Quantitative analysis of myelinated axons of corpus callosum in the human brain.

In this study, the myelinated axons of the rostrum, genu, truncus and splenium parts of the corpus callosum were counted in the human brain by using a camera lucida. The numerical densities of these axons were compared with each other by means of quantitative analytical statistical methods. The number of myelinated axons of genu and truncus of the corpus callosum were found to be highest in number and they were nearly the same with each other. However, number of the myelinated axons of splenium was found to be lower in number, when compared with the other parts of corpus callosum.

Vascular pedicles of infrahyoid muscles: an anatomical study.

This study was designed to determine the entering sites of vascular pedicles of the infrahyoid muscles. The neck regions of 12 cadavers were investigated bilaterally. The vascular pedicles of the infrahyoid muscles (except the thyrohyoid and inferior belly of the omohyoid muscle) were dissected and measurements taken with a caliper in reference to the attachments of the muscles. For the sternothyroid muscle, two vascular pedicles were found bilaterally in all cadavers. Two vascular pedicles were found bilaterally for the sternohyoid muscle in 11 cadavers; in one cadaver the inferior vascular pedicle was absent bilaterally. One vascular pedicle was found bilaterally for the superior belly of the omohyoid muscle in all cadavers. These data regarding the vascular pedicles of the infrahyoid muscles might be useful for preserving the vascular supply of the infrahyoid muscles during flap preparation.

Quantitative analysis of myelinated axons of commissural fibers in the cat brain.

OBJECTIVE: There are limited data related to the number of commissural axons found in various species. Although the corpus callosum has been investigated in cat, there are no data on the number of its myelinated axons. Additionally, the number of myelinated axons of anterior, posterior and habenular commissures are not documented for the cat. Therefore, we aimed to examine the topographic distribution and regional numerical differences of myelinated axons in encephalic commissures of the cat. METHODS: This study was carried out at the Faculty of Medicine, Hacettepe University, Ankara, Turkey, from March 2003 to July 2003. The myelinated axons of the encephalic commissures of one cat were counted in this study. RESULTS: In parts of the corpus callosum, a statistically significant difference was found between rostrum and genu, rostrum and truncus, genu and truncus, genu and splenium and truncus and splenium. However, no statistically significant difference was found between rostrum and splenium. When comparing the number of myelinated axons of anterior, posterior and habenular commissures, statistically significant differences were found between anterior and habenular commissures, and between posterior and habenular commissures. No statistically significant difference was found between anterior and posterior commissures. CONCLUSION: These numerical data, evaluated by quantitative analytical statistical methods, might be useful in filling the lack of information on the mean numbers of myelinated axons of different commissures. Knowledge of the number of myelinated axons in different parts of the corpus callosum may also be very important when performing surgical procedures of the corpus callosum, such as commissurectomies.

MR imaging determination of the normal level of conus medullaris.

The location of conus medullaris according to age and sex was retrospectively evaluated with a 0.5-T magnetic resonance (MR) imaging system. A total of 639 subjects without any conspicuous spinal canal pathology on the lumbar MR imaging examination were selected. The level of conus medullaris was most commonly located at the T(12)-L(1) intervertebral disc level in the whole population. Our results do not correlate with the previous studies. No significant difference in the conus level was found with increasing age.