Why Do Head Injuries Bleed so Much?
Why Do Head Injuries Bleed so Much?
Bleeding occurs when trauma damages a blood vessel. When that trauma involves your head鈥攚hether the scalp, skull, or brain鈥攊t鈥檚 considered a head injury. These head injuries range in severity from a mild bump to a severe traumatic brain injury (TBI). According to the Centers for Disease Control and Prevention (CDC), more than 2 million people visit for TBIs every year.
Types of Head Injuries
Head injuries fall into two main categories:
- Closed head injury: Something that hits your head hard, but the skull remains intact. Although there is no skull fracture, you can still have significant, life-threatening injuries
- Open head injury: The object penetrates the skull and enters the brain.
Bleeding from head injuries can be internal or external:
- Internal bleeding happens inside the head and may have no evidence of trauma on looking at the scalp and head.
- External bleeding occurs when blood escapes through a break in the skin.
Bleeding can occur in brain tissues, layers surrounding the brain, or the scalp. Most minor scalp wounds can bleed heavily but are usually not dangerous. When bleeding is confined to one area, bruising and swelling鈥攌nown as a hematoma鈥攎ay appear. Superficial hematomas are usually harmless, especially on the scalp.
Why Does the Head Bleed So Much?
The short answer: blood vessels鈥攍ots of them.
Your brain needs a tremendous amount of oxygen to function鈥攁bout of your heart鈥檚 blood goes to the brain. Other organs in your head, like your eyes, also require a steady supply of oxygen-rich blood to work well.
Here鈥檚 how it works:
- Arteries deliver oxygen and nutrient-rich blood from the heart to the body.
- The cells of your body absorb the oxygen and nutrients from the blood, which causes the cells to create carbon dioxide and other toxins.
- Veins carry carbon dioxide and toxins away from cells and back to the heart and lungs.
Blood vessels in the skin also help regulate body temperature. When you鈥檙e hot, blood flow increases near the surface to release heat; when you鈥檙e cold, it decreases. These superficial vessels are vulnerable to trauma.
Your scalp is especially prone to bleeding. Here鈥檚 why:
- Many tiny arteries and veins serve muscles and the skin on your head.
- Superficial arteries and veins are close to the surface of your skin, while blood vessels supplying your brain lie deep within the skull.
Because of the extensive blood supply, a small cut to the head can lead to heavy bleeding.
What to Do for a Bleeding Head Injury
While most head injuries are minor and do not require medical attention, they can bleed a lot. For minor head injuries:
- Apply pressure to stop the bleeding.
- Wash the wound thoroughly in a sink or shower.
- Apply antibiotic ointment to help with the healing process.
Seek medical attention if:
- Bleeding doesn鈥檛 stop with pressure.
- The wound edges are significantly separated.
- The person shows signs of confusion, vomiting, weakness, or loss of consciousness.
Special Considerations for Children
Children may show similar symptoms as adults but can also:
- Cry persistently
- Refuse to eat
- Vomit repeatedly
- Be irritable
Infants and toddlers may develop a 鈥済oose egg鈥濃攁 swelling under the scalp that could signal a more serious injury. Their behavior and mechanism of injury should be a better marker of concern for bleeding.
Getting Help
If you or someone you know receives an injury to the head, make sure someone is there to monitor them. Watch for signs of confusion or significant drowsiness鈥攂oth are reasons to take someone to the emergency department.
Even if symptoms seem mild, a headache after a head injury can indicate a concussion. Follow up with a doctor for further care and avoid contact sports until you are cleared by your doctor to return.
