Two immunocytochemical markers were used to label the rod pathway of the rat retina. Rod bipolar cells were stained with antibodies against protein kinase C and AII-amacrine cells with antibodies against parvalbumin. The synaptic circuitry of rod bipolars in the inner plexiform layer (IPL) was studied. Rod bipolar cells make approximately 15 ribbon synapses (dyads) in the IPL. Both postsynaptic members of the dyads are amacrine cells; one is usually the process of an AII-amacrine cell and the other one frequently provides a reciprocal synapse. No direct output from rod bipolar cells into ganglion cells was found. AII-amacrine cells make chemical output synapses with cone bipolar cells and ganglion cells in sublamina a of the IPL. They make gap junctions with cone bipolar cells and other AII-amacrine cells in sublamina b of the IPL. The rod pathway of the rat retina is practically identical to that of the cat and of the rabbit retina. It is very likely that this circuitry is a general feature of mammalian retinal organization.
This study examines the anatomic relationships and variability of the facial nerve trunk and its branches, with emphasis on the intraparotid connections between the divisions. Microdissections were performed on 30 Korean half-heads, and the facial nerve trunks and branches were exposed. The average depth of the stylomastoid foramen from the skin surface was 21.0 +/- 3.1 mm, and the distance between the stylomastoid foramen and the bifurcation of the temporofacial (upper) and cervicofacial (lower) divisions was 13.0 +/- 2.8 mm. In 26 of 30 dissections (86.7%), the facial nerve trunk bifurcated into two main divisions, and a trifurcation pattern was seen in the other four cases (13.3%). According to the origin of the buccal branches, we classified the branching patterns of the facial nerve into four categories. In type I (13.8% of cases), the buccal branches arose from the two main divisions of the trunk but not from other branches of the facial nerve. In type II (44.8% of cases), the buccal branches arising from the two main divisions were interconnected with the zygomatic branch. In type III (17.3% of cases), the marginal mandibular branch sent nerve twigs to the buccal branch, which originated from the upper and lower divisions. In type IV (17.3% of cases), the nerve twigs from the zygomatic and marginal mandibular branches merged to the buccal branch arising from the two main divisions. Communications between the facial and auriculotemporal nerve branches, which are known as "communicating auriculotemporal nerves," were observed in 28 of the 30 cases (93.3%). Familiarity with these common variations in the facial anatomy provides useful information for the surgeon in careful dissection, preservation of the facial nerve, and complete removal of the tumors in parotidectomies.
Radiographs and computed tomography (CT) images have been increasingly applied and accepted in forensic sciences. Along with radiographs and CT images, the frontal sinus is often used for the individual identification because of its unique and unchangeable characteristics. The purpose of this study is to define the usefulness of three-dimensional (3-D) images of the frontal sinus for identification. CT images from 119 Korean cadavers were built up for 3-D reconstruction and surveyed with 15 measurements. The total volume of the sinus, some nonmetric characteristics, and the bilateral asymmetry index in men differed significantly from those in women (p < 0.05). The digit codes, six sections and 10-digit number, were almost able to accurately identify individuals (98%). This study showed a statistical difference between the sexes and classified the fused and prominent middle sinuses for the first time. This proposed method for identification is more accurate than those used in other studies.
The aim of this study was to assess the histomorphological features of the fourth rib and to develop age-predicting equations for Koreans. Sixty-four rib samples (36 males and 28 females) obtained from forensic cases were used for developing equations. Two thin sections (<100-microm thick) per sample were prepared by manual grinding. Multivariate analysis of covariance revealed statistically significant differences in age-adjusted histomorphological variables between sexes. Using stepwise regression analysis, osteon population density and average osteon area were correlated with unknown sex (r2 = 0.826), and sex plus two histomorphological variables provided the best results for an age-predicting equation given the assumption of knowing the sex of a specimen (r2 = 0.839). Average Haversian canal area had little influence on age estimation for male or female samples, and relative cortical area was not significantly related to age for any specimen.
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