A study of patients with temporomandibular disorders reported that two skeletal measurements, coronoid process length and angulation, were lower in both TMD groups than published reference values. The measurements were lower still in the group classified with dislocation or subluxation than in the group with internal derangement. The difference was reported as statistically significant, with a P value below 0.0001.
How the comparison was made
The finding comes from a prospective cross-sectional observational study, meaning the researchers captured a snapshot rather than tracking changes over time. It included 79 patients with TMD: 27 in Group I, dislocation/subluxation, and 52 in Group II, internal derangement. The study set out to characterize skeletal and masticatory-muscle morphology, compare the two subgroups and examine relationships between muscle and bone measurements, including whether such anatomy might eventually contribute to TMD risk-assessment models.
To make the comparisons, investigators used non-contrast computed tomography of the face. The scans were used for craniofacial skeletal measurements and for masticatory-muscle cross-sectional areas, a way to record the size of a muscle on an imaging slice. Measurements were compared with published reference values and with the other TMD subgroup. The analysis used descriptive statistics, t-tests and Pearson correlation, a measure of how closely two measurements vary together, with a reported significance level of 0.05.
Bone and muscle measurements diverged
The muscle results did not follow one uniform pattern. Temporalis cross-sectional area was decreased, while lateral pterygoid cross-sectional area and pterygoid plate length were increased predominantly among patients with internal derangement. The authors describe these and other measurements as distinct anatomical patterns across the TMD subgroups.
Some of the clearest relationships appeared in Group I. Temporalis cross-sectional area showed strong reported correlations with coronoid length and angulation. The Pearson correlation coefficients were 0.74 for length and 0.70 for angulation. A correlation describes how measurements move together in the data; it does not by itself show that a larger muscle caused a longer or more angled coronoid process.
The lateral pterygoid findings showed a different level of association. Its cross-sectional area had significant positive correlations with lateral pterygoid plate length in both groups: the reported coefficient was 0.39 in Group I and 0.48 in Group II. In plain terms, larger values for one measurement tended to occur alongside larger values for the other in this dataset, but the study does not show why the measurements were related.
The findings point to a research lead
Those cautions matter because the design was observational and cross-sectional. It can describe how the measurements differed among the 79 patients and how they were related, but it cannot establish whether the anatomical features caused dislocation/subluxation or internal derangement, or whether they would predict future TMD risk. The comparison also used published reference values rather than a concurrently enrolled control group, so the findings are not established for people without TMD or for other TMD subgroups.
The authors present the findings as evidence of distinct craniofacial skeletal and masticatory-muscle patterns across the two subgroups. They say the differences and muscle-bone relationships may inform future work on TMD assessment, risk evaluation and individualized management. The study therefore offers a research direction, not a validated risk-assessment model or a treatment recommendation.
The version of record was published on 21 August 2026. The report says informed consent was obtained from all participants, the underlying data are available as part of the article, and further clarification or data can be requested from the corresponding author on reasonable request. The authors report that the study received no funding and that they have no competing interests.
Paper data and sources
Original title: Morphometric analysis of craniofacial skeletal and masticatory muscle morphology in patients with temporomandibular disorders: An observational study.
Authors: Devanshu, Rudra Deo Kumar, Shivendra Choudhary et al.
Journal/Repository: Oral and maxillofacial surgery
Status: Peer-reviewed
First online: 2026-08-21
DOI: 10.1007/s10006-026-01626-5
Original paper · Full text