cranio/maxface Flashcards
A 54-year-old woman comes to the office for consultation regarding a mass in the mouth that was diagnosed as squamous cell carcinoma. Physical examination shows one ipsilateral 1-cm lymph node. A photograph and CT scan are shown. Which of the following is the most appropriate TNM staging of this patient’s tumor?
A) I B) II C) III D) IV
D.
According to the American Joint Committee on Cancer (AJCC) TNM staging, if a tumor invades the mandible through the cortical bone, it is, by definition, a stage IV tumor regardless of size. In this case, considering that there is one node less than 3 cm on the ipsilateral side, the appropriate staging of this tumor is IVA.
Stage II and III tumors do not involve invasion of the mandible or adjacent structures. Stage IVB involves metastasis to a lymph node more than 6 cm in greatest dimension. Stage IVC involves distant metastasis.
Oral Cavity:
T1 Tumor <2 cm
T2 Tumor >2 but <4 cm
T3 Tumor >4 cm
T4 Tumor invades adjacent structures such as cortical bone, tongue, skin, or soft tissues of
the neck
N1 One ipsilateral node <3 cm
N2a One ipsilateral node >3 and <6 cm
N2b Multiple ipsilateral nodes <6 cm
N2c Bilateral contralateral nodes <6 cm
N3 Any nodes >6 cm
M0 No distal metastasis
M1 Distal metastasis
During development of a fetus, a cleft of the lip results when the maxillary process fails to fuse normally with which of the following processes?
A) Lateral nasal
B) Frontonasal
C) Medial nasal
D) Mandibular
C. Medial nasal
The developing fetus has five facial prominences that are populated by neural crest cells. These five facial prominences are the frontonasal, paired maxillary, and paired mandibular. The frontonasal prominence gives rise to the nasal pit or placode, around which develops the medial and lateral nasal processes. A failure of fusion between the maxillary prominence and the medial nasal process results in a common cleft of the lip.
Which of the following structures passes through the pterygomaxillary fissure?
A) Mandibular artery
B) Mandibular nerve
C) Maxillary artery
D) Maxillary nerve
C. maxillary artery
The pterygomaxillary fissure appears on lateral cephalograms as an upside-down teardrop. It serves as a radiographic point of orientation. The posterior border of this opening is the anterior aspect of the pterygoid plates. The anterior border is the posterior aspect of the maxilla, and the superior border is the pterygopalatine fossa and sphenoid bone and the orbital process of the palatine bone. The inferior orbital fissure and the pterygomaxillary fissure are oriented at right angles to each other. They are separated by the small pterygopalatine fossa. The pterygomaxillary fissure connects the small pterygopalatine fossa with the much larger infratemporal fossa. It transmits the terminal branches of the maxillary artery and veins. The inferior orbital fissure transmits the maxillary nerve and branches of the pterygopalatine ganglion from the pterygopalatine fossa to the orbit. The mandibular nerve and branches pass through the infratemporal fossa but not through the pterygomaxillary fissure. Appropriate care must be taken during separation of the face from the pterygoid plates to avoid injury to the maxillary artery and veins. After separation of these components, down-fracture is often performed using digital pressure alone.
A 15-year-old boy is brought to the office by his parents because he has had swelling in the right lateral mandibular region for the past two months. Physical examination shows a firm, nonmobile mass of the body of the mandible. CT scan is shown. Biopsy of the lesion shows ameloblastoma. Which of the following is the most appropriate management?
A) Cryotherapy
B) Curettage
C) Enucleation
D) Segmental resection
D.
Treatment modalities include cryotherapy, curettage, enucleation, or segmental resection and reconstruction. There are three main types of ameloblastomas: peripheral, unicystic, and multicystic tumors. Peripheral tumors.are odontogenic in origin and have histologic characteristics consistent with intraosseous ameloblastomas. However, they occur in the soft tissues covering the tooth-bearing parts of the jaw. These peripheral tumors can be treated with local excision. Unicystic ameloblastomas can be treated conservatively with enucleation because they appear clinically as a cyst. When the tumor involves the periphery of the connective tissue wall of the cyst, a peripheral ostectomy should be considered. Multicystic ameloblastomas or large ameloblastomas that involve the surrounding of the bone and extend into the soft tissues are locally aggressive and should be treated with segmental resection and reconstruction.
