Is repaired.

The viscera of a dead body on the autopsy (able are not in the same positions, as when the same person was alive and in standing position, or was bent over in a state of emotional tension, at the time of an assault. During fight, fright and flight, the victim may be moving or changing position in a variety of postures, which change by the second. When tense, the abdomen is usually contracted, and

Fig. (8-11) Assessment of depth of penetration of a stab wound.

the distance between the abdominal wall and the spine is reduced. When the same body is on the autopsy table, the abdominal wall is relaxed and this distance increases. Similarly, the anatomical relationship between the lungs, liver and other viscera is not the same as when the person is bent at the hips and when lying flat. In a stab wound on the anterior wall of the chest, the post-mortem depth is greater than it was during life, because of the collapse of the lung. If the stab is on the back of the chest, the depth of the wound will be less, as the lungs will collapse posteriorly,

The force required to inflict stab wound is subjective, and can only be stated in comparative terms, such as slight pressure, moderate force, considerable force, and violent penetration. The depth of stab depends on: (1) Condition of the knife: The sharpness of the extreme tip of the knife is the most important factor in skin penetration. Once the tip has perforated the skin, the cutting edge is of little importance, and the rest of the blade will pass into the body with ease, without any further force being applied. A thin, slender, double-edged knife will penetrate more deeply than an equally sharp, wide, single-edged blade inserted with the same force. A blunt-pointed instrument requires considerable force to puncture the skin and penetrate the soft tissues. (2) The resistance offered by the tissues or organs: Apart from bone and calcified cartilage, the skin is most resistant to knife penetration. (3) Clothing: The amount of clothing and its composition, e.g. multiple layers of tough cloth, leather belts, thick leather jackets, or coats.

etc. require greater force. (4) The speed of thrust of the knife. (5) Stretched skin is easier to penetrate than lax skin, e.g. chest wall. (6) When the knife strikes the skin at right angle, it usually penetrates more deeply than when it strikes from some acute angle. (7) When the knife penetrates the skin rapidly, e.g. if the body falls or runs on to the blade, the momentum of the forward moving body is sufficient to cause fatal injury. However, the knife must be sharp-pointed and held firmly so as to penetrate easily, as a blunt knife held loosely will be turned aside by the approaching body.

A piece of pliable tubing may be introduced gently, and if it goes in easily may reveal the true track. Later, the tubing can be made more rigid and straight by inserting a probe into it. Dissection in the tissues parallel to, but away from the wound, will reveal the track. Radio-opaque material or dyes can be injected into stab wound to demonstrate the wound track by X-rays.

(5) fihape : The size and shape of a stab wound in the skin is dependent on the shape of the weapon, the direction of thrust, the movement of the blade in the wound, cleavage direction, the movement of the person stabbed, and the condition of tension or relaxation of the skin. Stab wounds and incised wounds are slit-shaped with two acute angles, or gape open depending on their location and their orientation, with regard to the so-called cleavage lines of Langer (Fig. 8-13). The pattern of fibre arrangement of the dense feltwork of intimately intermingled dermal collagen and elastic fibres is called the cleavage direction or lines of cleavage of the skin, and their linear representation on the skin are called Langer's lines. A stab wound which runs parallel to the cleavage lines will remain slit-shaped and narrow and the dimensions of the blade will be represented with considerable accuracy. A stab wound which cuts through the cleavage lines transversely will gape. If the knife is inserted in an oblique plane, the skin defect is wider and the wound may gape asymmetrically and assume a semicircular or crescentic shape. .To ascertain the shape of the instrument, the edges of a wound may be manually approximated with slight twisting or they may be held together with a transparent adhesive tape. The resulting slit is considerably longer than the original oval-shaped wound. This will counter the claim of the defence that the suggested knife could not have produced a stab wound of the type as seen before reconstruction, The dimensions of the gaping wound are not useful to assess the shape of the blade.

