Where is mandibular ramus

Modified 17 with permission. Magnitudes and durations of jaw muscle activities were measured using ambulatory electromyography EMG calibrated via bite force vs EMG data from each muscle and subject as previously reported. Subjects were asked to record for 2 days and 2 nights, for at least 6 hours per session Figure 4 A,B. To characterize DF associated with muscle activity magnitudes, two laboratory sessions of static and dynamic bite force and EMG data Figure 4 C,D were collected and plotted.

DF were averaged for muscles and subject for daytime and for nighttime. Ambulatory muscle activities recorded during one A day and B night. To test for Co-Go phenotype differences associated with MBS, data were normalized within females and males to standardize for sex differences in scale.

K-means cluster analysis tested normalized data for subject groupings. Of 92 enrolled subjects 53 females, 39 males , 73 50 females, 23 males provided complete data and are reported upon. Average ages of females and males were Co-Go measurements ranged from SN-GoGn measurements ranged from Subjects produced daytime and nighttime EMG recordings with average durations of 7.

Average DF were 0. There were no significant differences in DF between females day: 1. Among these groups defined by the cluster analysis, SN-GoGn was not significantly different between the two dolichofacial subgroups B Cluster analysis showed normalized Co-Go vs MBS centroid distances segregated a group with brachyfacial features from two subgroups with dolichofacial features.

Mechanobehavior, the product of magnitude and frequency of jaw loading behaviors, influences TMJ growth and maintenance as well as degenerative changes, which generally occur earlier in the human TMJ than in other post-cranial joints. The combination of these low-level jaw muscle activities duty factors , and the mechanical work input per disc volume during jaw functions energy densities , produced the mechanobehavior scores MBS.

Also unknown is whether asymmetric differences in mechanosensitive genes, like those seen in asymmetric craniofacial anomalies, 22 , 23 affect unilateral differences in mechanosensitive genes in response to symmetric mechanobehavior. Mandibular condyle growth can increase ramus length. Although hypothetical currently, if dolichofacial subgroups with high and low MBS also exist in growing children, early interventions to optimize mandibular condyle growth and, thus, optimize ramus length and jaw relationships may be possible and should be investigated in the future.

As a theoretical example, in dolichofacial individuals with low MBS, increasing DF by prescribing a gum-chewing protocol, and thereby increasing the MBS into the optimal range, might be a simple means of improving outcomes of orthopedic treatment. Also theoretically, some individuals with high MBS may be expected to have poorer outcomes from orthopedic treatment as children and adolescents, and also be more prone to precocious development of degenerative TMJ changes as adults.

Focusing on awake-state muscle activities may be more fruitful given that previous studies showed significantly larger DF during the awake state compared to sleep state, 24 and significantly larger TMJ ED during loaded asymmetric, compared to symmetric jaw movements. The current study's limitations included: adult subjects only, MBS based on symmetric jaw movements, unilateral ambulatory EMG recordings, imbalanced numbers of females and males, and incomplete data that excluded some subjects.

Futures studies should investigate facial type differences in three-dimensional craniomandibular anatomy and effects on TMJ forces and should follow younger subjects with potential for jaw growth longitudinally to test if MBS can predict ramus length.

In addition, MBS based on actual jaw behaviors of individual subjects may be possible via application of computing recognition algorithms to ambulatory EMG recordings for specific jaw behavior detection.

Mechanobehavior scores were significantly different between subjects with brachyfacial features longer ramus length, flatter mandibular plane angle compared to two subgroups of subjects with dolichofacial features shorter ramus length, steeper mandibular plane angle. Mechanobehavior scores were lower and higher in dolichofacial subgroups than the brachyfacial group. Recipient s will receive an email with a link to 'Mechanobehavior and mandibular ramus length in different facial phenotypes' and will not need an account to access the content.

Subject: Mechanobehavior and mandibular ramus length in different facial phenotypes. Sign In or Create an Account. User Tools. There are no clear indications and contraindications about open or closed treatment of these fractures. Management of these fractures is still an enigma; however, certain aspects of treatment remain amenable to personal opinions and clinical impression.

