Erection Treatments include oral medication (such as colchicine) or surgery, which is most often reserved as a last resort. The following table shows how common various erection angles are for a standing male. In the table, zero degrees (0°) is pointing straight up against the abdomen, 90 degrees is horizontal and pointing straight forward, while 180 degrees would be pointing straight down to the feet. An upward pointing angle is most common. Erectile dysfunction (also known as ED or "(male) impotence") is a sexual dysfunction characterized by the inability to develop and/or maintain an erection. The study of erectile dysfunction within
Antiparallel (mathematics) and only if they make the same angle formula_18 in the opposite senses with the bisector of that angle (Fig.3). In a Euclidean space, two directed line segments, often called "vectors" in applied mathematics, are antiparallel, if they are supported by parallel lines and have opposite directions. In that case, one of the associated Euclidean vectors is the product of the other by a negative number. Antiparallel (mathematics) In geometry, anti-parallel lines can be defined with respect to either lines or angles. Given two lines formula_1 and formula_2, lines formula_3 and formula_4 are anti-parallel with respect to formula_1 and formula_2