A 24-year-old woman comes to the office for consultation regarding her appearance when smiling. Physical examination shows the mesiobuccal cusp of the first maxillary molar lying distal to the buccal groove of the first mandibular molar. Which of the following is the most appropriate Angle classification?
A) I B) IIA C) IIB D) III
D. III
Occlusion as described by the Angle classification uses the relationship of the permanent first molars of the maxilla and mandible as its reference point. Patients with class I occlusion (normal) have the mesiobuccal cusp of the maxillary first molar lying in the buccal groove of the mandibular first molar. Patients with class II occlusion have the mesiobuccal cusp of the maxillary first molar located mesial to the buccal groove of the mandibular first molar. Class III occlusion, as illustrated in this case, is described as having the mesiobuccal cusp of the maxillary first molar positioned distal to the buccal groove of the mandibular first molar.
In planning open reduction and internal fixation in a patient with a low subcondylar neck fracture, which of the following extraoral incisions provides the safest and most versatile exposure to the fracture site?
A) Postauricular
B) Preauricular
C) Retromandibular
D) Submandibular
C) Retromandibular
The retromandibular incision provides the safest and most versatile exposure for open reduction and internal fixation of submandibular fractures. When compared with the subcondylar and preauricular incisions, there is significantly less injury to the marginal mandibular, temporal, and zygomatic branches of the facial nerve.
The retromandibular incision allows access superiorly to the coronoid notch and inferiorly to the angle of the mandible. The addition of a transfacial trocar to this approach facilitates access to higher level subcondylar fractures as well. The preauricular, postauricular, and submandibular incisions provide a more limited view of low subcondylar fractures.
A 56-year-old woman undergoes reconstruction of the mandible using a free fibular flap. During the procedure, the microsurgeon dissects the external carotid artery; however, the superior thyroid artery cannot be located for anastomosis. Which of the following branches of the external carotid artery is the next distal vessel that would be suitable for anastomosis?
A) Lingual
B) Occipital
C) Posterior auricular
D) Maxillary
A. Lingual
During the dissection of the neck vessels, the microsurgeon must be comfortable with the anatomy of the entire neck including the orientation and suitability of the available arteries. The branches of the external carotid artery, in order from proximal to distal, are as follows: superior thyroid, ascending pharyngeal, lingual, occipital, facial, posterior auricular, and maxillary arteries.
A 16-year-old boy with history of cleft lip and palate comes to the clinic for management of malocclusion. Medical history includes several surgical procedures on the palate for closure of an oral nasal fistula. Intraoral evaluation shows Class III malocclusion and 15- mm negative overjet. Lateral cephalometry shows decreased SNA angle with normal SNB angle. Which of the following surgical procedures is most appropriate for correction of this deformity?
A) Mandibular setback
B) Le Fort I osteotomy with bilateral sagittal split osteotomy of the mandible
C) Le Fort I advancement by distraction osteogenesis
D) Le Fort II advancement by distraction osteogenesis
E) Le Fort III advancement by distraction osteogenesis
C) Le Fort I advancement by distraction osteogenesis
For this patient, the most appropriate surgical option is a Le Fort I advancement by distraction osteogenesis because he requires correction of the malocclusion and needs a large amount of movement. Le Fort I advancement can correct the malocclusion by moving the tooth-bearing segment of the maxilla. Distraction osteogenesis allows for large movement because it stretches the soft tissue envelope gradually to accommodate the bony framework. Also, this patient’s prior surgery probably has resulted in scarring of the soft tissue of the palate. Such scarring is also an indication for distraction, which gradually stretches the scars. In contrast, an immediate large advancement is likely to be limited by scarring.
In this patient, mandibular setback alone produces too large a movement to correct the malocclusion and risks posterior placement of the base of the tongue, which could narrow the airway. In addition, it would not be aesthetically pleasing. A mandibular setback could be used as an adjunct if it were not possible to obtain the needed advancement by moving the maxilla alone.
Because this patient’s nose, orbital rim, and malar prominences are in good position, a Le Fort II or Le Fort III advancement is not indicated.
A 64-year-old man comes to the office because he has numbness of the left medial cheek and infraorbital area. Physical examination shows a mass of the hard palate. Incisional biopsy shows adenoid cystic carcinoma. Further evaluation is most likely to show tumor involvement of which of the following foramina at the base of the skull?
