The importance of the zygomatic arch in complex midfacial fracture repair and correction of posttraumatic orbitozygomatic deformities

Collapse of the zygomatic arch following trauma results in inadequate anteroposterior projection of the zygomatic body and an increase in facial width. Accurate assessment of the position of the zygomatic arch in relation to the cranial base posteriorly and the midface anteriorly is the key to the acute repair of complex midfacial fractures and the secondary reconstruction of posttraumatic deformities of the orbitozygomaticomaxillary complex. Loss of projection of the zygomatic arch may occur with injuries confined to the orbitozygomaticomaxillary region or in association with complex midfacial fractures. A safe anatomic approach to the zygomatic arch allows exact anatomic restoration of the zygomatic arch using miniplates and screws and results in the reconstruction of an outer facial frame with a correct anteroposterior projection and facial width. The zygomatic arch injury is diagnosed using axial CT scanning. Three-hundred and seventeen arches have been exposed through a coronal incision following acute trauma and 47 arches have been exposed in patients requiring late correction of a posttraumatic orbitozygomaticomaxillary deformity. Permanent palsy to the frontal branch of the facial nerve has occurred in one patient following the exact definition of the anatomy of this region.     

Aplasia of the maxillary sinus in a Tibetan macaque (Macaca thibetana) with implications for its evolutionary loss and reacquisition

The skull of an adult female Tibetan macaque, Macaca thibetana, was found to completely lack the maxillary sinus (MS). This absence was accompanied by a slight lateral concavity where the ostium should have formed in the MS, a slight drop of the orbital floor, posterior and medial displacement of the zygomaxillary suture, an unusual position of the lacrimal canal, malocclusion with severely worn cheek teeth, and abnormalities in the temporomandibular joints. The facial component was disproportionally large compared with the neurocranium and mandible. This hypertrophic face probably caused the malocclusion and associated anatomical disorders and simultaneously displaced the lacrimal canal posterior to other nasal structures to preclude the possibility of maxillary pneumatization. These modifications in the spatial relationships to nasal structures might help explain the evolutionary loss and reacquisition of the MS in some primate lineages displaying great variations in facial anatomy.     

Analysis and treatment of hemifacial microsomia

Our experience over the past 25 years leads us to conclude that hemifacial microsomia is a progressive skeletal and soft-tissue deformity with the earliest skeletal manifestations in the mandible. We find that not only does the mandibular asymmetry become worse with time, but as the contralateral side grows, the deformed mandible also increases ipsilateral secondary deformation of the maxilla, nose, and orbit. We also find that there is virtually no "catch up" growth on the affected side of the face and that these patients always become more deformed with age. The psychological problems also increase with time and progression of the facial deformity. Based on our experience with correction of end-stage deformities, we now treat these patients at the earliest possible age, as determined by the patient's skeletal classification. We treat the mandible first in the hope that this repositioning in a more physiologic position will unlock the growth potential of the adjacent structures, minimize secondary deformity, and improve function and appearance to the greater benefit of the skeletal and psychological growth of the patient.     

Cephalometric Analysis of the Facial Skeletal Morphology of Female Patients Exhibiting Skeletal Class II Deformity with and without Temporomandibular Joint Osteoarthrosis

Purpose

This study evaluated the differences in the facial morphological characteristics of female patients exhibiting skeletal class II deformity with and without temporomandibular joint osteoarthrosis.

Methods

Eighty-three female patients with skeletal class II deformity were included in this study; these patients were classified into three groups on the basis of the condylar features shown in cone-beam computed tomography scans: normal group, indeterminate for osteoarthrosis group, and osteoarthrosis group. The cephalometric differences among the three groups were evaluated through one-way ANOVA.

Results

Of the 83 patients, 52.4% were diagnosed with osteoarthrosis, as indicated by the changes in the condylar osseous component. The cephalometric measurements that represented skeletal characteristics, including mandibular position relative to the cranial base, mandibular plane angle (MP-SN), posterior facial height (S-Go), and facial height ratio, were significantly different among the three groups (p < 0.05). The patients in the osteoarthrosis group yielded the smallest S-Go, the highest MP-SN, and the most retruded mandible.

Conclusions

Temporomandibular joint osteoarthrosis is commonly observed in female patients with skeletal class II deformity. The morphological characteristics of the facial skeleton in patients with bilateral condylar osteoarthrosis may be altered.     

Anatomy of the mandibular branches of the facial nerve.

