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PubMed2006

Transcanal approach to the singular nerve.

OBJECTIVES/HYPOTHESIS: Intractable benign paroxysmal positional vertigo is rare, and surgery is indicated in only a very small number of cases. Transcanal singular neurectomy is considered a difficult and risky procedure possibly leading to hearing loss and vertigo. The objective of this study was to evaluate the feasibility of the singular neurectomy through the external ear canal in an attempt to explain the contradictory results of previous reports of anatomists and of surgeons who abandoned the technique, considering that the singular neurectomy could not be reached via the external auditory canal without damaging the labyrinth. MATERIALS AND METHODS: Anatomical study on 100 halves of human heads in which the canal of the singular nerve (SN) was identified and opened at its extremities, the internal auditory canal and the ampulla of the posterior semicircular canal, via a posterior fossa approach. Next, the canal of the SN was dissected via the external auditory canal, at the floor of the round window (RW) niche. The relation of the SN canal to the ampulla of the posterior semicircular canal was evaluated. RESULTS: In 90 cases, the canal was transected medially to and away from the ampulla of the posterior semicircular canal, and in 8, at its emergence from the posterior ampullary recess. In these 98 cases, the RW membrane and the bony labyrinth were kept intact. In two cases, the canal of the SN could not be reached at the floor of the RW niche. CONCLUSION: Singular neurectomy is feasible via the external auditory canal, without damaging the RW membrane or the labyrinth in 98% of the cases. Because singular neurectomy is indicated in a very small number of cases, it is difficult to master this particular surgical procedure. This may explain why most surgeons abandoned the technique after a few attempts, followed by an unacceptable rate of sensorineural hearing loss.

Aged↗

PubMed2005

Cadaveric study of methods for subscapularis muscle needle insertion.

OBJECTIVE: To evaluate the accuracy for three methods for needle insertion into the subscapularis muscle for electromyography, botulinum toxin injection, and phenol nerve block. DESIGN: Three needle insertion methods were evaluated by cadaver injection by an American Board of Electrodiagnostic Medicine certified physician. An anatomist, blinded to the method used, served as the dissector to evaluate the effectiveness of the methods tested. RESULTS: A posterior axillary approach was most effective for needle insertion into the subscapular muscle compared with a medial scapular or a superior scapular approach. No approach was ideal for subscapular nerve injection. CONCLUSIONS: A posterior axillary approach is best for needle insertion of the subscapularis muscle for electromyography or botulinum toxin injection. Subscapular nerve injection is difficult from all of the three approaches tested.

Adult↗

PubMed2000

Construction of a human topological model from medical data.

Medical imaging can provide data for useful views of the interior details of human anatomy. In addition to visualization, which in general has been the primary reason for obtaining these data, many other uses are possible. These include modeling of different elements and their inter-relationships-topological modeling, simulation of physical processes, analysis of movements, and validation of models. Here, we describe some of the modeling issues from medical imaging. The issues are particularly related to topological modeling of different anatomical elements: bones, muscles, articulations, etc. A three-dimensional topological modeler is presented with which anatomists and other users can build a topological database containing structural, topological, and mechanical information of anatomical elements.

Diagnostic Imaging↗

PubMed1993

Dominant maxillary artery as a cause of failure in maxillary artery ligation for posterior epistaxis.

Ligation of the maxillary artery is a logical and effective method for the arrest of severe uncontrollable posterior epistaxis. The failure rates for arrest of haemorrhage are given in the literature as 10-13%. In our centre, over the last 9 years, 23 patients have undergone maxillary artery ligation to control epistaxis without a failure. Bilateral maxillary artery ligation was carried out whenever the maxillary artery of the bleeding side was found to be of small diameter. To investigate whether there is an asymmetry in the size of the maxillary arteries we performed 13 cadaveric dissections. In 6 of the cadavers one maxillary artery was significantly larger than the other. This fact has hitherto not been observed by otolaryngologists or anatomists. Failure to arrest haemorrhage may have resulted from ligation of the non-dominant maxillary artery with consequent opening of cross-anastomoses from the dominant side.

Adult↗

PubMed1989

The development of the sulci and gyri of the bovine cerebral hemispheres.

