FMGE 2025 - Anatomy Practice Questions

Q: What stage of embryonic development is shown in the following image?

Blastocyst. ***Blastocyst*** - The image shows a structure with a distinct fluid-filled cavity (the **blastocoel**, labeled X), an inner cell mass (**embryoblast**), and an outer cell layer (**trophoblast**), which are the defining features of a blastocyst. - This stage occurs around day 5 post-fertilization and is responsible for implantation into the **endometrium** of the uterine wall, which is depicted superior to the blastocyst in the illustration. *Morula* - A morula is a solid, compacted ball of 16-32 cells (**blastomeres**) that precedes the blastocyst stage; it does not have the large internal cavity shown in the image. - The morula forms around day 3-4 after fertilization, and it is the entry of fluid into the morula that transforms it into a blastocyst. *Ova* - An ovum (plural: ova) is a single, unfertilized female gamete (egg cell). - The image shows a multicellular embryo that is the result of fertilization and several rounds of cell division, not a single cell. *Gastrula* - Gastrulation is the process that follows the blastocyst stage, where the embryo organizes into three primary germ layers: **ectoderm**, **mesoderm**, and **endoderm**. - The structure shown is a pre-implantation embryo and has not yet undergone gastrulation, which is characterized by the formation of the **primitive streak**.

Q: Identify the structure marked as 'X' in the image below

Buccopharyngeal fascia. ***Buccopharyngeal fascia*** - This fascia is a subdivision of the **pretracheal layer** of the deep cervical fascia that encloses the pharynx, esophagus, and buccinator muscle. - The pointer 'X' correctly identifies this structure, which forms the anterior boundary of the **retropharyngeal space** located immediately posterior to the pharynx. *Prevertebral fascia* - This layer of deep cervical fascia encloses the **vertebral column** and the deep muscles of the neck (e.g., longus colli, scalene muscles). - It is located posterior to the **alar fascia** and forms the floor of the posterior triangle of the neck. *Pharyngobasilar fascia* - This is a strong fibrous sheet that forms the internal framework of the **pharyngeal wall**, situated between the mucous membrane and the muscular layer. - It is an **internal** structure and is not visible on the external surface of the pharynx as indicated in the image. *Alar fascia* - This is a thin fascial layer located between the **buccopharyngeal fascia** anteriorly and the **prevertebral fascia** posteriorly. - It subdivides the space behind the pharynx into the true **retropharyngeal space** and the more posterior **danger space**.

Q: A 45-year-old patient presents with difficulty reacting to bright light. On examination, the pupillary light reflex is absent but the near reflex is preserved. Where is the lesion likely located?

Pretectal area of the midbrain. ***Pretectal area of the midbrain*** This clinical presentation describes **light-near dissociation** (Argyll Robertson pupil), where the pupillary light reflex is absent but the near (accommodation) reflex is preserved [2]. **Pathway Analysis:** - **Light reflex pathway**: Retina → optic nerve → optic tract → pretectal nucleus → bilateral Edinger-Westphal nuclei → pupillary constriction [1]. - **Near reflex pathway**: Visual cortex → frontal eye fields → Edinger-Westphal nucleus (bypasses pretectal area) **Why this lesion causes the finding:** A lesion in the **pretectal area** interrupts the light reflex pathway while sparing the near reflex pathway (which doesn't pass through the pretectal area), resulting in the characteristic light-near dissociation [2]. **Clinical significance:** - Classic finding in neurosyphilis (tabes dorsalis) [1] - Also seen in diabetes mellitus, multiple sclerosis, and midbrain lesions [1] - Pupils are typically small, irregular, and show poor light response *Incorrect - Edinger-Westphal nucleus* - This is the parasympathetic nucleus that provides the **final common pathway** for BOTH light and near reflexes [2] - A lesion here would abolish **both reflexes**, not cause dissociation *Incorrect - Optic nerve* - Lesion would cause an **afferent pupillary defect** (Marcus Gunn pupil) - Light reflex would be impaired in the affected eye, but near reflex would remain intact in both eyes - This doesn't explain bilateral light-near dissociation *Incorrect - Oculomotor nerve* - Carries parasympathetic fibers from Edinger-Westphal nucleus to the eye [2] - Lesion would cause **efferent defect** affecting both light AND near reflexes - Would also cause ptosis, ophthalmoplegia, and pupil dilation

Q: Identify the tarsal bone marked by the arrow in the given X-ray of the right foot.

