Weber's syndrome is a form of stroke

Stroke

A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

 characterized by the presence of an oculomotor nerve palsy

Oculomotor nerve palsy

Oculomotor nerve palsy is an eye condition resulting from damage to the third cranial nerve or a branch thereof. As the name suggests, the oculomotor nerve supplies the majority of the muscles controlling eye movements. Thus, damage to this nerve will result in the affected individual being unable...

 and contralateral hemiparesis

Hemiparesis

Hemiparesis is weakness on one side of the body. It is less severe than hemiplegia - the total paralysis of the arm, leg, and trunk on one side of the body. Thus, the patient can move the impaired side of his body, but with reduced muscular strength....

 or hemiplegia.

Cause and presentation

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

Structure damaged	Effect
substantia nigra Substantia nigra The substantia nigra is a brain structure located in the mesencephalon that plays an important role in reward, addiction, and movement. Substantia nigra is Latin for "black substance", as parts of the substantia nigra appear darker than neighboring areas due to high levels of melanin in...	contralateral parkinsonism Parkinsonism Parkinsonism is a neurological syndrome characterized by tremor, hypokinesia, rigidity, and postural instability. The underlying causes of parkinsonism are numerous, and diagnosis can be complex...  because its dopaminergic projections to the basal ganglia Basal ganglia The basal ganglia are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit. They are situated at the base of the forebrain and are strongly connected with the cerebral cortex, thalamus and other brain areas...  innervate the ipsilateral hemisphere motor field, leading to a movement disorder of the contralateral body.
corticospinal fibers	contralateral hemiparesis and typical upper motor neuron Upper motor neuron Upper motor neurons are motor neurons that originate in the motor region of the cerebral cortex or the brain stem and carry motor information down to the final common pathway, that is, any motor neurons that are not directly responsible for stimulating the target muscle...  findings
corticobulbar tract	difficulty with contralateral lower facial muscles and hypoglossal nerve Hypoglossal nerve The hypoglossal nerve is the twelfth cranial nerve , leading to the tongue. The nerve arises from the hypoglossal nucleus and emerges from the medulla oblongata in the preolivary sulcus separating the olive and the pyramid. It then passes through the hypoglossal canal...  functions
oculomotor nerve Oculomotor nerve The oculomotor nerve is the 3rd of 12 paired cranial nerves. It enters the orbit via the superior orbital fissure and controls most of the eye's movements, including constriction of the pupil and maintaining an open eyelid by innervating the Levator palpebrae superiors muscle. The optic nerve is...  fibers	ipsilateral oculomotor nerve palsy Oculomotor nerve palsy Oculomotor nerve palsy is an eye condition resulting from damage to the third cranial nerve or a branch thereof. As the name suggests, the oculomotor nerve supplies the majority of the muscles controlling eye movements. Thus, damage to this nerve will result in the affected individual being unable...  with a drooping eyelid and fixed wide pupil pointed down and out. This leads to diplopia Diplopia Diplopia, commonly known as double vision, is the simultaneous perception of two images of a single object that may be displaced horizontally, vertically, or diagonally in relation to each other...

It is caused by midbrain infarction

Infarction

In medicine, infarction refers to tissue death that is caused by a local lack of oxygen due to obstruction of the tissue's blood supply. The resulting lesion is referred to as an infarct.-Causes:...

 as a result of occlusion of the paramedian branches of the posterior cerebral artery

Posterior cerebral artery

-External links: - Posterior Cerebral Artery Stroke* at strokecenter.org* at State University of New York Upstate Medical University* at psyweb.com* at neuropat.dote.hu...

 or of basilar bifurcation perforating arteries.

History

It carries the name of Sir Herman David Weber, a German-born physician working in London, who described the condition in 1863. It is unrelated to Sturge-Weber syndrome

Sturge-Weber syndrome

Sturge–Weber syndrome, sometimes referred to as encephalotrigeminal angiomatosis, is a rare congenital neurological and skin disorder. It is one of the phakomatoses and is often associated with port-wine stains of the face, glaucoma, seizures, mental retardation, and ipsilateral leptomeningeal...

 or Klippel-Trenaunay-Weber syndrome

Klippel-Trénaunay-Weber syndrome

Klippel-Trénaunay-Weber syndrome, often simply Klippel-Trénaunay syndrome and sometimes angioosteohypertrophy syndrome and hemangiectatic hypertrophy, is a rare congenital medical condition in which blood vessels and/or lymph vessels fail to form properly...

.

External links

• http://medinfo.ufl.edu/year2/neuro/review/bsc.html
• http://www.neuropat.dote.hu/table/kereszt7.htm