English Idioms and Idiomatic Expressions 

Body Idioms: Arms and Elbow
from: 'arms of the law'   to:  'elbow room'

ARMS

• arm of the law
  • The expression 'arm of the law' refers to the extent to which the authority or power of the law extends.
    "He fled to South America hoping to escape the arm of the law."
    
    
• chance one's arm
  • If you chance your arm, you try to do something even though there is little hope of success.
    "Tony knew there was little hope of getting into Harvard but he decided to chance his arm anyway."
    
    
• cost an arm and a leg
  • If something costs an arm and a leg, it is very expensive.
    "The new house cost us an arm and a leg, but we have no regrets."
    
    
• give your right arm
  • If you say "I'd give my right arm for that", you mean that you want it a lot and would do almost anything to obtain it.
    "I'd give my right arm to have an apartment on Central Park."
    
    
• up in arms
  • If you are up in arms about something, you are very angry.
    "The population was up in arms over the demolition of the old theatre."
    
    
• (keep) at arm's length
  • If you keep someone at arm's length, you do not allow yourself to become too friendly with them.
    "It's not easy to become friends with Sophie; she tends to keep everyone at arm's length."
    

ELBOW:

• more power to your elbow
  • The expression 'more power to your elbow'  is used to express praise or encouragement to someone for doing something.
    "I've left my job and I'm going to work free-lance from now on."  "Well, more power to your elbow!"
    
    
• (use) use elbow grease
  • If you use elbow grease, you need energy and strength to do physical work such as cleaning or polishing.
    "It took a considerable amount of elbow grease to renovate the house."
    
    
• elbow room
  • If you need some elbow room, you need more space to move.
    "We shared a small office where neither of us had enough elbow room."