Navicular. ***Navicular*** - The arrow correctly identifies the **navicular** bone, a boat-shaped tarsal bone situated on the **medial side** of the midfoot. It articulates proximally with the head of the **talus** and distally with the three **cuneiform** bones. - The navicular is a crucial component of the **medial longitudinal arch** of the foot and is a common site for avascular necrosis (**Köhler disease** in children) or stress fractures. *Cuboid* - The **cuboid** bone is located on the **lateral aspect** of the foot, articulating with the calcaneus proximally and the fourth and fifth metatarsals distally. The structure indicated by the arrow is on the medial side. - It forms the keystone of the **lateral longitudinal arch** and is not the bone indicated in the X-ray. *Intermediate cuneiform* - The **intermediate cuneiform** bone is located **distal** (further towards the toes) to the navicular bone, between the medial and lateral cuneiforms. - It articulates distally with the base of the **second metatarsal**, forming part of the **Lisfranc joint** complex. *Lateral cuneiform* - The **lateral cuneiform** is also situated **distal** to the navicular, lateral to the intermediate cuneiform, and medial to the cuboid bone. - It articulates distally with the base of the **third metatarsal** and is not the bone marked by the arrow, which is more proximal.

Q: Identify the bone indicated by the arrow in the image.

Navicular. ***Navicular*** - The arrow points to the navicular bone, a key tarsal bone located on the **medial side** of the foot. It articulates proximally with the **talus** and distally with the three **cuneiform** bones. - Its characteristic boat-like shape is identifiable on this AP radiograph, and it serves as the keystone of the **medial longitudinal arch** of the foot. *Cuboid* - The **cuboid** bone is located on the **lateral side** of the foot, articulating proximally with the **calcaneus** and distally with the fourth and fifth metatarsals. The indicated bone is medial. - The cuboid has a more cubical shape, which differentiates it from the scaphoid or boat-like shape of the navicular. *Intermediate cuneiform* - The **intermediate cuneiform** is located **distal** to the navicular bone and proximal to the base of the second metatarsal. The arrow points to a more proximal bone. - It is situated between the medial and lateral cuneiforms, forming part of the transverse arch of the foot. *Lateral cuneiform* - The **lateral cuneiform** is also located **distal** to the navicular, articulating with the third metatarsal. The arrow indicates the bone proximal to the cuneiform row. - It articulates with the intermediate cuneiform medially and the cuboid bone laterally, which is inconsistent with the indicated structure.

Q: A woman presents with a breast lump, associated with skin dimpling and nipple retraction. What is the most likely anatomical structure responsible for the skin dimpling?

Suspensory (Cooper’s) ligaments. ***Suspensory (Cooper’s) ligaments*** - These are fibrous septa that run from the deep pectoral fascia to the dermis of the skin, providing structural support to the breast [1]. - Invasion and shortening of these ligaments by a growing tumor pull on the overlying skin, causing the characteristic **skin dimpling** or peau d'orange appearance [1]. *Lactiferous ducts* - These are the milk ducts that converge and open at the nipple [1]. - Malignant infiltration of the lactiferous ducts is more commonly associated with **nipple retraction** and pathologic nipple discharge, rather than skin dimpling [2]. *Pectoral fascia* - This is a deep layer of connective tissue that covers the pectoralis major muscle, on which the breast lies [1]. - Tumor invasion into the pectoral fascia can cause the breast to become **fixed** to the chest wall, a sign of advanced disease, but does not directly cause superficial skin dimpling. *Subcutaneous fat* - This tissue makes up the bulk of the breast volume and surrounds the glandular components. - Subcutaneous fat itself lacks the tensile strength to pull the skin inward; it is the **fibrous ligaments** passing through the fat that cause retraction [1].

