LAUSR

The deep suboccipital muscles has been shown to connect the spinal dura mater via dense connective tissue termed the myodural bridge (MDB). The MDB has both physiological and clinical implications. Data on morphological and imaging anatomic l parameters of the deep suboccipital muscles are scare. In this study, T2-weighted images of rectus capitis posterior major (RCP ma) and obliqus capitis inferior (OCI) of 109 healthy adults were obtained by 0-degree sagittal and 30-degree oblique sagittal continuo us MRI scanning of the head and neck of the subjects. Sectional area parameters of the RCPma and the OCI were measured. The 0-degree s agittal section was measured with 5 mm bias from the median sagittal plane, the sectional area of the RCPma was 186.34 ± 55.02 mm on the left, and 202.35 ± 59.76 mm on the right. The sectional area of OCI was 221.72 ± 68.99 mm on the left, and 224.92 ± 61.34 mm on the right; At the section with 30-degree bias from the oblique sagittal plane, the sectional area of RCPma was 183.30 ± 42.24 mm in males, and 133.05 ± 26.44 mm in females. The sectional area of OCI was 254.81 ± 46.20 mm in males, and 167.42 ± 27.85 mm in females. Significant sex difference exists in the sectional areas of the RCPma and OCI, the values of the male subjects were predominant ly larger (P < 0.05), however there were no agerelated significant difference. The sectional area of RCPma is bilateral asymmetric, the RCPma on the right side is larger than that of the left side (P < 0.05), but the OCI is bilaterally symmetric (P >0.05). The MRI imag e features, imaging anatomical data and sexual dimorphism of the RCPma and the OCI are presented in this study. This imaging anatomical dat will be useful for functional and clinical studies on the RCPma, OCI, and the MDB.