Dissection and instruments

Dissection and instruments

1. Dissection & Instruments By Dr.T.C.Singel (prof. & HOD) M.P.Shah (Govt.) Medical College, Jamnagar (Gujarat) Mob: [phone] E-Mail:- [email protected]

2. I express my gratitude to my respected teachers. Dr. D. N. Chhatrapati sir Dr. B. R. Kulkarni sir Dr. Dangarwala madam Dr. G. N. Mankad sir Dr. Buch sir Dr. P. M. Raval sir it is their guidance that made me what I am today.

3. Dissection Definition – The term “dissection” is a Latin equivalent of the Greek term anatome, meaning to cut up. Dissection means to cut a part and see. Dissection means to separate and clean the structures

4. Cadaver care and safety measures in dissection lab. One must give respect to cadaver/dead body. Cadaver - means preserved dead body. Maintain the dignity of cadaver and dead body. Cover the cadaver to prevent drying effect because once the part is dried it can’t be restored.

5. SAFTY MEASURES Apron- To protect the clothing. Shoes/boot – Use shoes/boot because it gives safety to foot from dropped scalpels or sharp instruments. Gloves – Use gloves to avoid the contact from preservatives and other chemicals but the naked hand is best for palpation and feeling the structures. So, one should avoid gloves as far as possible. Specs or goggles - While cutting bones use specs or goggles to protect the eyes against any foreign body during cutting.

6. Seating arrangement- The seating arrangements has to be such that, everyone can participate safely and can observe what is happening on the dissection table, comfortably and safely. The dissection lab must be well ventilated, to prevent suffocation due to formalin.

7. TYPES OF DISSECTION and instruments used For different purposes various dissections are carried out and for the various dissections, set of instruments used differ. Here I have narrated the instruments according to various types of dissection. Comprehensive study dissection Composite study dissection Composite window corridor dissection Unistructural dissection Comprehensive window dissection Dissection for embalming

8. Comprehensive study dissection This is carried out for the routine dissection of part of body or limb. In this study dissection is carried out on a region as a whole. Students’ dissection instruments box is used. Dissection instruments box contains: 1) plain forceps 2) toothed forceps 3) pointed forceps 4) scissors- small, big, straight, curved, angular 5) knife handle with blade 6) one piece scalpel 7) painting brush

9. 2. Composite study dissection It is carried out for demonstration and display purpose. In this study dissection is carried out in a particular region or a part of body where some parts may be removed totally or partly. The instruments used are: dissection instruments box + chisel, hammer, bone cutter, bone cutting saw, retractors

10. 3. Composite window corridor dissection It is carried out for making museum specimens. It appreciates the depth and relations of the deeper structures. The instruments used are: dissection instruments box + chisel, hammer, bone cutter, bone cutting saw, retractors , and very long needles

11. 4. Uni -structural dissection It is carried out for making museum specimens and for study and demonstration of normal variations and abnormalities in a given structure. Retaining some important relations of a given structure all other structures are removed. The instruments used are: dissection instruments box + chisel, hammer, bone cutter, bone cutting saw, retractors , and bone nibbler

12. 5. Comprehensive window dissection Commonly called as window dissection. It is carried out for post graduate dissections. Window dissection is carried out to demonstrate a given structure in a given region with its relations. In this dissection all the structures including skin are preserved and as and when necessary they are incised and regulated like a window in such a way that all structures can be preserved back in-situ. The instruments used are: dissection instruments box + chisel, hammer, bone cutter, bone cutting saw, retractors , pins (to fix up the skin flaps and maintain the relations of the structures in situ)

13. 6. Dissection for embalming It is carried out for to embalm the dead body. The common site of dissection for embalming purpose is cervical region and/or femoral region. The instruments used are: Along with dissection instruments box we need Gloves , Cap Mask, goggles & guan , Saving kit, Embalming apparatus with Murphy’s chamber & controlling device and vessels cannula / vessels catheter , Knife handle with blade , Artery forceps-Small, Big, Mosquito, Forceps- Plain , Toothed, Hook retractor with eye , Retractors, Thread , Needle holder, Needle- Straight – cutting, Curved – cutting , Gauge piece

14. Dissection techniques and instruments used The dissection can be carried out as follow: Blunt dissection Sharp dissection Dissection for cleaning structures To clean muscles To clean nerves To clean vessels Underwater dissection technique

15. 1. Blunt dissection- Blunt dissection means pulling/tearing instead of cutting. This can be done by fingers, probe and scissors. Fingers are the first and best dissecting instruments. The next instrument is probe and next scissors with its back edge. Vessels and nerves can be separated by scissors. Scissors techniques – A closed pair of scissor is inserted into connective tissue or in between two structures and then it is opened. During this process it tears the connective tissues in between two structures and it cleans the two structures.

16. 2. Sharp dissection It is done by scalpel and scissors. To cut the skin and reflect the flap, the scalpel is used. Otherwise, scalpels are not used because it may cut the wanted and important structures.