Q: What is the embryological basis for the uterine anomaly shown in the images?

Non-fusion of paramesonephric ducts. ***Non-fusion of paramesonephric ducts*** - The image shows a **uterus didelphys**, which is a complete duplication of the uterus and cervix. This anomaly occurs due to a complete failure of the two **paramesonephric (Müllerian) ducts** to fuse medially during embryogenesis. - The **paramesonephric ducts** are the embryological precursors to the fallopian tubes, uterus, cervix, and the upper one-third of the vagina. Their proper fusion is essential for forming a single uterine cavity. *Non-fusion of mesonephric duct* - The **mesonephric (Wolffian) ducts** are precursors to male internal genitalia (e.g., epididymis, ductus deferens, seminal vesicles) and largely regress in females. - Remnants of the mesonephric duct in females may form **Gartner's cysts**, but they do not contribute to the formation of the uterus. *Failure of fusion of metanephric duct* - The **metanephric duct**, or **ureteric bud**, is involved in the development of the urinary system, specifically the ureters, renal pelves, calyces, and collecting ducts of the kidneys. - This structure is entirely unrelated to the embryological development of the female reproductive tract. *Complete agenesis of Müllerian structures* - Complete agenesis of the **Müllerian structures** results in the congenital absence of the uterus, fallopian tubes, and upper vagina, a condition known as **Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome**. - The image clearly depicts the presence of uterine horns and a cervix, which contradicts a diagnosis of agenesis (complete absence).

Q: Which of the following veins is involved in the formation of esophageal varices?

Left gastric vein. ***Left gastric vein*** - The **left gastric vein** (coronary vein) is the primary vessel involved in esophageal varices formation through **portosystemic anastomoses** at the **gastroesophageal junction** during portal hypertension [1]. - It connects the **portal circulation** to the **systemic circulation** via esophageal veins, creating the most clinically significant pathway for variceal development [1]. *Left gastroepiploic vein* - This vein drains the **greater curvature of the stomach** and flows into the splenic vein, not forming significant connections with esophageal circulation. - It does not participate in **portosystemic anastomoses** at the esophageal level where varices typically develop. *Right gastric vein* - Drains the **lesser curvature of the stomach** and flows directly into the portal vein [2], with minimal anatomical connection to esophageal vessels. - Does not form the critical **portosystemic anastomoses** necessary for esophageal varices formation during portal hypertension. *Right gastroepiploic vein* - Drains the **greater curvature of the stomach** and connects to the superior mesenteric vein, distant from esophageal circulation. - Lacks the anatomical connections required for **portosystemic anastomoses** at the gastroesophageal junction where varices develop.

Q: Injury to which part causes difficulty in dorsiflexion of the foot?

B. ***B*** - This arrow points to the **head and neck of the fibula**. The **common fibular (peroneal) nerve** wraps around the fibular neck, making it susceptible to injury in this location. - Damage to the common fibular nerve results in paralysis of the muscles in the anterior and lateral compartments of the leg, leading to **foot drop**, which is the inability to dorsiflex and evert the foot. *A* - This arrow points to the **medial condyle of the femur**. Injury to this area typically affects the knee joint, potentially damaging ligaments like the MCL or the medial meniscus. - It does not directly involve the nerves responsible for foot dorsiflexion, which are located more laterally and distally. *C* - This arrow indicates the **shaft of the femur**. A fracture of the femoral shaft is a severe injury but does not typically cause isolated difficulty with foot dorsiflexion. - Foot drop could occur if the **sciatic nerve** is injured proximally in the thigh, but this would result in a more widespread neurological deficit affecting both plantarflexion and dorsiflexion. *D* - This arrow points to the **lateral condyle of the femur**. Similar to the medial condyle, an injury here would primarily compromise the structures of the knee joint itself, such as the LCL or lateral meniscus. - The course of the common fibular nerve is posterior to the lateral femoral condyle before it wraps around the fibular neck, so an isolated condylar fracture is unlikely to cause foot drop.