This study contributes to the existing knowledge and includes a complete description of the gyri and sulci of the bovine cerebral hemisphere, the chronological order of appearance of these sulci and gyri and the ages at which the sulci and gyri reach their final pattern as seen in the bovine adult. The research was undertaken because this specific area has not been covered by anatomists in any depth. The results of this study will contribute to the more complete descriptions of the anatomy of the bovine adult, as well as of the embryological development of the animal. A number of bovine embryos and fetuses were collected from the abattoir. Serial sections of the embryos were studied histologically, while the brains of the fetuses were examined macroscopically or with a dissection-microscope. Up until day 58 the cerebral hemisphere is smooth. Then an indentation appears which marks the position of the Fissura sylvia. The Sulcus rhinalis lateralis appears at day 68. At day 90 the following grooves are visible: the Sulcus suprasylvius, the Sulcus cinguli, the Sulcus splenialis, the Sulcus genualis, and the Sulcus corporis callosi. At this age, all the gyri associated with these sulci develop, although the gyri are well developed only after the grooves have formed. At day 110 the Sulcus ectosylvius, the Sulcus marginalis, and the Sulcus presylvius are visible, once again with their associated gyri appearing a short time thereafter. At day 130 the following grooves are visible: the Sulcus coronalis, the Sulcus cruciatus, the Sulcus ansatus, and the Sulcus endomarginalis. The cerebrum of the foetus at this stage has well developed gyri. At day 160 the Sulcus proreus, the Sulcus ectomarginalis, the Sulcus suprasplenialis, the Sulcus endosplenialis, the Sulcus calcarinus, and the Sulcus endogenualis have developed. The final groove to form is the Sulcus rhinalis medialis. Then the brain looks like that of the adult animal.

Animals↗

PubMed1992

The humeroscapular bone of the great horned owl (Bubo virginianus) and other raptors.

A small, separate, bony density dorsal to the shoulder joint is radiographically visible in several species of large hawks and owls. Gross dissection and histological examination show the bone to lie on the deep surface of the major deltoid muscle in intimate association with the dorsal coracohumeral ligament of the shoulder joint. The tendon of the supracoracoideus muscle passes immediately cranial to the humeroscapular bone. Two ligaments distinct from the shoulder joint capsule attach the humeroscapular bone to the proximal humerus: one passes to the proximal edge of the pectoral crest of the humerus, and the other passes to the ventral tubercle of the humerus. The bone was described as the humeroscapular bone in reference to a similar fibrocartilaginous structure possessed by some birds. The humeroscapular bone is present in the great horned owl (Bubo virginianus), the screech owl (Otus asio), the barred owl (Strix varia), the red-tailed hawk (Buteo jamaicencis), the Cooper's hawk (Accipiter cooperii), and the sharp-shinned hawk (Accipiter striatus). The bone is absent in the barn owl (Tyto alba), the osprey (Pandion haliaetus), the golden eagle (Aquila chysaetos), and the turkey vulture (Cathartes aura), though some of these species possessed a similar fibrocartilaginous structure. Whether the humeroscapular structure develops as bone or cartilage in a given species may be related to other morphological features of the wing, and/or to characteristics of the predatory behavior of the species. Clinicians and anatomists dealing with birds of prey must be aware of the presence of the humeroscapular bone to avoid misinterpreting it as a fracture fragment.

Animals↗

PubMed2004

An anatomical study of an electric organ and its nerve supply in the electric ray (Torpedinidae Narke japonica).

Despite anatomist's great interest in the electric organ (EO) of the electric ray, its detailed morphology remains unclear. In order to understand more completely the architecture of the EO and the branchial organ, it is necessary to examine detailed relationships regarding the origin, course and distribution of nerves innervating the EO. We thus carried out a macroscopic and microscopic anatomical study, focusing on issues, using the 18 sides of nine electric rays. The following results were obtained: (i) the EO was innervated exclusively by the facial, glossopharyngeal and vagus nerves; (ii) although these three cranial nerves consistently innervated the EO, variation in the number of the nerves innervating the EO was observed; (iii) cranial nerves innervated the EO in a segmental manner, at both entry and in the area of distribution. These results suggest that the EO of the electric ray might have differentiated from a non-constant branchial muscle anlage but preserves the branchial segments in terms of the craniocaudal, dorsoventral and proximodistal axes.

Animals↗

PubMed2005

The Kenneth Fitzpatrick Russell Memorial Lecture: 'Of books and libraries: a reflection inspired by surgeon William Bland's copy of Manec's Treatize on the Ligature of Arteries'.

Kenneth Russell, bibliophile, anatomist, surgeon and historian helped to acquire Leslie Cowlishaw's historical library for the College, and subsequently cared for and catalogued the collection. One book in the collection is especially interesting as it bears the name of every owner since 1656; another belonged to William Bland of Sydney, sometime surgeon, convict, educator and legislator, whose surgical ability and inventive mind stimulated this reflection on libraries and book lovers. Bland was almost certainly Australia's first vascular surgeon.

Australia↗

PubMed1994

Pattern of development of the callosal transfer of visual information to cortical areas 17 and 18 in the cat.