As this fracture seldom causes occlusion derangement and due to difficulty in access to fracture they are conventionally managed by closed treatment [ 23 ]. Surgeons hesitantly opt for ORIF treatments mainly because of troublesome surgical exposure, particularly by the proximity of facial nerve branches. Inevitable scars caused by cutaneous incision, risks of facial palsy, and difficulty of incorporating technological innovations, with long-term learning curves and extended operating time, account for some of the drawbacks related to operative interventions.

The primary advantage of this technique is minimal scar; however, despite this aesthetic advantage, it has some inherent disadvantages like requirement of specialized armamentarium and the long learning curve as it is a technique sensitive procedure.

Furthermore, its clinical applicability in ramus fracture still remains to be investigated. Ramus fractures are seldom lonely. There was no predictable pattern of associated fractures observed in our study.

These are preferred owing to its larger cross-sectional area to avoid torqueing and splaying at either ends of fracture which might occur under the influence of the muscles attached.

Open reduction and rigid internal fixation provide a number of advantages like functional as well as anatomical reduction and immobilization of the fracture, early return to function, easier maintenance of oral hygiene, improved nutrition, and reduced risk of airway compromise. All of the cases treated by ORIF and closed treatment had satisfactory, stable occlusion at the conclusion of the treatment without any major complications. The present report on clinical potential of mandibular ramus fracture and analysis of its management is limited because the study is from a single institution which compromises results in retrospective manner.

Providing clear treatment recommendations on the basis of a series of 12 patients is challenging. The observation of this study should be supported by further well designed elaborative randomized controlled studies, comparing open versus closed treatment and also different modalities of open treatment with each other, for substantial evidence based management of these fractures.

Within the limitations of the current study, we conclude that ramus fracture is a relatively rare subsite to get fractured amongst mandible fractures. ORIF of ramal fractures by two noncompression mini plates confers adequate anatomical, functional reduction comprising length, alignment, and rotational axis of adjacent fracture fragments, and immobilization with good outcomes and relatively early return to function in our small series.

The authors declare that there is no conflict of interests regarding the publication of this paper. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article of the Year Award: Outstanding research contributions of , as selected by our Chief Editors. Read the winning articles. Special Issues. Academic Editor: Hiroshi Mizuno. Received 30 Jul Revised 22 Sep Accepted 15 Oct Published 03 Nov Abstract Aim. Introduction Since the earliest report on mandibular fractures dating back to BC in Egypt [ 1 ], oral and maxillofacial surgeons have studied the pattern of mandibular fractures without reaching a consensus on the most common pattern.

Patients and Method A retrospective analysis was conducted of the medical records of all trauma patients who presented with signs and symptoms associated with mandibular fractures on presentation to Department of Oral and Maxillofacial Surgery, Acharya Vinoba Bhave Rural Hospital, Datta Meghe Institute of Medical Sciences, from May through May Figure 1.

Fracture line running vertically from the sigmoid notch to the posterior border of the mandible, considered in ramus fracture. Figure 2. Fracture line extending from sigmoid notch vertically downwards to lower border of mandible, considered in ramus fracture.

Table 1. Figure 3. Figure 4. Postoperative check radiographs showing fixation of mandibular ramus fracture by two noncompression mini plates. References E. The results are visualized by using the first two principal components as axes Fig. The rami in group 1 have a larger height and width, a larger mean bone thickness and a smaller gonion angle in comparison to group 2.

In contrast to the standard deviation when all rami are examined, it is smaller for the height, width and the gonion angle within the two groups. The standard deviation of the mean bone thickness, considering all measured values of one ramus, is approximately the same size. However, as the Figs. The distribution of the bone thickness for the two groups is shown below Fig.

In line with the lower mean bone thickness in group 2, there are more prominent thin areas displayed in the map Fig. The areas with thin bone on the foramen are more extensive in group 2. As the images were taken with a medical indication, a bias had to be contemplated.

To address this problem, patients with morphological abnormalities such as fractures, cysts or other pathological lesions of the mandible were excluded. For each measurement using X-ray images and 3D reconstructions, measurement inaccuracy must be considered. By comparing the applied reconstruction method to mechanical measurements, it could be determined in a pilot study, that the accuracy was in the range of the voxel size of the CBCT scans.

