Nodular fasciitis on the zygomatic region: a rare presentation.
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The phenotypic interdependence of the musculoskeletal characters of the mandibular arch in mice.
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Evidence from studies of craniofacial anomalies and the evolutionary transition from reptiles to mammals suggests that the temporomandibular joint (TMJ), bony zygomatic arch, middle ear ossicles and mandibular muscle pattern may form a correlated suite of characters. To test the degree of phenotypic interdependence among these features, mandibular arch defects were analysed in prenatal mice. Retinoic palmitate was administered to pregnant mice on day 8.7 to produce test foetuses with malformations of the mandibular arch. A rating scale was developed for each of the four characters so that numerical values could be assigned to each phenotype encountered. Control animals were used to establish normal phenotypes for each character which were assigned a value of 1. Data from each test age, 16, 18 and 19 days postconception, were pooled and Spearmann rank correlation coefficients between each of the traits were calculated. Coefficients (R) range from a high of 0.87, between the TMJ and zygomatic arch, to a low of 0.67 between the zygomatic arch and the mandibular musculature showing highly significant correlations (P less than 0.0001) among all characters. Therefore, the data suggest that the musculoskeletal features of the mandibular arch are phenotypically interdependent during development. (+info)
Head position trainer application for research and clinical use.
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The head position trainer (HPT) is a frequently used biofeedback device for improving the head control of cerebral palsied children. When the HPT is used as a training or evaluative device, questions may arise regarding the consistency and accuracy of positioning it on the head and the position of the trainee's head. This article describes a technique for positioning and orienting the head and the HPT to one another and to common axes. With the subject in a supine position on a specially designed platform, the long axes of the zygomatic arch and the control box of the HPT were oriented vertically. The headband of the HPT then was tightened about the midforehead and the occipital areas. Reference marks were made on the forehead and the HPT was removed. After the subject assumed the sitting position, the HPT was reapplied using the forehead reference marks and the occipital areas as guides. Test-retest procedures were conducted using different therapists to apply the HPT to healthy and to handicapped subjects. The criterion score was the degrees difference between the long axes of the HPT control box and the zygomatic arch, an angle that would be 0 degree if the two long axes were parallel. No significant differences were observed between Trials 1 and 2, and the correlation coefficient between the two trials was statistically significant (p less than .02) in all situations. The HPT referencing platform can be constructed at minimal expense, and the technique of HPT application is relatively quick and reliable, and it produces minimal stress in handicapped subjects. (+info)
Granulocytic sarcoma preceding leukaemic transformation in myelofibrosis.
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A granulocytic sarcoma expanded the malar region in a patient with proven myelofibrosis over a 22 month period before undergoing rapid increase in size concomitantly with transformation to acute granulocytic leukaemia in the marrow and the widespread appearance of subcutaneous tumour deposits. Rapid response was obtained with local radiotherapy, and the systemic disease manifestations were controlled on combination courses of oral 4'-demethoxydaunorubicin and the epipodophyllotoxin VP16-213. This appears to be the first example of a granulocytic sarcoma occurring in a patient with myelofibrosis. (+info)
Normal eruption of the maxillary canine quantified in three dimensions.
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The normal eruption path of maxillary canine teeth was quantified on annual lateral and depressed postero-anterior cephalometric radiographs of 15 females and 15 males aged 5-15 years. The lateral view was rotated so that the horizontal coincided with the Frankfort plane on the depressed views, thus orientating the two views in space. Successive positions of canine cusps were marked on tracings of both views superimposed on the anterior outline of the zygomatic process. All positions of the canine cusps were digitized and the horizontal, vertical and lateral annual differences found by subtraction, taking the first position of the canine as the origin. The chronological data were corrected for enlargement and adjusted to increments of 12 months. Adjustments were also made to take into account varying ages of eruption. Posterior movement occurred between 7 and 13 years (all three years before eruption, the year of eruption and the following year). Vertical movement occurred between 5 and 13 years (all of the six years before eruption, the year of eruption and the following year). Lateral movement tended to be in a palatal direction up to 2 years before eruption followed by significant buccal movement in the year before eruption, the year of eruption and the following year. Data are given for eruption in three planes. (+info)
Effects of experimental unilateral condylectomy followed by altered mandibular function on the maxilla and zygoma.