The shape of the wound usually corresponds to the weapon used, but the shape of the wounds made by the same weapon may differ on different parts of the body. (I) If a single-edged weapon is used, the surface wound will be triangular or wedge-shaped, and one angle of the wound will be sharp, the other rounded, blunt or squared off. Blunt end of the wound may have small splits in the skin, so-called "fishtailing". Some stab wounds caused by single-edged weapon have bilateral pointed ends like those due to double-edged weapons. This is due to: (a) The initial penetration by the knife point to a depth of about one cm., first produces a dermal defect with sharp angles at each end. As the knife penetrates more deeply, the end in contact with the cutting edge of the blade continues to be sharply angulated. The opposite end which is in contact with non-cutting surface of the knife, also remains sharply angulated because the dull surface does not imprint its shape to the skin defect. It merely causes further separation of the skin which continues to be torn along the course of its original direction, (b) The knife penetrating the skin at an oblique angle. As the knife perforates, it is pulled down with the cutting edge cutting through the skin and the blunt surface of the back of the knife does not impart its shape to the skin defect, as it does not contact it, (c) Many single-edged knives have a cutting edge on both sides at the tip. The initial thrust into the skin will produce a double-pointed wound, and as the blade passes through the skin, if it is pulled down slightly, the blunt back portion of the knife will not come in contact with the skin. The serosal planes and muscle fasciae (pleural surface, liver capsule and the pericardial sac) often clearly show the wedge-like shape of a knife. In some stab wounds both ends are blunt. In some single-edged knives, between the cutting edge of the knife and the handle, there is a small section of blade which is blunt like on the back, called the ricasso. When the full length of such knife up to the handle enters the body, both

Fig. (8-12) Cleavage lines of Langer,

ends will be blunt. By examination of a single wound, it is not possible to say, whether it was caused by a single-edged or double-edged weapon. If multiple stabs are produced by a single-edged weapon, examination of all the stab wounds will reveal the single-edged nature of the weapon. (2) If a double-edged weapon is used, the wound will be elliptical or slit-like and both angles will be sharp, or pointed. (3) A round object like the spear may produce a circular wound. (4) A round blunt-

p ointed object, such as a pointed stick, or metal rod may produce a circular surface wound with inverted ragged and bruised edges. Foreign material, such as dirt, rust or splinters may be found in the wound. (5) A pointed square weapon may produce a cross-shaped injury, each of the 4 edges tearing its way through the tissues. (6) A fall on a pointed article, e.g., pieces of broken glass, will produce a wound with irregular and bruised margins, and fragments of glass may be found embedded in the soft tissues. (7) Stab wounds inflicted with a broken bottle, appear as clusters of wounds of different sizes, shapes, and depth, with irregular margins. (8) Stabbing with a fork produces clusters of two or three wounds depending upon the number of prongs on the fork. (9) A screwdriver will produce a slit-like stab wound with squared ends and abraded margins. (10) Thick relatively blunt-edged blades, e.g., bayonets, may produce cross-shaped stab wounds, because cutting and tearing of the skin occurs simultaneously and at right angles to each other. When a knife is twisted as it is withdrawn from the tissues, the external wound may have a cruciate appearance. (11) Ice-picks or similar instruments produce stab wounds, resembling small caliber bullet wounds. (12) Irregularly-shaped stab wounds such as L or V-shaped may be mistaken to be produced by two distinct stabbings in the same location. These atypical in jries are produced by stabbing, followed by simultaneous twisting and cutting (rocking), rr the victim moving relative to the knife, or by a combination of the two. There will be a primary stab wound with an extension of

Fig. (8-13) Appearances of stab wounds on (be skis by different types of weapons*.

Fig.(8-14) Multiple homicidal stab injuries on the back.

it, due to the knife edge cutting the skin in a different direction as it exits. Small notches in margins of the skin defects can be produced by the same mechanism. A great number of possibilities capable of causing atypically shaped stab wounds exist, the interpretation of which are usually difficult, (m) If the scissors is closed, the tip of the scissors splits rather than cuts the skin, producing a linear stab wound with abraded margins. Deep penetration will produce 'Z'-shaped wound. If the screw holding the two blades is projecting, there are small lateral splits in the wound centre. If the two blades of the scissors are separated, each thrust will produce two stab wounds, (n) A knife with a serrated back edge will produce a stab wound, the back edge of which may be torn or ragged. If the knife enters obliquely, serrated abrasions may be seen on the skin adjacent to the end of the wound.

(6) Direction : When the knife penetrates at an angle, the~~woDnd will have a bevelled margin on one side with undermining (undercut) on the other, so that subcutaneous tissue is visible, indicating the direction from which the knife entered. In solid organs like the liver, the track made by the weapon is better seen. The principal direction should be noted first and other next, e.g., backwards and to the right. If the weapon is partially withdrawn and thrust again in a new direction, two or more punctures are seen in the soft parts with only one external wound. If the wound is perforating, it should be described in sequential order: the wound of the entrance, the path of the wound track, and the wound of exit. If the wound is penetrating, the wound of entrance should be described first, then the depth and direction of wound track, and specific termination.

