Okajimas folia anatomica Japonica最新文献

To clarify the cause of posterolateral rotatory instability after damage to the lateral ulnar collateral ligament (LUCL), the morphological characteristics of the LUCL were reinvestigated and three-dimensional (3D) image of the ligament was reconstructed using 35 human elbows. The results were as follows: 1) the insertion point of the LUCL on the humerus was almost at the center of the capitellum, and its width was 2.61 ± 1.02 mm. The insertion point of the LUCL on the ulna was located from the lesser sigmoid notch to the supinator crest and had a width of 9.0 ± 2.8 mm. The proximal insertion of the LUCL on the ulna was 7.0 ± 3.0 mm, and the distal part was on the articular surface of the radial head. 2) Three-dimensional imaging of the LUCL revealed an anterior curved shape that covered the radial head. Based on these results, it was clear that both the supinator crest and the lesser sigmoid notch could be useful as osseous landmarks. We think that these anatomical results are useful for surgeons performing LUCL reconstruction.

At birth, the ductus arteriosus (DA) merges with the aortic arch in the caudal side of the origin of the left subclavian artery (ltSCA). Since the SCA (seventh segmental arteries) were fixed on the levels of the seventh cervical-first thoracic vertebral bodies, the confluence of the DA should migrate caudally toward the lower level. We aimed to describe the changing topographical anatomy of the DA and SCA using serial sections. First, we examined serial sagittal sections of 11 embryos (Carnegie stage 15-18), but the specimens were clearly divided into 2 groups with and without the lower confluence of the DA. Next, we examined serial horizontal sections of 40 specimens (Carnegie stage 14-16) and we chose 5 specimens (CRL 11 mm, 3 specimen; 1, 14 mm; 1, 15 mm) including the DA near (within 1-vertebral segment from) the ltSCA. The final approach of the DA occurred during the heart descent in which the apex of the heart migrated from the level of the first to the fourth thoracic vertebral body. Thus, the DA reached the SCA level before establishment of the heart descent. The right aortic arch maintained its entire course in 2 of the 5 specimens. Therefore, the positioning of the DA along the left aortic arch might occur independently of degeneration of the right arch. Notably, the tracheal bifurcation level was higher when the DA-ltSCA distance was greater. A contribution of the increased pulmonary volume was suggested for the final approach of the DA.

The superficial morphology of the acinus of the mandibular gland in rats, which corresponds to the submandibular gland in humans, is very difficult to observe under scanning electron microscope due to a closely adherent capsule. Therefore, we evaluated the most effective protocol for removing this capsule from the acinus using various solutions, at different temperatures and for different durations of soaking. Based on the data for 50 male Wistar rats, the most effective method was soaking in an 8 N hydrochloric acid solution at 60°C for 70 min, in a water bath, followed by soaking in a 0.1-0.2% collagenase solution at 37°C for 330-350 min.

In human fetuses, the palatine process of the maxilla is attached to the inferior aspect of the horizontal plate of the palatine bone (HPPB). The fetal palatomaxillary suture is so long that it extends along the anteroposterior axis rather than along the transverse axis. The double layered bony palate disappears in childhood and the transverse suture is formed. To better understand the development of the double layered bone palate, we examined histological sections obtained from 25 fetuses of gestational age 9-11, 16-18 and 30 weeks. The double layered palate was seen in all of the specimens examined. Inferior angulation of the posterior end of the HPPB was evident at 9-11 weeks, but the initial palatine aponeurosis did not attach to the angulation but to a slightly anterior site. Both the maxilla and the HPPB were tightly attached to the vomer at 16-18 weeks. In both bones, bilateral plates met at the midline. The palatomaxillary suture was filled with short, randomly arranged collagen fibers. The nasal end of the suture was covered by a tight periosteum. Immunohistochemical examination of 3 fetuses at 16-18 weeks showed: 1) no expression of versican, tenascin-c or type II collagen in the suture; 2) few mitotic cells positive for proliferating cell nuclear antigen; 3) no or few CD34-positive developing vessels; and 4) no CD68-positive macrophages. These findings suggested that the fetal palatomaxillary suture was inactive for reconstruction and growth and that soft palate muscles likely did not contribute to the development of the double layered configuration.

The origin of the posterior scrotal nerve is considered to be the bilateral pudendal nerves but the course to the midline is still obscure. Using 5 late-stage human male fetuses, we identified the single nerve through the intramuscular midline septum of the bulbospongiosus and the bilateral nerves along the left and right sides of the septum. Thus, the posterior scrotal nerve showed a variation: a single midline trunk or bilateral nerves. Branches of the bilateral pudendal nerves ran medially between the muscle and Cowper's gland and, at the midline area, they joined or associated closely. During the proximal course, much or less, the nerve penetrated the superior part of the muscle. The nerve entered the subcutaneous tissue at and near the perineal raphe. The communication with intrapelvic autonomic nerves were suggested behind Cowper's gland. Notably, the midline skin immediately anterior to the anus carried a considerable dense supply of thin sensory nerves. However, these nerves seemed to come from a space between the rectal smooth muscle and the external anal sphincter, not from the posterior scrotal nerve. Therefore, surgical treatment of the intersphincteric layer was likely to injure the original sensory nerve supply to the anterior anal skin.

The median nerve passes through the humeral and ulnar heads of the pronator teres muscle (PT), although variations such as absence of the ulnar head may exist. We observed histological sections of the upper extremity from 24 embryos and fetuses. In the early stage, the PT extended between the radius and the medial epicondyle of the humerus, but no candidate for the ulnar head was found. In mid-term fetuses, the ulnar margin of the PT was attached to the elbow joint capsule. Moreover, in late-stage fetuses, a small deep part of the PT arose from the thick joint capsule of the humero-ulnar joint near the coronoid process of the ulna. This joint capsule also provided the most proximal origin of the flexor digitorum profundus muscle. Therefore, we considered fetal PT origin from the capsule as a likely candidate for the ulnar head. Consequently, the PT seemed to develop from a single anlage through which the median nerve passed, but later - possibly after birth - a small PT origin from the joint capsule appeared to obtain an aponeurosis connecting the muscle fiber to the ulna. This secondary change in PT morphology might explain the muscle variation seen in adults.

We microscopically examined the dorsal lingual surface of an adult chimpanzee (Pan troglodytes). The tongue of the chimpanzee was about 13 cm long. Filiform papillae were distributed over the entire dorsal surface of the lingual body. There were many fungiform papillae scattered among the filiform papillae. At the posterior end of the lingual body, a triangular arrangement of the vallate papillae, with the apex of the triangle directed posteriorly, was observed. The filiform papillae on the lingual apex consisted of a main papilla and secondary papillae. The filiform papillae on the lingual body had several pointed processes. There were dome-shaped fungiform papillae scattered among the filiform papillae. The vallate papillae were surrounded by grooves and were flattened-oval shaped. Many foliate papillae were observed on the posterolateral regions of the tongue.