Q: A 30-year-old man came with choking episodes after ingestion of fish bone while eating. The fishbone got impacted at the level of T4 in the esophagus. Which is the most likely site of obstruction?

Arch of aorta. ***Arch of aorta*** - The esophagus has three principal anatomic constrictions where foreign bodies, such as swallowed fish bones, commonly lodge; the second constriction occurs at the level of **T4/T5** where the **arch of the aorta** passes anteriorly. - This large anatomical structure compresses the esophagus against the vertebral column, creating a localized narrowing precisely matching the T4 level described for the obstruction [1]. *Left bronchus* - The **left main bronchus** also crosses anterior to the esophagus and contributes significantly to the formation of the **middle esophageal constriction** at the T4/T5 level. - However, in standard radiological and endoscopic visualization, the compression caused by the arch of the aorta is often considered the dominant landmark at this specific location [1]. *Cricopharyngeus* - This structure forms the initial and **uppermost esophageal constriction** (upper esophageal sphincter), located at the level of the **C6 vertebra** (cervical spine). - Obstruction at the cricopharyngeus would occur in the neck, which is anatomically much higher than the reported **T4 (thoracic spine)** impaction site. *Diaphragm* - The passage of the esophagus through the **esophageal hiatus** of the diaphragm forms the **third and lowest physiological constriction**, typically located at the vertebral level of **T10**. - This site of potential foreign body obstruction is significantly distal and caudal to the T4 level described in the clinical case. Management of such objects often involves careful endoscopy under general anesthesia to prevent perforation [2].

Question 1

What stage of embryonic development is shown in the following image?

Accepted Answer

Blastocyst

Answer

Gastrula

Answer

Morula

Answer

Ova

Question 2

Identify the structure marked as 'X' in the image below

Accepted Answer

Buccopharyngeal fascia

Answer

Prevertebral fascia

Answer

Pharyngobasilar fascia

Answer

Alar fascia

Question 3

A 45-year-old patient presents with difficulty reacting to bright light. On examination, the pupillary light reflex is absent but the near reflex is preserved. Where is the lesion likely located?

Accepted Answer

Pretectal area of the midbrain

Answer

Edinger–Westphal nucleus

Answer

Optic nerve

Answer

Oculomotor nerve

Question 4

Identify the tarsal bone marked by the arrow in the given X-ray of the right foot.

Accepted Answer

Navicular

Answer

Cuboid

Answer

Intermediate cuneiform

Answer

Lateral cuneiform

Question 5

Identify the bone indicated by the arrow in the image.

Accepted Answer

Navicular

Answer

Intermediate cuneiform

Answer

Lateral cuneiform

Answer

Cuboid

Question 6

A woman presents with a breast lump, associated with skin dimpling and nipple retraction. What is the most likely anatomical structure responsible for the skin dimpling?

Accepted Answer

Suspensory (Cooper’s) ligaments

Answer

Lactiferous ducts

Answer

Subcutaneous fat

Answer

Pectoral fascia

Question 7

What is the embryological basis for the uterine anomaly shown in the images?

Accepted Answer

Non-fusion of paramesonephric ducts

Answer

Failure of fusion of metanephric duct

Answer

Non-fusion of mesonephric duct

Answer

Complete agenesis of Müllerian structures

Question 8

Which of the following veins is involved in the formation of esophageal varices?

Accepted Answer

Left gastric vein

Answer

Left gastroepiploic vein

Answer

Right gastric vein

Answer

Right gastroepiploic vein

Question 9

Injury to which part causes difficulty in dorsiflexion of the foot?

Accepted Answer

B

Answer

D

Answer

C

Answer

A

Question 10

A 30-year-old man came with choking episodes after ingestion of fish bone while eating. The fishbone got impacted at the level of T4 in the esophagus. Which is the most likely site of obstruction?

Accepted Answer

Arch of aorta

Answer

Diaphragm

Answer

Left bronchus

Answer

Cricopharyngeus

FMGE 2025 — Anatomy