The need for imaging in patients who have suffered a minor head injury is debated. A non-contrast CT of the head should be performed immediately in all those who have suffered a moderate or severe head injury, an MRI is also an option. Computed tomography (CT) has become the diagnostic modality of choice for head trauma due to its accuracy, reliability, safety, and wide availability. The changes in microcirculation, impaired auto-regulation, cerebral edema, and axonal injury start as soon as head injury occurs and manifest as clinical, biochemical, and radiological changes.

In children with uncomplicated minor head injuries the risk of intra cranial bleeding over the next year is rare at 2 cases per 1 million. In some cases transient neurological disturbances may occur, lasting minutes to hours. Malignant post traumatic cerebral swelling can develop unexpectedly in stable patients after an injury, as can post traumatic seizures. Recovery in children with neurologic deficits will vary. Children with neurologic deficits who improve daily are more likely to recover, while those who are vegetative for months are less likely to improve. Most patients without deficits have full recovery. However, persons who sustain head trauma resulting in unconsciousness for an hour or more have twice the risk of developing Alzheimer's disease later in life.

Head injury may be associated with a neck injury. Bruises on the back or neck, neck pain, or pain radiating to the arms are signs of cervical spine injury and merit spinal immobilization via application of a cervical collar and possibly a long board.If the neurological exam is normal this is reassuring. Reassessment is needed if there is a worsening headache, seizure, one sided weakness, or has persistent vomiting.

To combat overuse of Head CT Scans yielding negative intracranial hemorrhage, which unnecessarily expose patients to radiation and increase time in the hospital and cost of the visit, multiple clinical decision support rules have been developed to help clinicians weigh the option to scan a patient with a head injury. Among these are the Canadian Head CT rule, the PECARN Head Injury/Trauma Algorithm, and the New Orleans/Charity Head Injury/Trauma Rule all help clinicians make these decisions using easily obtained information and noninvasive practices.

While any number of injuries may occur during the birthing process. A number of specific conditions are well described. Brachial plexus palsy occurs in 0.4 to 5.1 infants per 1000 live birth. Head trauma and brain damage during delivery can lead to a number of conditions include: caput succedaneum, cephalohematoma, subgaleal hemorrhage, subdural hemorrhage, subarachnoid hemorrhage, epidural hemorrhage, and intraventricular hemorrhage.

The most common fracture during delivery is that of the clavicle (0.5%).

Sequelae can occur in both the mother and the infant after a traumatic birth.

Birth trauma is uncommon in the Western world in relation to rates in the third world. In the West injury occurs in 1.1% of C-sections.

Evidence does not support the use of preventative antibiotics regardless of the presence of a cerebral spinal fluid leak.

The majority of blast-related ocular injuries occur in soldiers who present with other life-threatening injuries that require immediate intervention. Current Combat Support Hospital (CSH) protocol requires the surgical stabilization of any life-threatening injuries, as well as hemodynamic stability, prior to initial eye evaluation and surgical repair. Therefore, initiation of emergency ophthalmic care often occurs hours after injury. Initial examination by a military ophthalmologist begins with gross examination of each eye and orbital. 73-82% of all ocular injuries resulting from mine explosions are due to fragmentation of shrapnel upon detonation, so gross anatomical inspection by penlight may not rule out open globe injury. Harlan JB, Pieramici DJ. Evaluation of patients with ocular trauma. Ophthalmol Clin North Am. 2002; 15(2):153-61./ref> Computerized tomography (CT) may detect foreign matter and aid the clinician in determining the presence of an open-globe injury.

Non-displaced fractures usually heal without intervention. Patients with basilar skull fractures are especially likely to get meningitis. Unfortunately, the efficacy of prophylactic antibiotics in these cases is uncertain.

