Embryology Key Concepts

Which of the following glands is not derived from endodermal lining?

Which of the following tissues are responsible for the fusion of the medial nasal prominences?

A 3-year-old boy presents with a developmental disorder characterized by immunological deficiencies, cardiac anomalies, and hypoparathyroidism. The defect is the result of a lack of differentiation of which of the following pharyngeal pouches?

Which of the following developing muscles will most likely be affected following injury to the vagus nerve (CN X)?

The utricular (dorsal) portion of the otic vesicles gives rise to the:

The image below represents a condition called coloboma of the iris. Which of the following is the most likely cause of this condition?

A 5-year-old boy is diagnosed with a cyst that is located high in the median plane of the neck. Which of the following events most likely occurred during development?

Which of the following factors/conditions is the LEAST likely to be involved in congenital hearing loss?

Regarding the optic vesicle, which of the following statements is NOT true? It:

The external lining of the tympanic membrane is derived from the:

A developmental disorder characterized by mucous discharge from the anterior border of the neck due to formation of a continuous opening to the pharynx is diagnosed as:

During development, the palatine shelves meet each other horizontally, and with which of the following structures?

A nine-month-old baby boy presents with an enlarged left eye, whitish cloudy cornea, photophobia, and elevated intraocular pressure. Genetic evaluation indicates a mutation of the CYP1B1 gene. Which is the most likely diagnosis?

Which anatomical structure is derived from the dorsal part of the 4th pharyngeal pouch?

In the figure below, which structure (A-E) gives rise to the photoreceptors in the adult?

The first pharyngeal groove (also called cleft) gives rise to:

Which of the following statements is NOT true regarding the development of the oral part of the tongue?

Through the process of induction, what does the optic vesicle cause surface ectoderm to form?

The otic vesicle (otocyst):

The incus is derived from:

The rima glottidis is widest during which action?

Which intrinsic laryngeal muscle is the only one that abducts the vocal cords?

The pharyngeal tonsils are also known as what when enlarged?

Which of the following is a target of parasympathetic innervation in the head?

A 45-year-old man presents with sudden onset of right-sided facial weakness, difficulty closing his right eye, drooping of the mouth, inability to raise his right eyebrow, diminished taste sensation on anterior two-thirds of tongue, and hyperacusis. Most likely diagnosis?

Damage to the right vagus nerve (CN X) would most likely result in which clinical finding?

Which nerve provides the main sensory innervation to the pharynx?

The piriform recess is clinically significant because it contains which nerve?

Which artery is the primary blood supply to the pharynx?

A patient presents with severe, stabbing pain along the right side of the face, triggered by activities such as chewing and brushing teeth, most pronounced in the maxillary region. What is the most likely diagnosis?

A 25-year-old woman loses sensation over the skin of the anterior aspect of her clavicle up to the shoulder region. Numbness is most likely due to injury of which of the following structures?

A 24-year-old man needs facial surgery due to a broken lower lip. Which nerve needs to be anesthetized before surgically repairing this area?

The mandible of a woman remained depressed while eating, unable to close her mouth. Excessive contraction of which muscle may cause anterior dislocation of the mandible?

Which structure is NOT ensheathed by the pretracheal layer of deep cervical fascia?

Which anatomical passage provides direct communication between the pterygopalatine fossa and the orbit?

After ingesting a toxic substance, a boy cannot close his lips. Which muscle may be paralyzed?

Occlusion of which artery will decrease blood supply to the masseter muscle?

A woman is unable to open her mouth due to tetanus. Which muscle's paralysis would normally prevent mouth opening?

Which artery courses through the transverse foramina marked by the arrow in the axial cervical spine image?

A woman with a painless left neck mass suspected to be thyroid-related. Which lymph nodes would NOT initially enlarge?

While attending a high school baseball game, a 65-year-old man receives a blow to the head, causing excessive displacement of the brain. A computed tomographic (CT) scan confirms a venous leakage from a superior cerebral vein into the superior sagittal sinus. The physician diagnoses:

75-year-old man was admitted to the emergency room after fainting in the morning in his house. He briefly lost consciousness, experienced weakness in his left arm, and had difficulty dressing himself. Which of the following cerebral arteries do you correctly suspect an infarction due to an occlusion?

