Methods and materials Seventy-seven patients were divided into two groups based on the syrinx/cord (S/C) ratio: one with distended syrinx (S/C ratio > 0.5) and the other with non-distended syrinx (S/C ratio < 0.5). Anteroposterior diameter of the spinal canal was measured at each cervical level on midsagittal T2-weighted MR images, and a linear trend line was ft by least-square regression to ca...

Calcification of intervertebral disc (IVD) is an uncommon but well-defined clinical syndrome in children. Despite its benign nature, occasionally, calcified nucleus pulposus can herniate into the spinal canal. We report an interesting case of calcified disc herniation in the thoracic spine. Although it resulted in cord compression and syrinx formation, it well responded to conservative manageme...

The earliest description of cavities in the cord is generally ascribed to Charles Estienne (1504–c.1564) in La dissection des parties du corps humain... Paris, 1546. But the fi rst use of the term ‘syringomyelia’ was probably that of Charles P. Oliviers d’Anger in De la moelle épinière et ses maladies in 1824; in a later two-volume work he described: ‘Syringomyélie ou cavité centrale dans la mo...

We studied the mechanism of song production in the outbred common or domestic canary (Serinus canaria). The contribution that each side of the syrinx makes to song was investigated by observing the effect of unilaterally occluding the left or right primary bronchus, followed by section of the ipsilateral branch of the tracheosyringeal nerve. In other birds with a bilaterally intact vocal system...

The vocal organ of birds, the syrinx, is formed by modified cartilages of the trachea and bronchi. Recently, the use of thin, flexible endoscopes has made direct observation of the syrinx possible in situ. The effects of direct muscle stimulation on the syringeal aperture identified adductor and abductor muscles, confirming results from electromyographic studies. Endoscopic observations also re...

The diverse vocal signals of songbirds are produced by highly coordinated motor patterns of syringeal and respiratory muscles. These muscles control separate sound generators on the right and left side of the duplex vocal organ, the syrinx. Whereas most song is under active neural control, there has been a growing interest in a different class of nonlinear vocalizations consisting of frequency ...

Unlike many other sexually dimorphic systems, gonadal secretions do not explain sex differences in the morphology of the telencephalic song control nuclei of zebra finches. It is important to understand whether a novel mechanism for controlling structure is restricted to the forebrain regions specialized for song, and whether other areas respond more typically to gonadal steroids. Therefore, th...

Cerebrospinal fluid (CSF) flow abnormalities are known to be present in Chiari I malformation and to underlie the origin and progression of associated syringomyelia. The incidence of syrinx formation, however, is variable for unknown reasons. The aim of this study was to investigate whether differences in CSF flow dynamics in patients with Chiari I malformation may account for the different cli...