DFT-ANATOMY MINI TEST 20/09/2025

1. A 68-year-old male with a history of poorly controlled hypertension and type 2 diabetes mellitus is brought to the emergency department for sudden onset of slurred speech and right-sided facial weakness that began two hours ago. On examination, there is a noticeable flattening of the right nasolabial fold and drooping of the right corner of the mouth. He is unable to puff out his right cheek against resistance. Neurological examination reveals that he can wrinkle his forehead bilaterally and close both eyes tightly, although with minimal asymmetry. There is no associated limb weakness or sensory deficit. Which muscle's preserved function is the most critical localizing feature of this patient's neurological deficit?

• Frontalis

• Zygomaticus major

  
  

• Orbicularis oris

• Platysma

Answer explanation

The frontalis muscle, responsible for wrinkling the forehead, receives bilateral innervation from the motor cortex. Its preserved function in the presence of lower facial weakness strongly indicates a central (supranuclear) lesion, such as a lacunar stroke.

A 28-year-old man sustains a deep laceration posterior to the angle of the mandible during a physical assault. In the emergency department, examination reveals profuse, non-pulsatile hemorrhage from the wound, located within the substance of the parotid gland. Surgical exploration is undertaken to achieve hemostasis. The surgeon identifies a large, transected vein formed by the confluence of the superficial temporal and maxillary veins. After clamping the proximal stump, the surgeon observes that this vessel bifurcates inferiorly. Ligation of the posterior division of this vein is required to control bleeding. This specific maneuver will interrupt the primary inflow into which of the following vessels?

•  External jugular vein

  
  

• Internal jugular vein

•  Common facial vein

  
  

• Transverse facial vein

  
  

Answer explanation

The retromandibular vein, formed by the union of the superficial temporal and maxillary veins, divides into an anterior and posterior division. The posterior division joins the posterior auricular vein to form the external jugular vein.

1. A 22-year-old male presents to the emergency department unable to close his mouth after a wide yawn. On examination, there is a palpable preauricular depression, and the mandibular condyle is felt anteriorly. During the reduction maneuver for this anterior TMJ dislocation, the physician applies downward and backward pressure. This action is primarily aimed at overcoming the spasm of which muscle?

• Lateral pterygoid

  
  

• Posterior fibers of the temporalis

• Masseter

  
  

• Digastric

Answer explanation

Anterior TMJ dislocation occurs when the mandibular condyle moves anterior to the articular eminence and gets locked. This is caused by the strong pulling action of the lateral pterygoid muscle during maximal mouth opening. The subsequent reflex spasm of this muscle is what holds the condyle in the dislocated position, preventing spontaneous reduction. The reduction maneuver (downward and backward pressure) is designed to stretch and overcome this specific muscle spasm, allowing the condyle to slip back into the mandibular fossa.

1. A 58-year-old female is undergoing a posterior fossa craniotomy for the resection of a large tentorial meningioma. To facilitate surgical exposure and reduce venous bleeding, she is placed in the Fowler’s (sitting) position. Following the opening of the dura mater, the anesthesiologist notes a sudden, sharp drop in the end-tidal CO2 from 35 mmHg to 18 mmHg, accompanied by acute hypotension to 70/40 mmHg. A faint, continuous "mill-wheel" murmur becomes audible over the precordium. In addition to notifying the surgeon to flood the surgical field with saline, which of the following is the most crucial immediate action related to patient positioning?

• Lowering the operating table to a horizontal or slight Trendelenburg position

•  Administering a 1L bolus of lactated Ringer's solution and starting a vasopressor infusion

•  Manually compressing both jugular veins bilaterally in the neck

• Placing the patient in a steep reverse Trendelenburg position

Answer explanation

This classic presentation signifies a venous air embolism. Immediately lowering the patient's head increases central venous pressure at the surgical site, which helps to prevent further air entrainment and can assist in expelling the existing air from the right heart.

A 58-year-old female presents to the neurology clinic with a 3-month history of progressive hoarseness, difficulty swallowing solids, and a noticeable drooping of her right shoulder. On examination, there is an absent gag reflex on the right, deviation of the uvula to the left, and profound weakness of the right sternocleidomastoid and trapezius muscles. A subsequent MRI of the head reveals a well-circumscribed, intensely enhancing mass. This mass is most likely located within and compressing the contents of which foramen?

• Jugular foramen

• Foramen ovale

•  Hypoglossal canal

• Superior orbital fissure

Answer explanation

The constellation of symptoms involving cranial nerves IX (glossopharyngeal), X (vagus), and XI (accessory) is pathognomonic for jugular foramen syndrome (Vernet's syndrome). These three cranial nerves traverse the jugular foramen.

According to the classification of dural venous sinuses, which structure is considered unpaired and is formed by the union of the inferior sagittal sinus and the great cerebral vein of Galen before draining into the confluence of sinuses?

• Straight sinus

• Transverse sinus

• Superior petrosal sinus

• Sigmoid sinus

  
  

Answer explanation

The straight sinus is a midline, unpaired sinus formed by the confluence of the inferior sagittal sinus and the great cerebral vein of Galen. It runs posteroinferiorly to join the confluence of sinuses.

1. A 58-year-old male undergoes a superficial parotidectomy for a Warthin's tumor located in the tail of the gland. Postoperatively, he complains of significant numbness over the skin of his left earlobe and the region overlying the angle of the mandible. Which of the following structures was most likely injured during the creation of the skin flap?

• Greater auricular nerve

• Auriculotemporal nerve

  
  

• Cervical branch of the facial nerve

• External carotid artery

Answer explanation

The greater auricular nerve provides cutaneous sensation to the inferior part of the auricle and the skin overlying the angle of the mandible and parotid gland. It is the most commonly injured nerve during parotidectomy.

1. The embryological development of the structures implicated in DiGeorge syndrome is critically dependent on the programmed migration and differentiation of a specific cell population. A defect in which of the following cell lineages is the primary underlying cause of this syndrome?

• Cranial neural crest cells

• Paraxial mesoderm

• Pharyngeal endoderm

•  Splanchnic mesoderm

Answer explanation

Cranial neural crest cells are essential for forming the connective tissue and skeletal components of the pharyngeal arches and regulate the development of the thymus, parathyroids, and conotruncal region of the heart.

1. A 45-year-old patient presents with ageusia localized to the tip and body of the tongue following a complicated middle ear surgery. Which cranial nerve is most likely implicated in this specific sensory deficit?

• Cranial Nerve VII (Facial Nerve)

  
  

• Cranial Nerve IX (Glossopharyngeal Nerve)

• Cranial Nerve V3 (Mandibular Nerve)

• Cranial Nerve XI (Accessory Nerve)

  
  

Answer explanation

The facial nerve (CN VII), through its chorda tympani branch, provides special sensory (taste) innervation to the anterior two-thirds of the tongue. This branch's proximity to the middle ear makes it vulnerable during surgery.

1. A 58-year-old male undergoes a posterior C1-C2 fusion for atlantoaxial instability. During the placement of a C1 lateral mass screw, there is brisk, pulsatile arterial bleeding. The surgical team is concerned about iatrogenic injury to the third part (V3 segment) of the vertebral artery. This vessel is most vulnerable as it courses through which anatomical landmark?

• Groove on the posterior arch of the atlas

  
  

• Foramen transversarium of the axis

• Sulcus arteriosus of the sphenoid bone

•  Anterior surface of the scalenus anterior muscle

Answer explanation

The third (suboccipital) part of the vertebral artery emerges from the C1 transverse foramen and courses medially in a groove on the posterior arch of the atlas before entering the foramen magnum. This is a critical landmark during C1 screw placement.