A) Anterior ethmoid foramen
B) Foramen ovale
C) Foramen rotundum
D) Jugular foramen
E) Stylomastoid foramen
C. rotundum
Numbness in the left medial cheek and left infraorbital area suggest that the tumor has invaded the infraorbital nerve, which exits the middle cranial fossa from the foramen rotundum. Approximately 80% of patients with adenoid cystic carcinoma have perineural spread. The anterior ethmoid foramen emerges from the frontoethmoid suture line and contains the anterior ethmoid vessels. The foramen ovale and the stylomastoid foramen, respectively, contain the mandibular nerve (V3) and the facial nerve (cranial nerve VII). Cranial nerves IX (glossopharyngeal), X (vagus), and XI (spinal accessory) emerge from the jugular foramen
A 5-year-old boy who underwent repair of cleft palate via double opposing Z-plasty four years ago has hypernasality indicative of velopharyngeal insufficiency. Direct nasendoscopy shows a coronal closure pattern of the velopharyngeal port and little or no motion of the lateral pharyngeal wall. Which of the following surgical procedures is most appropriate for correction of the velopharyngeal insufficiency?
A) Augmentation of the posterior pharynx
B) Inferiorly based posterior pharyngeal flap C) Sphincter pharyngoplasty
D) Superiorly based posterior pharyngeal flap E) V-Y pushback palatoplasty
C.
Velopharyngeal competence results from sufficient apposition of the velar mucosa against the posterior pharyngeal wall and from motion of the lateral pharyngeal wall that causes sphincteric closure of the velopharyngeal port. Many patients with velopharyngeal insufficiency after cleft palate repair have a shortened, scarred velum, resulting in a deficiency in the anterior-posterior coronal closure pattern. Other patients, such as those with velocardiofacial syndrome, have generalized pharyngeal dysfunction with poor lateral pharyngeal wall motion, which contributes to a large central gap that leads to velopharyngeal incompetence.
To correct velopharyngeal insufficiency in this patient, a sphincter pharyngoplasty is most appropriate. In this procedure, the posterior tonsillar pillars (palatopharyngeus muscles) are bilaterally dissected from the tonsillar fossae and rotated 90 degrees medially. Then they are affixed in an overlapping fashion against the posterior pharyngeal wall. Because the palatopharyngeus muscles are a continuation of the soft palate and lateral pharyngeal walls, this procedure narrows the entire pharyngeal port in a sphincteric fashion and augments the posterior pharyngeal wall.
In a patient with little or no motion of the lateral pharyngeal wall, augmentation of the posterior pharynx is not appropriate. Although it may decrease the anterior-posterior coronal deficiency, it does nothing to treat the poor lateral wall motion. In addition, augmentation of the posterior pharynx has been attempted with multiple materials (including fat, Teflon, and silicone) in the past, without success. Today, the procedure has all but been abandoned.
Likewise, a posterior pharyngeal flap (whether inferiorly based or superiorly based) is not appropriate because it may not completely correct the hypernasality associated with velopharyngeal insufficiency. This is true because it does not allow the lateral pharyngeal walls to move medially and seal off the lateral ports between the pharyngeal flap and lateral pharyngeal walls.
Which of the following muscles elevates the mandible?
A) Digastric
B) Genioglossus
C) Geniohyoid
D) Medial pterygoid
E) Mylohyoid
D. medial pterygoid
The mandible is subject to muscular forces, which tend to add to the instability of certain fractures and necessitate treatment. The masseter, temporalis, and medial pterygoid muscles elevate the mandible, and the geniohyoid, genioglossus, mylohyoid, and digastric muscles tend to depress the mandible. The lateral pterygoid muscle inserts into the capsule of the temporomandibular joint and tends to remain attached and pull the condyle head medial when there is a high fracture.
An 8-year-old girl has bilateral coloboma and retraction of the lower eyelids, ptosis of the upper eyelids, inferior displacement of the lateral canthi, hypoplasia of the temporalis muscles, microtia, and abnormal hairline. Which of the following additional findings in this patient represents the main underlying characteristic of the full expression of Treacher Collins syndrome?
A) Absence of the malar bone and zygomatic arch B) Bilateral Tessier cleft number 4
C) Deformed mandibular condyle
D) Premature fusion of the coronal sutures
E) Tessier cleft numbers 0 and 14
A
According to Tessier, the main characteristic of the complete form of Treacher Collins syndrome is the absence of the malar bone and zygomatic arch. This absence is caused by combined Tessier clefts numbers 6, 7, and 8. These clefts result in severe dysplasia or even absence of the zygoma. The number 6 cleft produces the lower eyelid findings. The number 7 cleft results in absence of the zygomatic arch, hypoplasia of the temporalis muscles, microtia, and abnormal hairline. The number 8 cleft causes inferior displacement of the lateral canthi.
