Marked lateral deviation of the phrenic nerve due to variant origin and course of the thyrocervical trunk: a cadaveric study

Phrenic nerve impairment can often lead to serious respiratory disorders under various pathological conditions. During routine dissection of an 88-year-old Japanese male cadaver, a victim of heart failure, we recognized an extremely rare variation of the right thyrocervical trunk arising from the subclavian artery laterally to the anterior scalene muscle. In addition to that, the ipsilateral phrenic nerve was drawn and displaced remarkably laterad by this vessel. We examined all of the branches arising from subclavian arteries, phrenic nerves and diaphragm muscles. The embryological background of this arterial variation is considered. The marked displacement with prolonged strain had a potential to cause phrenic nerve impairment with an atrophic change of the diaphragm muscle. Recently many image diagnostic technologies have been developed and are often used. However, it is still possible that rare variations like this case may be overlooked and can only be recognized by intimate regional examination while keeping these rare variations in mind.

The right ovarian artery arising from the right inferior phrenic artery: a case report

OBJECTIVE

To report a case of the right ovarian artery arising from the right inferior phrenic artery.

MATERIAL AND METHOD

The authors carried out the standard dissection survey of 810 embalmed female cadavers between 1983 and 2010.

RESULTS

The authors encountered a case of the right ovarian artery arising from the right inferior phrenic artery in a donated cadaver aged 53 years at decease.

CONCLUSION

With the advent of intra-abdominal laparoscopic techniques, the anatomy of the ovarian artery has assumed much more importance.

Complicated bronchiolitis: another use for your bedside ultrasound in the emergency department

Diaphragmatic eventration or diaphragmatic herniations are congenital defect that involve abnormal development of the diaphragm and stretching of the muscular fibers leading to protrusion of abdominal organs into the thoracic cavity. Left sided defects will lead to stomach contents into the chest cavity while, right sided defects will have bowel or liver in the thoracic cavity. Infants with Congenital diaphragmatic hernia often present with respiratory distress that can be life-threatening unless treated appropriately. Bedside ultrasound in the Emergency Department, performed by the Emergency Physician can be a very useful tool in diagnosing conditions such as this one. We present a case of diaphragmatic eventration in a two month old male sent to Emergency Department (ED) by his primary care physician due to a severe case of bronchiolitis.

A variation of the phrenic nerve: case report and review

During routine dissection in the department of anatomy, the following anatomical variations of the phrenic nerve were observed on the right side of the neck of a 30-year-old male cadaver. The phrenic nerve, in its early course close to its origin, gave a communicating branch to the C5 root of the brachial plexus. At the level of the root of neck just before entering the thorax, the phrenic nerve was located anterior to the subclavian vein. This unique case of phrenic nerve variation gains tremendous importance in the context of subclavian vein cannulation, implanted venous access portals, and supraclavicular nerve block for regional anaesthesia.

Technical Considerations for Myocardial Revascularization in Congenital Bilateral Hypoplasia of the Pericardium

Congenital hypoplasia of the pericardium is a rare clinical condition that is typically encountered as an incidental finding during routine thoracic imaging or cardiothoracic surgery. Chest pain symptoms, when they occur, are often initially attributed to coronary ischemic syndromes, but herniation of cardiac structures through the pericardial defect, ischemia from torsion of great vessels, or compression of pulmonary parenchyma through defects between the aortic and pulmonary arteries can occur. Careful attention to cannulation techniques, conduit length, and the aberrant course of the phrenic nerves, typically through pericardial fibrous bands, is critical to the successful conduct of cardiac surgery.

Aberrant morphology and residual transmitter release at the Munc13-deficient mouse neuromuscular synapse

In cultured hippocampal neurons, synaptogenesis is largely independent of synaptic transmission, while several accounts in the literature indicate that synaptogenesis at cholinergic neuromuscular junctions in mammals appears to partially depend on synaptic activity. To systematically examine the role of synaptic activity in synaptogenesis at the neuromuscular junction, we investigated neuromuscular synaptogenesis and neurotransmitter release of mice lacking all synaptic vesicle priming proteins of the Munc13 family. Munc13-deficient mice are completely paralyzed at birth and die immediately, but form specialized neuromuscular endplates that display typical synaptic features. However, the distribution, number, size, and shape of these synapses, as well as the number of motor neurons they originate from and the maturation state of muscle cells, are profoundly altered. Surprisingly, Munc13-deficient synapses exhibit significantly increased spontaneous quantal acetylcholine release, although fewer fusion-competent synaptic vesicles are present and nerve stimulation-evoked secretion is hardly elicitable and strongly reduced in magnitude. We conclude that the residual transmitter release in Munc13-deficient mice is not sufficient to sustain normal synaptogenesis at the neuromuscular junction, essentially causing morphological aberrations that are also seen upon total blockade of neuromuscular transmission in other genetic models. Our data confirm the importance of Munc13 proteins in synaptic vesicle priming at the neuromuscular junction but indicate also that priming at this synapse may differ from priming at glutamatergic and gamma-aminobutyric acid-ergic synapses and is partly Munc13 independent. Thus, non-Munc13 priming proteins exist at this synapse or vesicle priming occurs in part spontaneously: i.e., without dedicated priming proteins in the release machinery.

