Thumbcuffs are a metal restraining

Physical restraint

Physical restraint refers to the practice of rendering people harmless, helpless or keeping them in captivity by means such as handcuffs, fetters, straitjackets, ropes, straps, or other forms of physical restraint...

 device that lock thumb

Thumb

The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...

s in proximity to each other.

Rarely used due to an increased possibility of injury

Injury

-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...

, most commonly by tight cuffs blocking blood circulation, handcuffs

Handcuffs

Handcuffs are restraint devices designed to secure an individual's wrists close together. They comprise two parts, linked together by a chain, a hinge, or rigid bar. Each half has a rotating arm which engages with a ratchet that prevents it from being opened once closed around a person's wrist...

 are used instead.

Thumbcuffs may also be used as improvised toecuffs by locking the big toes in proximity to each other.

Thumbcuffs with double locks have a lockspring which when engaged, usually using the top of the key, stops the thumbcuff from ratcheting tighter and prevents the subject from tightening them, possibly causing injury. Double locks also make picking the locks more difficult.

See also

• Handcuffs
  Handcuffs
  Handcuffs are restraint devices designed to secure an individual's wrists close together. They comprise two parts, linked together by a chain, a hinge, or rigid bar. Each half has a rotating arm which engages with a ratchet that prevents it from being opened once closed around a person's wrist...
  
  
• Legcuffs
  Fetters
  Legcuffs, shackles, footcuffs, fetters or leg irons are a kind of physical restraint used on the feet or ankles to allow walking but prevent running and kicking. The term "fetter" shares a root with the word "foot"....
  
  
• Bondage cuffs
  Bondage cuffs
  Bondage cuffs are restraints designed for use in sexual bondage situations. Compared to conventional handcuffs, they are wide wrist and ankle restraints generally made of leather, often padded with soft leather or fake fur. Bondage cuffs may be fastened at the wrists and/or ankles by a locking...
  
  
• BDSM
  BDSM
  BDSM is an erotic preference and a form of sexual expression involving the consensual use of restraint, intense sensory stimulation, and fantasy power role-play. The compound acronym BDSM is derived from the terms bondage and discipline , dominance and submission , and sadism and masochism...
  
  
• Thumbs
• Testicle cuffs