Head & Neck Anatomy Flashcards
The muscles of facial expression, the posterior belly of the digastric muscle, and the stapedius muscle are derived from which of the following pharyngeal arches?
A) First
B) Second
C) Third
D) Fourth
E) Sixth
The correct response is Option B.
The pharyngeal, or branchial, arches are developmental structures derived from all three germ layers and also contain neural crest cells. These arches give rise to bony, cartilaginous, vascular, muscular, and neural structures of the head and neck.
The second pharyngeal arch gives rise to the muscles of facial expression, posterior belly of the digastric muscle, and the stapedius muscle. These muscles are innervated by the facial nerve (VII), which also arises from this arch.
The first pharyngeal arch gives rise to the muscles of mastication, anterior belly of the digastric, mylohyoid, tensor tympani, and tensor veli palatini muscles as well as the trigeminal nerve (V). The third pharyngeal arch gives rise to the stylopharyngeus muscle as well as the glossopharyngeal nerve (IX). The fourth pharyngeal arch gives rise to the cricothyroid muscle and all intrinsic muscles of the soft palate except the tensor veli palatini, as well as the superior laryngeal nerve (X). The sixth pharyngeal arch gives rise to the intrinsic muscles of the larynx except the cricothyroid muscle as well as the recurrent laryngeal nerve (X). The fifth pharyngeal arch does not give rise to structures in humans.
2017
A 6-year-old boy is brought to the office because of a draining sinus in the midline of the neck. His mother reports that the drainage developed after he had an upper respiratory infection a few weeks ago. Physical examination shows a palpable mass in the mid third of the neck that moves upward when the patient protrudes his tongue. Which of the following is the most likely diagnosis?
A) Infected sebaceous cyst
B) Infected thyroid gland
C) Lymph node
D) Thyroglossal duct cyst
E) Type II branchial cleft cyst
The correct response is Option D.
During embryologic development, the thyroid gland descends from the foramen caecum to the midline of the neck. The tract in descent is typically absorbed but sometimes remains. This can be secondarily infected from infections of the head and neck. Rarely, the thyroid gland does not fully descend into its position in the midline neck.
Diagnosis of this mass over other types of midline mass include elevation of the mass on tongue protrusion. This is because of the remaining attachment to the base of the tongue.
Lymph nodes can present in the midline, but they are infrequent at the level of the hyoid and typically do not drain percutaneously. A type II branchial cleft cyst presents laterally, not in the midline. Infected sebaceous cysts can drain in any hair-bearing area, but do not move with protrusion of the tongue.
2017
A 32-year-old woman with bilateral masseter hypertrophy comes to the physician because she wants to have a more heart-shaped face. She has normal occlusion otherwise. Which of the following is the most appropriate initial treatment option for this patient?
A) Injection of botulinum toxin type A 30 to 50 U into the area of the masseter bulk
B) Intraoral debulking of the deep masseteric muscles
C) Sagittal split of the mandible with retrusion
D) Selective denervation of the masseter muscles
E) Use of an orthodontic dental appliance to realign the dentition
The correct response is Option A.
One of the determinants of beauty is facial shape. For a woman, a heart-shaped face is considered youthful and attractive. With a history of bruxism, masseter hypertrophy changes the face into a more square, masculine shape. Botulinum injections can reduce the facial bulk, redefine the lower facial width, and make the face more youthful and heart-shaped.
The other surgical options are associated with significant morbidity and may not give the desired shape. Orthodontic care is used for patients whose malocclusion has altered the facial shape.
2017
A 5-year-old child is brought to the office for evaluation of several supernumerary teeth. Which of the following is most characteristic regarding this anomaly?
A) More common in the primary dentition than in the secondary dentition
B) More frequent in the maxilla than in the mandible
C) More prevalent in females than in males
D) Occurs most often from disruption during the morphodifferentiation stage of tooth development
E) Typically associated with ectodermal dysplasia
The correct response is Option B.
