UPSC-CMS 2020 - Anatomy PYQs Practice Questions

Q: Which one of the following cranial nerves does NOT supply the external ear?

Cranial nerve VI. ***Cranial nerve VI*** - Cranial nerve VI, the **abducens nerve**, solely innervates the **lateral rectus muscle** of the eye, responsible for eye abduction. - It has no known role in the sensory or motor innervation of the external ear. *Cranial nerve V* - The **auriculotemporal nerve**, a branch of the **mandibular division of the trigeminal nerve (V3)**, provides sensory innervation to the anterior aspect of the external ear and the temporomandibular joint. - Therefore, cranial nerve V contributes to the innervation of the external ear. *Cranial nerve IX* - The **glossopharyngeal nerve (IX)** contributes to the innervation of the external ear through its **auricular branch**, which supplies a small area of skin near the external auditory meatus. - This provides some sensory input from the external ear. *Cranial nerve VII* - The **facial nerve (VII)** supplies motor innervation to the **auricular muscles** and provides sensory innervation to a small area of the concha via the **nervus intermedius**. - Its involvement is evident in various reflexes and sensations related to the ear. [Practice more Anatomy PYQs on OnCourse]

Q: Which one of the following is NOT a support of uterus, preventing its descent?

Inguinal ligament. ***Inguinal ligament*** - The **inguinal ligament** is a fibrous band extending from the **anterior superior iliac spine** to the **pubic tubercle**, forming the inferior border of the anterior abdominal wall [2]. - It plays no direct role in supporting the uterus; its primary function is to serve as an attachment site for muscles and define the **inguinal canal** [2]. *Endopelvic fascia* - The **endopelvic fascia** is a connective tissue layer that surrounds pelvic organs and contributes significantly to their support [1]. - It forms condensations such as the **uterosacral** and **cardinal (Mackenrodt's) ligaments**, which directly stabilize the uterus [1]. *Mackenrodt's ligament* - Also known as the **cardinal ligament** or **transverse cervical ligament**, it extends from the cervix and lateral vaginal fornix to the lateral pelvic walls [1]. - This ligament is a primary support of the uterus, preventing its descent and maintaining its position [1]. *Pubocervical ligament* - The **pubocervical ligament** extends from the anterior aspect of the cervix to the posterior surface of the pubic symphysis. - It is a condensation of the **endopelvic fascia** and provides anterior support to the uterus and bladder [1]. [Practice more Anatomy PYQs on OnCourse]

Q: Implantation of a fertilised ovum occurs on which day following fertilisation?

Day 6. ***Day 6*** * Fertilization occurs in the **ampulla** of the fallopian tube, and the zygote undergoes cleavage as it travels towards the uterus. * By day 5-6, the embryo develops into a **blastocyst** with an outer trophoblast layer and inner cell mass. * **Implantation begins on day 6-7** post-fertilization when the blastocyst attaches to the endometrium, making day 6 the correct answer for when implantation occurs. * The process continues and is complete by day 10-12, but the initial attachment (implantation) starts on day 6. *Incorrect: Day 14* * Day 14 marks the time of **ovulation** in a typical 28-day menstrual cycle, not implantation. * By day 14 post-fertilization, the embryo would have been implanted for approximately one week. *Incorrect: Day 20* * Implantation occurs much earlier, around day 6-12 post-fertilization. * By day 20 post-fertilization, the implanted embryo would be well into **gastrulation and organogenesis**. *Incorrect: Day 10* * While the implantation process may continue until day 10-12, it **begins on day 6**, not day 10. * Day 10 represents a later stage when implantation is nearly complete, but the question asks when implantation occurs (i.e., begins). [Practice more Anatomy PYQs on OnCourse]

Question 1

Which one of the following cranial nerves does NOT supply the external ear?

Accepted Answer

Cranial nerve VI

Answer

Cranial nerve V

Answer

Cranial nerve IX

Answer

Cranial nerve VII

Question 2

Which one of the following is NOT a support of uterus, preventing its descent?

Accepted Answer

Inguinal ligament

Answer

Endopelvic fascia

Answer

Mackenrodt's ligament

Answer

Pubocervical ligament

Question 3

Implantation of a fertilised ovum occurs on which day following fertilisation?

Accepted Answer

Day 6

Answer

Day 14

Answer

Day 20

Answer

Day 10

UPSC-CMS 2020 — Anatomy