One of my teachers had mentioned that upward facing dog was like Golden Gate bridge.  You balance only with your hands and the tops of the feet. The rest of your body is suspended between this strong support of the hands and the feet. What a great visual! This image stuck with me forever, for there are not too many things more beautiful than GG bridge.

It expands the chest, strengthens the spine, helps blood circulate in the pelvic region.

Cobra has no drama or elegance. If upward facing dog can help the spine get stronger, I would like to avoid Cobra. I look up Yoga bible (Light on Yoga by BKS Iyengar) to shed more light on these two poses. I see they are listed one after the other. Lie on the floor, lift the body up from the trunk and throw the head back like a serpent about to strike. I like the description. Embody the spirit of the animal, like in Kalari.

Bhujangasan is listed as a pose that can help the spine, even an injured spine with slightly displaced discs. This pose helps replace the discs in their original position. How powerful is that! I am beginning to like Bhujangasan already. It is also a milder pose than upward facing dog, in terms of strength required to execute.

As I have tight hamstrings, I have to be very careful when I do the forward bends, as it puts tremendous pressure on these delicate joints of the spine. I do keep my knees slightly bent and am careful in forward bends. Now, I know Cobra can help me sort out the damage that I might have caused to the spine. So, I get the answer to my question. Even though the upward dog and cobra strengthen the spine, they do a few more things differently. Cobra and Dog are related, yet different in where the energy is initiated. Cobra starts at the pelvis and the lower spine. Upward dog’s energy lies in the chest, support of hands and feet.

Here’s a nice video that explains Cobra and Up dog.