Magnetic resonance imaging of normal lumbar intervertebral foraminal height

To study the pattern and changes of lumbar intervertebral foraminal heights in an asymptomatic Jordanian sample relative to age, sex, level, and correlate values with midpoint vertebral and disc heights. One hundred and fifty-three patients [87 male and 66 female] were selected during the study period. The study was carried out at the Jordan University Hospital, Amman, Jordan from June 1999 to June 2000. Parasagittal magnetic resonance images were used to measure intervertebral foraminal heights at all lumbar levels. Values were statistically analyzed and the significance of differences in the means of foraminal heights at different levels in every age group and among age groups was determined. Foraminal height indices and correlation coefficients with midpoint vertebral and disc heights were calculated. The study revealed that the mean foraminal height measured is 20.9 mm +/- 1.7 with a range of 17.1-24 mm. Foraminal heights increased significantly in a craniocaudal pattern reaching a maximum at lumber [L]2/3 in females and at L3/4 in males followed by continuous significant decrease reaching their minimum at L5/sacral [S] 1. In relation to age, foraminal heights decreased significantly in females reaching their minimum in the 7th decade. In males, foraminal heights at L3/4 until L5/S1 increased significantly reaching their maximum in the 5th decade followed by significant decrease reaching their minimum in the 7th decade. Foraminal height indices remained relatively constant. A fair degree of correlation of foraminal heights with intervertebral disc heights and vertebral body heights was evident. Foraminal heights show different level and age-dependent characteristic pattern of change between asymptomatic males and females. Changes of foraminal heights seem to directly reflect changes of vertebral body heights. These changes are considered normal age-dependent changes, and are discussed under consideration of adaptation to physical activity and changing hormonal levels

location of the abducent nucleus and its dentate input "degeneration and fluorescence study in the rat"

Following the injection of the lateral rectus muscle of the eye with the fluorescing dye DAPI-Pr, labeled [fluorescing] nerve cells are found outside the internal genu of the facial nerve. In contrast to descriptions made by many authors, none is found contained within this genu. Degeneration fibers of the ipsilateral dentate nucleus are traced to the spot where the abducent nerve cells are located, and they are found to round up [terminating] at this spot. The findings explained the discrepancy in the literature concerning the dentatoabducent input; and made of the abducent nucleus to exemption when compared with those of the oculomotor and of the trochlear nuclei, for all these nuclei of the extraocular muscle receive such a direct cerebellar input. The dissociation, in place of the abducent nucleus from the other more conglomerated extraocular muscle nuclei is presumably a functional issue related to the independence of the lateral rectus muscle to a precedent firing of the trochlear nucleus. The initimate relationship of the abducent nucleus to the internal genu of the facial nerve is brought about, more likely by the consequence of the transformation of the spinal cord into brainsterm. Still, it lies outside it. In normal stained section no nerve cell is found within the confinement of the internal facial genu regardless of its kind

Descending and ascending somaesthetic pathways, and their interdigitations in the middle tectal layers of the midbrain

The relationship between the ascending and descending somaesthetic collicular afferents in the middle superior collicular layers is investigated at light microscopic level. The study is based on albino rats surviving forty-eight to seventy-two hours following the combined stereotaxic placement of electrolytic lesions in the homolateral somaesthetic cerebral cortex and in the heterolateral subnucleus interpolaris of the trigeminal nuclear complex in the same animal. The method reveals interdigitating degenerated terminals that form bands occupying most of the mediolateral collicular extent as determined by the collicular topography of the particular parts of the body that are represented in the ablated or lesioned trigeminal nuclear areas. Correlation of the degenerating terminals with directions of the representation lines of the optical meridia in the superficial collicular layers is discussed on the light of the present findings and an explanation for the patchy appearance of degeneration of the various collicular afferents is proposed