FMGE 2024 — Anatomy
11 Previous Year Questions with Answers & Explanations
A surgical procedure is performed on the great saphenous vein, around 2.5 cm anterior to the medial malleolus. Which of the following structures is most likely to be injured?
In the given image, the physician is trying to palpate which of the following arteries?
Which of the following structures develop from the 6th pharyngeal arch artery on the left side?
Which of the following is the type of joint between epiphysis and diaphysis of a long bone?
Which of the following nerves supplies the muscle that is involved in the moment given below?
Which nerve defect causes lagophthalmos?
Which nerve innervates the lateral rectus muscle?
Identify the marked structure:
Which muscle is innervated by the Abducens nerve?
Anencephaly occurs due to the inability of the neural tube to close at which week of intrauterine life?
FMGE 2024 - Anatomy FMGE Practice Questions and MCQs
Question 1: A surgical procedure is performed on the great saphenous vein, around 2.5 cm anterior to the medial malleolus. Which of the following structures is most likely to be injured?
- A. Tibial nerve
- B. Deep peroneal nerve
- C. Sural nerve
- D. Saphenous nerve (Correct Answer)
Explanation: ***Saphenous nerve***- The **saphenous nerve**, a terminal cutaneous branch of the femoral nerve, accompanies the **great saphenous vein (GSV)** throughout the length of the leg on the medial side.- It crosses the ankle just anterior to the medial malleolus, lying immediately adjacent to the GSV, making it highly susceptible to injury during surgical procedures like GSV cannulation, harvesting, or varicose vein surgery in this region.*Sural nerve*- The **sural nerve** is located laterally, typically accompanying the **small saphenous vein (SSV)**, and runs behind the **lateral malleolus**.- Therefore, it is anatomically distant from the surgical site located anterior to the medial malleolus.*Deep peroneal nerve*- The **deep peroneal nerve** is located deep within the **anterior compartment** of the leg and supplies the muscles of the anterior compartment.- Although its terminal branches cross the dorsum of the foot, it is not directly associated with the superficial GSV or the medial malleolus in a manner that would predispose it to injury during this specific superficial procedure.*Tibial nerve*- The **tibial nerve** passes through the **tarsal tunnel**, located deep and posterior (behind) the **medial malleolus**.- This nerve supplies the posterior compartment muscles and is deep to the fascia, making it unlikely to be injured during a superficial procedure performed 2.5 cm *anterior* to the medial malleolus.
Question 2: In the given image, the physician is trying to palpate which of the following arteries?
- A. Anterior tibial artery
- B. Posterior tibial artery (Correct Answer)
- C. Lateral plantar artery
- D. Dorsalis pedis artery
Explanation: ***Posterior tibial artery***- The standard location for palpation of the **posterior tibial artery** pulse is just posterior and slightly inferior to the **medial malleolus**, ensuring evaluation of the posterior circulation of the foot.- Palpating this pulse, along with the **dorsalis pedis artery** pulse, is essential for determining adequate distal perfusion and diagnosing conditions like **Peripheral Arterial Disease (PAD)**.*Anterior tibial artery*- The **anterior tibial artery** is located deep within the anterior compartment of the leg.- It is typically not palpated in the leg; rather, its continuation, the **dorsalis pedis artery**, is palpated on the dorsum of the foot.*Dorsalis pedis artery*- Palpation of the **dorsalis pedis artery** (DPA) occurs on the dorsum of the foot, lateral to the tendon of the **extensor hallucis longus**.- This pulse assesses the blood flow supplied by the anterior circulation, differentiating it from the site behind the medial malleolus.*Lateral plantar artery*- The **lateral plantar artery** is situated deep within the sole of the foot, alongside the lateral plantar nerve.- Its deep location makes it generally inaccessible and impractical for routine clinical pulse assessment.
Question 3: Which of the following structures develop from the 6th pharyngeal arch artery on the left side?
- A. Arch of Aorta
- B. Subclavian artery
- C. Carotid arteries
- D. Ductus arteriosus (Correct Answer)
Explanation: ***Ductus arteriosus*** - The **ductus arteriosus** develops from the persistence of the distal portion of the **left 6th pharyngeal arch artery**. [2] - This structure is critical in fetal circulation, allowing blood to bypass the non-functional fetal lungs by shunting flow from the left pulmonary artery to the descending aorta. [1], [3] *Arch of Aorta* - The **arch of the aorta** mainly develops from the **aortic sac** and the distal part of the **left 4th pharyngeal arch artery**. - The 6th arch contributes only to the pulmonary system and the ductus shunt, not the primary aortic arch. *Carotid arteries* - Both the **common carotid arteries** and the **internal carotid arteries** are major derivatives of the **3rd pharyngeal arch arteries**. - The 3rd arch artery structure is completely separate from the 6th arch involvement in lung circulation development. *Subclavian artery* - The **left subclavian artery** arises largely from the **7th cervical intersegmental artery**, which is not part of the aortic arch system itself. - The **right subclavian artery** develops from the right 4th pharyngeal arch artery, the 7th intersegmental artery, and the right dorsal aorta.
