ABSTRACT
Introduction: The posterior cranial fossa is the largest and the deepest of the three fossae. Contents of posterior cranial fossa include occipital part of cerebral hemispheres, cerebellum, midbrain, pons and medulla oblongata. Variations in the volume of posterior cranial fossa may cause compression of these structures which may lead to various disorders. There is increasing evidence on the diagnostic potential of posterior cranial fossa measurements. The present study on morphometry of posterior cranial fossa based on CT images of patients without any clinical abnormality was undertaken for the first time in south Indian population. Subjects and Methods: To study and compare sex-wise and age-wise differences in the supratentorial and posterior cranial fossa (PF) measurements in the normal CT scan images of 62 males and 38 females who attended the Neurology department of SVIMS belonging to Rayalaseema region was undertaken. The measurements that were recorded are transverse diameter (TD) and anteroposterior diameter (APD) of supratentorial part and also posterior cranial fossa and height and volume of posterior cranial fossa. Results: The mean supratentorial TD and APD were found to be less in male but were not statistically significant sex-wise and age-wise. The mean posterior fossa APD was significant, PF height and volume were highly significantly in males. Discussion: There are no reports on supratentorial parameters in literature for comparing the results of present study. Except for one study on CT on height and volume of posterior cranial fossa there are no other studies for comparing the values of present study. Conclusion: Observations on supratentorial parameters of the present study are the first to be reported in literature.Age-wise and sex-wise observation of parameters of TD and APD of PF are the first to be reported in literature.
ABSTRACT
OBJECTIVE: This study was designed to determine the most reliable cephalometric measurement technique in the normal population and patients with basilar invagination (BI). METHODS: Twenty-two lateral radiographs of BI patients and 25 lateral cervical radiographs of the age, sex-matched normal population were selected and measured on two separate occasions by three spine surgeons using six different measurements. Statistical analysis including intraclass correlation coefficient (ICC) was carried out using the SPSS software (V. 12.0). RESULTS: Redlund-Johnell and Modified (M)-Ranawat had a highest ICC score in both the normal and BI groups in the inter-observer study. The M-Ranawat method (0.83) had a highest ICC score in the normal group, and the Redlund-Johenll method (0.80) had a highest ICC score in the BI group in the intra-observer test. The McGregor line had a lowest ICC score and a poor ICC grade in both groups in the intra-observer study. Generally, the measurement method using the odontoid process did not produce consistent results due to inter and intra-observer differences in determining the position of the odontoid tip. Opisthion and caudal point of the occipital midline curve are somewhat ambiguous landmarks, which induce variable ICC scores. CONCLUSION: On the contrary to other studies, Ranawat method had a lower ICC score in the inter-observer study. C2 end-plate and C1 arch can be the most reliable anatomical landmarks.