Which of the following muscles can function to close off the oral cavity from the oropharynx?
A) Levator veli palatini
B) Musculus uvulae
C) Palatoglossus
D) Palatopharyngeus
E) Tensor veli palatini
C. palatoglossus
The palatoglossus is a paired muscle that elevates the posterior tongue and pulls it against the soft palate, separating the oral cavity from the oropharynx. The muscle attaches to the side of the tongue on one end and the palatine aponeurosis on the other.
The levator veli palatini elevates the soft palate during swallowing and yawning. It attaches superiorly to the cartilage of the auditory tube and the petrous part of the temporal bone and inferiorly to the palatine aponeurosis.
The palatopharyngeus muscle is part of the palatopharyngeal arch, attaching to the lateral wall of the pharynx, the hard palate, and the palatine aponeurosis. During swallowing, it tenses the soft palate while pulling the walls of the pharynx superiorly, medially, and anteriorly, effectively closing off the nasopharynx from the oropharynx.
The tensor veli palatini also tenses the soft palate and opens the eustachian tube during yawning and swallowing. It extends from the palatine aponeurosis to the medial pterygoid plate and spine of the sphenoid bone and the cartilage of the eustachian tube.
The musculus uvulae pulls the uvula superiorly and shortens it. The muscle fills the substance of the uvula, attaching to its mucosa and to the posterior nasal spine and palatine aponeurosis.
A 5-year-old child has malocclusion and limited opening of the mouth after falling from playground equipment. A CT scan is shown. Which of the following is the most likely long- term sequela of this patient’s injury?
A) Bimaxillary prognathism
B) Mandibular hypoplasia
C) Mandibular prognathism
D) Maxillary hypoplasia
E) Maxillary prognathism
B
This child is at increased risk for mandibular hypoplasia. The condyle serves as a growth center for the mandible and contributes primarily to vertical growth. The condylar cartilage is a site of secondary passive growth dependent on forces acting on it, notably the medial and lateral pterygoid muscles. Pediatric condylar fractures generally remodel and do not often cause growth disturbance. However, the thin, localized functional matrix of the condyle may disallow normal mandibular growth after it has been injured and may result in unilateral or bilateral hypoplasia depending on the injury. Pediatric mandibular fractures are frequently treated conservatively via closed reduction and short periods of maxillomandibular fixation.
A 29-year-old woman comes to the office for evaluation of orthognathic profile and class I occlusion. Physical examination shows isolated retrogenia and moderate vertical mandibular excess. Which of the following types of genioplasty is most appropriate?
A) Advancement with horizontal osteotomy only
B) Advancement with horizontal osteotomy and downgrafting
C) Advancement with inferiorly angled osteotomy
D) Alloplastic augmentation, extraoral approach
E) Alloplastic augmentation, intraoral approach
C
The most appropriate genial treatment option is advancement with the osteotomy angled inferiorly. The angle of the osteotomy has an impact on the vertical dimension of the mandible as the segment is advanced forward. An osteotomy angled inferiorly in relation to the occlusal plane will provide a progressive decrease in the vertical dimension as the osteotomy segment is advanced. A 2- to 4-mm reduction in chin height can be achieved with this technique. When a larger height reduction (in excess of 5 mm) is indicated, a horizontal wafer of bone is removed above the horizontal sliding osteotomy. A horizontal osteotomy, relatively parallel to the occlusal plane, would provide a more pure anteroposterior movement.
Downgrafting the osteotomy site, with an interpositional bone graft or alloplastic material, would be indicated to increase the vertical dimension in a patient with vertical mandibular deficiency.
Alloplastic augmentation alone, whether placed through an intraoral or extraoral approach, is best indicated for a unidimensional change, such as a pure sagittal deficiency.
A 7-year-old boy is being evaluated after sustaining facial injuries when he fell while climbing playground equipment. Radiographs show a fracture of the orbit. Which of the following additional findings best supports urgent surgical repair in this patient?
