The attachments of muscles onto the hyoid bone were observed macroscopically, and the lengths and widths of each muscles onto the hyoid bone were measured. The tongue-pharyngeal block as a whole obtained from 50 cadavers were used. Each muscle was colored by acrylic pigments for identification. The results showed that the mylohyoid muscles were attached onto the lower anterior surface of the hyoid bone body. The geniohyoid muscles had many types of attachment forms and significant individual differences. The hyoglossal muscles showed various attachments at the posterior end of the greater cornu. The middle pharyngeal constrictor muscles attached with two bundles in some cases. The sternohyoid muscles and omohyoid muscles were classified by their positional relationship with each other. The thyrohyoid muscles were classified by the conditions of their overlaps with the omohyoid muscles and the sternohyoid muscles. From the aforementioned results, the following muscles were found attached to the hyoid bone in a further developed state: mylohyoid muscles, geniohyoid muscles, hyoglossal muscles, thyrohyoid muscles and hyoglossal muscles.

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Spermatoza contain various autoimmunogenic materials, which are recognized as foreign by the self immune system. Therefore, the blood-tesits-barrier (BTB) formed by Sertoli cells, basal lamina and myoid cells protects autoimmunogeneic spermatozoa from attack by the self immune system. However, the BTB at the tubuli recti (TR) and the rete testis (RT) is known to be incomplete against humoral substances. We investigated here whether the BTB is physiologically penetrated by lymphocytes in mice. We performed light and electron microscopical observation of the seminiferous tubules (ST), the TR and the RT in normal C3H/He mice. Although no lymphocytes were observed inside the ST, a very few lymphocytes could be found beyond the basal lamina of the TR and the RT. These lymphocytes were close to testicular spermatozoa in the TR lumen. These findings provide a possibility that lymphocytes may gain access to autoantigens of spermatozoa inside the TR and RT under physiological conditions in mice.

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A divided maxillary artery was found in the left infratemporal fossa of a 63-year-old male cadaver during a student dissection practice. The maxillary artery, which arose from the external carotid artery at the posterior border of the ramus of the mandible, was divided into two branches in the infratemporal fossa. The deep branch of the maxillary artery was deep to the lateral pterygoid muscle and the inferior alveolar, buccal and lingual nerves, giving off the anterior tympanic, middle meningeal, anterior deep temporal, buccal, and posterior superior alveolar arteries. The deep branch passed through the pterygomaxillary fissure. On the other hand, the superficial branch of the maxillary artery, which was superficial to the lateral pterygoid muscle, gave off the inferior alveolar artery and other branches. The maxillary artery on the right side displayed a normal branching pattern within the infratemporal fossa.
These findings indicate that the deep and superficial branches of the maxillary artery remained without disappearing during the development of the maxillary artery originated from the stapedial artery.

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We carried out a morphometric comparison of tissue sections from the human spinal cord, medulla oblongata, cranial nerves, autonomic nerves and spinal nerves with the help of a very accurate method³⁾ that includes two-step fixation, nitrocellulose embedding and discriminative staining. We conducted morphometric evaluations to compare various axonal areas between different individuals using a combination of an image analyzer and a high power microscope. Our study showed a negative correlation between age and axonal area in all nerves except the greater splanchnic nerve. We believe that such data would not have been discovered without the use of our sophisticated electronic equipment together with the special preparation method we employed. Recourse to such methodology will allow more precise study of neurohistology and lead to better understanding of the aging process in human beings.

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Using a preparation method composed of secondary chromic acid fixation, nitrocellulose embedding and Luxol fast blue-PAS-hematoxylin stain (a discriminative staining method) for the purpose of axonal discrimination, we examined 43 human spinal cords (31 males and 12 females) at the C5 level to find the differences due to gender and aging in axons of the lateral corticospinal tract. These results can be of great help in understanding the motor functions in relation to gender differences and the aging process.

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