A chancre usually appears on the external genitalia in which of the following condition:

Correct Answer: A

Rationale: Rationale: A chancre is a painless ulcer that is characteristic of primary syphilis infection. It usually appears on the external genitalia as a result of Treponema pallidum infection. This is distinct from the other conditions listed: Gonorrhea presents with urethritis and discharge, Trichomoniasis with vaginal discharge and irritation, and Herpes genitalis with painful vesicles or ulcers. Syphilis is the only condition among the choices that typically presents with a chancre on the external genitalia.

Correct Answer: B

Rationale: The correct answer is B: Amenorrhea. Amenorrhea refers to the absence of menstruation, which can be caused by various factors such as hormonal imbalances, stress, pregnancy, or medical conditions. Rhinorrhea (A) is the medical term for a runny nose, unrelated to menstruation. Menorrhagia (C) is excessive menstrual bleeding, the opposite of absence of menstruation. Leucorrhea (D) is a vaginal discharge, not related to the absence of menstruation. Therefore, B is the correct answer as it directly addresses the absence of menstruation.

Correct Answer: B

Rationale: The correct answer is B: Episiotomy. An episiotomy is a surgical incision made in the perineum during childbirth to enlarge the vaginal opening and prevent severe perineal tears. This procedure is performed to facilitate the delivery of the baby and reduce the risk of complications for both the mother and the baby. Perineorrhaphy (A) is a surgical repair of a perineal tear or episiotomy after childbirth, not the procedure of making the incision. Cesarean section (C) is a surgical procedure to deliver a baby through an incision in the mother's abdomen and uterus, not related to perineal tears. Tubal ligation (D) is a permanent form of female sterilization by blocking or sealing the fallopian tubes to prevent pregnancy, not relevant to perineal tears during childbirth.

Correct Answer: C

Rationale: The correct answer is C: Parietal bone. The parietal bone forms the roof and upper part of the sides of the cranium. It articulates with other bones, such as the frontal, temporal, and occipital bones, to create the structure of the skull. The frontal bone (A) forms the forehead, the temporal bone (B) is located on the sides of the skull, and the occipital bone (D) forms the back and base of the skull. Therefore, the parietal bone is the only bone among the choices that specifically fits the description of forming the roof and upper part of the sides of the cranium.

Correct Answer: C

Rationale: The patella is a sesamoid bone located within the tendon of the quadriceps femoris muscle. Sesamoid bones are small, round bones embedded within tendons, providing protection and improving the mechanical advantage of the muscle. It is not irregular (A), short (B), or flat (D) as it does not fit the structural characteristics of those bone types. Therefore, the correct answer is C.