion of the chest. Enjoy the openness of the heart and throat, but be careful not to hyper-extend the cervical spine by crunching the back of the neck or resting too much weight on the head. Keep the legs engaged to support the posture as you breathe deeply into your chest.