In operative dissections of mandibular branches of the facial nerve, we identified certain branches below the inferior border of the mandible in all cases. These usually supplied the depressor labii inferioris and mentalis muscles, though infrequently the branch to the depressor anguli oris was also below the mandible. At least 3 nerve branches were identified in all dissections. The clinical applications of this include the necessity to identify and protect these nerve branches during operations in the submandibular triangle, as well as when incising the platysma muscle or removing fat from over the body of the mandible in a face-lift procedure.     

Craniofacial changes in hemifacial microsomia

Cephalometry, X-ray cephalometry, and somatoscopy were used in the studies of 65 adult males with a severe unilateral microtia subdivided into three groups: with marked asymmetry, with slight asymmetry, and without any obvious facial asymmetry. The group with marked asymmetries was designated as hemifacial microsomia. In this group the affected side of the face was depressed on the average from above and from below towards the level of the external auditory canal. The center of the anteroposterior reduction was situated in the region in front of the pterygomaxillar fissure. The anteroposterior and vertical facial dimensions on the affected side were reduced most markedly, while the width dimensions showed the slightest changes. Hypoplasia was most severe within the lower face and increased towards the otocephalic centre. The mandibular joint was displaced in an anteroinferior and medial direction. Hypertelorism did not occur, but the orbit on the affected side was smaller in height and was frequently vertically dislocated. The facial profile was unchanged except for retrusion of the chin and increased frequency of bite disorders. The mobility of the mandible was limited. Hemihypoplasia also exerted an influence on structures that were not of branchiogenic origin, e.g., the cranial base (narrowing, asymmetry, and more pronounced curvature), the neurocranium (depression in mastoid and tympanotemporal regions, posterior rotation of the vault), and the frontonasal component (deviation of the nose and premaxilla). The cranial vault and the bottom of the occipital bone showed on the average no asymmetries. The similar character of deviations in slightly affected groups revealed that in spite of the high variability of changes typical for branchiogenic malformations the development of the face in these defects was subjected to certain rules. Marked facial asymmetry occurred only in every fifth patient with a severe degree of microtia, while definite signs of asymmetry were absent in every third patient.     

Incomplete trisomy 22

Summary Two brothers with duplication of the distal segment of 22q inherited from a t(6;22)(q27;13) translocation carrier mother presented with intraurine growth retardation, congenital hydrocephalus, cleft palate, genital hypoplasia with cryptorchidism and hypospadias, and similar facial features including mongoloid position of eyeaxes, hypertelorism, small nose with prominent bridge, prominent upper lip, and small mandible. In addition the second sib revealed renal hypoplasia, arrhinencephaly and pentalogy of Fallot. The patients died at ages eight days and one day, respectively. The two brothers appear to be the first instances of familial trisomy 22q13qter.     

Normal and abnormal pathfinding of facial nerve fibers in the chick embryo.

Development of the facial nerve was studied in normal chicken embryos and after surgical disruption of ingrowing sensory facial nerve fibers at 38-72 h of incubation. Disruption of facial nerve fibers by otocyst removal often induced a rostral deviation of the facial nerve and ganglion to the level of the trigeminal ganglion. Cell bodies of the geniculate ganglion trailed their deviating neurites and occupied an abnormal rostral position adjacent to the trigeminal ganglion. Deviating facial nerve fibers were labeled with the carbocyanine fluorescent tracer DiI in fixed tissue. Labeled fibers penetrated the cranium adjacent to the trigeminal ganglion, but they did not follow the trigeminal nerve fibers into the brain stem. Rather, after entering the cranium, they projected caudally to their usual site of entrance and proceeded towards their normal targets. This rostral deviation of the facial nerve was observed only after surgery at 48-72 h of incubation, but not in cases with early otocyst removal (38-48 h). A rostral deviation of the facial nerve was seen in cases with partial otocyst removal when the vestibular nerve was absent. The facial nerve followed its normal course when the vestibular nerve persisted. We conclude that disruption of the developing facial pathway altered the routes of navigating axons, but did not prevent pathfinding and innervation of the normal targets. Pathfinding abilities may not be restricted to pioneering axons of the facial nerve; later-developing facial nerve fibers also appeared to have positional information. Our findings are consistent with the hypothesis that navigating axons may respond to multiple guidance cues during development. These cues appear to differ as a function of position of the navigating axon.     

