Branches of the thoracic sympathetic trunk in the human fetus

Summary The segmental organization of the thoracic sympathetic trunk and all its ramifications was studied in 6 human fetuses (16–22 weeks) by means of the acetylcholinesterase in toto staining method. Each trunk was divided into 12 sympathetic segments. A segment is defined as that part of the sympathetic trunk which is connected via its rami communicates with one spinal nerve, without discriminating between grey and white rami. The diameter of the rami communicantes and their direction towards the spinal nerves are variable. The number of peripheral segmental ramifications of the trunk is much larger than assumed previously. Each thoracic sympathetic segment gives off at least 4–5 nerves. Three categories of nerves are discerned: (1) large splanchnic rootlets confined to the greater, lesser and least thoracic splanchnic nerves, (2) medium-sized splanchnic nerves directed towards thoracic viscera, some of which give off branches towards costovertebral joint plexuses and, described for the first time in man, (3) small nerves which ramify extensively and form nerve plexuses in the capsule of the costovertebral joints. The majority of the ramifications is formed by the nerves of the third category. The existence of Kuntz's nerve, connecting the 2nd intercostal nerve and 1st thoracic spinal nerve, is confirmed in four specimens. The nerve plexuses of the costovertebral joints receive a segmentally organized innervation: they receive their input from the neighbouring sympathetic segment and the one cranial to it.It is concluded that the thoracic sympathetic branches in man show a complex, segmentally organized pattern and may have a considerable component of somatosensory nerve fibers. The complex relationships must be taken into account in surgical sympathectomies.     

颞下颌关节与颅面指标的计算机相关及回归分析

本文用计算机分析统计了118例(236侧)颞下颌关节的12项骨性指标及10项颅面指标的正常值及相关关系。结果表明颞下颌关节各项指标之间、颞下颌关节与颅面各主要指标之间,均存在良好的相关关系。说明颞下颌关节,特别是关节窝和髁突的形态大小具有明显的规律性。由于颅面诸指标与颞下颌关节主要指标之间高度相关,因而本文用逐步回归方法,建立了由颅面特征指标推算髁突形态的回归方程。本文的结果可为该关节的形态研究及人工关节的设计和应用提供有益的依据。     

掌指关节的三维解剖及形态分析

目的：观测掌指关节关节面的几何形态,为人工关节的设计和应用提供解剖学依据。方法：10只成人手标本,解剖掌指关节,测量侧副韧带起点距掌骨头关节面的直线距离,三维数据检测仪获得关节面三维坐标数据,应用SPSS软件进行统计分析和成像。结果：掌骨头有双髁结构,桡侧髁略大,第1掌骨头形态特殊;各掌骨头高度的比较无显著差异;其掌侧关节面大于背侧,第2、3掌骨头关节面面积明显较大。近节指骨底在形态、高度和面积方面各序列相似;各序列侧副韧带起点桡侧较尺侧距离掌骨头关节面远。结论：手指人工关节的设计应符合解剖形态,并根据各序列形态的差异进行个体化设计,尤其拇指更应区别对待;手指人工关节的设计和应用中应注意软组织保护,关节的切除范围应注意保留侧副韧带的起止点。     

Source of the slippage in the universal joints of the Hoffmann external fixator

An investigation was conducted to determine what improvements in the resistance to slippage could be obtained in selected interfaces (rod/clip torsional, cheek/bowl and cheek/clip) of the Hoffmann external fixator. The modification involved changing the standard wing-nut clamp for a bolt with a thread of 7 mm and a 1 mm pitch and placing an FAG 28–303 thrust-bearing (needle roller and cage assembly) between the bolt and the cheek. The results showed a significant improvement in the slippage values of all interfaces; increases of approximately six times were obtained at all torque values of the wing-nut clamp or fastener tested. Such improvements would markedly increase the reliability of external fixation systems and thus reduce the incidence of loss-of-reduction of fracture due to slippage of the universal joint.     

Study of the carrying angle of the human elbow joint in full extension: a morphometric analysis

This study measured the carrying angle of the elbow joint in full extension in 600 students, using the supplementary angle to that between the longitudinal axis of the arm and that of the forearm. The mean carrying angle was 12.88°±5.92: 10.97°±4.27 in men and 15.07°±4.95 in women. The carrying angle changes with skeletal growth and maturity. The angle is always greater on the side of the dominant hand. We confirmed the inverse relationship between the carrying angle and the intertrochanteric diameter. Also, the type of constitution influences the value of the carrying angle, especially in women.     