A compound elevated skull fracture is a rare type of skull fracture where the fractured bone is elevated above the intact outer table of the skull. This type of skull fracture is always compound in nature. It can be caused during an assault with a weapon where the initial blow penetrates the skull and the underlying meninges and, on withdrawal, the weapon lifts the fractured portion of the skull outward. It can also be caused the skull rotating while being struck in a case of blunt force trauma, the skull rotating while striking an inanimate object as in a fall, or it may occur during transfer of a patient after an initial compound head injury.

Children with a simple skull fracture without other concerns are at low risk of a bad outcome and rarely require aggressive treatment.

The presence of a concussion or skull fracture in people after trauma without intracranial hemorrhage or focal neurologic deficits was indicated in long term cognitive impairments and emotional lability at nearly double the rate as those patients without either complication.

Those with a skull fracture were shown to have "neuropsychological dysfunction, even in the absence of intracranial pathology or more severe disturbance of consciousness on the GCS".

The presence of an open globe injuries may be determined by clinical examination and CT. However, full globe exploration with 360-degree removal of the conjunctiva (periotomy), separation of the rectus muscles, and subsequent examination of the sclera remains the most effective way to determine whether or not the globe has been injured. During exploratory surgery, foreign debris may be removed with microsurgical tools by inspection under the operating room microscope. Globe lacerations are typically repaired as far posteriorly as possible to prevent any further deficits in visual acuity. Lacerations posterior to the exposed area are not sutured; attempts to seal these injuries often results in the extrusion of intraocular components. Healing of these injuries occurs naturally by scarring of dorsal orbital fat to the sclera. If a clinically significant increase in intraocular pressure is detected with orbital compartment syndrome, the ophthalmologist may perform an emergency canthotomy on the lateral canthus. Canalicular injuries, as well as lid lacerations, are also commonly repaired in the military hospital setting. Suturing the laceration after the removal of foreign bodies depends on the location of global fissure: 10-0 nylon with cyanoacrylate glue is commonly used on the cornea, and processed human pericardium may be employed if it is surgically available. Globe closure of the limbus and sclera requires 9-0 and 8-0 nylon, respectively.

If damage to the globe is irreparable, the ophthalmologist may conduct a primary enucleation, evisceration (ophthalmology), or exenteration in the combat hospital. 14% of globe injuries sustained during Operation Iraqi Freedom have required enucleation. Implantation of an oculoplastic silicone sphere or similar device commonly follows these procedures.

Diagnosis of a cerebrospinal fluid leak is performed through a combination of measurement of the CSF pressure and a computed tomography myelogram (CTM) scan of the spinal column for fluid leaks. The opening fluid pressure in the spinal canal is obtained by performing a lumbar puncture, also known as a spinal tap. Once the pressure is measured, a radiocontrast agent is injected into the spinal fluid. The contrast then diffuses out through the dura sac before leaking through dural holes. This allows for a CTM with fluoroscopy to locate and image any sites of dura rupture via contrast seen outside the dura sac in the imagery.

Both computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have been proved to be effective in diagnosing intracranial vascular malformations after ICH. So frequently, a CT angiogram will be performed in order to exclude a secondary cause of hemorrhage or to detect a "spot sign".

Intraparenchymal hemorrhage can be recognized on CT scans because blood appears brighter than other tissue and is separated from the inner table of the skull by brain tissue. The tissue surrounding a bleed is often less dense than the rest of the brain because of edema, and therefore shows up darker on the CT scan.

Magnetic resonance imaging is less effective than CT at directly imaging sites of CSF leak. MRI studies may show pachymeningeal enhancement (when the dura mater looks thick and inflamed), sagging of the brain, pituitary enlargement, subdural hygromas, engorgement of cerebral venous sinuses, and other abnormalities. For 20% of patients, MRIs present as completely normal. There is disagreement over whether MRI should be the study of choice. MRIs performed with the patient seated upright (vs. laying supine) are not better for diagnosing CSF leaks, but are more than twice as effective at diagnosing cerebellar tonsillar ectopia, also known as Chiari malformation. Cerebellar tonsillar ectopia shares many of the same symptoms as CSF leak, but originates either congenitally or from trauma, including whiplash strain to the dura.