A newborn was found on physical exam with a large head (macrocephaly), separation of sutures, and tense anterior fontanelle. The most likely etiology of his symptoms is a/an:

A 22-year-old man is brought to the emergency department following a bar fight in which he was struck on the right side of his head with a heavy object. Witnesses report that he briefly lost consciousness but then seemed alert and oriented. Over the next hour, he becomes increasingly drowsy and complains of a severe headache. Neurological examination reveals a sluggish right pupil and mild weakness in the left arm. Based on this clinical presentation and including non-contrast head CT, what is the most likely diagnosis?

A 39-year-old man presents with a six-month history of progressively worsening headaches, pulsatile tinnitus, and occasional blurred vision. He reports that the headaches are most severe upon waking in the morning and have recently been accompanied by nausea and vomiting. On examination, there is papilledema consistent with increased intracranial pressure. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the brain reveal a large, midline vascular structure in the region of the pineal gland with multiple enlarged feeding arteries and an abnormally dilated venous channel.

A 38-year-old woman presents with severe facial pain that started approximately two (2) weeks ago. She describes this pain as intermittent, severe, and shock-like in nature, involving her left cheek and left jaw region. It is worse when the cold wind hits her face or when she chews food. Denies any photophobia, phonophobia, nausea, or autonomic features with pain (such as lacrimation, nasal congestion, ptosis, etc). How long should the pain episodes last?

A 75-year-old woman presents to the office with a sudden severe 10/10 intensity headache that reached its peak intensity spontaneously within one (1) minute. She describes this as the “worst headache of her life”. She recalls very few tension-type headaches due to stress when younger but no history of migraine or any severe headaches in the past. She complains of photophobia, neck pain, and nausea. Which of the following diagnoses is the most likely present in this patient?

A 19-year-old man reports frequent headaches described as bilateral forehead and pulsatile quality. He reports feeling better after vomiting and resting in a quiet, dark room. What is the most probable headache type?

Which of the following is a red flag when evaluating a headache patient?

Arachnoid granulations:

The CT scan of a 77-year-old man shows a calcified tuft of choroid plexus, the glomus choroideum. Which of the following represents the location of this structure?

A 68-year-old man patient was involved in a car accident. During the next few days, the family noticed him progressively confused, sometimes talking incoherently, and agitated at night. He was taken to the emergency room, where a head computer tomography (CT) was performed, showing a subdural hematoma. The bleeding usually comes from damage to which of the following vessels?

A 23-year-old man presents to the emergency department with a sudden onset of severe headache that he describes as "the worst headache of my life." He loses consciousness shortly after arrival. On examination, his blood pressure is 160/95 mm Hg, and he exhibits neck stiffness. A non-contrast CT scan of the head reveals an intracerebral hemorrhage in the left parietal lobe with a significant mass effect. Subsequent cerebral angiography demonstrates a tangle of enlarged, tortuous vessels communicating directly between arteries and veins, without an intervening capillary network. Which of the following best describes the underlying lesion in this patient?

A 42-year-old woman presents for evaluation of worsening headaches. She reports headaches started as an adolescent, in which they occurred once a month on average. Throughout the last three (3) years, they increased in frequency to 20 days a month, of which at least half of those days headaches are moderate to severe in nature. Her most bothersome headache days are also described as a throbbing pain that requires her to lie down and is associated with both photophobia and phonophobia. She denies nausea, vomiting or visual disturbances. Neurological examination is normal. Brain MRI without gad and blood work were performed and unremarkable. Which of the following is the most likely diagnosis?

During the quarantine, a 55-year-old man fights over a tissue paper with another customer and falls, suffering a fracture posterior to the asterion in the occipital bone. In the emergency room, the patient experiences a brief loss of consciousness, followed by a lucid interval of a few hours. Subsequently, however, he becomes drowsy and then slips into a coma. This sequence of events is most likely due to damage to the:

A 27-year-old man baseball pitcher was hit with a ball on his head. The patient immediately became confused, complained of a headache, and had several episodes of vomiting. You are suspecting increased intracranial pressure. On physical exam, you expect to find:

A 52-year-old man presents to the office complaining of recurrent headaches over a period of weeks. Further tests revealed a brain tumor along the lateral wall of the anterior horn of the lateral ventricle, which did not produce hydrocephalus. Which of the following brain regions is the most likely affected by the tumor?

A 68-year-old man patient presents with a new onset headache. He reports that the headache is mainly in his right temporal region. Pain has been described as throbbing, severe, and continuous in nature for the past month. He denies photophobia, phonophobia, or nausea but does report double vision intermittently. Also mentions fatigue of his jaw while chewing and 10 lbs weight loss in the past month. Vital signs are normal. The workup is still pending. Which is the most suspected diagnosis in this patient?