Die Beanspruchung des menschlichen Ellenbogengelenks

Zusammenfassung Bei 80 Objekten werden die Gelenkflächen des menschlichen Ellenbogengelenks untersucht. Die Trochlea und das Capitulum humeri sowie das Caput radii zeigen keine nennenswerten Unterschiede in der Ausdehnung der mit typischem Gelenkknorpel bedeckten Flächen. Dagegen lassen sich für die Ulnazange drei charakteristische Formgruppen abgrenzen: In 3 Fällen kann eine einheitliche Knorpelfläche beobachtet werden. Bei etwa zwei Drittel der untersuchten Objekte liegt im mittleren Bereich der Incisura trochlearis in horizontaler Richtung ein 2–5 mm breiter knorpelfreier Streifen, der den Gelenkknorpel in 2 vollständig getrennte Flächen unterteilt. Das restliche Drittel der Objekte besitzt eine unvollständige Trennung der Gelenkfläche. Unter Berücksichtigung der Vorstellungen von Pauwels über die causale Histogenese der mesenchymalen Stützgewebe sowie der Materialverteilung im Knochengewebe in Abhängigkeit von der einwirkenden Spannungsgröße werden die morphologischen Befunde den für die jeweiligen Skeletelemente von Pauwels ermittelten Spannungsdiagrammen gegenübergestellt. An der Trochlea und dem Capitulum humeri und am Caput radii findet sich eine geradezu ideale Übereinstimmung in der Ausdehnung der Knorpelfläche und der Knochendichte unter den Gelenkflächen mit den entsprechenden Spannungsdiagrammen. An der Ulna trifft dies nur für einen geringen Teil der Objekte zu. Für die unterschiedliche Ausgestaltung der Incisura trochlearis werden zwei mögliche Ursachen diskutiert: 1. die Resultierende R verharre während des Bewegungsablaufes in einzelnen Positionen innerhalb der Incisura trochlearis verschieden lange; 2. der Krümmungsradius der Trochlea humeri sei größer als derjenige im mittleren Bereich der Ulnazange, so daß hier wegen des fehlenden Kontaktes der Gelenkflächen keine Druckübertragung möglich ist.

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The stress of the human elbow jointI. Functional morphology of the articular surfaces

Summary The articular surfaces of 80 human elbow joints are analysed. The trochlea and capitulum humeri and the caput radii of the investigated individuals show no particular differences in the extent of their surfaces covered with typical articular cartilage. On the other hand the form of the incisura trochlearis is rather variable. Three characteristic formgroups are to be discerned. In three objects a continuous cartilage surface has been observed. In 50 of the investigated joints there is a small intersection free from cartilage in the midst of the incisura trochlearis, dividing the articular cartilage in two isolated surfaces. In the rest of the analysed objects the articular surface is divided only partially. According to Pauwels' hypothesis on the causal histogenesis of the mesenchymal supporting tissues and of the density distribution of the bone dependence upon the magnitude of the local unit stress the morphological findings in the single investigated parts of the elbow joint are confronted with the corresponding stress diagram as described by Pauwels. In the trochlea and capitulum humeri and in the caput radii a nearly ideal correspondence of the extent of the articular surface and the density of the bone tissue with the unit stress diagrams are found. In the ulna this correspondence exists only in few of the analysed objects. For the different form of the incisura trochlearis two possible explanations are discussed: 1, during the motion the resultant of forces may stay for a different time in their single positions in the incisura trochlearis; 2. the curvature radius of the trochlea humeri may be greater than that one of the incisura trochlearis in the central area. So no pressure occurs in this part of the articular surface.

Mit freundlicher Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Morphomechanics of the humero-ulnar joint: II. Concave incongruity determines the distribution of load and subchondral mineralization

Background: A deeper joint socket (concave incongruity) is found at most angles of flexion of the humero-ulnar joint and maintained over a wide range of physiological loading. It is, however, unclear how far this incongruity affects the distribution of load and subchondral mineralization of this joint as compared with a congruous configuration. Methods: Two nonlinear, axisymmetrical finite element models with two cartilage layers were constructed, one congruous and one incongruous, with a joint space of realistic magnitude. The distribution of subchondral mineralization was determined by computed tomography osteoabsorptiometry in the same six specimens that were investigated in the first part of the study, and compared with the biomechanical data obtained there and the predictions of the models. Results: In the congruous case, the center of the socket is highly loaded, whereas the periphery does not experience mechanical stimulation. A central bone density maximum is predicted. With concave incongruity the position of the contact areas shifts from the joint margin towards the center as the load increases, and the peak stresses are considerably lower. A bicentric ventro-dorsal distribution pattern of subchondral mineralization is predicted, and this is actually found in the six specimens. Conclusions: Concave incongruity is shown to determine load transmission and subchondral mineralization of the humero-ulnar joint. It is suggested that this shape leads to a more even distribution of stress, provides intermittent stimulation of the cartilaginous tissue, and has beneficial effects on the metabolism, nutrition, and lubrication of the articular cartilage during cyclic loading. © 1995 Wiley-Liss, Inc.     

