Right angle Right angle In geometry and trigonometry, a right angle is an angle of exactly 90° (degrees), corresponding to a quarter turn. If a ray is placed so that its endpoint is on a line and the adjacent angles are equal, then they are right angles. The term is a calque of Latin "angulus rectus"; here "rectus" means "upright", referring to the vertical perpendicular to a horizontal base line. Closely related and important geometrical concepts are perpendicular lines, meaning lines that form right angles at their point of intersection, and orthogonality, which is the property of forming right angles, usually applied
Cerebellopontine angle syndrome There are different defined degrees of surgical excision, termed 'subtotal resection', 'radical subtotal resection', 'near-total resection', and 'total resection' in order or increasing proportion of tumor removed. Lesser amount of tumor removal may increase likelihood of preservation of nerve function (hence better post-operative hearing), but also likelihood of tumor regrowth, necessitating additional treatment. The overall complication rate following surgery is around 20%; cerebrospinal fluid leak is the most common. Cerebellopontine angle syndrome The cerebellopontine angle syndrome is a distinct neurological syndrome of deficits that can arise due to the closeness of the cerebellopontine angle to specific cranial nerves. Indications include