A 40-year-old man presents with a severe headache that involves his right eye region with associated ipsilateral lacrimation, ptosis, and nasal congestion. He cannot stay still during these episodes because he feels restless and needs to pace. Pain is 10/10 intensity, and he can even get aggressive during these episodes. Which characteristic is not typically associated with this headache disorder?

A 42-year-old man comes to the emergency department with a severe headache localized to the back of his head. He describes it as a "pulling" sensation at the base of his skull, worsened by bending forward. Neurological examination is unremarkable except for tenderness when applying pressure over the suboccipital region. The physician explains that certain cranial nerves provide sensory innervation to the posterior aspect of the dura and that irritation in this region can present as occipital headaches. Which of the following statements regarding the cranial meninges is true?

A 35-year-old man is brought to the emergency room after a car accident. Upon arrival, he had a fixed and dilated pupil, hemiplegia (unable to move one side of the body), and progressively deteriorating mental status until he went into a coma. His pulse was 40 beats/min (bradycardia), and his blood pressure 140/70 mm Hg (hypertension). You immediately suspect increased intracranial pressure and a herniation syndrome. The most likely herniation syndrome is:

A 27-year-old woman fell from the stairs. She lost consciousness for approximately 5 minutes and then recovered. She was talking to her mother when she suddenly fell unresponsive. She was taken to the emergency room, where a Head CT was performed, showing an epidural hematoma. The bleeding usually comes from damage to which of the following vessels?

A 3-month-old infant is brought to the pediatric neurology clinic by his parents due to progressive enlargement of his head over the past several weeks. They report that he appears irritable and has episodes of projectile vomiting. On examination, the infant's head circumference is above the 97th percentile for his age, and the anterior fontanelle is notably bulging. A cranial ultrasound reveals significant dilation of both lateral ventricles with a narrowed interventricular foramen. Which of the following statements best explains the cause of this infant's clinical presentation of hydrocephalus?

A 45-year-old man presents with gradually worsening headaches over the past several weeks. He notes that the pain is often most severe upon waking and is occasionally accompanied by nausea. Neurological examination reveals papilledema but no other focal deficits. An axial MRI of the brain (shown below) is reportedly normal on initial review. Despite the normal appearance, the clinician is concerned about a possible early lesion that could obstruct cerebrospinal fluid (CSF) flow if it enlarges. Using the MRI below, which labeled structure would most likely be the potential site of obstruction leading to this patient's symptoms of increased intracranial pressure?

A 63-year-old man with a history of poorly treated hypercholesteremia and arterial hypertension presented to the emergency room after developing right facial and hemibody numbness. Vital signs were only remarkable for BP of 210/100. A Head CT scan is included. Which of the following is most consistent with the imaging findings?

Which of the following is the thickest component of the cornea?

A 60-year-old man goes to the ophthalmologist. He complains of eye pain and blurry vision that is worst in the periphery. Tonometry reveals elevated intraocular pressure in both eyes. What is the most likely condition?

A 48-year-old secretary complains of frequent headaches and difficulty focusing on close objects. She holds reading material farther away. Her doctor diagnoses presbyopia. What is the main reason for this condition?

Which description is accurate for lens fibers?

Cataracts are very common in elderly patients. They represent opacities that affect the function of which of the following structures?

A 50-year-old diabetic male on corticosteroids complains of clouded vision, halos around lights, and night vision trouble. Retinal exam is normal. What is the likely diagnosis?

A 68-year-old teacher complains of blurred vision, difficulty reading, and reduced central vision. What is the most likely condition?

Meniere's disease is characterized by vertigo, fluctuating hearing loss, and tinnitus. What is a possible cause?

Which cells in the inner ear are involved in detecting movements of the head?

A boxer suffers a blow to the ear and develops vertigo and hearing loss. He is diagnosed with perilymphatic fistula. Where is perilymph normally found?

The epithelial cells within the organ of Corti are supported by which of the following structures?

Which of the following statements about the fovea is FALSE?