An alternate method of locating the site of a CSF leak is to use heavily T2-weighted MR myelography. This has been effective in identifying the sites of a CSF leak without the need for a CT scan, lumbar puncture, and contrast and at locating fluid collections such as CSF pooling. Another highly successful method of locating a CSF leak is intrathecal contrast and MR Myelography.

Pain, especially headache, is a common complication following a TBI. Being unconscious and lying still for long periods can cause blood clots to form (deep venous thrombosis), which can cause pulmonary embolism. Other serious complications for patients who are unconscious, in a coma, or in a vegetative state include pressure sores, pneumonia or other infections, and progressive multiple organ failure.

The risk of post-traumatic seizures increases with severity of trauma (image at right) and is particularly elevated with certain types of brain trauma such as cerebral contusions or hematomas. As many as 50% of people with penetrating head injuries will develop seizures. People with early seizures, those occurring within a week of injury, have an increased risk of post-traumatic epilepsy (recurrent seizures occurring more than a week after the initial trauma) though seizures can appear a decade or more after the initial injury and the common seizure type may also change over time. Generally, medical professionals use anticonvulsant medications to treat seizures in TBI patients within the first week of injury only and after that only if the seizures persist.

Neurostorms may occur after a severe TBI. The lower the Glasgow Coma Score (GCS), the higher the chance of Neurostorming. Neurostorms occur when the patient's Autonomic Nervous System (ANS), Central Nervous System (CNS), Sympathetic Nervous System (SNS), and ParaSympathetic Nervous System (PSNS) become severely compromised https://www.brainline.org/story/neurostorm-century-part-1-3-medical-terminology . This in turn can create the following potential life-threatening symptoms: increased IntraCranial Pressure (ICP), tachycardia, tremors, seizures, fevers, increased blood pressure, increased Cerebral Spinal Fluid (CSF), and diaphoresis https://www.brainline.org/story/neurostorm-century-part-1-3-medical-terminology. A variety of medication may be used to help decrease or control Neurostorm episodes https://www.brainline.org/story/neurostorm-century-part-3-3-new-way-life.

Parkinson's disease and other motor problems as a result of TBI are rare but can occur. Parkinson's disease, a chronic and progressive disorder, may develop years after TBI as a result of damage to the basal ganglia. Other movement disorders that may develop after TBI include tremor, ataxia (uncoordinated muscle movements), and myoclonus (shock-like contractions of muscles).

Skull fractures can tear the meninges, the membranes that cover the brain, leading to leaks of cerebrospinal fluid (CSF). A tear between the dura and the arachnoid membranes, called a CSF fistula, can cause CSF to leak out of the subarachnoid space into the subdural space; this is called a subdural hygroma. CSF can also leak from the nose and the ear. These tears can also allow bacteria into the cavity, potentially causing infections such as meningitis. Pneumocephalus occurs when air enters the intracranial cavity and becomes trapped in the subarachnoid space. Infections within the intracranial cavity are a dangerous complication of TBI. They may occur outside of the dura mater, below the dura, below the arachnoid (meningitis), or within the brain itself (abscess). Most of these injuries develop within a few weeks of the initial trauma and result from skull fractures or penetrating injuries. Standard treatment involves antibiotics and sometimes surgery to remove the infected tissue.

Injuries to the base of the skull can damage nerves that emerge directly from the brain (cranial nerves). Cranial nerve damage may result in:

- Paralysis of facial muscles

- Damage to the nerves responsible for eye movements, which can cause double vision

- Damage to the nerves that provide sense of smell

- Loss of vision

- Loss of facial sensation

- Swallowing problems

Hydrocephalus, post-traumatic ventricular enlargement, occurs when CSF accumulates in the brain, resulting in dilation of the cerebral ventricles and an increase in ICP. This condition can develop during the acute stage of TBI or may not appear until later. Generally it occurs within the first year of the injury and is characterized by worsening neurological outcome, impaired consciousness, behavioral changes, ataxia (lack of coordination or balance), incontinence, or signs of elevated ICP.