Other studies came to the conclusion that CBCT and CT imaging techniques rendered comparable measurement accuracies [ 10 ] and have been verified by in-situ measurements [ 11 ].

By applying an anatomical grid, comparable thickness measurements could be achieved for an average of 81 points per ramus for which the mean bone thickness could be calculated. This allowed for a more detailed inspection of the ramus anatomy than in previous studies, where the bone thickness of the mandibular ramus was measured at individual points for specific questions, for example to analyse the bone thickness in the course of sagittal split osteotomies by taking one thickness measurement [ 4 ] or seven bone thickness measurements at different levels of the ramus [ 5 ] or to evaluate the bone thickness for implantation and bone harvesting as performed by Chrcanovic et al.

Of course, individual mandibles presented a deviation from the calculated mean values, which was found in the standard deviation. Nevertheless, the acquired data can serve as a guide for identifying areas with adequate bone thickness for placing screws. Zhou et al. Our evaluations show comparable results with an angle of However, the authors of a study on the measurement of panoramic images stated, that the gonion angle is smaller in men than in women.

Since the selection criteria and sample size of that study are similar to ours, the different imaging methods should be considered as the reason for the discrepancy [ 13 ].

Susilo et al. Moreover, we could not detect any significant difference in ramus height and width between men and women. In contrast, Indira et al. Our study showed a small but significant correlation between the patient age and the gonion angle, which is in contradiction to the results of Abu-Taleb et al. Abu-Taleb et al. When comparing these results with the literature, it should be considered that the measurements may have been based on different ethnic groups.

Further studies should be carried out to identify possible differences. The measured rami could be assigned to two groups by cluster analysis based on the parameters of bone thickness, height, width and gonion angle. Similarities and differences in the distribution of bone thickness are shown in the maps, which were based on the measured thicknesses on the anatomical grid. The grouping of rami with similar parameters results in a lower standard deviation within the formed groups.

This allows for more precise statements, for example on the distribution of bone thickness over anatomically related rami. In our study the proportions of the mandibular ramus and the position of the lingula as well as the bone thickness could be measured with an accuracy in the range of the voxel size of the CBCT scan.

By applying a skew-angled grid oriented to anatomical landmarks, the measurements could be made comparable and visualized with the help of false-colour maps. Statistical evaluations revealed significant correlations between height and width, width and angle and between height and angle. No significant correlation between the mean bone thickness and age or sex was found. In addition, a cluster analysis was performed to group the measured rami according to anatomical similarities.

In clinical practice, these results can support the selection of anatomically appropriate osteosynthesis materials and provide guidance for screw positioning. In addition, the two distributions of mean bone thickness identified by the cluster analysis enable the specification of two sets of osteosynthesis plates for the ramus with insertion slots in the areas with higher bone thickness. Taking into consideration a broad age spectrum, general conclusions could be drawn about the ramus morphology, which can be useful for fracture treatment or orthognathic surgery, among other things.

In order to collect data specifically for the target group of orthognathic patients, further studies with a more specific age selection should be aimed for. The data sets examined for this study are available from the corresponding author upon reasonable request. Mandibular thickness measurements in young dentate adults. Arch Otolaryngol Head Neck Surg. Article PubMed Google Scholar.

George O, Lindquist CC. Optimal placement of bicortical screws in sagittal split-ramus osteotomy of mandible. Article Google Scholar. Evaluation of mandibular anatomy associated with bad splits in sagittal Split ramus osteotomy of mandible. J Craniofac Surg. Mandibular ramus thickness based on cone beam computed tomography scan.

J Phys Conf Ser. A morphometric analysis of the mandibular canal by cone beam computed tomography and its relevance to the sagittal split ramus osteotomy. Oral Maxillofac Surg. A mandibular ramus is a quadrilateral process projecting upward and backward from the posterior part of the body of the mandible and ending on the other side at the temporomandibular joint in a saddle-like indentation called the sigmoid notch between the coronoid and condylar processes.

It may serve as a source for bone grafting. The lateral surface of the mandibular ramus is the attachment site of the masseter muscle. In bone grafting, the mandibular ramus provides a good source of autogenous cortical graft best suited for the correction of ridge deficiencies prior to the placement of an implant.