Normal and abnormal pathfinding of facial nerve fibers in the chick embryo

Development of the facial nerve was studied in normal chicken embryos and after surgical disruption of ingrowing sensory facial nerve fibers at 38–72 h of incubation. Disruption of facial nerve fibers by otocyst removal often induced a rostral deviation of the facial nerve and ganglion to the level of the trigeminal ganglion. Cell bodies of the geniculate ganglion trailed their deviating neurites and occupied an abnormal rostral position adjacent to the trigeminal ganglion. Deviating facial nerve fibers were labeled with the carbocyanine fluorescent tracer Dil in fixed tissue. Labeled fibers penetrated the cranium adjacent to the trigeminal ganglion, but they did not follow the trigeminal nerve fibers into the brain stem. Rather, after entering the cranium, they projected caudally to their usual site of entrance and proceeded towards their normal targets. This rostral deviation of the facial nerve was observed only after surgery at 48–72 h of incubation, but not in cases with early otocyst removal (38–48 h). A rostral deviation of the facial nerve was seen in cases with partial otocyst removal when the vestibular nerve was absent. The facial nerve followed its normal course when the vestibular nerve persisted. We conclude that disruption of the devloping facial pathway altered the routes of navigating axons, but did not prevent pathfinding and innervation of the normal targets. Pathfinding abilities may not be restricted to pioneering axons of the facial nerve; later-developing facial nerve fibers also appeared to have positional information. Our findings are consistent with the hypothesis that navigating axons may respond to multiple guidance cues during development. These cues appear to differ as a function of position of the navigating axon. © 1992 John Wiley & Sons, Inc.     

The retaining ligaments of the cheek

The zygomatic ligaments (McGregor's patch) anchor the skin of the cheek to the inferior border of the zygoma just posterior to the origin of the zygomaticus minor muscle. The mandibular ligaments tether the overlying skin to the anterior mandible. Both these ligaments are obstacles to surgical maneuvers intended to advance the overlying skin. They also restrain the facial skin against gravitational changes, and they delineate the anterior border of the "jowl" area. The platysma-auricular ligament is a thin fascial sheet that extends from the posterosuperior border of the platysma and that is intimately attached to the periauricular skin; it serves as a surgical guide to the posterosuperior border of the platysma. The anterior platysma-cutaneous ligaments are variable fascial condensations that anchor the SMAS and platysma to the dermis. They can cause anatomic disorientation with dissection of false planes into the dermis. These four ligaments are useful as anatomic landmarks during facial dissections. The tethering effects of the zygomatic and mandibular ligaments must be interrupted if a maximum upward movement of the facial skin is desired.     

Tooth wear and the position of the mental foramen

Variation in the position of the mental foramen with respect to the teeth ("apparent" position) seems to be associated with race, but in the determination of this position, factors which affect the disposition of the teeth plainly have a bearing on the results. The apparent position was investigated in a sample of southern Chinese skulls of known age which were classified by the degree of tooth wear. Controlling for "true" position and size of the mandible, a highly significant correlation between wear and position was found, age and tooth size having no significant contribution as additional explanatory variables. The effect of tooth wear on the apparent position of the foramen may partly explain racial variation.     

Cementifying fibroma diagnosed by fine needle aspiration cytology. A case report.

A case of cementifying fibroma in the right lateral mandible was diagnosed by fine needle aspiration (FNA) cytology. The aspirate was a cellular specimen composed of clusters of oval and spindle-shaped fibroblasts with no atypical features. These cells were admixed with spherical, calcified structures. A diagnosis of "consistent with benign fibroosseous lesion, suggestive of cementoossifying fibroma" was made, and subsequent histologic examination confirmed this cytologic diagnosis. The clinical, cytologic and histologic findings in the case are presented, and the value of FNA cytology in the diagnosis of jaw lesions is discussed.     

THE PAROTID GLAND—A Reinterpretation of Its Anatomic Structure

The parotid gland does not have a constant size and shape and relationship to the facial nerve. It consists of two glandular masses, one lying on the masseter muscle and the other in the pterygoid space to a varying depth. These two masses are connected by a glandular bridge, either wide or narrow, which lies on the posterior border of the mandible. The course of the facial nerve may be through this connecting bridge or it may pass to one side or a branch may pass on either side. In passing forward, the nerve branches may lie wholly within the glandular mass on the masseter, wholly beneath it or partly within it and partly beneath it.     

The parotid gland; a reinterpretation of its anatomic structure

The parotid gland does not have a constant size and shape and relationship to the facial nerve. It consists of two glandular masses, one lying on the masseter muscle and the other in the pterygoid space to a varying depth. These two masses are connected by a glandular bridge, either wide or narrow, which lies on the posterior border of the mandible. The course of the facial nerve may be through this connecting bridge or it may pass to one side or a branch may pass on either side. In passing forward, the nerve branches may lie wholly within the glandular mass on the masseter, wholly beneath it or partly within it and partly beneath it.     

