After injury hair bulbs are seen crushed under microscopy. Probable type of wound;
**Core Concept**
Lacerations result from blunt trauma, which causes crushing and tearing of tissues. The microscopic appearance of hair bulbs crushed under the scalp indicates that the injury was caused by blunt force, leading to laceration.
**Why the Correct Answer is Right**
The presence of crushed hair bulbs under microscopy is characteristic of lacerations. This occurs because the blunt force of the trauma causes the skin to tear, resulting in the hair bulbs being compressed between the skin edges. This is in contrast to incised wounds, which are caused by sharp objects and result in clean cuts through the skin with intact hair bulbs.
**Why Each Wrong Option is Incorrect**
**Option A:** Abrasions are caused by rubbing or friction against a rough surface, resulting in epidermal loss and underlying dermal damage. However, crushed hair bulbs are not a characteristic feature of abrasions.
**Option B:** Avulsions involve the tearing of a full-thickness wound, often resulting in the removal of a portion of the skin. While avulsions can cause significant tissue damage, they do not typically result in crushed hair bulbs.
**Option C:** Penetrating wounds, such as stabs or gunshot wounds, may cause a range of tissue damage, but the characteristic finding of crushed hair bulbs is more typical of blunt trauma.
**Clinical Pearl / High-Yield Fact**
Remember the "4 Ps" of lacerations: pain, pallor, pulselessness, and paresthesia. These signs indicate potential nerve or vascular injury and warrant further investigation.
**Correct Answer: B. Avulsion.**