An example of description of a stab wound: Stab wound, wedge-shaped on the right upper chest, placed obliquely, with the inner end lower than the upper outer end. Length was 4 cm. The maximum width at the centre was 5 mm. The centre of the wound was just below the line joining the nipples, being 5 cm. from the midline, 6 cm, from the right nipple, and 18 cm. below right collar bone. The inner end was sharp and outer blunt. The lower margin was undermined. A track is established on the right anterior thoracic wall, passes through the fifth interspace, through upper lobe of right lung to a depth of 1 cm. A right haemothorax of 400 ml. of fluid and clotted blood is present. ^Complications \\ 1) External haemorrhage is slight but there may be marked internal haemorrhage or injuries to internal organs. (2) The wound may get infected due to the foreign material carried into the wound. (3) Air embolism may occur in a stab wound on the neck which penetrates jugular veins. Air is sucked into the vessels due to the negative pressure. (4) Pneumothprax, and (5) Asphyxia due to inhalation of blood^

Concealed Puncture Wounds : These are puncture wounds caused on concealed parts of the body, such as nostrils, fontanella, fornix of the upper eyelids, axilla, vagina, rectunvand nape of the neck. Fatal penetrating injuries can be caused without leaving any readily visible external marks, e.g.. dirusting a needle or pin into the brain through the fontanelles, through the inner canthus of the eye. or into the medulla through the nape of the neck. These injuries may not be detected unless searched carefully:

Examination : The following points should be noted : (1) Identification and labelling of cuts and damage to clothing. (2) Distribution of blood stains. (3) Removal of clothing, layer by layer. (4) Identification and labelling of wounds. (5) Wounds: (a) Position (height from heels), (b) location (measurements from fixed anatomical landmarks).fc) description including size, shape, extension, (d) direction, (el depth, (f) trauma to viscera, (g) estimation of force required, (h) foreign bodies. To indicate the general character of the instrument which inflicted the stab wound, the term "incised' or 'lacerated' should be included in the description of the stab wound, . e.g., 'incised-stab wound', 'lace rated-stab wound', etc. The relationship between the wound and weapon can be established by the shape, width, length, and presence of blood on the weapon.

Incised-stab wound: Inciscd-stab wound is a wound which starts as an incised wound and ends as a stab wound by the sudden thrust of the blade into the body, or starts as a stab wound and becomes incised wound as the knife is pulled out of the body at a shallow angle to the skin surface producing an incised wound. If a nick or forked-shape cut is present at the end of the stab wound opposite to ihe incised portion, then the wound has started as an incised wound and ended as a slab wound. If ihe fork is at the end of the stab wound where the incised wound arises, then the wound has started as a stab wound.

Flg.(8-15) Multiple stab injuries, some of them showing tailing.

The external and internal appearances of a stab wound help to give an opinion upon: (1)dimensions of the weapon. (2) the type of weapon. (3) the taper of the blade, (4) movement of the knife in the wound, (5) the depth of ihe wound. (6) the direction of the stab, and (7) the amount of force used.

Examination of the Weapon : The doctor should note : (1) the length, width and thickness of the blade. (2) whether single-edged or double-edged. (3) the degree of taper from tip to hilt. (4) the nature of the back edge in a single-edged weapon, e.g. squared-off. serrated, etc.. (5) the face of the hilt guard adjacent to the blade. (6) any grooving, serration or forking of the blade, and (7) sharpness of the extreme lip of the blade and the cutting edge.

In some cases of stabbing, the blade of the knife may not be bloodstained. In solid organs. bleeding occurs only after the knife is withdrawn. because bleeding is prevented by the pressure of the knife. During the withdrawal of the knife, the muscular and elastic tissue of the solid organs, and the elastic tissue of the skin may contract about the knife, wiping off the blood present on the knife blade. The clothing if present, may also wipe ol'i the blood. An injury may cause deep shock and severe circulatory collapse. Subsequently, even if a deeply penetrating wound is produced, there may be little bleeding.

^Medico-legal Importance : (1) The shape of the wound may indicate the class and type of the weapon which may have caused the injury. (2) The depth i of the wound will indicate the force of penetration. (3) Direction and dimensions of the wound indicate the relative positions of the assailant and the victim. (4) The age of the injury can be determined. (5) Position, number and direction of wounds may indicate manner of production, i.e., suicide, accident, or homicide. (6) If a broken fragment of weapon is found, it will identify the weapon or will connect an accused person with the crime. S

/Circumstances of Injuries : ^JjiicidexSuicide by stabbing is not common. Suicidal stab wounds are found over accessible areas of the body. The common site is the chest over the heart region. The direction of the wound is upwards, backwards and to the right. The depth is