Question 4: Which of the following is the type of joint between epiphysis and diaphysis of a long bone?
- A. Synchondrosis (Correct Answer)
- B. Syndesmosis
- C. Synostosis
- D. Symphysis
Explanation: ***Synchondrosis***- A **synchondrosis** is a cartilaginous joint in which the bone parts are united by **hyaline cartilage**. - The classic example is the **epiphyseal plate** (growth plate) found between the epiphysis and diaphysis of a growing long bone, which permits bone lengthening. [1] *Symphysis*- A **symphysis** is a type of cartilaginous joint where articulating surfaces are covered by hyaline cartilage but separated by a broad plate of **fibrocartilage**.- Examples include the **pubic symphysis** and the joints between vertebral bodies (intervertebral discs). *Synostosis*- A **synostosis** is an immobile bony joint formed when two bones grow together and completely fuse, typically resulting from the ossification of a fibrous or cartilaginous joint.- After skeletal maturity, the synchondrosis of the epiphyseal plate ultimately forms a **synostosis** (the epiphyseal line/scar). [1] *Syndesmosis*- A **syndesmosis** is a type of fibrous joint where articulating bones are joined by a sheet of fibrous tissue, specifically a **ligament** or an **interosseous membrane**.- Key examples include the distal **tibiofibular joint** and the joints between the shafts of the radius and ulna.
Question 5: Which of the following nerves supplies the muscle that is involved in the moment given below?
- A. A. Spinal accessory nerve (Correct Answer)
- B. C. Axillary nerve
- C. D. Radial nerve
- D. B. Long thoracic nerve
Explanation: ***A. Spinal accessory nerve*** - This nerve provides motor innervation to the **Trapezius muscle**, which is responsible for elevation (shrugging) and retraction/rotation of the scapula, allowing the movement described. - It also innervates the **Sternocleidomastoid muscle**, which is crucial for turning the head to the opposite side and neck flexion. *B. Long thoracic nerve* - The long thoracic nerve supplies the **Serratus anterior** muscle, which protracts the scapula and stabilizes it against the chest wall. - Damage to this nerve results in **winged scapula**, particularly noticeable when pushing against a wall. *C. Axillary nerve* - The **Axillary nerve** primarily supplies the **Deltoid** (responsible for shoulder abduction after the initial 15 degrees) and the **Teres minor** muscles. - Impairment typically involves difficulty initiating or maintaining shoulder abduction and loss of sensation over the **regimental badge area**. *D. Radial nerve* - The radial nerve is the nerve of the posterior compartment of the arm, supplying all the **extensor muscles** of the upper limb. - It is vital for elbow extension via the **Triceps** and extension of the wrist and fingers, not the primary nerve for scapular movement.
Question 6: Which nerve defect causes lagophthalmos?
- A. 7th nerve (Correct Answer)
- B. 5th nerve
- C. 4th nerve
- D. 6th nerve
Explanation: ***7th nerve***- The **Facial nerve (CN VII)** is crucial for eyelid closure as it innervates the **orbicularis oculi** muscle, one of the muscles of facial expression.- Paralysis of the 7th nerve prevents the eye from closing fully, leading to the condition known as **lagophthalmos** and subsequent exposure keratopathy.*6th nerve*- The **Abducens nerve (CN VI)** innervates the **lateral rectus** muscle, which is responsible for abducting (moving outward) the eye.- A defect results in **esotropia** (inward turning of the eye) and horizontal diplopia, unrelated to eyelid function.*4th nerve*- The **Trochlear nerve (CN IV)** innervates the **superior oblique** muscle, assisting in depression and intorsion of the eye.- Defect typically causes characteristic vertical and torsional **diplopia**, often worse when looking down and in, and does not cause lagophthalmos.*5th nerve*- The **Trigeminal nerve (CN V)** is primarily the sensory nerve of the face, with the **ophthalmic division (V1)** providing sensation to the cornea.- While a V1 defect abolishes the **afferent limb of the corneal reflex** and can lead to neurotrophic keratopathy, it does not supply the motor function required for eyelid closure.
Question 7: Which nerve innervates the lateral rectus muscle?