A 52-year-old patient presents with a complaint of recurrent episodes of severe dizziness, ringing in the ears, hearing loss, and a feeling of fullness or congestion in the right ear. The patient mentions that these episodes can last for several hours and are often accompanied by nausea and vomiting. After extensive testing, he is diagnosed with Meniere's disease. The most likely cause of his condition is:

During a boxing match, a 23-year-old fighter sustains a strong direct blow to his left ear. He presents with vertigo, nausea, vomiting, and tinnitus. He has some hearing loss. His symptoms increase with coughing, sneezing and exertion. He is diagnosed with a perilymphatic fistula, which allows leakage of perilymph. In which of the following structures is perilymph normally found?

The cochlear duct is also called the:

Aqueous humor drains from the eye by passing:

Contraction of muscles in the ciliary body will:

A 22-year-old man involved in a car accident suffers a severe blow to the orbit of the eye. He presents with blurred vision and the emergency room physician suggests a possible case of retinal detachment. Histologically, this detachment occurs due to the separation of which of the following structures?

A 55-year-old man after a visit to the ophthalmologist is found to have increased intraocular pressure in both eyes. After a visual field test, he is diagnosed with glaucoma. With the advancement of the disease, which of the following layers will be most affected?

Type I vestibular hair cells in the macula of the utricle are characterized by:

Which of the following statements concerning the spiral organ of Corti is NOT TRUE?

After ingesting a toxic substance found in her friend's home, a 12-year-old boy is unable to close his lips. Which of the following muscles may be paralyzed?

The mandible of a 25-year-old woman remained depressed while eating a large hamburger, being unable to close her mouth. Excessive contraction of which of the following muscles may cause the head of the mandible to dislocate anteriorly?

A 24-year-old man is taken to the emergency room after being in a motorcycle accident. The patient needs facial surgery due to a broken lower lip. Which of the following nerves needs to be anesthetized before surgically repairing this facial area?

A 25-year-old woman loses sensation over the skin of the anterior aspect of her clavicle up to the shoulder region. Numbness in this area is most likely due to an injury of which of the following structures?

A 31-year-old woman with no past medical problems is referred to the clinic due to a painless left neck mass, which has been gradually increasing in size for the past nine months. Physical exam showed a left mobile mass of two centimeters with firm consistency anterior to scalene muscle. The physician suspects a tumor in the thyroid gland. Which of the following lymph nodes would you NOT expect to be enlarged initially?

A 45-year-old man presents with a midline neck swelling that visibly moves upward when he swallows. Ultrasound imaging suggests the lesion is confined within the pretracheal fascia of the deep cervical fascia. As the surgical team prepares for possible exploration, they review which nerves, muscles, and glands lie within the pretracheal fascial compartment. Which of the following structures is NOT ensheathed by the pretracheal layer of deep cervical fascia?

The anterior and middle scalene muscles of a 25-year-old man are hypertrophied. The most likely health problem resulting from this hypertrophy is:

Occlusion to which of the following arteries will decrease blood supply to the masseter muscle?

After practicing for more than six consecutive hours for his next boxing match, a 22-year-old man goes to the hospital complaining of pain and numbness in the upper lip, extending to his nose's lateral aspect. These symptoms are most likely due to:

A bony overgrowth narrows the pterygomaxillary fissure, compressing the third part of the maxillary artery. As a result, blood flow will most likely be reduced in which of the following arteries?

A 42-year-old man has been scheduled for surgical resection of a benign tumor located in the pterygopalatine fossa. During the preoperative planning, the surgical team discusses the various pathways through which the tumor could potentially spread to adjacent structures. They are particularly concerned about the extension of the tumor into the orbit. Which of the following anatomical passages provides direct communication between the pterygopalatine fossa and the orbit?

A 28-year-old man is rushed to the emergency department after a high-speed motorcycle collision. He was thrown from his vehicle and landed on his head and neck. On examination, he complains of severe neck pain, limited range of motion, and numbness radiating into both upper extremities. Radiographic imaging reveals a fracture involving the odontoid process (dens), a bony projection critical for head rotation. The fractured vertebra described in the imaging is most likely which of the following?

A 71-year-old man presents to the clinic with sudden swelling of the left side of his neck. The swelling occurred after he sneezed while lying on his back and working with his hands over his head. He reports that he had noticed a slight painless swelling of the neck a few months before. He did not complain of dyspnea or pain. The swelling extends from his clavicle to the submandibular space. You initially suspect the swelling is due to:

A 17-year-old boy suffers an injury of the phrenic nerve by a knife wound in the neck. The damaged nerve passes by which of the following structures in the neck?

After ligation of the thyrocervical trunk, which of the following arteries would continue to provide blood supply?

