An anatomical study of the relationship between the sympathetic trunk and intercostal veins of the third and fourth intercostal spaces during thoracoscopy

The complexity of the anatomy of the sympathetic trunk and intercostal veins in the third and fourth intercostal space may lead to intraoperative or postoperative bleeding. The purpose of this study was to investigate the anatomical variations of the sympathetic trunk and intercostal veins in the third and fourth intercostal spaces. The size and crossing type of veins in the third and fourth intercostal spaces in 44 Korean patients with palmar hyperhidrosis were analyzed. We classified intercostal veins by their size (small, medium, and large) and crossing type (anterior or posterior to sympathetic nerve). Large intercostal veins susceptible to bleeding were found in 36.4 and 68.2% of patients in the right third and fourth intercostal spaces, respectively and in 2.3 and 4.5% of left third and fourth intercostal spaces, respectively. More than 80% of the left third and fourth intercostal veins were small. Anterior crossing intercostal veins, which often cause problems at the third and fourth right intercostal spaces, were found in 27.3% (third) and 15.9% (fourth). However, there were only two cases of anterior crossing veins on the left side. Large anterior crossing veins were found only on the right side. In conclusion, surgical procedures of the right sympathetic ganglia may have increased risks due to a higher frequency of large anterior crossing intercostal veins. Careful dissection is necessary to decrease the incidence of intraoperative or postoperative bleeding. Clin. Anat. 23:702–706, 2010. © 2010 Wiley‐Liss, Inc.     

The influence of transducer position on the M-mode echocardiographic measurement of the left atrial dimension

Eighty-five subjects were investigated to see if the left atrial dimension (LAD) determined by M-mode echocardiography varies with different placements of the transducer in the parasternal long-axis view. Satisfactory images from the third and fourth intercostal spaces were obtained in all subjects. A satisfactory image from the second, third and fourth intercostal spaces was obtained in 58 subjects and from the third, fourth and fifth intercostal spaces in 27 subjects. The mean LAD was significantly smaller (P less than 0.001) in the fourth intercostal space than in the third. The mean value obtained from the fifth intercostal space was smaller than that from the fourth. The beam pathway seen on the two-dimensional echocardiogram indicates that the transducer should preferably be placed in the third intercostal space. If the transducer is placed in a lower intercostal space the measured left atrial dimension might be underestimated.     

A study on the communication between the pectoral nerve and the extramural nerve branches of the intercostal nerves]

Kumaki et al. (1979) defined the extramural nerve as the rudimentary sensory nerve which appeared on the upper thoracic wall; it branched off the root of the lateral cutaneous nerve of the second, third or fourth intercostal nerve, ran inferomedially adhering to the fascia of the intercostalis externus muscle and ended supplying the membrane covering the adjacent rib. They also stated that the extramural nerve (Rxm) occasionally became a cutaneous nerve which pierced the pectoralis muscles and supplied the skin covering the thoracic wall similar to the lateral cutaneous nerve (Rcl) or the anterior cutaneous nerve (Rca). Further, they proposed that the muscular nerves to the obliquus externus abdominis muscle which are usually situated below the fifth rib might be considered a part of this Rxm series. Although the definition of Rxm is still not widely accepted, Rxm is thought to be a key morphological factor influencing the variations of peripheral nerve arrangement on the thoracic wall. In the student course of gross anatomy dissection at Iwate Medical University School of Medicine during the years 1987-1991, three cases of Rxm communicating with the pectoral nerve and supplying the pectoralis major muscle were observed. Some cases have been reported in which Rcl innervates part of the pectoral muscles. However, the communication between the pectoral nerve and Rxm has not yet been discussed. Therefore, to clarify the morphological significance of the communication between Rxm and the pectoral nerve, the branching pattern and the distribution of the pectoral nerves were extensively investigated and the intramuscular nerve supply of some pectoral nerves, especially the pectoral nerves which communicated with Rxm, was examined in detail under a stereomicroscope. The results are summarized as follows: 1. In the first case, Rxm of the second intercostal nerve originated from Rcl, ran inferomedially adhering to the fascia of the intercostalis externus muscle and pierced the origin of the pectoralis minor muscle at the third intercostal space. Then Rxm turned superolaterally to communicate with a pectoral nerve which originated from the loop composed of the lateral and medial pectoral nerves and passed inferior to the pectoralis minor muscle. After communication, the pectoral nerve with Rxm supplied the caudalmost part of the sternocostal portion of the pectoralis major muscle. In the second case, a similar branch of Rxm of the second intercostal nerve passed inferior to the pectoralis minor muscle.(ABSTRACT TRUNCATED AT 400 WORDS)     

