UPSC-CMS 2020 — Anatomy

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]

3 Previous Year Questions with Answers & Explanations

Questions

All Subjects Anatomy (3)Anesthesiology (1)Biochemistry (1)Community Medicine (34)Dermatology (1)Forensic Medicine (2)Internal Medicine (10)Microbiology (3)Obstetrics and Gynecology (32)Orthopaedics (4)Pathology (2)Pharmacology (3)Radiology (2)Surgery (21)

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

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

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