"Pes anserinus" of the right phrenic nerve innervating the serous membrane of the liver: a case report (anatomical study)

During the preparations of cadavers for educational purposes we followed the course of the right phrenic nerve. On one of them and especially a female cadaver aged 72-year-old we found a branch arising from the thoracic portion of the right phrenic and passing through the two layers of the falciform ligament distributed to the upper surface of the serous layer of the liver in the form of "pes anserinus". As it is known, pain referred from the diaphragmatic peritoneum is classically felt in the shoulder tip but pain from thoracic surfaces supplied by the phrenic nerve is usually located there albeit vaguely. We believe that the above anatomical finding is the explanation of distinct radiating pain from the hepatic region to the right shoulder in some patients. The stimulations is carried through the phrenic nerve to the fourth cervical neurotome from were arise the supraclavicular nerves which are distributed to the shoulder region.

Anatomical variations of the phrenic nerve and its clinical implication for supraclavicular block

This paper reports a case of simultaneous diaphragmatic and brachial plexus stimulation followed by a successful nerve block using the supraclavicular approach. An explanation for the qualitative differences in phrenic nerve block between interscalene and supraclavicular block is postulated, based on known anatomical variations.

Roles of neurotransmitter in synapse formation: development of neuromuscular junctions lacking choline acetyltransferase

Activity-dependent and -independent signals collaborate to regulate synaptogenesis, but their relative contributions are unclear. Here, we describe the formation of neuromuscular synapses at which neurotransmission is completely and specifically blocked by mutation of the neurotransmitter-synthesizing enzyme choline acetyltransferase. Nerve terminals differentiate extensively in the absence of neurotransmitter, but neurotransmission plays multiple roles in synaptic differentiation. These include influences on the numbers of pre- and postsynaptic partners, the distribution of synapses in the target field, the number of synaptic sites per target cell, and the number of axons per synaptic site. Neurotransmission also regulates the formation or stability of transient acetylcholine receptor-rich processes (myopodia) that may initiate nerve-muscle contact. At subsequent stages, neurotransmission delays some steps in synaptic maturation but accelerates others. Thus, neurotransmission affects synaptogenesis from early stages and coordinates rather than drives synaptic maturation.

Bronchial trifurcation in a congenital pulmonary venolobar syndrome

Congenital malformations of the tracheobronchal tree and the related arterial blood supply are a complex group of lesions in which there are abnormalities of the venous drainage and lung parenchyma. These malformations are examples of congenital pulmonary venolobar syndrome (CPVS). Tracheal trifurcation is an extremely rare anomaly associated with CPVS. We report on an unusual case of lower right extralobar sequestration connected to the trachea, plus a type I posterior laryngeal cleft, an aberrant systemic artery, and an anomalous route of the phrenic nerve. This paper discusses the place of this unusual abnormality in the spectrum of congenital bronchopulmonary vascular malformations.

Complete left pericardial defect with dual passage of the phrenic nerve: a challenge to the widely accepted embryogenic theory

We report a patient with complete left pericardial defect whose phrenic nerve, split into two portions, passes both ventral and dorsal to the defect. The dorsal part of the phrenic nerve passes over the ventral surface of the pulmonary artery and veins, indicating that the pericardio-pleural foramen has been obliterated. Contrary to the widely accepted embryogenic theory that pericardial defect results from persistence of the pericardiopleural foramen, we consider that the defect in this patient resulted from a tear in the pericardio-pleural membrane immediately lateral to the common cardinal vein.

[A case of congenital partial pericardial defect and anomaly of phrenic nerve with cystic bronchiectasis]

Congenital partial pericardial defect is a rare anomaly that causes no symptoms and is often noticed by chance at autopsy or thoracotomy. During an operation on a patient with bronchiectasis, a partial pericardial defect and anomaly of left phrenic nerve were found incidently. A 58-year-old man complaining hemoptysis was referred to our hospital for surgical treatment of the left cystic bronchiectasis. During a thoracotomy, a partial pericardial defect was noticed. Moreover the left phrenic nerve could not be found within the operative field. We performed left pneumonectomy without repair of pericardial defect, and the patient had a satisfactory postoperative course. A relationship was suggested between congenital pericardial defect and the anomaly of the phrenic nerve.

Pulmonary hypoplasia resulting from phrenic nerve agenesis and diaphragmatic amyoplasia

We report the clinical, general postmortem, and pulmonary morphometric features of a unique case of pulmonary hypoplasia resulting from phrenic nerve agenesis and diaphragmatic amyoplasia. The lungs showed a marked reduction in the number of bronchial branches with relatively normal intra-acinar growth, indicating interference with lung development before the sixteenth week of gestation. The pulmonary abnormalities arose early in gestation, suggesting that normal diaphragmatic neuromuscular development is essential for maintaining thoracic volume and permitting lung growth even before the fetus is capable of regular respiratory movements. The infant also had remodeling of the pulmonary circulation, causing persistent pulmonary hypertension. This case clarifies the interrelationship of diaphragmatic innervation, thoracic volume, fetal respiration, and lung development.

The anatomy of phrenic nerve termination and the motor innervation of the diaphragm

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