Triceps brachii comes from the Latin for “three-headed muscle of the arm”.
It is the large muscle on the back of your arms and is responsible for extension of the elbow. It is also the antagonist to the biceps brachii and brachialis muscles. The triceps help to fixate the elbow when the hand is involved in fine or intricate movements such as writing. It originates from the scapula, so therefore also becomes a stabilising muscle for the shoulder joint and aids adduction of the arm. The muscle is also capable of contracting statically.
The triceps muscles can be trained either through isolation or compound extension movements. Examples of isolation movements would include cable push downs and extensions where the arms go behind the back.
Examples of compound movements include close grip bench press and military press. A close grip on the bar really targets the triceps more than a wider grip.
You should always train your triceps through their full range of movement as they cross two joints (shoulder and elbow).
It is very rare to rupture or tear your triceps muscles.