M. articularis genus Observations on arrangement and consideration of function

Summary On the basis of 44 adult Japanese cadavers, the mode of origin, insertion and innervation of the articularis genus muscle (m. articularis genus: AG) is described. All the muscle bundles that are inserted into the posterior aspect of the synovial membrane of the joint capsule as well as the suprapatellar bursa are defined as AG. The inserting fibers spread medially and laterally over the subsynovial connective tissue which is the outer layer of synovial membrane facing the femur. The fatty tissue between each muscle bundle gradually increases with depth. A few deeper muscle bundles of AG seem to be separated by a layer of fat from those of the superficial layer. The deepest muscle bundles arise from the anterior surface of the femur at a slighlty lower level than the proximal apex of the suprapatellar bursa. It is inserted into the synovial membrane at the level of the junction of the suprapatellar bursa and proper joint cavity when the knee is extended. It is difficult to distinguish AG from m. vastus intermedius (Vi) only on the basis of the manner of origin and the surrounding fatty tissue. The innervation is in common with that of Vi, namely, a few nerves which run down obliquely to the lower medial part of Vi.Dedicated to Professor Emeritus Tomoo Nakayama in commemoration of his 77th birthday     

Changes in extracellular potassium concentration in cat spinal cord in response to innocuous and noxious stimulation of legs with healthy and inflamed knee joints

Summary In 20 cats anaesthetized with alpha-chloralose and spinalized at the thoracolumbar junction we investigated the role of stimulation induced accumulation of extracellular potassium in the spinal cord in the processing of nociceptive discharges from the knee joint. For that we electrically stimulated the posterior articular nerve of the knee. We further performed innocuous and noxious stimulation of the knee and of other parts of the leg and studied the effect of an acute inflammation of the knee on [K⁺]₀ in the spinal cord. Innocuous stimulation of the skin (brushing or touching) and innocuous movements in the knee joint all induced rises in [K⁺]₀ which were maximal at recording depths of 1500 to 2200 m below the surface of the cord dorsum. Peak increases were 0.4 mM for touching the leg and 1.7 mM during rhythmic flexion/ extension of the knee joint. Noxious stimulation of the skin, the paw, the tendon and noxious movements of the knee joint also produced rises in [K⁺]₀, which were somewhat larger for the individual types of stimuli than those produced by innocuous intensities. Electrical stimulation of the posterior articular nerve induced rises in [K⁺]₀ by up to 0.6 mM. Stimulus intensities sufficient to activate unmyelinated group IV fibers were only slightly effective in raising [K⁺]₀ above the levels reached during stimulation of myelinated group II and III fibers. During development of an acute inflammation of the knee joint (induced by kaolin and carrageenan), increases in [K⁺]₀ and associated field potentials became larger by about 25%. We assume that this reflects an increase in neuronal responses. In conclusion, changes in [K⁺]₀ in the spinal cord are some-what larger during noxious stimulation than during innocuous stimulation. The absolute level reached depended more on the site and type of stimulation than on the actual stimulus intensity itself. Hence a critical role of spinal K⁺ accumulation for nociception is unlikely.     

Examination of the Diagnostic Value and Estimation of the Chaos Phenomenon in Temporomandibular Joint Sounds Using Fractal Dimension

.The aim of this study is to estimate the chaos phenomenon in temporomandibular joints (TMJ) sound using fractal dimension (FD), and to examine the diagnostic value of the FD in comparing TMJ sounds produced by 6 asymptomatic and 25 symptomatic TMJ. Multiple mandibular opening and closing cycles recorded were used to calculate the waveform dimension and correlation dimension in the FD. Chaos in the TMJ sounds was estimated by the FD that was saturated with some constant value to an increase of embedding dimension. Results reveal that fractal analysis produces a high degree of reproducibility within, and similarity across subjects, and indicate that both FD values of the asymptomatic TMJ sounds are significantly higher than those of the symptomatic. These findings suggest that chaos is present in TMJ sounds and the difference in the FD is of diagnostic value in evaluation of pathological change in TMJ sound signals.