Polynesian face and dentition: functional perspective

Widely dispersed throughout the Pacific, Polynesians are a biologically distinctive people in form and size of both body and head. Large-bodied and well-muscled, their body phenotype is suited to life in a thermolabile oceanic environment. Their craniofacial skeleton is large and robust, with mandibular size and form (the "rocker" mandible) being especially characteristic. In this paper the Polynesian variants of body form, and of facial size (including dentition) and form, are interpreted from a functional perspective.     

Cleft lip and palate treated by presurgical orthopedics, gingivoperiosteoplasty, and lip adhesion (POPLA) compared with previous lip adhesion method: a preliminary study of serial dental casts.

Comparing the treatment protocols for cleft lip and palate requires a study of facial growth and development. Serial orthodontic study models aid in delineating the effects of surgery on maxillary mandibular relationships. In 1978, a new protocol, POPLA (presurgical orthopedics followed by periosteoplasty and lip adhesion), was developed and put into practice. This article compares the results obtained using POPLA (group I) with those using the previous method (lip adhesion alone) (group II) for cases of unilateral and bilateral clefts. Complete orthodontic study models were available for 124 patients, 63 in group I and 61 in group II. Specific timing sequences and surgical details are discussed. Dental cast analyses evaluated alveolar gap, arch width, anteroposterior distance, incisor crossbite (single tooth and multiple tooth), and buccal crossbite (single and multiple tooth) at birth and at 3, 6, and 9 years of age. X-ray studies evaluated the bony bridge. Additional comments are made regarding the incidents and effects of pharyngeal flaps and bone grafts on maxillary-mandibular relationships. Results included less buccal crossbite in the POPLA group, with a wider transverse distance of the upper dental arch. There was a greater frequency of anterior crossbite in the POPLA group, and the anteroposterior distance was shorter at 6 years of age but less so by age 9. This may be because of the different orthodontic care received by the patients in the two groups. In conclusion, the POPLA approach achieves the main goal of moving the palate into a normal position and stabilizing the arch with a bony bridge that attracts teeth. It avoids the difficult anterior fistulae and presents a more symmetrical platform upon which the lip can be united and the nose can be corrected early.     

Brow suspension,a minimally invasive technique in facial rejuvenation

People tend to prefer noninvasive or minimally invasive methods of facial rejuvenation, especially when it involves their face, which is the hallmark of a person's identity and impossible to hide. It is widely known that brow ptosis gives the face a "tired look" and also accentuates deformities of the upper eyelid. Most people who are interested in facial rejuvenation may not accept even a minor surgery, such as an endoscopic surgery. The senior author has developed a minimally invasive method of suspending the brow at a higher position. In this technique, there is neither surgical dissection nor a surgical incision except for four stab incisions and suture insertion, which is why we refer to it as a nonsurgical brow suspension. It is done under local anesthesia, and the brows are fixed in the position that they assume when the patient is supine. In the past 6 years, we performed 387 brow suspensions on 324 female and 63 male patients. The youngest patient was 19 years old, and the oldest was 74 years old. A retrospective chart review was done. These 387 cases were reviewed by comparison of preoperative and postoperative photographs. This approach was not only used for patients who were not interested in surgical rejuvenation but was also combined with lipofilling, laser resurfacing, and/or upper blepharoplasty. This technique is useful for correcting postsurgical brow asymmetry. We present this technique as an adjunct to the established techniques of facial rejuvenation. Despite the high patient acceptance and technical ease, it is not a replacement for the established techniques of facial rejuvenation.     

Growth of the masseter muscle in rhesus monkeys (Macaca mulatta)

The growth of the masseter muscle in eight infant, juvenile, and adolescent female rhesus monkeys (M. mulatta) was examined over a 2.5 year period using serial radiographic cephalometric techniques with the aid of radiopaque muscle markers. The radiopaque markers, which are composed of small pieces of root canal broach inserted into the muscle belly, make it possible to determine longitudinal masseter muscle growth as well as migration of the masseter muscle relative to the mandible. It was found that the masseter muscle increased in length by 64% during the total growth period, most of which occurred between 6 and 18 months of age. Relative to the cranium, the masseter muscle grew markedly inferiorly and only slightly posteriorly. Relative to the mandible, the masseter migrated in a posterior and slightly superior direction, keeping pace with the ramus and condyle as they grew posteriorly and posterosuperiorly throughout the study period. It was concluded that: 1) radiopaque muscle markers are a valuable tool for analysis of muscle growth and alteration of muscle location; 2) the masseter muscle in the rhesus monkey undergoes elongation, probably due to addition of sarcomeres at the fiber-tendon junctions; and 3) posterior migration of the masseter muscle relative to the corpus of the mandible, probably due to the nature of its periosteal attachment, results in a stability of the anteroposterior position of the masseter muscle despite the anterior displacement of the mandible.