Teratoma:  Tumor or growth made up of several different types of tissue (fat, bone, muscle, skin).
Thalamus:  Brain cells that lie in the upper part of the brainstem.
Thrombolytic agent:  A clot-busting" drug; such agents may be administered into veins or arteries.
Thrombus:  A blood clot attached to the wall of an artery.
Tic douloureux:  See trigeminal neuralgia.
Torticollis:  The spasmodic contraction of neck muscles drawing the head to one side with the chin pointing to the other side. More about movement disorders.
Transsphenoidal approach:  Operative method of reaching the pituitary gland or skull base traversing the nose and sinuses. More about pituitary surgery.
Transverse process:  The wing of bone on either side of each vertebral arch where the pedicle meets the lamina.

 A neurologic movement disorder characterized by involuntary fine rhythmic tremor of a body part or parts, primarily the hands and arms (upper limbs). In many affected individuals, upper limb tremor may occur as an isolated finding. However, in others, tremor may gradually involve other anatomic regions, such as the head, voice, tongue, or roof of the mouth (palate), leading to difficulties articulating speech (dysarthria). Less commonly, tremor may affect muscles of the trunk or legs. More about essential tremor.

Trigeminal nerve:  The fifth cranial nerve and the largest, it is primarily sensory except for a small motor branch that supplies the muscles for chewing. The branches of the trigeminal nerve provide sensation to the eye and forehead, midface, and upper and lower jaw.
Trigeminal neuralgia:  Paroxysmal pain in the face. Pain may be so severe that it causes an involuntary grimace or "tic" (tic douloureux). More about trigeminal neuralgia.

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