Scalpel
From Wikipedia, the free encyclopedia
A scalpel is a very sharp knife used for surgery, anatomical dissection, and various arts and crafts. Scalpels may be disposable or re-usable. Re-usable scalpels can have attached, resharpenable blades or, more commonly, non-attached, replaceable blades. Disposable scalpels usually have a plastic handle with an extensible blade (like a utility knife) and are used once, then the entire instrument discarded.
Scalpel blades are usually of hardened and tempered steel (stainless), but Titanium, Ceramic, Diamond and even Obsidian are not uncommon. For example, when performing surgery under MRI guidance, metallic blades are unusable (the steel blades would be drawn to the magnets) or may cause image artifacts. Alternatives to scalpels in surgical applications include electrocautery and lasers.
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[edit] Surgical scalpels
Surgical scalpels are usually made in two parts:
The blades are only used once, even if just for a single, small cut, then discarded. The handles can be sterllized and used again.
Most surgical procedures, performed on humans, will use either a size three or four handle and one of the following types of blade.
Blades for use with a #3 handle:
No. 10: used for cutting through skin and muscle. A 10-blade is curved along the cutting edge and straight along the back edge (see photo at right of a #10 blade on a #3 handle).
No. 11: An elongated triangular blade used for delicate cutting. A #11 blade comes to sharp point and is sharpened along the hypotenuse edge of the triangular blade.
No. 12a: A small, pointed, crescent-shaped blade sharpened on the inside edge of the curve.
No. 12b: A small, pointed, crescent-shaped blade sharpened on both sides of the curve.
No. 15: A small version of a #10 blade. The other "most common" surgical blade.
No. 15c: A 15 blade with the blade angled down toward the cutting edge. The blade is flatter and thinner than a regular 15.
Blades for use with a #4 handle:
A #4 handle is larger than a #3 handle and the blades commensurately larger as well.
No. 20, 21, 22: Large versions of a #10 blade, with a curved cutting edge and a flat, un-sharpened back edge. The 22 blade is a bit larger than the 21, and the 21 larger than the 20.
No. 23: A leaf-shaped blade, sharpened on the leading edge.
No. 24: Slightly larger than the 23 blade with a similar, but mor semi-circular blade.
No. 25: A straight-edged blade, similar to an 11 blade, but with a more sharply angled back edge making the blade almost equilateral in shape.
No. 60: Similar to a long #10 blade, the 60 has a very long straight edge, ending in a rounded tip.
No. 10a: This blade is a small disk, sharpened all the way around, except where it attaches to the handle.
There are different ways of gripping a medical scalpel:
Palmar grip: Also called the "dinner knife" grip. The blade is held with the second through fourth fingers, the handle secure along the base of the thumb, with the index finger extended along the top rear of the blade and the thumb along the side of the handle. This grip is best for initial incisions and larger cuts.
Pencil grip: Best used for more precise cuts with smaller blades (e.g. #15). The scalpel is held with the tips of the first and second fingers and the tip of the thumb with the handle resting on the "anatomical snuff box," at the fleshy base of the index finger and thumb. Care should be taken not to allow the handle to rest too far along the index finger as this promotes an unstable grip and cramped fingers.
[edit] Graphic design and arts and crafts blades
Graphical and model-making scalpels tend to have round handles, with textured grips (either knurled metal or soft plastic). These are often called by the name of the most well-known manufacturer of graphic arts blades, "X-Acto" knives. The blade is usually flat and straight, allowing it to be run easily against a straightedge to produce straight cuts.
There are many kinds of graphic arts blades, the most common around the graphic design studio is the #11 blade which is very similar to a #11 surgical blade (q.v.). Other blade shapes are used for wood carving, cutting leather and heavy fabric, etc.
[edit] Ancient Scalpels
Ancient Egyptians made incisions for embalming with scalpels of sharpened Obsidian and it is even used in moderns times. Ayurveda mentions the use of sharp bamboo splinters.
