Quick answer
MedlinePlus defines a head injury as “any trauma to the scalp, skull, or brain.”[1] Head injuries range from scalp wounds and skull fractures to concussions and bleeding inside the skull.[1] Most are minor because the skull protects the brain, but some are serious enough to require a hospital stay.[1]
What counts as a head injury
According to MedlinePlus, head injuries include:[1]
- Concussion, usually from the brain being shaken, which is the most common type of traumatic brain injury
- Scalp wounds
- Skull fractures
- Bleeding in the brain tissue or in the layers that surround the brain (subarachnoid hemorrhage, subdural hematoma and epidural hematoma)
Injuries to the face, eyes, ears, jaw and teeth are also covered on this site, because they result from the same kinds of impacts and often happen together with injuries to the scalp, skull or brain.
Head injury vs. brain injury
A head injury does not always involve the brain. A traumatic brain injury (TBI) is specifically an injury that affects how the brain works.[2] MedlinePlus notes that the brain can be bruised by hitting the inside of the skull even when the skull itself is not fractured, and that bleeding or swelling inside the skull can cause problems.[1] NINDS adds that not every blow or jolt to the head results in a TBI.[3]
Closed and open head injuries
MedlinePlus describes two broad categories:[1]
Closed head injury
A hard blow to the head from striking an object, where the object does not penetrate the skull.[1]
Open (penetrating) head injury
An object breaks the skull and enters the brain, for example from a gunshot or from going through a windshield in a crash.[1]
MedlinePlus also notes that closed injuries are not always less severe than open ones.[4]
Common causes
MedlinePlus lists common causes of head injury as accidents at home, at work, outdoors or during sports; falls; physical assault; and traffic accidents.[1] For brain injuries specifically, the CDC reports that people most commonly get TBIs from a fall, a firearm-related injury, a motor vehicle crash or an assault, and that falls lead to nearly half of TBI-related hospitalizations.[5]
MedlinePlus notes that the spinal cord is also likely to be injured in falls from a significant height or ejection from a vehicle.[1]
Where to go next
- Types of head injuriesThe main ways head injuries are classified
- Mild, moderate and severeHow severity is measured
- Head injuries by areaBrain, skull, scalp, face and more
This page provides general information from the sources listed below. It is not medical advice and is not a substitute for evaluation by a qualified healthcare provider. In an emergency, call 911.
Sources
- MedlinePlus Medical Encyclopedia. “Head injury – first aid.” https://medlineplus.gov/ency/article/000028.htm
- Centers for Disease Control and Prevention. “About Mild TBI and Concussion.” https://www.cdc.gov/traumatic-brain-injury/about/index.html
- National Institute of Neurological Disorders and Stroke. “Traumatic Brain Injury (TBI).” https://www.ninds.nih.gov/health-information/disorders/traumatic-brain-injury-tbi
- MedlinePlus. “Head Injuries.” https://medlineplus.gov/headinjuries.html
- Centers for Disease Control and Prevention. “Facts About TBI.” https://www.cdc.gov/traumatic-brain-injury/data-research/facts-stats/index.html
Sources last checked: October 11, 2026