Scalenus muscles in macaque monkeys

The attachment and innervation of the scalenus muscles in both sides of two Japanese monkeys and a rhesus monkey were observed to discuss their morphological significance while comparing their findings in humans. The scalenus ventralis muscle in macaques had almost the same attachments as the scalenus anterior muscle in humans and was innervated by the cervical nerve branches, which were lower in spinal segment than in humans and had a close relationship with the branches to the intertransversus ventralis muscles. Furthermore, the scalenus ventralis muscle was penetrated by the phrenic nerve in all cases observed. The posterior part of the scalenus muscle in macaques (the scalenus dorsalis muscle) was divided into short (the scalenus dorsalis brevis) and long (the scalenus dorsalis longus) parts according to their attachments. The former was attached to the transverse processes of the lowest two cervical vertebrae and the first rib, whereas the latter was attached to the 3rd-5th ribs. It is notable that the scalenus dorsalis muscles in macaques were innervated by branches from the long thoracic nerve in addition to direct branches from the cervical nerve roots. In addition, the scalenus dorsalis longus was supplied by twigs from the lateral cutaneous branches of the 2nd and 3rd intercostal nerves. This indicates that the scalenus dorsalis muscles contain a muscular component derived from the upper limb girdle musculature, unlike the human scalenus muscles, which have been considered to belong to the cervical trunk muscles.     

Mechanical effect of muscle spindles in the canine external intercostal muscles

High-frequency mechanical vibration of the ribcage increases afferent activity from external intercostal muscle spindles, but the effect of this procedure on the mechanical behaviour of the respiratory system is unknown. In the present study, we have measured the changes in external intercostal muscle length and the craniocaudal displacement of the ribs during ribcage vibration (40 Hz) in anaesthetized dogs. With vibration, external intercostal inspiratory activity increased by ∼50 %, but the respiratory changes in muscle length and rib displacement were unaltered. A similar response was obtained after the muscles in the caudal segments of the ribcage were sectioned and the caudally oriented force exerted by these muscles on the rib was removed, thus suggesting that activation of external intercostal muscle spindles by vibration generates little tension. Prompted by this observation, we also examined the role played by the external intercostal muscle spindles in determining the respiratory displacement of the ribs during breathing against high inspiratory airflow resistances. Although resistances consistently elicited prominent reflex increases in external intercostal inspiratory activity, the normal inspiratory cranial displacement of the ribs was reversed into an inspiratory caudal displacement. Also, this caudal rib displacement was essentially unchanged after section of the external intercostal muscles, whereas it was clearly enhanced after denervation of the parasternal intercostals. These findings indicate that stretch reflexes in external intercostal muscles confer insufficient tension on the muscles to significantly modify the mechanical behaviour of the respiratory system.     

胸内侧皮瓣血管的巨微解剖

在手术显微镜下,解剖了成人尸体50侧,对胸内侧区皮瓣血管源进行了研究。胸廓内动脉在上4个肋间隙发出的穿动脉中,以第Ⅱ穿动脉的出现率最高,平均管径最粗,分布面积也最大。进行胸内侧皮瓣吻合血管移植时,宜首选第Ⅱ穿动脉作为血管蒂。第Ⅰ穿动脉的分布面积和中心分布区,均大于第Ⅲ或第Ⅳ穿动脉,是第二选择。胸廓内动脉跨越了几个肋间隙,其中,第2肋间隙位置较浅,距胸骨缘较远,较其他肋间隙宽,这些有利于以第Ⅱ穿动脉,甚至连同一段胸廓内动脉,作为皮瓣血管蒂的采取。如果切除一段第2肋软骨,以胸廓内动脉连同第Ⅰ、Ⅱ穿动脉为血管蒂,可以扩大皮瓣的采取范围。根据穿动脉的起源、位置、管径、浅出点、行程、分布区范围和吻合情况等,讨论了采取吻合血管胸内侧皮瓣时应注意的问题。     

腹外斜肌的神经入肌点定位与肌内神经分布研究

目的　对人腹外斜肌的神经入肌点定位和肌内神经染色观察，为其临床应用提供形态学资料。 方法　成尸11具定位神经入肌点和5具行Sihler’s 肌内神经染色。 结果　腹外斜肌受下8对肋间神经外侧肌支支配，各个肌齿的神经入肌点距离相应肌齿起端中点(1.54±0.33)cm，位于锁骨中线与第5肋下缘的交界处至腋后线与第11肋下缘交界处的连线上。Sihler’s染色显示支配腹外斜肌的肋间神经外侧肌支入肌后分出小分支分布到各肌齿的起端1/3，然后约在各肌齿的近、中1/3交界处分出2支二级神经分支，即上支与下支，它们分出小分支分布到各肌齿的中间1/3，相邻两个肌齿的上支与下支在各肌齿中远部形成“U”形吻合，从“U”形吻合弓上分出小分支分布到各肌齿的止端1/3。在腹外斜肌上半部，各肌齿的神经分支分布到相应的肌齿，但在腹外斜肌下半部，上一肌齿的远侧下份是由下一肌齿的神经分支(上支)分布。 结论　①为临床上腹壁局部麻醉和术后切口疼痛的神经阻滞提供指导意义；②腹外斜肌中远部从上至下形成“波浪形”的神经分支密集区；③腹部手术切口建议不要超过四个肌齿。     

Are the external and internal intercostal muscles synergist or antagonist in the cat?

