Forceps are a handheld, hinged instrument used for grasping and holding objects. Forceps are used when fingers are too large to grasp small objects or when many objects need to be held at one time while the hands are used to perform a task. The term forceps is used almost exclusively within the medical field. Outside medicine, people usually refer to forceps as tweezers, tongs, pliers, clips or clamps.
The singular and plural form of forceps is always forceps, never 'forcep.' Nor is it referred to as a "pair of" as one refers to a pair of scissors. Grammatically, the word derives from the Latin 'Forca,' meaning a snare or trap.
Mechanically, forceps employ the principle of the lever to grasp and apply pressure.
Surgical forceps are commonly made of high-grade carbon steel. Lower quality steel is used in forceps made for other uses. High carbon steel ensure that the instruments can withstand repeated sterilization in high-temperature autoclaves. Some forceps, intended to be used once and then discarded, are made of plastic.
There are two basic types of forceps: non-locking (often called 'thumb forceps' or 'Pick-ups') and locking, though these two types come in dozens of specialized forms for various uses. Non-locking forceps also come in two basic forms, hinged at one end, away from the grasping end (colloquially such forceps are called tweezers, though a medical professional would not likely refer to them a such) and hinged in the middle, rather like scissors (though, unlike scissors, forceps meet on flat, grasping surfaces rather than in interposing blades). Locking forceps are almost always hinged in the middle, though some forms place the hinge very close to the grasping end. Locking forceps use various means to lock the grasping surfaces in a closed position to facilitate manipulation or to independently clamp, grasp or hold an object.
Thumb forceps are commonly held between the thumb and two or three fingers of one hand, with the top end resting on the anatomical snuff box at the base of the thumb and index finger. Spring tension at one end holds the grasping ends apart until pressure is applied. This allows one to quickly and easily grasp small objects or tissue to move and release it or to grasp and hold tissue with easily variable pressure. Thumb forceps are used to hold tissue in place when applying sutures, to gently move tissues out of the way during exploratory surgery and to move dressings or draping without using the hands or fingers.
Thumb forceps can have smooth tips, cross-hatched tips or serrated tips (often called 'mouse's teeth'). Common arrangements of teeth are 1x2 (two teeth on one side meshing with a single tooth on the other), 7x7 and 9x9. Serrated forceps are used on tissue; counter-intuitively, teeth will damage tissue less than a smooth surface (you can grasp with less overall pressure). Smooth or cross-hatched forceps are used to move dressings, remove sutures and similar tasks.
Adson tissue forceps
Note the 1x2 "mouse's teeth" on the lower tip.
Locking forceps, sometimes called clamps, are used to grasp and hold objects or tissue. When they are used to compress an artery to forestall bleeding they are called hemostats. Another form of locking forceps is the needle holder, used to guide a suturing needle through tissue. Many locking forceps use finger loops to facilitate handling (see illustration, below, of Kelly Forceps). The finger loops are usually grasped by the thumb and middle or ring fingers, while the index finger helps guide the instrument.
The most common locking mechanism is a series of interlocking teeth located near the finger loops. As the forceps are closed, the teeth engage and keep the instrument's grasping surfaces from separating. A simple shift of the fingers is all that is needed to dis-engage the teeth and allow the grasping ends to move apart. Forceps are also used for surgery.
Shown closed and open. Note the toothed locking mechanism near the finger loops.