The sciatic nerve is one of the longest nerves in our bodies, extending from the base of the spine, down the back of the thigh, all the way to the toes, after dividing at the knee joint. Because of its length and large diameter, sciatic pain can be quite severe, and may be felt from the base of the spine, in the buttock, and/or all the way down the leg.
Sciatic pain may originate for a variety of reasons, and can last a considerable amount of time depending on how severely the nerve is damaged, pinched or otherwise affected. However, the most common underlying causes of sciatic pain is piriformis syndrome (where the piriformis muscle in the buttocks gets irritated and pushes on the sciatic nerve) or a herniated disc (a bulging or ruptured disk in the spine).
It is very important to decipher what the underlying cause of your sciatic pain is before attempting any asanas, especially if you are experiencing severe pain in your lower lumbar spine; however, from experience with piriformis syndrome (that resulted from going too deep into bakasana), I will share what I found very effective for healing quickly and regaining feeling in my legs and buttocks within a few days.
First, using a topical treatment like magnesium lotion or Traumeel can be very helpful in reducing discomfort. Alternating between heat and cold packs can also be helpful for immediate relief.
Second, it may be helpful to supplement your diet with natural anti-inflammatories like curcumin (turmeric) and omega-3 fatty acids (salmon, chia or flax seeds). (Learn more about turmeric in Why Do Yogis Love Turmeric?)
Third, the following asanas, if practiced very carefully, preferably with the supervision of a teacher that knows you well, can ease sciatic pain and discomfort.
Ardha matsyendrasana or simple half spinal twist, gently stretches the piriformis muscle encouraging it to release. To get into this pose, sit on the floor with your legs stretched straight in front of you as in dandasana (staff pose). Next, place the left foot on the outside of the right thigh, above the knee line (if possible). If you are comfortable here, you may fold the right leg into a cross-legged position, bringing it as close as possible to the left buttock. Again, if you are feeling okay there, bring the right elbow to the outer side of the left knee with the hand pointed upward, creating a twist in the body. In addition to stretching the muscles of the buttocks, ardha matsyendrasana clams the mind, and strenghtnes the nervous system, alleviating stress. It also stimulates the manipura (solar plexus) chakra, which governs self-esteem, willpower and self-discipline. Energizing this chakra aids in exercising control over one's life which may be helpful when recovering from injury.
Modified supta padangusthasana or reclining hand-to-big-toe pose can also be very helpful. For this pose, lay on your back, with your hips propped up on a thin pillow or folded blanket. Then bend one knee so your foot is resting on the floor. Next, reach for your knee, gently hugging it to your chest. If you feel okay there, you can gently pull the folded leg across your chest.
Eka pada rajakapotasana (one-legged king pigeon pose) is a deeper hip opener than the previous two and, therefore, should only be practiced by more experienced yogis or under the supervision of a teacher. To enter this asana, enter into a half split, with one leg outstretched behind you and the front leg bent so the outside of the calf rests on the floor. This provides a deep stretch to the hip and muscles surrounding the hip joint. Note, in the full expression of this pose, the back leg bends upward, then the torso bends backward to reach the foot and hold it against the back of the head. Furthermore, eka pada rajakapotasana stimulates the svadisthana (spleen or sacral) chakra, which may increase vitality.
Because these asanas are all hip openers, you may experience a deep emotional release as the hips soften and release built-up stress, negative energy and anxiety.