17. 3. Dissection for cleaning the structures To clean the muscles The surface of muscle is covered by fat and connective tissues. It can be cleaned with scissors. Scalpel can be used carefully. The border of the muscles is cleaned by fingers or prob. To clean the nerves The nerves are cleared by removing connective tissue around the nerves with the help of probe and/or scissors. Don't use scalpel to clean the nerve because it may cut the branches of nerves. To clean the vessels Vessels are covered by fat and connective tissues. The connective tissue is tear or stripped or removed with probe, scissor and forceps. Don't use scalpel to clean the vessels because it may cut the branches of vessels.

18. 4. Underwater dissection techniques Maze of fat and connective tissues can be dissected out and removed by underwater dissection techniques. In this method, the dissection part/specimen is submerged in water and it is trimmed out in the same condition. (That is in the water.) This technique is used to prepare the museum’s specimens and to prepare specimen for plastination.

19. 1. Skin marking pencils – Uses- It is used for surface marking of structures and to mark the bony and other landmarks on cadavers. It is also used for marking skin incisions. Instruments required for Dissection

20. 2. Fingers – First dissecting tool is and must be finger. Always dissect first with finger then probe and then scissors for blunt dissection. Instruments required for Dissection

21. All metal instruments must be of stainless steel metals. 3. Dissecting probe It is primary dissecting instrument. Uses – It is used for tearing connective tissues. It can also be used for feeling the structures like vessels and nerves. Description – It has handle and other end is angular with a rounded end (tip).

22. Use – It is use to cut and reflect the skin . It is used to cut the tissue and dissection of tough connective tissue. It is used to divide the vessels, pedicels and other structures. It is used for the sharp dissection. Disadvantages – It may cut or injure the important structure during dissection. Scalpel

23. Scalpel Descriptions Two parts – Handle Blade Types – Scalpel with fixed handle and blade. Handle and blade are separated. (Normally separated handle and blade are used.)

24. Advantage of scalpel with fixed handle and blade- It is handled in one piece and it is strong. It is reusable.   Disadvantage of scalpel with fixed handle and blade- Sharpness of blade required frequent sharpening. Advantage of scalpel with disposable blade- Various size, shape and curvatures of blade are available and used according to the need. Disadvantage of scalpel with disposable blade- The blades are use and throw. Once sharpness is gone we have to use a new blade. Handle has a slot for the fixing of the blade. So, slot of the handle and surgical blade must be matching one otherwise it is not used.

25. The shaft of dissecting forceps is closed by thumb and fingers so it is known as thumb forceps. Uses It is used for blunt dissection (i.e. for pulling or tearing instead of cutting). It is used to grasp, lift and hold the tissues. Plain forceps is used to hold the delicate structures like peritoneum, vessels, nerves and muscles. Tooth forceps is used for better grip. Tooth forceps is used to insert the blade over handle and to remove blade from handle. DISSECTING FORCEPS / THUMB FORCEPS :

26. Descriptions – It has two shafts and no joints. So, two shafts (blade) are joined at the top end and they have a spring action. Objects are hold by tip when the shafts (blade) are pressed by thumb and fingers. It provide firm grip on tissue and the firmness depends upon the pressure on the shaft. The two consecutive movements can be done faster by the dissecting forceps. (artery forceps also give firm grip but the two consecutive movements are slow) DISSECTING FORCEPS / THUMB FORCEPS :

27. Types Plain forceps. Tooth forceps / tissue forceps. (Tooth forceps is used for gripping the tissue is also known as tissue forceps.) Descriptions It has two parts one blade and other tip. Blade is long. On outer surface, there are serration for better grip for handling. Plain forceps is having ridges and grooves and tooth forceps is having tooth and socket which prevent the slippage of the tissue. DISSECTING FORCEPS / THUMB FORCEPS :

28. Use It is used in cutting and sectioning of tissue. It is used to cut tough structures like tendons, ligaments etc. For blunt dissection, straight scissors is used. For delicate work, curved scissors is used. SCISSORS

29. Description – It is having blade and body (handle) joined by pivot joint. (Axis is formed by the screw) . Blade It has two edges – Cutting edge Non cutting edge SCISSORS

30. Blade may be plain, curved or having angle between shaft and blade. According to that scissors are known as Plain scissors Curved scissors Angular scissors The Curved scissor used for the trimming purpose. The angular scissor is used for the deeper structures. The tip of the blade may be pointed or blunt. Pointed scissors may be used for the blunt dissection. SCISSORS

31. HAEMOSTATIC FORCEPS (ARTERY FORCEPS) Normally it is also known as artery forceps. Haemostatic forceps are used on artery, veins and capillaries. Use :- It is used for strong grasping and holding and catching. Disadvantage It crushes the delicate structures. When it is used as a holding forceps, two consecutive holding of structure is slow. (But in dissecting forceps two consecutive movements are fast.)

