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Sawsharks (Pristiophoriformes) are slender, medium-sized sharks with elongated, saw-like snouts, and include the monotypic Pliotrema and Pristiophorus with seven species. The phylogenetic position of sawsharks is still problematic as phylogenetic hypotheses based on morphological and molecular evidence disagree about their relationships, whether closer to batoids (morphological data) or grouped with squaliforms, angelsharks, and hexanchiforms in an all shark higher taxon (molecular data). However, many aspects of the morphology of sawsharks are poorly known. The present article describes the clasper musculature and skeleton of a sawshark (Pristiophorus japonicus); the clasper skeleton of a sawshark is described for the first time. The clasper musculature is similar to squaliforms and most batoids, whereas the clasper skeleton is similar to that found in Squatina and Squalus. However, the ventral marginal, dorsal terminal (dt), and ventral terminal cartilages are distinct and diagnostic at least for Pristiophorus japonicus. Comparisons with galeomorph sharks are necessary to further refine our conclusions in relation to the systematic significance of the clasper muscles and skeleton of the Japanese sawshark. Anat Rec, 302:1666-1670, 2019. © 2019 American Association for Anatomy., (© 2019 American Association for Anatomy.)

We investigated muscle development in the Japanese flounder Paralichthys olivaceus, focusing primarily on the cranial muscles, using a whole mount immunohistochemical staining method. It is well established that during the very early stages of morphogenesis, until 4 days post hatching (dph), muscles required for feeding develop. Later, between 8 and 16 dph, the muscle composition in the dorsal branchial arches changes to the adult form. We discovered the presence of larval-specific muscles in this ontogenetic period, termed the larval branchial levators 2 and 3, located in the dorsal branchial arches. The larval branchial levators 2 and 3 disappear during the course of development, whereas the others remain as levator internus 1 and levator posterior, which have also been described in adult fish. In place of these regressed muscles, the levatores externi and levator internus 2 develop and regulate the branchial arches. In addition, we found that the levator posterior, which is thought to represent the fifth levator externus, and the levatores externi exhibit different origins. We also found that at least a part of the caudal fin musculature develops from the trunk myotome.

To clarify the detailed anatomy of the insertions of the levator aponeurosis and Müller's muscle, 10 upper eyelids of 5 fixed Japanese cadavers were examined. The eyelids were dissected in a manner that the authors devised to disclose the delicate pretarsal structures in close proximity. After removing the orbital roof and fat, they divided the levator aponeurosis at the origin and dissected along its posterior aspect up to the upper tarsal area. The dissected eyelids were evaluated grossly and histologically with a special staining technique. Gross and histological examinations revealed that the dense collagenous levator aponeurosis was transformed distally into fine elastic fibers, which inserted into the pretarsal orbicularis layer. They also found a distinct fascia covering the anterior aspect of the tarsus that continued proximally to Müller's muscle. Conclusively, the levator aponeurosis has no direct collagenous insertion into the tarsus, but is connected mainly to the pretarsal tissue via fine elastic fibers. A fibrous tissue covering the anterior aspect of the tarsus is not the levator aponeurosis, but an extension of Müller's muscle.

The anthropometric data of the health check programme in the Oita Wheelchair Marathon Race were analysed. In the past 10 years, a total of 2677 competitors participated in this programme. Age, height, body weight, body fat, lung vital capacity, girth of chest, girth of upper arm, grasping force and power of upper arm were compared between 710 fine competitors and 99 poor competitors. Power of the upper arms and lung vital capacity played a major part in the result of the races. It was suggested that these two factors had major influences on the achievement of this type of sports activity.

Out of 546 upper limbs (273 cadavers), supernumerary heads of the biceps brachii were found in 75 limbs (13.7%) of 58 cadavers (21.3%). The form, origin, and insertion of the supernumerary heads, and branching pattern of the musculocutaneus nerve were studied. In addition, the dimensions of the heads were measured. In many cases, the supernumerary head arose from the humerus, between the insertion of the coracobrachialis and the upper part of the origin of the brachialis, and/or from the medial intermuscular septum. In a few cases, a supernumerary head arose from the tendon of the pectoralis major or the deltoid, or from the articular capsule, or from the crest of the greater tubercle. The supernumerary heads typically joined the common belly, or the aponeurosis of the biceps brachii. Some heads joined the belly of the long head or that of the short head. In the examination of the branching pattern of the musculocutaneus nerve, communication between the musculocutaneus nerve and the median nerve was found in 43 out of the 75 limbs (57.3%). The communicating branch ran from the musculocutaneus nerve to the median nerve in 24, from the median nerve to the musculocutaneus nerve in 12, in both directions in 5, or in another type of pattern in 2 out of 43 limbs. Sometimes a branch of the musculocutaneus nerve ran around a supernumerary head and then fused with the present trunk. The presence of a supernumerary head seemed to affect the course and branching of the musculocutaneus nerve.