Hyperdontia is an anomaly of number of teeth and occurs most frequently in the maxilla (90%). It occurs during the initiation or proliferation stage. Morphodifferentiation issues lead to an anomaly of enamel/dentin/cementin composition. It is more common in males (2:1). It is 5 times more common in permanent dentition than in primary dentition. Finally, ectodermal dysplasia is associated with hypodontia.
2017
Which of the following is the most common origin of the superior thyroid artery?
A) Bifurcation of the carotid artery
B) Common carotid artery
C) External carotid artery
D) Internal carotid artery
The correct response is Option C.
The origin of the superior thyroid artery is predictable and most commonly it arises from the external carotid artery. It has, however, been described to arise from all three of the other options, just less frequently.
2016
A 6-year-old girl with cerebral palsy is evaluated for sialorrhea. Medical treatment has been unsuccessful. Surgical intervention for drooling control is planned. Which of the following glands contributes the most to basal salivary production?
A) Lacrimal
B) Minor salivary
C) Parotid
D) Sublingual
E) Submandibular
The correct response is Option E.
Daily saliva production is on the scale of 500 to 2000 mL per day. Excessive drooling in patients with cerebral palsy or other severe neurologic impairment is caused by inefficient swallowing. The submandibular glands contribute the most to basal salivary production, approximately 60%. The parotid gland contributes approximately 20% to basal salivary production. Sublingual glands and minor salivary glands each contribute 10%. The lacrimal gland is responsible for production of the aqueous layer of the tear film.
2016
Which of the following tooth types is most commonly the last one to erupt when the primary teeth are replaced by permanent teeth?
A) Maxillary canine
B) Maxillary central incisor
C) Maxillary first molar
D) Maxillary first premolar
E) Maxillary lateral incisor
The correct response is Option A.
Aside from the third molars, the maxillary canines are typically the last teeth to erupt of the available options (around 11 to 12 years of age). It is important to give the tooth a large area of viable bone to traverse and become supported by, and alveolar bone grafting is typically performed well in advance of the eruption of the maxillary canine in order to preserve the native tooth.
The maxillary central incisor is often the second permanent tooth a child will erupt, typically at age 7 to 8 years.
The maxillary lateral incisor is often the third permanent tooth a child will erupt, typically at age 8 to 9 years.
The maxillary first premolar is often the fourth permanent tooth a child will erupt, typically at age 10 to 12 years.
The maxillary first molar is often the first permanent tooth a child will erupt, typically at age 6 to 7 years.
2016
Which of the following surgeries addresses the most common anatomic site of obstruction in patients with obstructive sleep apnea?
A) Bilateral sagittal split osteotomy
B) Geniohyoid advancement
C) Septoplasty
D) Tracheostomy
E) Uvulopalatopharyngoplasty
The correct response is Option E.
The answer is uvulopalatopharyngoplasty (UP3). The mainstay of UP3 surgery is to remove the uvula and lateral oropharyngeal tissues. The most common site of obstruction in obstructive sleep apnea (OSA) patients is the retropalatal area, including the lateral pharyngeal walls. This latter anatomic area is even more important if the patient has never had a tonsillectomy; in this case, the tonsils are removed in continuity with UP3. UP3 generally decreases the various indexes documented during a sleep study, such as the apnea-hypopnea index, by about 50%. Thus, those at the border of severe and moderate sleep apnea can see their reported indexes go to a level that can be managed by lifestyle changes without the need for a continuous positive airway pressure (CPAP) machine. On the other hand, in patients with very high indexes, these procedures merely make the disease less severe and may allow for a lower setting on the CPAP machine. Although the CPAP machine which applies positive pressure transnasally to patients can “cure” OSA, their compliance rates are low.
There are other procedures that can help with OSA, such as a septoplasty or those that deal with the tongue base (e.g., geniohyoid advancement), but neither directly treats the most common site of obstruction. A tracheostomy is a curative treatment for OSA, but it completely bypasses all of the obstructive points without addressing them. A tracheostomy has much morbidity, including a measurable mortality rate, and is reserved for life-threatening cases of OSA. A sagittal split operation of the mandible is used for occlusion, not OSA.
