The instruments are classified according to their function in five groups:
1. Dieresis Instruments
The term diaeresis refers to the action of cutting or sectioning the tissues with specific instruments for each type of tissue, classified according to the instrument as follows:
Acute diaeresis which is performed with specific cutting instruments with sharp edges, and
Blunt diaeresis, which is performed between two sharp edges.
2. Cutting Instruments
Cutting instruments are characterized by having a cutting surface such as a tip or a sharp-edged blade that is indicated for careful handling.
a) Scissors: These are instruments of specific structure and design that vary according to their purpose. These can be of different types such as straight scissors useful for cutting threads, gauze, etc. Curved scissors for sectioning tissues are also classified according to their size as long, short, and medium.
b) Scalpels: They are instruments of diaeresis formed by a disposable blade with a sharp edge and a reusable handle, the blades come in sterile envelopes that when fixed with the handle it is necessary the use of a forceps, these come in different sizes and shapes such for example for the handles No. 3 and No. 7 blades from No. 11 to No. 15 are used and for the handle of Scalpel No. 4 blades from No. 20 to No. 24 are used.
c) Osteotomes: They are instruments for manual use that are indicated for cutting or sectioning bone, they are useful in dentistry.
d) Costotome: They are specific instruments to perform cutting at the section of the rib level.
e) Gouges: These are instruments for sectioning bone, made up of a bit with the appearance of a spoon with sharp edges, its articulation provides great strength in the cutting branches.
f) Saws: They are instruments to a section or cut by friction the bone tissue, this is used with tweezers and is indicated in amputations.
g) Legras: These are instruments with cutting edges that are used for the section of tissues with infection and bone, used through the scraping technique.
3. Grasping Instruments
The term grasping refers to the action of grasping or holding tissues, structures, and organs using traction. To perform this function, certain types of instruments are required for mobilization in the operative field, which are the forceps, which have different shapes and specific designs and are classified as follows:
1) Elastic Forceps: These are instruments that stand out for their use and shape. The tip can be smooth or with teeth, these forceps are formed by branches and according to the size they are classified as a straight, curved, bayonet, and angled branches of long, short and medium length.
2) Zipper forceps: These are continuous grasping instruments, they stand out for the function they perform without requiring the strength of the hand due to their mechanism of having a zipper with different levels for better manipulation of the tissues. These forceps have the following parts: branches, zippers, jaws, and rings.
4. Exposure or Separation Instruments
The term separation or exposure refers to the traction and observation of the tissues at the moment of exposing them to the surgeon's view.
The instruments that allow us to expose or separate tissues are called separators. They serve the purpose of providing the surgeon with greater ease, clarity, and safety. These instruments are divided into two groups: those that require the surgeon's manipulation, the manual or dynamic separators, and those that use the opposition to provide fixation in the tissues, the auto-static separators.
5. Synthesis Instruments
The term Synthesis refers to the union of the tissues that were separated in the diaeresis, using the suture the cicatrization is performed, this process is carried out through the use of a variety of instruments such as needles, threads, needle holders, metallic staples, etc.
a) Needles: these are instruments made up of an eye, body, and tip which allow manipulation of the thread forming different types of sutures, the tip has different shapes adapting to the type of tissue.
b) Needle holders: these are instruments that make it easier to manipulate the needles in the placement of stitches.
c) Threads: these are instruments that are compatible with the tissues, they are made of different materials of natural or synthetic origin in the form of plastic strands that are absorbable or not.