The electrical activity of the external and internal intercostal muscles was recorded in decerebrated cats during eupnea and in the course of dyspnoea artificially induced to reinforce the inspiratory or expiratory central drive. In the cephalic part of the thorax (1st-5th ribs) the lateral part of the external and internal intercostal muscles are synergist and inspiratory. In the caudal part of the thorax (9th-13th ribs) these muscles are also synergist but expiratory. In the intermediate part (5th-9th ribs) the intercostal muscles are antagonist, the external ones are inspiratory and the internal ones are expiratory.     

Variability of the pulmonary oblique fissures presented by high-resolution computed tomography

The purpose of the study was to evaluate the radiological anatomy of oblique fissures (OFs) on high-resolution computed tomography (HRCT) scans. We retrospectively reviewed HRCT scans of 144 patients with normal lung parenchyma. The uppermost level of OFs with respect to the ribs, configuration (concave, straight, convex and others), orientation (medial or lateral facing), rotation and completeness of OFs were recorded. The most cranial level of the left OF was seen between the third and sixth ribs, and all but one were seen above or at the same level as the right OF. The uppermost extent of the OF was between the third and fourth intercostal space and seventh rib on the right lung. Only 2.2% of the right and 1.6% of the left OFs followed a parallel course to the ribs. The configuration of the OFs was generally concave in the upper zones (85.8% on the right and 72.1% on the left) and convex in the middle and lower lung zones (79.3% on the right and 73.9% on the left); 62.5% of the right and 59.7% of the left OFs were incomplete. Suprahilar portions of both OFs (98.9% on the right and 96.7% on the left) and the infrahilar portion of the right OF (54.2%) were generally facing laterally, whereas the infrahilar portion of the left OF was facing medially (80.9%). Angles of the MFs differed at the upper and lower levels. We detected reversal of 21 OFs in their craniocaudal course. In conclusion, the radiological anatomy of the right OF differs from the left OF. The uppermost extent of the left OF is almost always higher than the right. Thus, higher position of the right OF compared with the left almost always indicates a pathological process. Assessment of the angles of the OFs or comparison of the two sides cannot be used for the diagnosis of parenchymal disease like atelectasis. Occasionally, the classical propeller-like configuration is disrupted by the reverse course of the caudal part of the OF.     

Coupling between the ribs and the lung in dogs

In contrast to the conventional theory, the external and internal intercostal muscles show marked rostrocaudal gradients in their actions on the lung. We hypothesized that these gradients are the result of a non-uniform coupling between the ribs and the lung. Rib displacements ( X _r) and the changes in airway opening pressure ( P _a,o) were thus measured in anaesthetized, pancuronium-treated, supine dogs while loads were applied in the cranial direction to individual pairs of odd-numbered ribs and in the caudal direction to individual pairs of even-numbered ribs. During cranial loading, X _r induced by a given load increased gradually with increasing rib number. The decrease in P _a,o also increased from the third to the fifth rib pair but then decreased markedly to the eleventh pair. A similar pattern was observed during caudal loading, although X _r and Δ P _a,o were smaller. These results were then combined to calculate the net X _r and the net Δ P _a,o that a hypothetical intercostal muscle lying parallel to the longitudinal body axis would produce in different interspaces. The net X _r was cranial in all interspaces. However, whereas the net Δ P _a,o was negative in the cranial interspaces, it was positive in the caudal interspaces. These observations confirm that the coupling between the ribs and the lung varies from the top to the base of the ribcage. This coupling confers to both the external and the internal intercostal muscles an inspiratory action on the lung in the cranial interspaces and an expiratory action in the caudal interspaces.     

Anatomical variations of the upper thoracic sympathetic chain

The aim is to clearly delineate the upper thoracic sympathetic chains and neural connections between the chains and ventral rami of the thoracic nerves, and to provide an anatomical foundation for successful upper thoracic sympathicotomy for treating upper essential hyperhidrosis. The upper thoracic sympathetic chains, upper five intercostal nerves, and neural connections between them in 50 halves of 25 adult cadavers have been dissected, measured, and mapped. The stellate ganglion had an incidence of 80%. The second to the fourth thoracic sympathetic ganglia were commonly located in the corresponding intercostal spaces with the presence of 92%, 68%, and 50%, respectively. The incidence of the first and second intercostal rami was 40% and 6%, and that of the ascending or descending rami from the second, third and fourth ganglia was 54%, 24%, and 14%, respectively. Additional rami communicantes joined the ventral ramus of the 1st thoracic nerve proximal to the point where the latter gave a branch to the brachial plexus. The farthest horizontal distance from the sympathetic chain to the junction between the additional rami communicantes and the second to the fourth intercostal nerves was 29.1 mm. Only 16% of cadavers had similar anatomy bilaterally. Anatomical variations of the upper thoracic sympathetic trunk in relation to intercostal nerves, which may be one of the causes resulting in surgical failures and recurrences, were striking. Attention should be given to such anatomical variations when planning thoracic sympathicotomy. Clin. Anat. 22:595–600, 2009. © 2009 Wiley‐Liss, Inc.     

Double-layered two-directional somatopleural cell migration during chicken body wall development revealed with local fluorescent tissue labeling

Anatomical Science International - The thoracic ventral body wall consists of the rib, the sternum, the intercostal muscles, and the connective tissues surrounding them. The ribs and the...