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Dogs can get their heads stuck easily because the back of their head is wider than the front. Head entrapment is usually not a medical emergency unless your pet has trouble breathing. However your dog can become frantic and hysterical from being stuck and injure themselves further.

Symptoms:

Scrapes

Swelling

Cuts

Steps:

1. Calm your dog down to prevent him from struggling further
2. Place yourself behind the dog and push him closer to the object that he’s trapped in to avoid him backing up further and strangling himself
3. You may want to muzzle him to prevent him from biting you while you try to free him
4. Grease the fur on his neck and the top of his head with KY Jelly or Petroleum Jelly
5. While someone holds his from the back you should gently take the dogs muzzle and turn his head sideways and slide him through the fence or rails

Warnings:

Make sure that you muzzle your dog as he may try to bite you when you have to push him through the fence or rails

Tips:

It helps if someone stays behind him the entire time to prevent him from backing up while you try to free him

A dog’s head is narrower from top to bottom than side to side

(source: Gotoaid.com)