2016
A 50-year-old man who underwent superficial parotidectomy for a benign tumor 9 months ago comes to the office because of a 6-month history of gustatory sweating. Which of the following nerves carries the parasympathetic postganglionic nerve fibers to the parotid gland in a healthy patient?
A) Auriculotemporal
B) External carotid plexus
C) Facial (VII)
D) Great auricular
E) Marginal mandibular
The correct response is Option A.
2016
A 17-year-old boy is brought to the emergency department because of profuse bleeding from a stab wound to the neck above the angle of the mandible anterior to the sternocleidomastoid muscle. After airway stabilization is established, vascular repair of a laceration of the jugular vein is performed. Where is this injury located?
A) Posterior triangle
B) Zone I
C) Zone II
D) Zone III
The correct response is Option D.
Effective treatment of penetrating neck injuries depends on a thorough understanding of neck anatomy. The neck houses vital structures from six organ systems: The vascular system includes the innominate, subclavian, axillary, carotid, jugular, and vertebral vessels. The respiratory system includes the larynx, trachea, and the lung. The digestive system includes the pharynx and esophagus. The neurologic system includes the spinal cord, brachial plexus, cranial nerves, and the sympathetic chain. The endocrine system includes the thyroid and parathyroid. The skeletal system includes the cervical spine.
Anatomy of the neck may be considered using two anatomical paradigms: the concept of “triangles” and the concept of “zones.” The triangles are divided into anterior and posterior, while the zones are divided in a cranial/caudal orientation anterior to the sternocleidomastoid muscle. An understanding of both is important when considering penetrating injuries.
The neck may be divided into two triangles, anterior and posterior to the sternocleidomastoid muscle. The anterior triangle is bordered anteriorly by the midline, posteriorly by the sternocleidomastoid muscle, and superiorly by the lower edge of the mandible. Most vital structures are located in the anterior triangle. The posterior triangle is located within the boundaries of the sternocleidomastoid muscle anteriorly, inferiorly by the clavicle, and the anterior border of the trapezius muscle posteriorly. Trauma to the posterior triangle, excluding the spine, carries a much lower likelihood of significant injury.
Zone I is in the inferior neck and includes the base of the neck and thoracic inlet. It extends from the sternal notch and clavicles to the cricoid cartilage. Zone I contains the thoracic outlet vasculature, vertebral and proximal carotid arteries, apices of the lungs, trachea, esophagus, spinal cord, and thoracic duct.
Zone II is in the mid-neck and continues cephalad from the cricoid cartilage to the angle of the mandible, and contains the jugular veins, vertebral and common carotid arteries, and internal and external branches of the carotid arteries. It also includes nonvascular structures including the trachea, esophagus, larynx, and spinal cord.
Zone III (upper neck) includes the region above the angle of the mandible up to the base of the skull and contains the pharynx along with the jugular veins, vertebral arteries, and the distal portion of the internal carotid arteries. Its caudal border is distal to the common carotid arteries.
Portions of the jugular vein are located in all three zones. Only Zone III is located above the angle of the mandible.
2016
A 60-year-old man undergoes microvascular anastomosis. The proximal facial artery off the external carotid artery is to be dissected and used as a recipient vessel. During the procedure, a large, overlying, nerve-like structure is inadvertently transected. Which of the following is the most likely consequence?
A) Dysarthria
B) Lip elevation
C) Shoulder drop
D) Tongue numbness
E) Vocal cord paralysis
The correct response is Option A.
The facial artery generally starts as part of the lingual-facial trunk, then travels below the hypoglossal nerve before it enters into the submandibular gland and along the lateral border of the mandible. Failure to recognize this structure could cause injury and subsequent loss of motor function of the ipsilateral tongue. Ipsilateral hypoglossal (XII) nerve injury causes the tongue to move toward the side of damage, resulting in dysarthria, and problems moving solid food to the oropharynx.