A 70-year-old man...presents to the clinic with a painless enlargement over the right parotid gland...confirms a parotid tumor. The surgeon decides to perform a superficial parotidectomy. Which of the following structures is LEAST likely to be affected by the procedure?

A 37-year-old patient presents with a suspected skull base lesion affecting cranial nerve branches that pass through the middle cranial fossa. On imaging, multiple foramina appear to be involved. The neurosurgery team reviews the structures associated with the middle cranial fossa to determine the precise location for intervention. Which of the following structures is NOT associated with the middle cranial cavity?

A 64-year-old woman is unable to open her mouth or jaw because of tetanus resulting from a penetrating wound from a rusty nail. Which of the following muscles would most likely be paralyzed? [Note: Tetanus causes muscle spasm, not paralysis. Assume question means 'in spasm preventing opening']

Which branch of the vagus nerve innervates most intrinsic muscles of the larynx?

A patient presents with anisocoria (unequal pupil sizes). Further testing reveals that the affected eye has a permanently constricted pupil that does not respond to changes in light. Which neural structure is most likely damaged?

A 45-year-old man presents to the clinic with a sudden onset of right-sided facial weakness. He reports difficulty closing his right eye, drooping of the mouth, and inability to raise his right eyebrow. He denies weakness in his arms or legs. On examination, his forehead is involved, and he is unable to completely close his right eye. His taste sensation on the anterior two-thirds tongue is diminished, and he reports hyperacusis in the right ear. Which of the following is the most likely diagnosis?

A 42-year-old woman undergoes surgery to remove a tumor in the cavernous sinus. Postoperatively, she develops loss of corneal reflex on the right and numbness over her forehead. Which nerve is most likely injured?

A 30-year-old woman develops severe nausea and dizziness while on a turbulent flight. Which type of afferent fibers in the vagus nerve are primarily responsible for transmitting this sensation of nausea?

A 65-year-old man with a history of paroxysmal supraventricular tachycardia (PSVT) is advised to perform carotid sinus massage during symptomatic episodes. What is the primary physiological mechanism by which carotid sinus massage lowers heart rate?

Damage to the recurrent laryngeal nerve, as may occur during surgery of the thyroid gland, would result in which deficit?

A 50-year-old woman presents with pain and numbness over her right cheek following reactivation of varicella-zoster virus. Which nerve is most affected?

Which muscle prevents food from entering the nasopharynx during swallowing?

A patient presents with severe, stabbing pain along the right side of the face, triggered by activities such as chewing and brushing teeth. The pain is most pronounced in the maxillary region. What is the most likely diagnosis?

A 62-year-old man with a 40-pack-year smoking history presents with a 3-month history of drooping (ptosis) of his left eyelid, constriction (miosis) of his left pupil, and decreased sweating (anhidrosis) on the left side of his face. He denies pain or weakness. A chest X-ray reveals a mass in the apex of the left lung. Which of the following best explains this patient's symptoms?

A patient presents with loss of the gag reflex on the right side. Stimulation of the left side still produces a reflex response. Which nerve is most likely affected?

Which cranial nerve is primarily responsible for transmitting general sensory information from the majority of the pharyngeal mucosa?

While the glossopharyngeal nerve provides the main sensory innervation to the pharynx, which cranial nerve is primarily responsible for the motor innervation of the pharyngeal muscles involved in swallowing?

A patient complains of loss of sensation in the posterior part of their tongue and the region of the palatine tonsils. Which cranial nerve is most likely affected, leading to this sensory deficit in the oropharynx?

The afferent limb of the gag reflex, elicited by touching the posterior pharyngeal wall, is primarily mediated by which cranial nerve?

Prior to a medical procedure involving the oropharynx, local anesthesia is applied to block sensory input from the pharyngeal mucosa. Which nerve block would be MOST effective in achieving anesthesia of the general sensation in this region?

A 22-year-old college student comes to the clinic with a three-day history of redness, swelling, and pain around her new tragus piercing on the right ear. She reports that she had the piercing done at a friend's apartment two weeks ago without professional sterilization techniques. On examination, there is an obvious pustule at the tragus site, erythema extending slightly onto the auricle, and tenderness to palpation. She also has noticeable swelling and tenderness of a small cluster of lymph nodes located anteriorly to the ear. Which of the following groups of lymph nodes would most likely be the affected ones?