A) Acute enophthalmos
B) Corneal abrasion
C) Diplopia on upward gaze
D) Entrapment of the rectus muscle
E) Hyphema
D. entrapment
Hyphema represents blood from hemorrhage in the anterior chamber of the eye. Ocular injury is a contraindication to early surgical intervention. Orbital manipulation increases the risks of secondary bleed into the anterior chamber and the development of acute closed-angle glaucoma.
Indications for repairing orbital fractures include persistent diplopia in central gaze, early enophthalmos or vertical dystopia, and large fracture size, which may predispose later development of enophthalmos. Such fractures are repaired with some urgency within two weeks of the injury.
The firstborn child of a Caucasian couple with no abnormalities has bilateral cleft lip and palate. Which of the following percentages best represents the possibility that this couple’s next child will have cleft lip, with or without cleft palate?
A) 2% B) 4% C) 10% D) 16% E) 32%
B. 4%
The incidence of cleft lip with or without cleft palate for the sibling of a child with bilateral cleft lip but no cleft palate is 6.7%, for the sibling of a child with unilateral cleft lip and palate is 4.9%, and for the sibling of a child with unilateral cleft lip but no cleft palate is 4.0%. If there are two affected children with cleft lip with or without cleft palate, the risk for a third child would be at least 9%.
The overall risk of cleft lip with or without cleft palate in a Caucasian population is 1:1000. In a first-degree relative, that risk is multiplied by 40; in a second-degree relative, the risk is multiplied by 7; and in a third-degree relative, the risk is multiplied by 3. However, the risk is increased when more than one relative is affected, if the family member has a severe form of the disorder, if the family member is of the sex least likely to be affected, or if the parents are consanguineous. For one affected parent, the risk of having one child with cleft lip with or without cleft palate is 4%, and the risk for a second child increases to 17%.
A 12-year-old boy is brought to the emergency department after he fell while riding his bike and landed on the chin. Panorex radiographs show a minimally displaced fracture of the high right condylar neck and an open left parasymphyseal fracture. Which of the following is the most effective management?
A) Observation with serial radiographs and restriction to soft diet
B) Intermaxillary fixation with infraorbital and circummandibular wires for four weeks
C) Intermaxillary fixation with arch bars for four weeks
D) Open reduction with internal fixation of the parasymphyseal fracture and arch bars for two weeks
E) Open reduction with internal fixation of both the parasymphyseal fracture and the fracture of the high condylar neck
D.
Immobilization for a short period (i.e., two weeks) is the appropriate management of the condylar neck fracture. This will help to allow the fractures to become stable enough to maintain the reduction once movement is instituted. Early movement helps to decrease the risk of ankylosis of the temporal mandibular joint. Extended immobilization to allow for healing of the parasymphyseal fracture will increase the risk of ankylosis of the temporomandibular joint. Open reduction and internal fixation (ORIF) of the parasymphyseal fracture will ensure an anatomic reduction of a stable skeletal unit. This, in turn, will decrease the risk of infection and nonunion.
ORIF of the condylar neck fracture is not indicated because the fracture is minimally displaced. Conservative management of these fractures is well accepted and has stood the test of time. Open reduction would incur the risks of injury of the facial nerve.
A 6-year-old boy who underwent repair of a unilateral cleft lip and palate in infancy is brought to the office by his parents because he has had a sensation of numbness in the left anterior mobile tongue for the past two days, since he underwent repair of a palatal fistula during orotracheal intubation. During that procedure, the oral cavity and palate were retracted for two hours with a Dingman retractor. Which of the following nerves was most likely damaged during the procedure?
A) Glossopharyngeal (IX) B) Lingual
C) Mental
D) Recurrent laryngeal E) Superior laryngeal
B.
The lingual nerve provides sensation to the anterior two thirds of the tongue. Injury to the lingual nerve is a rare complication of airway manipulation. Virtually all equipment associated with airway management and/or oral cavity retraction has been implicated in its damage. Examples include direct laryngoscopy, tracheal intubation, laryngeal mask airway, and tonsillectomy. The etiology of lingual nerve damage is likely compression of the nerve in the floor of mouth against the mandible caused by forceful compression of the floor of mouth. The mental nerve exits the mental foramen just below the first or second premolar and supplies sensation to the lower lip and chin. The superior laryngeal nerve provides sensory innervation to the supraglottis. The glossopharyngeal nerve provides sensory innervation and taste sensation to the base of the tongue. The recurrent laryngeal nerve provides motor innervation to the laryngeal musculature.