Vocal cord paralysis is related to a recurrent laryngeal or vagus (X) nerve injury, which could happen after superior laryngeal artery or common carotid dissection, respectively.
Shoulder drop is related to accessory (XI) nerve injury, which has anatomic relation to the occipital artery.
Tongue numbness is from an injury to the lingual nerve (related mostly to the laryngeal artery and submandibular duct).
Lip elevation is related to a marginal mandibular (V3) nerve injury—this nerve runs with the facial artery lateral to the mandible, but not below the margin of the mandible.
2015
An 11-month-old male infant is noted by his parents to have a painless, progressive, right maxillary growth. At an outside facility, an incisional biopsy is performed. The pathology shows sinonasal myxoma. Postoperative MRI shows residual tumor with surrounding inflammation. Which of the following is the most appropriate treatment plan?
A) Chemotherapy and radiation therapy
B) Chemotherapy only
C) Curettage debulking of the tumor
D) Surgical resection with clear margin
E) Observation
The correct response is Option D.
Myxomas are slow-growing benign tumors. When they present in the infant face, they are most common in the maxilla or mandible. They present as a painless, progressive facial swelling and should be surgically removed with a clear margin. These tumors should have a clear margin to prevent incomplete resection and continued growth. They are not always well circumscribed, so a normal margin or tissue plane should be resected with the tumor.
2015
A 20-year-old woman with a history of bruxism is evaluated because of a 3-year history of gradual widening of the lower third of the face. Physical examination shows rectangular appearance of the face; occlusion shows no abnormalities. Anteroposterior x-ray study discloses bone spurs at both angles of the mandible. Which of the following is the most appropriate next step in management?
A) Excision of the submandibular gland
B) Injection of botulinum toxin type A to the masseter muscle
C) Marginal mandibulectomy
D) Suction-assisted lipectomy of the cheek
E) Superficial parotidectomy
The correct response is Option B.
The patient described has bilateral masseter hypertrophy. Treatment options for this condition include muscle relaxants, injection of botulinum toxin type A, or resection of the internal layer of the masseter muscle.
Superficial parotidectomy is indicated for benign and malignant tumors of the parotid gland.
Resection of the submandibular gland is indicated for recurrent sialadenitis (infection) or obstructive sialodocholithiasis (salivary stones), as well as for benign tumors such as pleomorphic adenomas.
Marginal mandibulectomy may be indicated for certain benign and malignant tumors of the intraoral cavity.
Suction-assisted lipectomy will not treat masseter hypertrophy.
2015
A 22-year-old man is brought to the emergency department after sustaining a stab wound to the face. The patient is hemodynamically stable, and physical examination shows a laceration that extends from the tragus of the right ear to the right oral commissure. Which of the following is the most likely primary complication of saliva extravasating into the wound because of parotid duct injury?
A) Parotid gland atrophy
B) Salivary fistula
C) Sialocele
D) Wound infection
E) Xerostomia
The correct response is Option C.
If parotid duct injury is not repaired immediately, saliva can leak into the surrounding soft tissues. This leakage most commonly increases the risk for sialocele (pseudocapsule), followed by salivary fistula formation. Wound infection, parotid gland atrophy, and xerostomia (dry mouth) are uncommon. Studies have shown that correction of the more common complications may require surgical or medical treatments such as use of anti-sialogogues, radiation therapy, parasympathetic denervation (tympanic denervation), cauterization of the fistulous tract, reconstruction of the duct, or superficial or total parotidectomy.
2015
An otherwise healthy term 6-month-old male infant is evaluated for a mobile, firm, well-circumscribed mass at the right lateral brow in the area of the zygomaticofrontal suture. Which of the following procedures is the most appropriate next step in management?
A) CT scan
B) Fine-needle aspiration of the mass
C) MRI
D) Surgical excision of the mass
E) Ultrasonography
The correct response is Option D.
