Symptoms vary depending on whether the spinal cord, brain stem, nerves or their blood supply is affected by the pressure.

Symptoms become apparent when the neck is bent. They include:

- Posterior head pain

- Neck weakness

- Periods of confusion

- Dysarthria (difficulty swallowing or talking due to loss of muscle control)

- Dizziness

- Loss of sensation

- Cranial nerve disturbance

- Loss of the ability to know how joints are positioned

- Lhermitte's sign ('electric shock sensation' down spine and/or to the extremities when the neck is flexed forward)

- Weakness of the arms and legs

- Orthostatic hypotension

- Patients will go into a pool and notice that below their belly button the water is not as cold as it is above.

Complications from this can include hydrocephalus, pseudotumor cerebri or syringomyelia because it blocks the flow of fluid around the brain and spinal cord.

Basilar invagination is invagination (infolding) of the base of the skull that occurs when the top of the C2 vertebra migrates upward. It can cause narrowing of the foramen magnum (the opening in the skull where the spinal cord passes through to the brain). It also may press on the lower brainstem.

This is similar to Chiari malformation. That, however, is usually present at birth.

VBD

- Hemifacial spasm

- Paresis

- Trigeminal neuralgia

ICD

- Progressive visual field defect

Foville's syndrome is caused by the blockage of the perforating branches of the basilar artery in the region of the brainstem known as the pons. Most frequently caused by vascular disease or tumors involving the dorsal pons.[3]

Structures affected by the infarct are the PPRF, nuclei of cranial nerves VI and VII, corticospinal tract, medial lemniscus, and the medial longitudinal fasciculus. There's involvement of the fifth to eighth cranial nerves, central sympathetic fibres (Horner syndrome) and horizontal gaze palsy.[3]

This produces ipsilateral horizontal gaze palsy and facial nerve palsy and contralateral hemiparesis, hemisensory loss, and internuclear ophthalmoplegia.

The term dolichoectasia means elongation and distension. It is used to characterize arteries throughout the human body which have shown significant deterioration of their tunica intima (and occasionally the tunica media), weakening the vessel walls and causing the artery to elongate and distend.

Benedikt syndrome, also called Benedikt's syndrome or paramedian midbrain syndrome, is a rare type of posterior circulation stroke of the brain, with a range of neurological symptoms affecting the midbrain, cerebellum and other related structures.

Medial inferior pontine syndrome is a condition associated with a contralateral hemiplegia.

"Medial inferior pontine syndrome" has been described as equivalent to Foville's syndrome.

Benedikt syndrome is caused by a lesion ( infarction, hemorrhage, tumor, or tuberculosis) in the tegmentum of the midbrain and cerebellum. Specifically, the median zone is impaired. It can result from occlusion of the posterior cerebral artery or paramedian penetrating branches of the basilar artery.

Hemotympanum or hematotympanum, refers to the presence of blood in the tympanic cavity of the middle ear. Hemotympanum is often the result of basilar skull fracture.

Although medial pontine syndrome has many similarities to medial medullary syndrome, because it is located higher up the brainstem in the pons, it affects a different set of cranial nuclei.

Depending upon the size of the infarct, it can also involve the facial nerve.

Raymond Céstan syndrome is caused by blockage of the long circumferential branches of the basilar artery. It was described by Étienne Jacques Marie Raymond Céstan and Louis Jean Chenais. Along with other related syndromes such as Millard-Gubler syndrome, Foville's syndrome, and Weber's syndrome, the description was instrumental in establishing important principles in brain-stem localization.

Raccoon eye/eyes (also known in the United Kingdom and Ireland as panda eyes) or periorbital ecchymosis is a sign of basal skull fracture or subgaleal hematoma, a craniotomy that ruptured the meninges, or (rarely) certain cancers. Bilateral hemorrhage occurs when damage at the time of a facial fracture tears the meninges and causes the venous sinuses to bleed into the arachnoid villi and the cranial sinuses. In layman's terms, blood from skull fracture seeps into the soft tissue around the eyes. Raccoon eyes may be accompanied by Battle's sign, an ecchymosis behind the ear. These signs may be the only sign of a skull fracture, as it may not show on an X-ray. They may not appear until up 2–3 days after the injury. It is recommended that the patient not blow their nose, cough vigorously, or strain to prevent further tearing of the meninges.

Raccoon eyes may be bilateral or unilateral. If bilateral, it is highly suggestive of basilar skull fracture, with a positive predictive value of 85%. They are most often associated with fractures of the anterior cranial fossa.

Raccoon eyes may also be a sign of disseminated neuroblastoma or of amyloidosis (multiple myeloma).

Depending on cause, raccoon eyes always require urgent consultation and management, that is surgical (facial fracture or post-craniotomy) or medical (neuroblastoma or amyloidosis).

Brain herniation frequently presents with abnormal posturing a characteristic positioning of the limbs indicative of severe brain damage. These patients have a lowered level of consciousness, with Glasgow Coma Scores of three to five. One or both pupils may be dilated and fail to constrict in response to light. Vomiting can also occur due to compression of the vomiting center in the medulla oblongata.

