Friday, July 22, 2022

Forensic Medicine:Blunt Force Injuries

 

                                      

                                      TOPIC: Blunt Force Injuries

Sub topics:

·         Injury/Wound//Legal definition/Medical Definition

·         Types of blunt force injuries/Mechanism of production

·         Blunt force injuries of the head, trunk and limbs

·         The general pattern of blunt force external and internal injuries in a death as a result of a fall from a height

Notes for the topic: Blunt force trauma is injury produced by weapons or objects with blunt edges or surfaces. Basically they are abrasion, contusion and laceration. An abrasion is defined as a superficial injury, inducing displacement of only epidermis in the skin by friction. A contusion is a haemorrhage into the skin, or into the tissues under the skin or both, as a result of rupture of small blood vessels, especially capillaries by a blunt impact. A laceration is a disruption of the continuity of tissue, produced by stretching or crushing type of blunt forces. Motor vehicle collisions represent the most common cause of major thoracic injury among emergency department patients. Various types of chest injuries encountered are; concussion of chest, contusion of chest, fracture ribs ,flail chest injury , injury to lungs ,injury to heart due to blunt/and sharp force trauma( buckled sternum, cardiac tamponade, injury to aorta/pulmonary artery/ inferior vena cava etc). ,injury to trachea and oesophagus, etc. Blunt force trauma to head with a non-penetrating object or from fall, or the head striking a flat surface can produce closed head injury. The mechanical force, which produces a brain injury, usually produces injury of the scalp, and fractures of the skull. Fractures of bones or dislocations of joints are grievous hurt so are of medicolegal importance.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Injury/Wound//Legal definition/Medical Definition

Trauma or injury is defined in two different ways, legally and medicolegally or clinically.

Legally trauma or injury is defined as “any harm whatsoever in nature illegally caused to the body, mind, reputation, or property.”

 Medicolegally (Clinically) trauma or injury is defined as breach or dissolution of the natural continuity of any of the tissues of a living body by actual physical violence.

Trauma is accordingly classified in two ways:

Legal Classification : Depending on the legal aspects, trauma includes two types and they are: simple  and  grievous.

Medicolegal Classification:  Depending on the causative factor, medico-legally trauma includes five types and they are: Mechanical ,Thermal , Chemical ,Electrical/lightning and Radiation.

Types of blunt force injuries/Mechanism of production

 

Blunt Force Trauma: It is injury produced by weapons or objects with blunt edges or surfaces. Basically they are: Abrasion, Contusion and Laceration.

Abrasion: An abrasion is defined as a superficial injury, inducing displacement of only epidermis in the skin by friction. Various causes leading to development of an abrasion are: a)Fall on a rough surface b)Blow with blunt weapon c)Dragging by a vehicle d) Hurt by fingernails, thorns, teeth bite, etc. Lesion produces minimum bleeding, heals rapidly within seven days and leaves no permanent scarring on healing. Various types of abrasions encountered routinely include scratches. Scratches are linear injuries due to a sharp object, e.g. pin, thorn, fingernail, etc .

Grazes are injuries due to frictional force of rubbing by a blunt object moving with great force, e.g. shoe kicks, dragging on the rough road by a vehicle, etc. Impact abrasions are due to direct impact or pressure of some object, which on crushing the cuticle casts a reproduction of its shape and surface marking upon the skin, e.g. gravel marks, radiator grill mark, tyre treads marks. Crushing abrasion will be caused by direct impact or linear pressure of a rough object over the skin accompanied with slight movement directed inwards resulting in crushing of superficial layers of the cuticle with some bruising underneath.

Contusion/Bruises: A contusion is a haemorrhage into the skin, or into the tissues under the skin or both, as a result of rupture of small blood vessels, especially capillaries by a blunt impact. These injuries can be produced by blunt force with fist, stone, stick, bar, whip, cane, shoes, etc. Examination of a Bruise Under this a mention must be made about the colour, site, size, shape, etc. of a bruise. A bruise usually shows no external bleeding, heals completely in 15 days leaving no permanent scars. However, contusions of the viscera such as brain, heart, liver, lungs, etc. could be fatal. Basically bruises are of three types and they are superficial, deep and patterned bruises. Superficial bruises are usually seen raised above the surface of the skin (swelling) due to infiltration of blood into the subcutaneous tissues. When a rod/whip etc in used to hit, skin with blood vessels underneath yeilds to the pressure at the edges and ruptures bleeding at the edges of the impacting object resulting in parallel bruises resulting in patterned contusion.