Dermoid cysts are common in the lateral brow. They present as firm, well-circumscribed, slow-growing masses that have the potential for infection or continued growth. Surgical excision is recommended and no imaging is required. CT scan or MRI require sedation and are unnecessary risks for this patient with a lateral dermoid. Midline masses do require imaging because of the risk for intracranial excision.
2015
A 24-year-old man with a history of left facial trauma and condylar fracture of the mandible is evaluated because of redness and perspiration of the left cheek and ear after ingesting certain foods. Aberrant regeneration of which of the following nerves is the most likely cause of this patient’s symptoms?
A) Auriculotemporal
B) Facial
C) Great auricular
D) Inferior alveolar
E) Lingual
The correct response is Option A.
Although it is most commonly seen after parotidectomy, Frey syndrome has also been encountered after condylar fracture of the mandible and treatment. The syndrome is thought to result from damage to auriculotemporal parasympathetic nerve fibers with subsequent aberrant regeneration and innervation of sympathetic fibers to the sweat glands.
The facial, inferior alveolar, greater auricular, and lingual nerves are not thought to be the underlying cause of Frey syndrome.
2015
A 12-hour-old male newborn has cyanosis that improves with crying. Which of the following is the most likely diagnosis?
A) Choanal atresia
B) Laryngomalacia
C) Macroglossia
D) Micrognathia
E) Subglottic stenosis
The correct response is Option A.
Choanal atresia is a unilateral or bilateral anatomic abnormality of the posterior nasal passages and choanae, which prevents nasal gas exchange in newborns. The classic presentation of bilateral choanal atresia is cyanosis that improves with crying. Nasal airway obstruction can also become apparent when attempting to breast-feed the baby. On clinical examination, there would be no fogging of a mirror when held under the nares. The remaining abnormalities are other causes of respiratory obstruction in the pediatric patient.
2015
A 54-year-old man comes to the office because of swelling of the left side of the face 3 days after cholecystectomy. Physical examination shows erythema and purulent drainage from the parotid duct. Which of the following is the most appropriate initial management?
A) Antibiotic therapy and sialogogues
B) Aspiration of the mass
C) Incision and drainage of the mass
D) Oral cultures and oral cavity antibiotic irrigation
E) Superficial parotidectomy
The correct response is Option A.
Initial treatment of acute suppurative sialadenitis begins with aggressive medical management. This includes prompt fluid and electrolyte replacement, oral hygiene, reversal of salivary stasis, and antimicrobial therapy. Stimulation of salivary flow is done by use of sialogogues such as lemon drops. Warm soaks and massage promote secretion and drainage of the gland.
Oral cultures are typically contaminated by oral flora and therefore do not direct antibiotic treatment. Needle aspiration is more accurate in isolating the cause of suppurative parotitis.
Incision and drainage is reserved for cases resistant to medical management. Surgical removal of the gland is not recommended in the case of an actively infected gland.
2015
A 65-year-old man undergoes surgery for management of a subtotal massive squamous cell carcinoma of the posterior larynx. History includes chemoradiation and subsequent bilateral selective neck dissections for persistent disease 9 months ago. An anterolateral thigh free flap is chosen for reconstruction, but the operative notes state that both external carotid systems were sacrificed. Which of the following recipient vessels is most appropriate in this patient?
A) Facial
B) Internal mammary
C) Occipital
D) Subclavian
E) Transverse cervical
The correct response is Option E.
When performing head and neck microsurgery, a strong background in the vascular anatomy of that region is imperative. As chemotherapy regimens have become commonplace for laryngopharyngeal cancers, so have the challenges of failures which generally require surgery. These cases have much higher complication rates, including fistulas, strictures, and carotid injury, among others. This case demonstrates another complexity that is increasingly observed, the “vascular or vessel-depleted neck.” The facial and occipital arteries are branches of the external system and would not be available. The subclavian is generally not a viable option due to its size, location, and potential complications through dissection. The internal mammary system has potential, but requires dissection through the ribs and has morbidities and the potential need of vein grafts. Generally speaking, even radical neck dissections do not sacrifice the transverse cervical vessels as they are usually used as the caudal margin. A number of reports have detailed the usefulness of these vessels as recipients in cases like the one described.