32. Descriptions Haemostatic forceps is designed specifically to catch/clamp and to crush the tissue. Parts Shaft of body (shank) :- It lies between joint and finger bows. Finger bow (ring):- It is used for holding the instruments. HAEMOSTATIC FORCEPS (ARTERY FORCEPS)

33. Catch / ratchet :- It lies between shaft and finger bow. When the catch / ratchet are pressed; the blades are kept in closed position. 3 catches are for, First catch for catching the tissue. Second catch for clamping the tissue. Third catch for crushing the tissue. HAEMOSTATIC FORCEPS (ARTERY FORCEPS)

34. Joints :- Joint is between the body and the blade. Joint may be pivot joint. (Screw form the axis). It may be the box joint. (Shaft passes in the slot of other shaft). Blades (jaw) The blade/jaw is having transverse serration on inner aspect. The blade may be straight or curved. HAEMOSTATIC FORCEPS (ARTERY FORCEPS)

35. Use It is used to hold the needle . Parts Shaft of body (shank):- It lies between joint and finger bows. Finger bow :- It is used for holding the instruments. NEEDLE HOLDER:

36. Catch / ratchet :- It lies between shaft and finger bow. When the catch / ratchet are pressed; the blades are kept in closed position. NEEDLE HOLDER:

37. Joint :- It is present between body and shaft. It is having modified box joint. Shaft passes in the slot of other shaft. Blades :- Blades are having cris-cross or transverse serrations and in the centre of the blade there is groove. NEEDLE HOLDER:

38. How to hold the needle holder Curved needle is hold by needle holder, at the junction between anterior 2/3 and posterior 1/3 of the needle. This gives maximum mechanical advantage of curved needle. If needle is hold nearer to the tip, the mechanical advantage is less but the penetrating power is more. If we hold needle nearer to eye, chances of breakage of needle nearer to eye is more. NEEDLE HOLDER:

39. Difference between haemostatic forceps and needle holder: Haemostatic forceps Needle holder 1 Lighter instrument Heavier instrument 2 Blades length 1/3 and shaft length 2/3 Blades smaller 3 Transverse serration on the inner side of blades Serrations –criss- cross or transverse and groove in blade 4 Joint screw type or may be box type Joint is box type only NEEDLE HOLDER:

40. Use It is used to suture the skin, subcutaneous tissues, connective tissues and other structures. It is also used to fix the structures together. It is also used to ligate around the tubular structure. NEEDLE

41. Description: the needle may be curved or straight. It may be cutting or non cutting. Eye Tip Body Eye: Eye allows the suturing thread to pass. It is the weakest part of the needle Tip: It is the pointed end of the body of the needle Body: It is tapering towards the tip. It may be triangular on cross section with a cutting edge. NEEDLE

42. Use It is use for cutting of bones. Now electrical saws are also available. Description Handle - Pistol grip handle, which is design to grip. Blade or edge- Edges is having two borders cutting and non-cutting SAW:

43. Use - It is used to cut the small and large pieces of bones, edges of the bones, spicules, spines and processes of bones. It is used for tearing away the remainings of muscles, ligaments and pieces of periosteum of bone as it gives firm grip on the tissue without cutting them. BONE CUTTING & BONE NIBBLER FORCEPS :

44. Description It has body or shaft, blades and joints. body or shaft:- It is strong and convex on outer side. The convex outer surface is ridged for firm grip. The concave inner surface of shaft is having resistance which allows sudden acute cutting force for cutting the bones. (If the gradual pressure is allowed then first crush and then may cut the bones.) BONE CUTTING & BONE NIBBLER FORCEPS :

45. Joint It is having pivot or modified box joint. Joints may be one or two joints. Advantage of two joint The cutting power is increase with less effort by these multiple lever system. blades It is having two straight and strong blades. BONE CUTTING & BONE NIBBLER FORCEPS :

46. Use It is used to cut the strong bones Description It is having handle and shaft Handle On one end of handle, there is head, where the hammer can be hit or stroked. On other end of handle, there is shaft. Shaft: The shaft is flat On one end, shaft is continues with the handle. On other end, shaft has cutting edge, cutting edge is bevelled on one side. CHIESEL :

47. Use: It is used to hit or stroke. It is used along with chisel to cut the bones. Description: Handle Striking end Striking end is heavier, which increase the strength of the stroke HAMMER / MALLET

48. Brain knife: Retractor:

49. comprehensive study(routine) dissection and window dissection comprehensive study(routine) dissection: comprehensive study(routine) dissection gives better exposure of the structure in whole region. comprehensive study(routine) dissection is useful for understanding & identification of structure and relation in general. comprehensive study(routine) dissection is useful for the gross anatomy study purpose but it may increase the cadaveric wastage.

50. WINDOW DISSECTION - When a particular specific structure are required to be demonstrated, window dissection is preferred It is done in given region It demonstrate the layer by layer relations of deeper structure It prevent dryness of deeper structures It minimizes the wastage of body parts It is useful for the museum part preparation also It give better view of the relations among skin, superficial fascia and deep fascia and other structures Routine and window dissection

51. I am thankful to Dr. Amit Singel, Dr. Dhaval Talsaniya, Dr. K. P. Patravala (Ex. Prof & HOD) and Dr. Mohit Changani for helping at each & every stages of this presentation.

52. I would like to congratulate Anatomy Department and KLE university’s, J. N. Medical College, Belgaum , for organizing CME on “postgraduate intensive training program”. I feel proud to be a part of this program which’ll help PG students of anatomy.