THE INTERNAL ARCHITECTURE OF HUMAN SINOATRIAL NODE / 解剖学报

The location, shape and internal architecture of the sinoatrial node (SAN) were studied histologically in serial section in 15 hearts (7 adults, 8 foetuses). Based on our observation, the human SAN may be divided into four layers, namely, (1) thesinoatrial node artery layer: its outer longitudinal muscular layer of its media partly lacked in the SAN concentrically; (2) the periarterial layer: the cells of this layer surround the artery concentrically; (3) the central layer, making up the main mass of the node: most P cells in which are arranged parallel to the node artery. In adult the diameter of P cells in this layer is 5.18 ?m; (4) the peripheral layer: most transitional cells in this layer radiate from SAN into the atrial muscle. These "tongues of transitional cells" extend mostly into right atrial-muscle and a few into the musculature of superior vena cava. The diameter of transitional cells of this layer in the adult is 7.28 ?m. In the adult the arrangement of dense collagen fibers appears circular in the periarterial layer, longitudinal in the central layer and radiative in the peripheral layer. According to the location, layers of sinoatrial node and the arrangement of the connective tissue, the functional significance and morphological basis of the re-entry are discussed.

THE ARTERIAL SUPPLY AND THE VASCULAR ARCHITECTURE OF HUMAN ELBOW / 解剖学报

After the arteries were injected with gelatin and ink, the arterial distribution and the vascular architecture of the elbow joint were observed in 20 fetal and 8 adult arms macroscopically and microscopically. The arteries of the elbow anastomose to form networks around the joint, from which many twigs supply the capusle and the intra-articular structures. In the capusle, the vessels make up a ladder-like mesh among the fibrous bundles. At the margin of the capusle, the vessels ramify to form a complex network, the circulus articuli vasculosus, between the fibrous and the synovial layers. The vessels from the circulus articuli vasculosus supply the synovial membrane, the synovial fold or the fat pad and the epiphysis or the epiphyseal cartilage. There are 2 to 4 layers of mesh in the synovial membrane of capusle, a glomerulus-like network in the synovial fold or the fat pad, many series of bow-shaped net in the synovial membrane on the surface of the neck of elbow bone. There is a central artery and a cage-like capillary network in the cartilage canal. The secondary center of ossification appears in the vascularized area of the cartilage. No intra-osseous intercommunications of the epiphyseal artery and nutritive artery exist in the epiphysis until the ossification of the epiphyseal plate.

ARCHITECTURE OF THE SPECIALIZED MYOCARDIAL FIBERS OF THE ATRIOVENTRICULAR JUNCTION AREA / 解剖学报

The architecture of the specialized myocardial fibers of the atrioventricular junction area(AVJ) were observed under microscope on serial sections. It was found that the human A-V node extend backward divergently to form two posterior extensions (left and right, LPE, RPE). The A-V node can be divided into a superficial layer and a deep layer, and the deep layer further divided into a upper part and a lower part. The fibers in the superficial layer are vertical, and join with the lower part of the deep layer at the anterior extremity of the node. The lower part of the deep layer is the main axis of the node. The fibers in the lower part of the deep layer are longitudinal, and join with the RPE at the posterior extremity of the node. The fibers in the upper part of the deep layer are oblique and join with the LPE at the posterior extremity of the node, and mix with the lower part at the anterior extremity. The longitudinal dissociation of the anterior part of the His bundle is more distinct than that of the posterior part. The lower-left part of the bifurcating part of the bundle extend to form the posterior left branch, the upper-left and upper-middle parts of the bifurcating part extend to form the anterior left branch, and the right part and lower-middle part of the bifurcating part extend to form the right bundle branch. The morphological evidence of the dual or multiple conducting pathways, the longitudinal dissociation and the reentry pathways in the AVJ were discussed.

ANATOMY OF THE KOCH'S TRIANGLE / 解剖学报

The Koch's triangle of 110 human hearts (adults 70, children 40) has been dissected. The morphology, relationship and landmark of the atrioventricular node were observed and measured. Muscle bundles from the interatrial septum and coronary sinus orifice above and below are connected with the node. In the children the tendon of Todaro is usually tendinous, but in the adults, its posterior part is usually muscular. Deep in the triangle, there is a pyramidal space bounded by the left and right atrial walls and the top of the interventricular septum, in which there are vessels and nerves leading to the atrioventricular nodal area. According to their construction, the Koch's triangle is divided into five parts. The functional and surgical significance of these structures has been discussed.

ORIENTATION AND MECHANICAL ANALYSIS OF THE LUMBAR ZYGAPOPHYSEAL JOINTS / 解剖学报

The stereoscopic orientation of the lumbar zygapophyseal joints and the stability triangle of the motion segments were studied on 56 sets of adult lumbosacral skeletons. The orientation of the lumbar zygapophyseal joints changed gradually from about sagittal plane in upper segment to about coronal in lower. The gravity center of the stability triangle of the motion segments moved backward from upper to ower progressively. Therefore, the stability of lumbar spine decreases and the mobility increases successively from upper downward.