Figure 4

Cross-sectional area along the studied upper cervical spinal cord length in ALS and controls. For analysis of CSA distribution along the spinal cord, five intermediate positions between dens axis and the center of the first intervertebral disk (IVD) and two between first and second IVD were calculated, as indicated in (a). The cross-sectional area in these positions is compared between ALS and controls in (b), displaying means for ALS and controls as well as the interquartile range (IQR) for both groups. Significantly smaller CSA values were found in ALS in all positions below the dens axis. The longitudinal change in CSA along the spinal cord in ALS in shown in (c), indicating that significant CSA changes are only found in the more caudal areas between IVD 1 and IVD 2. *p ≤ 0.05, **p ≤ 0.001 (all statistical models are adjusted for baseline age).