A 1-month-old infant is brought to the office by her parents for evaluation of a skull deformity. CT scan of the head is shown above. Which of the following cranial dysmorphologies is the most likely diagnosis?
A) Dolichocephaly
B) Plagiocephaly
C) Scaphocephaly
D) Trigonocephaly
E) Turricephaly
D.
The CT scan demonstrates an infant with a narrowed forehead and decreased bitemporal distance. There is also evidence of orbital hypotelorism and an obliterated or fused metopic suture. These findings are consistent with trigonocephaly.
Scaphocephaly is a cranial shape excessive in the anterior-posterior dimension and narrow in the bitemporal dimension. This results in a long and narrow (boat-like) shape of the head. This results from premature fusion of the sagittal suture.
Dolichocephaly is another term for scaphocephaly.
Plagiocephaly or “twisted head” is used to describe anterior or posterior deformities. Plagiocephaly is classified as anterior or posterior as well as synostotic and nonsynostotic or deformational. Anterior synostotic plagiocephaly refers to coronal craniosynostosis and posterior synostotic plagiocephaly refers to lambdoid craniosynostosis. Anterior or posterior nonsynostotic plagiocephaly refers to deformational plagiocephaly or skull molding from a persistent sleep position.
Turricephaly or oxycephaly is used to describe vertically tall head shapes that are usually associated with the brachycephaly (short in the anterior-posterior dimension) of bicoronal syndromic craniosynostosis.
A 34-year-old woman undergoes a down-fracture of the maxilla during Le Fort I osteotomy. Profuse bleeding is noted in the posterior aspect of the lateral nasal wall. Injury to which of the following arteries is most likely?
A) Anterior ethmoidal
B) Descending palatine
C) Greater palatine
D) Infraorbital
E) Nasopalatine
B.
The descending palatine artery is a branch of the third portion of the internal maxillary artery. It descends vertically within the perpendicular portion of the palatine bone. Injury to this vessel is not uncommon while performing a Le Fort I osteotomy. Division of this artery has been shown not to expose the maxilla to necrosis.
A 3-month-old infant has bifacial microsomia and mandibular hypoplasia (shown). Which of the following is the best rationale for performing tongue-lip adhesion in this patient?
A) Improve maxillary dentition
B) Optimize airway patency
C) Promote mandibular growth
D) Promote maxillary growth
E) Protect mandibular dentition
B.
Tongue-lip adhesion is performed in patients with retrognathia and glossoptosis to improve the airway. Pierre Robin sequence describes the clinical triad of microretrognathia, glossoptosis, and upper airway obstruction. Patients may present with airway obstruction, feeding difficulties, or both immediately after birth or during the following weeks of life. If left untreated, many these infants experience failure to thrive, chronic hypoxemia, and cor pulmonale. Pierre Robin sequence may be nonsyndromic or associated with syndromes such as bifacial or hemifacial microsomia.
A 1-month-old infant has right-sided microtia and hemifacial microsomia (shown). Weakness of which of the following branches of the facial nerve is demonstrated?
A) Buccal
B) Cervical
C) Mandibular
D) Temporal
E) Zygomatic
C. mandibular
The 2-year-old boy shown is scheduled to undergo cleft repair. Which of the following is the most appropriate Tessier classification of this cleft?
A) Tessier No. 0
B) Tessier No. 3
C) Tessier Nos. 6, 7, and 8 D) Tessier No. 7
E) Tessier No. 14
D.
The orbit, nose, and mouth are key landmarks through which craniofacial clefts cross. Tessier noted these landmarks and numbered craniofacial clefts from 0 to 14, with lower numbers (0 through 7) representing facial clefts and the higher numbers (8 through 14) representing theircranial extension. Tessier’s numeric system is purely a topographic map of the cleft fault line (see diagram below); it describes the axis of the cleft but does not specifically indicate which structures (soft tissue or bone) may be involved by the cleft. The combination of cranial and facial clefts usually totals 14. Cleft 0 is in the midline of the face, whereas cleft 14 is its cranial midline extension. Clefts 1, 2, and 3 begin at the Cupid’s bow, as does the common cleft lip. Treacher Collins syndrome is a combination of clefts 6, 7, and 8. The number 7 cleft is the most common of the craniofacial clefts and is more commonly referred to as hemifacial microsomia. The clinical expression of number 7 cleft is highly variable. In the photograph, this number 7 cleft is expressed only by macrostomia at the oral commissure.