Any damage to the head or brain usually results in some damage to the vascular system, which provides blood to the cells of the brain. The body can repair small blood vessels, but damage to larger ones can result in serious complications. Damage to one of the major arteries leading to the brain can cause a stroke, either through bleeding from the artery or through the formation of a blood clot at the site of injury, blocking blood flow to the brain. Blood clots also can develop in other parts of the head. Other types of vascular complications include vasospasm, in which blood vessels constrict and restrict blood flow, and the formation of aneurysms, in which the side of a blood vessel weakens and balloons out.

Fluid and hormonal imbalances can also complicate treatment. Hormonal problems can result from dysfunction of the pituitary, the thyroid, and other glands throughout the body. Two common hormonal complications of TBI are syndrome of inappropriate secretion of antidiuretic hormone and hypothyroidism.

Another common problem is spasticity. In this situation, certain muscles of the body are tight or hypertonic because they cannot fully relax.

When due to high blood pressure, they typically occur in the putamen or thalamus (60%), cerebrum (20%), cerebellum (13%) or pons (7%).

CT scan (computed tomography) is the definitive tool for accurate diagnosis of an intracranial hemorrhage. In difficult cases, a 3T-MRI scan can also be used.

When ICP is increased the heart rate may be decreased.

Traumatic brain injury (TBI, physical trauma to the brain) can cause a variety of complications, health effects that are not TBI themselves but that result from it. The risk of complications increases with the severity of the trauma; however even mild traumatic brain injury can result in disabilities that interfere with social interactions, employment, and everyday living. TBI can cause a variety of problems including physical, cognitive, emotional, and behavioral complications.

Symptoms that may occur after a concussion – a minor form of traumatic brain injury – are referred to as post-concussion syndrome.

It is important that a person receive medical assessment, including a complete neurological examination, after any head trauma. A CT scan or MRI scan will usually detect significant subdural hematomas.

Subdural hematomas occur most often around the tops and sides of the frontal and parietal lobes. They also occur in the posterior cranial fossa, and near the falx cerebri and tentorium cerebelli. Unlike epidural hematomas, which cannot expand past the sutures of the skull, subdural hematomas can expand along the inside of the skull, creating a concave shape that follows the curve of the brain, stopping only at the dural reflections like the tentorium cerebelli and falx cerebri.

On a CT scan, subdural hematomas are classically crescent-shaped, with a concave surface away from the skull. However, they can have a convex appearance, especially in the early stage of bleeding. This may cause difficulty in distinguishing between subdural and epidural hemorrhages. A more reliable indicator of subdural hemorrhage is its involvement of a larger portion of the cerebral hemisphere since it can cross suture lines, unlike an epidural hemorrhage. Subdural blood can also be seen as a layering density along the tentorium cerebelli. This can be a chronic, stable process, since the feeding system is low-pressure. In such cases, subtle signs of bleeding such as effacement of sulci or medial displacement of the junction between gray matter and white matter may be apparent. A chronic bleed can be the same density as brain tissue (called isodense to brain), meaning that it will show up on CT scan as the same shade as brain tissue, potentially obscuring the finding.

Computed tomography is the most sensitive and specific of the imaging techniques. The facial bones can be visualized as slices through the skeletal in either the axial, coronal or sagittal planes. Images can be reconstructed into a 3-dimensional view, to give a better sense of the displacement of various fragments. 3D reconstruction, however, can mask smaller fractures owing to volume averaging, scatter artifact and surrounding structures simply blocking the view of underlying areas.