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The effect of protruded mandibular function on the maxilla and zygoma was studied in young unilaterally condylectomized growing rats. Forty-eight-4-week-old rats were divided into two experimental and two control groups as follows: group A, 12 animals unilaterally condylectomized on the right side; the mandible was allowed to function normally; group B, 12 animals unilaterally condylectomized on the right side; the mandible was protracted forwards immediately by means of an appliance; group C, 12 animals sham-operated on the right side; no condylectomy or mandibular protraction; and group d, 12 control animals not subjected to any operation or mandibular protraction. The mandibular protraction was achieved by an appliance consisting of an acrylic collar brace fitted to the animal's neck and supporting rubber bands pulling on an intraoral part cemented on the animal's lower incisors. Twenty-five grams of pulling force and protrusion to a clinically and radiographically testes anterior crossbite was exercised for 12 hours per day. The experimental period was 30 days. Lateral and dorsoventral radiographs were taken on days 1 and 30 following condylectomies and mandibular protraction. Cephalometric analysis was performed for each animal with measurements evaluating the maxilla and zygoma. Statistical analysis and comparison of the findings in the four groups of animals can be summarized as follows: (i) condylectomy and altered mandibular function may produce remote skeletal reactions in other parts of the cranial complex; and (ii) the ipsilateral maxilla is affected by condylectomy of the mandible, but altered mandibular function by protraction compensates for the results of condylectomy. (+info)
Stereological analysis of bone architecture in the pig zygomatic arch.
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BACKGROUND: Stereological analysis of trabecular bone structure may reveal information about regional variations in stress distribution, especially in areas like the zygomatic arch in which those variations are difficult to assess mechanically. This study investigates regional differences in trabecular orientation, thickness, and density in the zygomatic and squamosal bones of pigs. METHODS: Zygomatic arches were serially sectioned frontally (n = 4), horizontally (n = 4), or parasagittally (n = 4), at a thickness of 0.8 mm. Sections were viewed under a stereomicroscope; video-images were digitized and analyzed with an automated program. RESULTS: All regions were anisotropic. Predominant orientation of trabeculae differed between and within bones. Three main patterns were seen. Anteriorly, zygomatic trabeculae were mainly arranged vertically and anteroposteriorly (relative to the occlusal plane). Posteriorly, including the jaw joint region, the squamosal featured primarily mediolateral trabeculae. In the midsection of the arch, where the two bones overlap, the trabeculae displayed a predominantly anteroposterior orientation with a secondary mediolateral peak. Trabeculae were typically 0.3-0.4 mm wide and occupied 40-50% of the area of the sections with few regional variations. CONCLUSIONS: Trabecular bone in the pig zygomatic arch is arranged orthogonally, relative to the occlusal plane. In conjunction with information from strain gauge recording, these data suggest that the zygomatic bone is bent in the parasagittal plane whereas the squamosal is bent out-of-plane. The mediolateral trabeculae in the posterior regions are consistent with a cantilever effect at the jaw joint. (+info)
Human facial muscles: dimensions, motor endplate distribution, and presence of muscle fibers with multiple motor endplates.
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BACKGROUND: Extrafusal muscle fibers of human striated skeletal muscles are known to have a uniform innervation pattern. Motor endplates (MEP) of the "en plaque" type are located near the center of muscle fibers and distributed within the muscles in a narrow band. The aim of this study was to evaluate the innervation pattern of human facial muscles and compare it with that of skeletal muscles. METHODS: Ten facial muscles from 11 human cadavers were dissected, the nerve entrance points located, and the dimensions measured. All muscles were stained in toto for MEPs using Acetylcholinesterase (AChE) and examined under the microscope to determine their location. Single muscle fibers were teased to evaluate the stained MEPs. RESULTS: The length of the different facial muscles varied from 29 to 65 mm, which correlated to the length of the corresponding muscle fibers. MEP zones were found on the muscles in the immediate vicinity of the nerves' entrance points and located eccentrically. Numbers and locations varied from muscle to muscle. Three MEP zone distribution patterns were differentiated: numerous small MEP zones were evenly spread over the muscle, a predominant MEP zone and two to three small zones were spread at random, and two to four MEP zones of equal size were randomly scattered. One MEP of the "en plaque" type was found in 73.8% of the muscle fibers and two to five MEPs were found in 26.2%. The distances between the multiple MEPs on one muscle fiber varied from 10 to 500 microm. CONCLUSIONS: This study suggests that facial muscles differ from skeletal muscles regarding distribution and number of MEPs. The eccentric location of MEP zones and multiple MEPs suggests there is an independent mechanism of neural regulation in the facial muscle system. (+info)