Welcome to module three of taking on trauma. In this module, we will discuss various soft tissue injuries including burns. Before watching the videos in this module, please review your anatomy, specifically of the skin. As we cover soft tissue injuries, you will note that there are varying degrees of injury that can occur with trauma, and many of the classifications have to do with how deep, or how much damage is done, and in what way to the skin and blood vessels. Let's get started. We will begin with some basic definitions of different types of soft tissue injuries. These can be broken into three categories; closed injuries, open injuries, and burns. Burns will be discussed in future videos. So, for now, let's focus on the various closed, and open injuries you may encounter. Recall from your anatomy that the skin is a durable structure composed of three layers; the epidermis, dermis, and subcutaneous. These work to protect us from the elements of the external environment. This understanding will be important for understanding closed and open injuries moving forward, as well as their implications. The various closed injuries include; hematomas, crush injuries, and contusions. These injuries are considered close, because there's no break in the skin that exposes the injury to the outside world. Recognize however, that multiple injuries may overlap with one another, and you may simultaneously have both a closed and open injury, to a single extremity or body part. A contusion is more commonly known as a bruise. It is caused by an injury to the soft tissue and blood vessels contained within the dermis. You may see some discoloration of the skin at the injury site, usually a bluish, purplish discoloration. This is due to small leakage of blood contents from injury to the blood vessels, and this discoloration is termed ecchymosis. This may occur from say, a car accident. The arm may hit the steering wheel, bruising the skin, and causing a contusion. A hematoma is similar to a contusion, but generally involves injury to a larger area of tissue, and involves larger blood vessels of which leak blood into the soft tissue. These can form a bump or a lump under the skin from the collection of blood and serous fluid under the skin. The same discoloration or ecchymosis, may be present overlying the injury. Again, the discoloration is from broken blood vessels. For example, if someone were to fall back onto the back of their head and hit the concrete ground, you can probably imagine a big lump on their head. That is a hematoma. A crush injury is almost exactly what it sounds like. It's when a force great enough to cause injury to the body, has been applied to an extremity or body part. This force can be brief or extended over a greater duration of time. Crush injuries can either be open or closed. They can cause significant bleeding or organ injury, which may lead to hemorrhagic shock, or organ rupture. For example, if someone has their arm trapped under a car, this may be deemed a crush injury. Now that we have an understanding of the various types of closed injuries, let's talk about the injuries that involve breaks in our protective skin barrier, or open injuries. Examples of open injuries include: abrasions, laceration, avulsions, amputations, penetrations, bites and crush injuries. Open injuries are a risk for external hemorrhage, or bleeding, and contamination which can eventually lead to infection. An abrasion is caused by shearing forces which disrupt the most superficial layer of the skin, the epidermis. These are generally not life threatening, and only involve capillary oozing, which can be controlled with direct pressure. However, these can be extremely painful due to exposed nerve endings. They're at places at increased risk for infection given the break in the skin, and they may be a sign of an underlying more serious injury. A simple example of an abrasion would be a skinned knee on a child that was running down the street. More dramatically, road rash sustained from a motorcycle crash. Abrasions can be full of debris and dirt, making them at risk for infection, and will need to be washed out as do all open injuries. Lacerations are breaks in the skin at various depths in lengths. If the laceration is a simple straight line, it is known as linear. However, if its edges are irregular or in the shape of a star, it would be described as stellate. Linear wounds are generally created by sharp edges, and tend to heal easier with less risk of a scar, such as a clean cut with a knife or a blade. In contrast, stellate ones tend to be caused by blunt objects, and carry a greater risk of scar formation such as being struck in the head with a bottle. Another type of injury is an avulsion. An avulsion is a flap of skin that has either been partially or fully torn off, exposing the underlying tissue. These are again due to shearing forces on the skin, and can be the result of heavy machinery, or motor vehicle accidents. Amputations are the partial or complete removal of a body part. As you can imagine, these can be quite serious or devastating. Amputations can be of a fingertip, or an entire extremity. They often involve significant injury to the blood vessels, bones, and nerves. They can have arterial bleeding, and can be life-threatening, depending on the amount of bleeding, and the location of the injury. A penetrating injury or puncture wound, is caused by a sharp, often pointed object that is driven into the soft tissue. Classic examples are stab wounds, or gunshot wounds. These may appear small and have little external bleeding that you can see. However, depending on the location, can have serious underlying deep tissue bleeding or organ injury, and can be life-threatening. In the case of gunshot wounds, it is generally not recommended to characterize as entry or exit wounds. Instead, you should count the number of holes and assume there may be more than one bullet involved. The external damage you see caused by the bullet, can be a tiny fraction of what may have occurred inside. We will just spend one more moment on gunshot wounds. The type of firearm used is important as different ballistics can cause different injury patterns. Some bullets are designed to fragment on impact, for example. So, there may be a small wound on the skin. However, internally, there may be multiple bullet fragments that have caused a massive amount of internal damage. Keep this in mind when evaluating for trauma. Remember, the external wound may be a small hole, but the internal wounds may be life-threatening. Crush injuries as discussed before, can either be closed or open. They are generally the result of blunt force, and may show little signs of external injury. It can be an ominous signs of severe internal injury or bleeding. Specific attention should be paid when lifting a crushing object off a patient, as it may have been tamponading the injured blood vessels, or preventing them from bleeding too much while I was on the patient. As such, they may begin to bleed freely when the object is lifted. Finally, to round out open injuries, we should discuss a special consideration of open injury bite wounds. Bite wounds are generally a combination of puncture and crush injuries. They are often associated with underlying deep tissue injuries, such as fractures, and they're at very high risk for infection, as the underlying tissues are exposed to oral bacteria depending on what type of animal was doing the biting. Human bites are especially at risk for infection as the human mouth contains more bacteria than many animals. All bites should be transported to the hospital for further care and evaluation, as they may require antibiotics and require extensive cleaning. Bites can also cause the other types of injuries that we talked about; lacerations, punctures, and crush. Another important consideration with bites occurs when someone punches another person in the mouth. Oftentimes, this causes damage to the person who is doing the punching with hand. It may cause an abrasion or laceration of the knuckles, for example. This is called a fight bite, and will often require antibiotics. Thus all cuts to the hand sustained in a fight should be assumed bite related. This ends the review of definitions in relation to the open and closed soft tissue injuries. Feel free to review these definitions as many times as you need, and remember to use the vocabulary you've learned when calling into the hospital, or describing an injury. Now, we will discuss the assessment and treatment of these injuries.