Research has shown that panoramic radiography is similar to computed tomography in its diagnostic accuracy for mandible fractures and both are more accurate than plain film radiograph. The indications to use CT for mandible fracture vary by region, but it does not seem to add to diagnosis or treatment planning except for comminuted or avulsive type fractures, although, there is better clinician agreement on the location and absence of fractures with CT compared to panoramic radiography.

There are various classification systems of mandibular fractures in use.

A "subarachnoid hemorrhage" is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain. Besides from head injury, it may occur spontaneously, usually from a ruptured cerebral aneurysm. Symptoms of SAH include a severe headache with a rapid onset ("thunderclap headache"), vomiting, confusion or a lowered level of consciousness, and sometimes seizures. The diagnosis is generally confirmed with a CT scan of the head, or occasionally by lumbar puncture. Treatment is by prompt neurosurgery or radiologically guided interventions with medications and other treatments to help prevent recurrence of the bleeding and complications. Since the 1990s, many aneurysms are treated by a minimal invasive procedure called "coiling", which is carried out by instrumentation through large blood vessels. However, this procedure has higher recurrence rates than the more invasive craniotomy with clipping.

Treatment of a subdural hematoma depends on its size and rate of growth. Some small subdural hematomas can be managed by careful monitoring until the body heals itself. Other small subdural hematomas can be managed by inserting a temporary small catheter through a hole drilled through the skull and sucking out the hematoma; this procedure can be done at the bedside. Large or symptomatic hematomas require a craniotomy, the surgical opening of the skull. A surgeon then opens the dura, removes the blood clot with suction or irrigation, and identifies and controls sites of bleeding. Postoperative complications include increased intracranial pressure, brain edema, new or recurrent bleeding, infection, and seizure. The injured vessels must be repaired.

Depending on the size and deterioration, age of the patient, and anaesthetic risk posed, subdural hematomas occasionally require craniotomy for evacuation; most frequently, simple burr holes for drainage; often conservative treatment; and rarely, palliative treatment in patients of extreme age or with no chance of recovery.

In those with a chronic subdural hematoma, but without a history of seizures, the evidence is unclear if using anticonvulsants is harmful or beneficial.

Computed tomography (CT scan): A CT scan may be normal if it is done soon after the onset of symptoms. A CT scan is the best test to look for bleeding in or around your brain. In some hospitals, a perfusion CT scan may be done to see where the blood is flowing and not flowing in your brain.

Magnetic resonance imaging (MRI scan): A special MRI technique (diffusion MRI) may show evidence of an ischemic stroke within minutes of symptom onset. In some hospitals, a perfusion MRI scan may be done to see where the blood is flowing and not flowing in your brain.

Angiogram: a test that looks at the blood vessels that feed the brain. An angiogram will show whether the blood vessel is blocked by a clot, the blood vessel is narrowed, or if there is an abnormality of a blood vessel known as an aneurysm.

Carotid duplex: A carotid duplex is an ultrasound study that assesses whether or not you have atherosclerosis (narrowing) of the carotid arteries. These arteries are the large blood vessels in your neck that feed your brain.

Transcranial Doppler (TCD): Transcranial Doppler is an ultrasound study that assesses whether or not you have atherosclerosis (narrowing) of the blood vessels inside of your brain. It can also be used to see if you have emboli (blood clots) in your blood vessels.

Diagnosis is principally by MRI. Frequently, arachnoid cysts are incidental findings on MRI scans performed for other clinical reasons. In practice, diagnosis of symptomatic arachnoid cysts requires symptoms to be present, and many with the disorder never develop symptoms.

Additional clinical assessment tools that can be useful in evaluating a patient with arachnoid cysts include the mini-mental state examination (MMSE), a brief questionnaire-based test used to assess cognition.

Many studies of the mechanical properties of brain edema were conducted in the 2010, most of them based on finite element analysis (FEA), a widely used numerical method in solid mechanics. For example, Gao and Ang used the finite element method to study changes in intracranial pressure during craniotomy operations. A second line of research on the condition looks at thermal conductivity, which is related to tissue water content.