- A. A. Sixth nerve (Correct Answer)
- B. B. Seventh nerve
- C. C. Third nerve
- D. D. Fourth nerve
Explanation: ***A. Sixth nerve***- Also known as the **abducens nerve**, the sixth cranial nerve is solely responsible for innervating the **lateral rectus muscle**.- The lateral rectus muscle's action is **abduction** (moving the eye laterally), which is why paralysis of the sixth nerve causes the eye to turn medially (**medial strabismus**) [1], [2].- *B. Seventh nerve*- The seventh cranial nerve (**facial nerve**) is primarily responsible for **facial expression muscles** and relays taste sensation from the anterior two-thirds of the tongue.- It has no role in the motor innervation of the **extraocular muscles**.- *C. Third nerve*- The third cranial nerve (**oculomotor nerve**) innervates most of the extraocular muscles, including the **superior, inferior, and medial recti**, and the **inferior oblique** [1].- Paralysis results in the classic **"down and out"** gaze due to the unopposed action of the abducens and trochlear nerves.- *D. Fourth nerve*- The fourth cranial nerve (**trochlear nerve**) innervates only the **superior oblique muscle** [1].- The action of the superior oblique muscle is primary **intorsion**, depression, and abduction.
Question 8: Identify the marked structure:
- A. Internal capsule (Correct Answer)
- B. Lateral ventricle
- C. Body of fornix
- D. Globus pallidus
Explanation: ***Internal capsule***- This highly organized tract of **white matter** separates the **lentiform nucleus** (globus pallidus and putamen) laterally from the **caudate nucleus** and **thalamus** medially in axial/coronal brain sections.- It contains vital ascending sensory fibers and all descending **cortical efferent fibers**, including the **corticospinal tract**.*Body of fornix*- The **fornix** is an arched **white matter** tract situated inferior to the **corpus callosum** and superior to the **third ventricle** in the midline of the brain.- It connects the **hippocampi** to the **mammillary bodies** and is a critical part of the **limbic system** involved in memory.*Globus pallidus*- The **globus pallidus** is a **gray matter** structure and forms the inner, medial portion of the **lentiform nucleus**.- It is situated immediately **lateral** to the **internal capsule** and plays a crucial inhibitory role in the **basal ganglia motor circuit***Lateral ventricle*- The **lateral ventricles** are C-shaped, paired, **CSF-filled** spaces located within the cerebral hemispheres.- They are typically situated adjacent to the **caudate nucleus** head/body, appearing as **hypodense** (dark) fluid spaces on neuroimaging.
Question 9: Which muscle is innervated by the Abducens nerve?
- A. Medial rectus
- B. Lateral rectus (Correct Answer)
- C. Inferior oblique
- D. Superior oblique
Explanation: ***Lateral rectus***- The **Abducens nerve (CN VI)** specifically innervates only the **lateral rectus muscle** [1].- This muscle is responsible for moving the eyeball **laterally**, a movement known as **abduction** [1].*Medial rectus*- This muscle is innervated by the **Oculomotor nerve (CN III)**, not the Abducens nerve [1].- The primary action of the medial rectus is **adduction** (moving the eye medially) [1].*Superior oblique*- This muscle is innervated by the **Trochlear nerve (CN IV)**, which is unique among cranial nerves.- Its primary functions are **intorsion** (internal rotation) and **depression** of the eye.*Inferior oblique*- This muscle is innervated by the **Oculomotor nerve (CN III)**, along with the other recti (except lateral) and the levator palpebrae superioris.- Its main actions are **extorsion** (external rotation) and **elevation** of the eye [1].
Question 10: Anencephaly occurs due to the inability of the neural tube to close at which week of intrauterine life?
- A. 2nd week
- B. 3rd week
- C. 4th week (Correct Answer)
- D. 5th week
Explanation: ***4th week***- The development of the **neural tube** occurs during the 4th week of intrauterine life, with the **anterior neuropore** normally closing around day 25 after conception. - Failure of this anterior closure, specifically at the cranial end during the 4th week, results in the severe congenital anomaly known as **anencephaly** [1].*3rd week*- The 3rd week is when **neurulation** (the folding of the neural plate) is initiated and the neural groove is formed, not when the final critical closure occurs.- The developing embryo is undergoing **gastrulation** during the 3rd week (formation of the three germ layers), preceding the completion of neural tube closure.*5th week*- By the 5th week, the neural tube is typically completely closed, and the process of **primary brain vesiculation** (forebrain, midbrain, hindbrain) is actively underway.- A closure defect leading to anencephaly would have necessarily occurred earlier, during the 4th week.*2nd week*- The 2nd week of development is characterized by the formation of the **bilaminar germ disc** (epiblast and hypoblast) and implantation.- **neurulation** (the process that forms the neural tube) does not begin until the start of the 3rd week, making the 2nd week too early for this specific closure defect.