Does rhinoplasty 'let down' or 'push down' technique harm the function of your nose. looks scary when dorsal hump is pushed down

I am not familiar with the push down technique but it sounds like standard rhinoplasty technique.  At any rate reducing the jump should not affect the breathing at all

It has always seemed to me to be waaaaaaay too much surgery and risk to get what might be a small improvement. Never made sense to me.But I'm the guy who always says that if the surgeon can prove to you that he gets great results using the technique, that's what's most important.
I usually make computer morphs when I'm answering a RealSelf question, to show the changes that are possible for your nose with a rhinoplasty. For example see this page:FacialSurgery.com/RealSelf/RealSelf_Morphs.html
But of course you didn't post any of your own photos. At the *very* bottom of the "Learn more" Web reference page (link is just below) is a link to instructions on taking photos that are more comprehensive and useful for online consultations like this, in case you'd like a more complete evaluation.

Hello,That's not how a hump is flattened. The photo of someone else's nose is not helpful; you may think it's similar but in fact may not be. Closed rhinoplasty is a limited technique that is not always best for everyone. Please visit a few ABPS certified/ASAPS member surgeons (or their AAFPRS equivalents) who specialize in rhinoplasty. Best of luck!

Choose a very experienced rhinoplasty surgeon who can show you many examples of his results for noses like yours. The experienced rhinoplasty surgeon has many techniques to choose from and will select the ones that are best for you. Don't be fooled by Imaging. Bring photos of noses you like. 

The changes that you are showing the photo are very realistic and should be achievable. The bony hump is rasped or cut and the bones are brought together to prevent open roof deformity. Not sure how well the push down technique works. Best wishes.

 The dorsal hump is composed of bone and cartilage which must be shaved down in order to remove it permanently.  Osteotomies placed in the nasal be required to narrow the bridge line and close the open roof created from the removal. A septoplasty is performed in the back of the nose to improve airflow when there is a deviated septum that is significant enough that blocking airflow. Septoplasty  is performed for medical necessity, and will not have any bearing on the shape of the nose, and is only performed  for airway improvement.

A push-down technique doesn't make any sense.  Theoretically, it would impact the airway to some degree.  Bumps are taken care of by removing (and not pushing in) tissue and bone.  This is done with boney cuts called osteotomies or shaving with special rasps.   If indeed you have a subtle bump on your bridge like the photo, a simple closed shave may be all that is needed.  Best wishes.

A patient considering rhinoplasty should have detailed discussions with their surgeon about the changes that will be made and the specific goals of their operation but pick the surgeon who shows you many examples of consistent excellent results, not the technique.