In traumatic heterotopic ossification (traumatic myositis ossificans), the patient may complain of a warm, tender, firm swelling in a muscle and decreased range of motion in the joint served by the muscle involved. There is often a history of a blow or other trauma to the area a few weeks to a few months earlier. Patients with traumatic neurological injuries, severe neurologic disorders or severe burns who develop heterotopic ossification experience limitation of motion in the areas affected.

In "central herniation", the diencephalon and parts of the temporal lobes of both of the cerebral hemispheres are squeezed through a notch in the tentorium cerebelli. Transtentorial herniation can occur when the brain moves either up or down across the tentorium, called ascending and descending transtentorial herniation respectively; however descending herniation is much more common. Downward herniation can stretch branches of the basilar artery (pontine arteries), causing them to tear and bleed, known as a Duret hemorrhage. The result is usually fatal. Other symptoms of this type of herniation include small, dilated, fixed pupils with paralysis of upward eye movement giving the characteristic appearance of "sunset eyes". Also found in these patients, often as a terminal complication is the development of diabetes insipidus due to the compression of the pituitary stalk. Radiographically, downward herniation is characterized by obliteration of the suprasellar cistern from temporal lobe herniation into the tentorial hiatus with associated compression on the cerebral peduncles. Upwards herniation, on the other hand, can be radiographically characterized by obliteration of the quadrigeminal cistern. Intracranial hypotension syndrome has been known to mimic downwards transtentorial herniation.

The main symptom of benign fasciculation syndrome is focal or widespread involuntary muscle activity (twitching), which can occur at random or specific times (or places). Presenting symptoms of benign fasciculation syndrome may include:

- Fasciculations (primary symptom)

- Blepharospasms (eye spasms)

- Generalized fatigue

- Muscle pain

- Anxiety (which can also be a cause)

- Exercise intolerance

- Globus sensation

- Paraesthesias

- Muscle cramping or spasms

Other symptoms include:

- Hyperreflexia

- Muscle stiffness

- Tremors

- Itching

- Myoclonic jerks

BFS symptoms are typically present when the muscle is at rest and are not accompanied by severe muscle weakness. In some BFS cases, fasciculations can jump from one part of the body to another. For example, it could start in a leg muscle, then in a few seconds jump to the forehead, then the abdomen, etc. Because fasciculations can occur on the head, this strongly suggests the brain as the generator due to its exclusive non-dependence on the spinal cord. (Together, the brain and spinal cord comprise the central nervous system.)

Anxiety is often caused as a result of BFS, and a lot of sufferers have hypochondria as BFS mimics symptoms of much more serious diseases such as amyotrophic lateral sclerosis (ALS).

Benign fasciculation syndrome (BFS) is a neurological disorder characterized by fasciculation (twitching) of various voluntary muscles in the body. The twitching can occur in any voluntary muscle group but is most common in the eyelids, arms, legs, and feet. Even the tongue may be affected. The twitching may be occasional or may go on nearly continuously. Usually intentional movement of the involved muscle causes the fasciculations to cease immediately, but they may return once the muscle is at rest again.

A basilar skull fracture is a break of a bone in the base of the skull. Symptoms may include bruising behind the ears, bruising around the eyes, or blood behind the ear drum. A cerebrospinal fluid (CSF) leak occurs in about 20% of cases and can result in fluid leaking from the nose or ear. Meningitis is a complication in about 14% of cases. Other complications include cranial nerve or blood vessel injury.

They typically require a significant degree of trauma to occur. The break is of at least one of the following bones: temporal bone, occipital bone, sphenoid bone, frontal bone, or ethmoid bone. They are divided into anterior fossa, middle fossa, and poterior fossa fractures. Facial fractures often also occur. Diagnosis is typically by CT scan.

Treatment is generally based on the injury to structures inside the head. Surgery may be done for a CSF leak that does not stop or an injury to a blood vessel or nerve. Preventative antibiotics are of unclear use. It occurs in about 12% of people with a severe head injury.

Weber's syndrome (superior alternating hemiplegia) is a form of stroke characterized by the presence of an ipsilateral oculomotor nerve palsy and contralateral hemiparesis or hemiplegia.

This lesion is usually unilateral and affects several structures in the midbrain including:

It is caused by midbrain infarction as a result of occlusion of the paramedian branches of the posterior cerebral artery or of basilar bifurcation perforating arteries.

Heterotopic ossification (HO) is the process by which bone tissue forms outside of the skeleton.

Diagnostic criteria require motor symptoms and at least one visual, sensory, or speech symptom, resembling basilar migraine. They may also be associated with cerebellar signs.

Locked-in syndrome usually results from quadriplegia and the inability to speak in otherwise cognitively intact individuals. Those with locked-in syndrome may be able to communicate with others through coded messages by blinking or moving their eyes, which are often not affected by the paralysis. The symptoms are similar to those of sleep paralysis. Patients who have locked-in syndrome are conscious and aware, with no loss of cognitive function. They can sometimes retain proprioception and sensation throughout their bodies. Some patients may have the ability to move certain facial muscles, and most often some or all of the extraocular muscles. Individuals with the syndrome lack coordination between breathing and voice. This prevents them producing voluntary sounds, though the vocal cords are not paralysed.

MRI features can be suggestive of cortical hyper intensity and edema.