2014
Which of the following cranial nerves provides parasympathetic innervention of the parotid gland?
A) V
B) VII
C) VIII
D) IX
E) X
The correct response is Option D.
Innervation of the parotid gland comes from parasympathetic fibers that travel with the glossopharyngeal nerve (cranial nerve IX). It also receives taste sensation (afferent) from the posterior one-third of the tongue.
The maxillary nerve of cranial nerve V (V2) is a sensory nerve and receives sensation from the mid face.
Parasympathetic fibers (efferent) innervate the submandibular and sublingual glands via the chorda tympani. Afferent fibers, via the chorda tympani, send taste sensation of the anterior two-thirds of the tongue.
The vestibulocochlear nerve (cranial nerve VIII) supplies sound and equilibrium to the brain.
The auricular branch of the vagus nerve (cranial nerve X), innervates the external acoustic meatus. Stimulation of the vagus nerve can lead to reflex coughing (Arnold reflex).
2014
A 9-year-old boy is brought to the office for evaluation of a nodule on the neck that appeared 1 week ago. The nodule measures 2 cm and is slightly to the right of midline. A photograph is shown. The lesion is slightly tender. Which of the following is the most appropriate management of this lesion?
A) Excision of lesion with any tract and a section of hyoid bone
B) Excision of lesion with any tract and a section of thyroid cartilage
C) Excision of lesion with any tract only
D) Fine-needle aspiration with cytology
E) Intralesional sclerotherapy under image guidance
The correct response is Option A.
Thyroglossal duct cysts are neck lesions that usually present during childhood, often after a localized inflammation or infection. They are usually neck lesions near the midline. Some may move with swallowing if they are close to the base of the tongue, but not all exhibit this finding. The congenital thyroglossal duct is the remnant of the descent of the developing thyroid gland, and it runs from the foramen cecum of the base of the tongue, down to the thyroid. Imaging is typically by ultrasound, but other modalities, including radioisotope scans to rule out ectopic thyroid tissue or confirm the location of the normal thyroid gland, have been suggested to avoid excising ectopic thyroid gland.
The Sistrunk procedure shows less recurrence and is a complete excision, including any associated tract, and about a 1-cm section of hyoid bone. Although proposed in 1928, this is still the most commonly recommended approach for thyroglossal duct cysts.
Fine-needle aspiration is appropriate for thyroid nodules, which are unlikely to present in an acute manner in this population.
Sclerotherapy is used for vascular anomalies and likely would have presented earlier on in childhood.
2019
Which of the following cranial nerves develops with the first branchial arch?
A) Facial (VII)
B) Glossopharyngeal (IX)
C) Hypoglossal (XII)
D) Trigeminal (V)
E) Vagus (X)
The correct response is Option D.
The first branchial arch is associated with the trigeminal nerve (V), second branchial arch with the facial nerve (VII), third branchial arch with the glossopharyngeal (IX), fourth branchial arch with the superior laryngeal (X), and sixth branchial arch with the recurrent laryngeal (X).
2020
A 2-year-old boy is evaluated because of a soft, nontender, noncompressible glabellar mass that has progressively grown since birth. A photograph is shown. Which of the following is the most appropriate next step in management before scheduling surgery?
A) Corticosteroid injections
B) MRI
C) Plain film x-ray study
D) Propranolol trial
E) Observation
The correct response is Option B.