We examined 94 axillary regions of 47 Japanese adults and found the muscular arch of the axilla (Maa) in five sides of three cadavers as well as the tendinous arch of the axilla (Taa) in two sides of two cadavers. The results are summarized as follows: 1) The frequency of Maa was 6.4% of the total bodies and 5.3% of the sides in this series. 2) In the left side of a 57-year-old male (No. 427), Maa was attached to the surface of the coracobrachialis muscle after fusing with the dorsal surface of the inserting tendon of the pectoralis quartus muscle. Both muscles were supplied by the caudal pectoral nerve (Npc) from the medial pectoral nerve. Moreover, in this same specimen, the sternalis muscle was recognized on the ventral surface of the pectoralis major muscle. In the left side of a 93-year-old female (No. 386), the cranial part of the muscular arch of the axilla (Cpa) was extended to the coracoid process by a tendon and attached to the abdominal part of the pectoralis major by two muscle bundles supplied by independent branches from Npc. One muscle bundle was attached to the lower margin of the abdominal part of the pectoralis major on the same plane, and the other bundle was located on the dorsal surface of the abdominal part. In a 74-year-old female (No. 411), the well-developed lateral part of the muscular arch of the axilla (Lpa) was attached to the inferior side of the tendinous arch. According to Ruge (1914) and Kasai et al. (1977), this arch was in the transition of the muscle bundle of Cpa to the arch. In the right side of the same specimen, only the thoracodorsal nerve (Ntd) was distributed into Lpa, whereas in the left side, only Npc supplied branches to Lpa. 3) The axillary arch was classified into 8 types based on the form and the supplying nerve of Cpa and Lpa. Cpa consisting of the muscle bundle is Type I, and Cpa consisting of the tendinous arch is Type II. We proposed that only Type II-A, with Cpa as tendinous arch and no Lpa, be designated as Taa (found in two cases), and the others as Maa. The following types were found in this study: Type I-A, consisting of only Cpa supplied by Npc (two cases); Type I-D, consisting of Cpa supplied by Npc and Lpa supplied by Ntd (one case); Type II-B, consisting of the tendinous arch and Lpa supplied by Npc (one case); Type II-D, consisting of the tendinous arch and Lpa supplied by Ntd (one case). 4) From the above findings, it can be suggested that Maa of varying shapes have been formed by a portion of the latissimus dorsi muscle supplied by Ntd, together with the pectoralis subcutaneous muscle, consisting of the pectoralis abdominalis, humeroabdominalis, humerodorsalis and ventrolateralis muscles supplied by Npc. The latter three muscles were proposed by Ura (1937) as the panniculus carnosus muscle, which was well developed in some lower mammalian orders. However, early investigators suggested that Maa was derived from the panniculus. Maa might have occurred as a rudimentary phylogenetic remainder in an early human embryonic stage.

The petropharyngeal muscles were observed in 7 cadavers, 8 cases (1.4%) [both side: one case (0.3%), one side: 6 cases (1.9%)] in 614 Japanese cadavers. All cases of this supernumerary muscles of the stylopharyngeal muscle took origin from the petrous part of the temporal bone to inserted to the outer surface of the middle constrictor pharyngeal muscles. And also of its muscle bundles were innervated by the glossopharyngeal nerve and supplied from the ascending pharyngeal artery. The appearance of the sex differences male was much higher than female in Japanese.

The value of creatinine height index (CHI), defined as milligrams of 24-h urinary excretion of creatinine divided by height in centimeters, was investigated on 21 healthy Japanese adults engaged in sedentary work. The average values were 10.58 in males and 6.68 in females. High partial correlation coefficients controlling sex were found among CHI, weight, fat-free mass, arm muscle area (AMA) and 24-h urinary excretion of creatinine. These indices had high loadings in the first factor of body size by principal component analysis. Regression of CHI on AMA differed in the intercept (i.e. the level of CHI at corresponding AMA) but not in the slope, from that studied under low-creatine diet in the U.S.A. Correcting AMA using arm bone area for Japanese and CHI with dietary factor, the relation between CHI and AMA in this study seemed to be in good agreement with that found in the U.S.A.

A rare muscle variation belonging to the forearm flexor muscle group has been observed in three forearms out of nearly 200 Japanese cadavers. It arose from the well developed fascia of the superficial forearm flexor group, crossed the median nerve obliquely and posteriorly lying radial to that nerve, and was inserted into the flexor retinaculum. The muscle variations in the three cases were discussed according to the concept of "corrected" nerve-muscle specificity and conservative morphology. They were conclusively ascribable to the original antebrachial flexor group of Yamada. This seemed to indicate that the variations were related or identical to Gantzer's muscle, and that they showed a possible original or archaic pattern of the original antebrachial flexors.