Laceration: A laceration is a disruption of the continuity of tissue, produced by stretching or crushing type of blunt forces. Tearing up of tissues by blunt force, e.g. splitting of the skin by the overstretching on fractured bones underneath, crushing of skin between two hard objects, etc. Split laceration occurs when the skin is crushed between two hard objects, e.g. incised-like laceration of the scalp and forehead. During a fall, the scalp, getting crushed between skull from inside and hard ground outside, splits, resulting in a wound, which usually mimics an incised wound, unless, examined closely. Stretch laceration occurs due to the over-stretching of the skin, beyond its elasticity, e.g. in fracture of femur/other long bones the fracture fragment of the bone may stretch and pierce the skin and project out; in run over accidents when the tyre passes over the anterior abdominal wall, stretch laceration are developed in the inguinal region. Avulsed laceration is a lesion wherein the skin (only) separates by tearing from the underlying tissues or peals off and overhangs the wound e.g. common in road traffic accidents.

Blunt force injuries of the head, trunk and limbs

INJURY TO CHEST/THORAX AND THORACIC STRUCTURES:

These are commonly seen among adults and  rarely seen among the children. Motor vehicle collisions represent the most common cause of major thoracic injury among emergency department patients. Several factors associated with a higher risk of thoracic injury are: high speed, not wearing a seatbelt , extensive vehicular damage and steering wheel deformity. Increased mortality and morbidity is associated with multiple rib fractures, increased age, and higher injury severity scores.

Various types of chest injuries encountered in routine medicolegal practice are: concussion of chest, contusion of chest, fracture ribs (commonly 4th to 8th ribs are involved and called knobbing fracture ribs) ,flail chest injury , injury to lungs ,injury to heart due to blunt/and sharp force trauma( buckled sternum, cardiac tamponade, heart avulsion), injury to major blood vessels like aorta/pulmonary artery/ inferior vena cava etc. ,injury to trachea and oesophagus,etc.

Various types of abdominal injuries encountered in routine medicolegal practice are incised wounds, which could be non-penetrating or penetrating, leading to death due to shock, haemorrhage sepsis or injury to vital organs such as liver, spleen, pancreas, kidneys, etc. Blunt injuries to abdomen such as contusions or laceration of viscera such as stomach, intestines, pancreas, liver, spleen, etc. are also seen.

Injuries to Head: They often result due to road traffic accidents , assaults, falls, etc. Blunt force trauma to head with a non-penetrating object or from fall, or the head striking a flat surface can produce closed head injury. The mechanical force, which produces a brain injury, usually produces injury of the scalp, and fractures of the skull. However a fatal brain injury may be caused without any damage to the scalp or skull. Head injuries can be classified as  scalp injuries, facial injuries , skull injuries , injury to meninges and brain injuries. Head injury is a morbid state, resulting from gross or subtle structural changes in the scalp, skull, produced by mechanical forces. These injuries include craniocerebral injury, trauma to the skull and brain, etc. Of all regional injuries, those of the head and neck are most common in routine forensic practice. Head is the target of choice in the great majority of assaults involving blunt trauma. It is also true that when a victim is pushed or knocked to the ground, he often strikes the head. Correct interpretation of head injuries is of great importance in providing the proper treatment in the living victim. It is also important for the purposes of accurate reconstruction of the events of injury in the dead.

Injuries to limbs: Fractures of bones or dislocations of joints are grievous hurt so are of medicolegal importance. Haemorrhage, shock, fat embolism, sepsis and death  can occur when not treated properly.Injuries to limbs  include all types of fracture bones of the extremities. Fractures are of different types:Closed ,Open ,Simple and many more as below.

 

Complete fracture: A fracture in which bone fragments separate completely. Incomplete fracture: A fracture in which the bone fragments are still partially joined.

Linear fracture: A fracture that is parallel to the bone's long axis.

Transverse fracture: A fracture that is at a right angle to the bone's long axis. Oblique fracture: A fracture that is diagonal to a bone's long axis.

 Compression fracture: A fracture that usually occurs in the vertebrae.

Spiral fracture: A fracture where at least one part of the bone has been twisted. Comminuted fracture: A fracture causing many fragments.

Compacted fracture: A fracture caused when bone fragments are driven into each other

Open fracture: A fracture when the bone reaches the skin

Bug fracture: A fracture when the bone is in place, but the fracture has the appearance of a crushed insect.

The general pattern of blunt force external and internal injuries in a death as a result of a fall from a height

In a decedent who has suffered a fall head first from a height, neck trauma and other internal injuries are expected along with injuries to the extremities or other parts of the body. A ring fracture at the base of the skull can also reasonably be expected. Depressed skull fractures may be seen in a fall from a height as well as in a forceful blow with a heavy object. One should not, however, anticipate contrecoup contusions in a fall from a great height. Direct blows to the top of the head may produce contusions of the underlying cortex, and they may be associated with fractures, including diastatic fractures. Energy is absorbed by the outbending of the skull and fractures. This energy absorption may account for the fact that contrecoup contusions may not be seen in such cases. Subarachnoid and subdural hemorrhages may also be produced. Contrecoup contusions may be identified in the victim of a fall or a victim who was pushed backward, generally from standing height. The presence of contrecoup contusions cannot be relied upon, however, as the sole factor in differentiating whether they resulted from a fall or a blow for they may also be seen in a victim who has blow to the head.

 

 

 

 

 

 

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