The differential diagnosis for a lesion in this location with the findings described include dermoid cyst, hemangioma, and encephalocele. Osteoma, which is a benign bony tumor, is unlikely because of patient age and examination findings. The noncompressible quality of the lesion makes hemangioma and encephalocele less likely. Propranolol therapy after 12 months of age is unlikely to help, even if the lesion is a hemangioma. If the lesion is a hemangioma, then observation would be appropriate, but because the lesion is still growing, this diagnosis is questionable. Corticosteroid injections are only moderately helpful in treating a hemangioma, but they are contraindicated for dermoid cysts and encephalocele. Diagnosis is the next step with a goal of ruling out intracranial communication, as it will impact the surgical approach. MRI is the best option. Plain x-rays films would not provide adequate information for management.
2021
A newborn female presents with a large intraoral mass arising from alveolar mucosa of the lower jaw that does not cause any airway obstruction. Photographs are shown. Which of the following is the most likely pathology of the lesion?
A) Congenital epulis
B) Hemangiopericytoma
C) Odontogenic keratocyst
D) Rhabdomyosarcoma
E) Teratoma
The correct response is Option A.
Congenital epulis is a rare, benign tumor of the oral cavity that is found in newborns. They are considered a form of granular cell tumor that can lead to mechanical obstruction, resulting in respiratory distress or difficulty eating. Surgical excision is the treatment of choice and recurrence after excision is rare. The female-to-male ratio is 10:1. It is observed three times more frequently on the maxilla than the mandible. They are solitary in most cases, but can be large and multiple.
Teratomas and rhabdomyosarcomas of the mandible are even more rare and are usually seen in the older patient population; they are not seen in the neonatal population.
Hemangiopericytomas are rare, vascular neoplasms that originate from vascular pericytes. They can occur anywhere in the body, including the mandible. They are slow-growing and present in the older patient population. The likelihood of presentation in a neonate is exceedingly low.
Odontogenic keratocysts are rare and benign, but locally aggressive lesions of the posterior mandible. They most commonly present in the third decade of life. They make up 19% of jaw cysts.
2021
A 4-year-old boy is seen following a pitbull bite to his face. The periorbital findings are shown in the photograph. A stent is placed and the ends of the stent are advanced across the canaliculus. The ends of the stent will enter the nasal cavity in which of the following locations?
A) Above the superior turbinate
B) Below the superior turbinate
C) Above the middle turbinate
D) Below the middle turbinate
E) Above the inferior turbinate
F) Below the inferior turbinate
The correct response is Option F.
Reconstruction of the lacrimal apparatus is a critical step in addressing this patient’s periorbital wounds. Failure to properly manage this aspect of the injury will lead to epiphora and the inevitable need for a secondary procedure to manage tear drainage. Delayed reconstruction of this injury would likely require a conjunctivodacryocystorhinostomy, a surgically created conduit between the eyelid and the nose. The best initial management of this lacrimal apparatus disruption is as described—placement of a stent through the canaliculi, into the lacrimal duct (contained within the maxillary bone), and into the nose. The exit point of the nasolacrimal duct is via the valve of Hasner, below the inferior turbinate. It is here that the ends of the stent can be identified and retrieved, although this is often quite challenging.
The frontal, maxillary, and anterior ethmoid sinus cells drain into the middle meatus, just below the middle turbinate. The sphenoid sinus and posterior ethmoid sinuses drain into the sphenoethmoid recess, between the nasal septum and the superior turbinate.
2021
A 12-month-old boy presents for evaluation of a soft, fixed lateral brow mass that has been enlarging since it was first noted at 2 months of age. A photograph is shown. The parents report that the mass does not change in size during crying or activity, nor did it change in size during recurrent pink eye infections. Which of the following is the most likely diagnosis?
A) Branchial cleft cyst
B) Dermoid cyst
C) Hemangioma
D) Lacrimal gland
E) Lymphatic malformation
The correct response is Option B.
Dermoid cyst is the correct answer and the most common cause of a lateral brow mass in an infant. If it were a hemangioma, its size would change during crying or any activity that increases blood flow. Lacrimal gland ptosis is unlikely in a child but can be seen in the adult population, and can be ruled out if the mass is above the orbital rim, as seen in the photograph. The mass is not in the distribution of any of the different types of branchial cleft cysts. Lymphatic malformations typically change in size during infections.