Which of the following anatomical structures is the most directly involved in the spread of an infection from the middle ear (tympanic cavity) to the inner ear (labyrinth)?

A 46-year-old woman presents with progressive headaches and recent deterioration in her peripheral vision over the past six months. On formal ophthalmologic testing, she has a bitemporal hemianopia, and laboratory studies reveal mildly elevated prolactin-levels. MRI of the brain shows a pituitary mass consistent with a macroadenoma, extending superiorly and impinging on the optic chiasm. After discussing treatment options, she is scheduled for a transsphenoidal surgical resection of the tumor. Which anatomical pathway is most utilized and less invasive to access the pituitary gland surgically through a transsphenoidal approach?

A 15-year-old man developed cavernous sinus thrombophlebitis after a one-week history of single acne-like lesion at the anterior tip of his nose. He presented with a headache, periororbital edema, diplopia, and a fever (103 F or 39.4 C). Which of the following veins is the most likely route for spreading this infection to the cavernous sinus?

A 64-year-old man is diagnosed with skin melanoma above his right eyebrow after years of excessive sun exposure. His dermatologist removes this cancerous lesion, but the doctor needs to rule out possible metastasis. What group of lymph nodes would his physician first check for possible spread of cancer?

A tumor is discovered embedded in the posterior wall of the tympanic cavity in a 45-year-old man. If the tumor erodes through this wall, which of the following structures will it first encounter?

A 23-year-old man was punched in the left eye in a bar fight, which resulted in periorbital edema and ecchymosis. In the ER, the man refuses to open his eyes, and when his eyelids are pried open, he exhibits vertical diplopia, specifically when asked to look up. Coronal CT reformat image reveals asymmetry in the left orbit and the superior antrum of the maxillary sinus, apparent in the given image. What is the most likely cause of the patient's diplopia?

A 35-year-old man presents with persistent irritation and dryness in his upper nasal cavity. He also reports a recent decrease in his ability to smell, especially when cooking or using scented products. On physical examination, the nasal mucosa appears dry and slightly inflamed, particularly in the superior portion of the nasal cavity. Which of the following pair of nerves would most likely explain this scenario?

A 75-year-old man tells his physician he has been having progressively more trouble opening his left eye because his upper eyelid tends to droop. Which of the following muscles is the most likely weakened?

A 14-year-old boy presents to the emergency department with a sudden-onset nosebleed from his right nostril. He mentions that he was playing basketball outdoors in hot, dry weather and felt some nasal irritation earlier in the day. On initial examination, bleeding appears to originate from the anteroinferior portion of the nasal septum. Simple compression of the nostrils with gauze helps slow the bleeding. Which of the following structures is most commonly associated with anterior epistaxis (nosebleeds) involving the nasal septum?

A 24-year-old woman presents to the emergency department with a three-day history of worsening left ear pain and swelling. She reports that she recently had her lobule pierced at a local tattoo parlor. Over the past 48 hours, she has noticed progressive redness, local warmth, and a small amount of purulent discharge from the piercing site. On examination, the left ear lobule is tender to palpation, with erythema and edema. The patient experiences a radiating, burning-type pain that travels toward her jawline when the lobule is gently manipulated. Despite these symptoms, she denies fever or systemic complaints. Her vital signs are stable, and no lymphadenopathy is detected in the neck or around the ear. Which of the following nerves is primarily responsible for transmitting pain sensation from the lobule of the ear in this patient?

A 35-year-old man complains to his physician that he feels congested, has trouble with nasal breathing, and is experiencing a yellowish nasal mucous discharge. He also mentions that his right side upper molar teeth ache terribly. A thorough physical examination reveals maxillary sinusitis. The discharge from the sinus initially drains into the nasal cavity at which of the labeled points within this drawing of the lateral nasal wall?

A 16-year-old girl experiences mild ptosis and miosis (pupillary constriction) in her right eye. Based on your anatomy knowledge, which of the following nerves do you suspect is a lesion?

A 32-year-old woman undergoes LASIK refractive surgery to improve her visual acuity and remove eyeglasses. To combat dry eyes, a common complication of this surgery, her ophthalmologist inserts a silicone plug, marked by an arrow in the given photo, to block the drainage of tears from the patient's left eye. Obstruction of what structure prevents tears from entering the lacrimal apparatus?

A 9-year-old girl with a history of middle ear infections presents with pain, tenderness, and inflammation located posterior to her right auricle. What is the most likely diagnosis, given her current symptoms?