Benign essential blepharospasm:  A rare disorder in which the muscles of the eyelids (orbiculares oculi) do not function properly, and that includes intermittent and involuntary contractions or spasms of the muscles around the eyes. Although the eyes themselves are unaffected, the patient may eventually become functionally blind because of an inability to open the eyelids. Benign essential blepharospasm is a form of dystonia, which is a group of neuromuscular disorders characterized by muscle spasms. More about dystonia.
Benign essential tremor:  A neurologic movement disorder characterized by involuntary fine rhythmic tremor of a body part or parts, primarily the hands and arms (upper limbs).  More about essential tremor.
Biopsy:  The removal of a small portion of tissue, usually for the purpose of pathological examination and diagnosis.
Bone graft:  Small piece(s) of extra bone that act as the "cement" for fusing vertebrae together.
Brachial plexus:  A network of nerves in the neck, passing under the collarbone and into the armpit. These nerves originate from the 5th, 6th, 7th and 8th cervical spinal nerves and the first 2 thoracic spinal nerves.
Bradykinesia:  Slowness in movement. More about movement disorders.
Brainstem:  The part of the central nervous system at the top of the spinal cord and the bottom of the brain; the brainstem controls most vital functions. More about brainstem tumors.
Brown-Sequard syndrome:

 The loss of sensation of touch, position, and movement on the side of a spinal cord lesion, with loss of pain sensation on the other side. The syndrome is caused by a lesion limited to one side of the spinal cord. More about spinal tumors.

Weill Cornell Medicine Brain & Spine Center 525 East 68 Street, Box 99 New York, NY 10065 Phone: 866-426-7787