2021
A 7-year-old girl presents with a tender and erythematous right pretragal abscess. Upon inquiring about the pit inferior to it, her parents report only recent drainage, despite presence since birth. They deny hearing deficits but report a family history of a similar defect. Facial cellulitis and excess granulation tissue are also noted on physical examination. Photographs are shown. Malformation of which of the following embryological structures most likely accounts for these findings?
A) Hillocks
B) Meatal plug
C) Otic capsule
D) Otic vesicle
E) Tubotympanic recess
The correct response is Option A.
Auricular hillocks are ectodermal derivatives of the first pharyngeal groove and are responsible for the formation of external ear structures (e.g., auricle and external auditory canal [EAC]). Incomplete fusion of the auricular hillocks (defective closure of the dorsal 1st pharyngeal groove) results in preauricular sinus. This is the only answer choice that contributes to the development of the external ear.
The meatal plug is an ectodermal derivative of the first pharyngeal groove (extends from the medial end of the EAC), which largely degenerates/canalizes, but is responsible for formation of the surface layer of the tympanic membrane. Persistence of the meatal plug results in conductive congenital deafness.
The otic vesicle is an ectodermal derivative of the developing brain that is responsible for formation of inner ear structures (e.g., saccule, utricle, semicircular and cochlear ducts, and membranous cochlea including the spiral organ of Corti). Abnormal development of the membranous labyrinth results in sensorineural congenital deafness.
The otic capsule is derived from mesenchyme of the first and second pharyngeal arches, surrounds/is induced by the otic vesicle, and is responsible for formation of inner ear structures (e.g., bony labyrinth). Abnormal development of the bony labyrinth results in sensorineural congenital deafness.
The tubotympanic recess is an endodermal derivative of the first pharyngeal pouch, responsible for the formation of middle ear structures (e.g., auditory tube, tympanic cavity, etc.). Abnormal/under-development of the middle ear structures increases the risk for chronic otitis media and can have an effect on conductive hearing.
2022
A 7-year-old boy sustains a deep laceration over the right side of the face. A photograph is shown. Injury to the parotid (Stensen) duct is suspected. At the anterior edge of the parotid gland, the duct should lie immediately superficial to which of the following structures?
A) Deep subcutaneous fat
B) Masseteric fascia
C) Submuscular aponeurotic system (SMAS)
D) Superficial parotid fascia
E) Temporoparietal fascia
The correct response is Option B.
The parotid gland is the largest of the three paired salivary glands (parotid, submandibular, and sublingual). It has two lobes, the deep and superficial, each of which is enveloped in a fascial sheath (parotid sheath) and between which passes the facial vein and nerve. The superficial lobe lies lateral (superficial) to the masseter muscle, and the deep lobe lies between the mastoid process and the mandibular ramus. The parotid, or Stensen, duct arises from the deep lobe of the parotid gland and receives contributions from the superficial lobe as it travels anteriorly. After exiting the anterior edge of the superficial lobe, the duct passes directly over the masseter muscle, crosses over the anterior edge of the masseter, extends medially and anteriorly over and through the buccinator muscle, and enters into the mouth via the parotid papilla, typically located opposite the second maxillary molar. The course of the duct has classically been described as following a line connecting the tragus and the midportion of the upper lip, but there is significant variation, and some studies report that this line should end in the lower half of the upper lip. The laceration shown in the photograph is just at the anterior border of the parotid and, at this level, the duct should be passing over the masseter muscle and its fascia. The course of the duct is below the superficial lobe of the parotid and, therefore, well below the subcutaneous tissue and the submuscular aponeurotic system (SMAS), which is confluent with the platysma inferiorly and the temporoparietal fascial superiorly. Superficial parotid fascia defines the layer of fascia that invests the superficial lobe of the parotid gland.
2022
