Chaturanga Dandasana – hovering on the carpet of fallen leaves …the nose grazing the sweet earth; Flex your ankles, press through the heels, resist the buttocks from rising, or dipping too low to a sag, strengthen the core- do not collapse the chest but rather lift & FLOAT – before the series of progressive releases are introduced. 
Shoulders should not collapse below the height of the elbows – a bit close here? Observing the need for upper body strength. Honestly do we want to hurt our shoulder girdles or do we want the integrity to be honest with ourselves. Always an option to bring your knees to mat/earth to modify if you are affected by fatigue or whatever restrictions, unable to muster enough strength. Do not strain – check in with your breath.
Warm up more or try core and upper arms/upper body strengthening before attempting this …so start out with down-dog, cobra, up-dog, plank, dolphins … any of these to get ready for this yoga push up … or again, skip to knees-chest-chin/forehead – modify. Allow your intention to inform your practice.
True Ribs (1-7); False Ribs (8-10); Floating Ribs(11-12) housing our lungs – rig cage, aka = “home” study for the anatomy geeks… 
Found a studio that offers a well-rounded offering of both solar (Ha) and lunar (Tha) styles of yoga with an incredible vent system to keep the air fresh and clean; Yes, to fresh oxygenated air … yes, yes; to boot, a thermostat you can control! YES! It’s like a practice you can dial up or dial down according to your condition while the sequence of poses stays relatively the same:) That way you can better figure out where you are – when the practice keeps changing, you lose your baseline … so that’s probably one of the reasons I see the popularity and benefits of Mysore and Bikram kind of discipline as you can really keep track, monitor your progress or condition, without the distractions. It’s great to be creative with the sequence – yes – but to not be so fragmented – it’s also nice to have something steady and something you can count on and rely on as general blueprint. Something unchanging and stable to come back to. The Rock. Okay, so some may say, boring; but shift the perspective, and I’d say, it’s like coming home. Time and time again – it’s the repetition that bears fruits even though we hate to admit it – the repetitions, the drills, over and over … that’s why it’s a “practice” not a performance. It’s soooo … clear and one-pointed.
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Having said that, the practice changes to honor the lunar cycle this week … tapping into the subtle Yin energies when our practice is imbued with that luminescent light within the shadows. The day becomes shorter and the night longer as we head into the Autumn season. Please take care – perhaps a cleanse to eliminate the toxins and start afresh to prepare for the holiday season. Strengthen the immune system with getting enough REST and targeted release/relief of body parts to enhance our organ health. Namaste.