The aim of this study was to investigate the development of visual callosal transfer in the normally reared cat. Two- to nine-week-old kittens and adults (used as controls) underwent section of the optic chiasm. Three days later, the animals were placed under anesthesia and paralysed; unit activities were recorded from visual cortical areas 17 and 18 and from the white matter in one hemisphere. The units were tested for their responses to visual stimulation of each eye successively. Out of 1036 recorded neurons, 185 could be activated through the eye contralateral to the explored cortex via callosal transfer. Most of them could also be driven through the ipsilateral eye via the 'direct' geniculo-cortical pathway. For animals aged > or = 2 weeks, virtually all of these units were located at the 17/18 border zone, with a majority in the supragranular layers. When activated through the corpus callosum, they displayed receptive fields located either on the central vertical meridian of the visual field or in the hemifield ipsilateral to the explored cortex. Such extension into the ipsilateral hemifield as well as receptive field disparities of binocular units decreased with age, while spontaneous activity, strength of response, orientation selectivity and ability to respond to slits moving at middle-range velocity increased. The main conclusion is that the transient callosal projections described by anatomists, which are present until 3 months of age, do not achieve supraliminar synaptic contacts with parts of areas 17 and 18 other than the 17/18 border zone, at least from 12 days after birth. However the visual callosal transfer in young animals displays some characteristics which disappear with age.

Aging↗

PubMedDate not supplied

Interspecies variation in orbital bone structure of psittaciform birds (with emphasis on Psittacidae).

OBJECTIVE: This text presents an anatomical study of the normal bony orbital structure of a sample of different bird species belonging to the order Psittaciformes. PROCEDURES: The bony anatomy of Psittaciformes' skulls was examined and described using cadavers of birds that were presented already dead to the Federal University of Paraná, Brazil or had been euthanized for humane reasons. Dissections of the orbital cavity were performed under 2-4 x magnification, and descriptions of the orbital bones were made from observations of macerated skulls that had been boiled and cleaned. The present paper discusses the main features of the bony orbit of psittaciform birds, describing known anatomical information but also bringing new information, mainly concerning species differences that might help not only veterinary anatomists but also zoologists, clinicians, researchers, and students of veterinary ophthalmology to better comprehend this order of birds. RESULTS AND CONCLUSIONS: Variations in the anatomic conformation of the bony elements of the orbit were observed in different species of Psittaciformes. Based on these differences, Psittaciformes were classified into two different groups. The first group of Psittaciformes shows an enclosed (complete) bony orbit formed by the junction of the orbital with the postorbital processes, creating a suborbital arch. The second group of Psittaciformes essentially lacked a suborbital arch, presenting an open (incomplete) bony orbit, typical of most modern birds. In the latter group, orbital and postorbital processes are present.

Animals↗

PubMed2005

Bachmann's bundle: does it play a role in atrial fibrillation?

BACKGROUND: Cardiac anatomists have known the presence of a group of specialized fibers connecting the right and left atrium for years. However, only recently have clinical cardiologists come to recognize the potential importance of this specialized conduction system. Anatomical and microscopic studies have shown that the Bachmann's bundle (BB) represents a distinct structure similar to the atrio-ventricular node and the His-Purkinje conduction system but without any insulating tissue. RESULTS: BB cells have specialized electrophysiological properties like supernormal excitability and faster longitudinal conduction that can facilitate more rapid impulse transmission compared to the normal atrial tissue. Experimental blockage of this pathway causes prolongation and widening of the P wave, which is associated with an increased incidence of atrial fibrillation. Atrial pacing is effective in reducing the incidence of atrial fibrillation by preventing bradycardia, synchronizing the atria, limiting anisotropy and reducing the dispersion of refractoriness. Various animal and human studies have shown pacing near the right atrial insertion of BB to have a beneficial effect in patients with interatrial conduction delay and atrial tachyarrhythmias. This mode of atrial septal pacing is convenient, safe, reliable, and clinically as effective as multisite pacing. CONCLUSION: This article is an effort to define the special properties of BB and its possible role in prevention of atrial fibrillation by permanent pacemakers.

Animals↗

PubMed2005

History of Wolff-Parkinson-White syndrome.

While Drs. Wolff, Parkinson, and White fully described the syndrome that bears their names in 1930, prior case reports had already described the essentials. Over the ensuing century this syndrome has captivated the interest of anatomists, clinical cardiologists, and cardiac surgeons. Stanley Kent described lateral muscular connections over the atrioventricular (AV) groove, which he felt were the normal AV connections. The normal AV connections were, however, clearly described by His and Tawara. True right-sided AV connections were initially described by Wood et al., while Ohnell first described left free wall pathways. David Scherf is thought to be the first to describe our current understanding of the pathogenesis of the Wolff-Parkinson-White (WPW) syndrome in terms of a reentrant circuit involving both the AV node--His axis as well as the accessory pathway. This hypothesis was not universally accepted and many theories were applied to explain the clinical findings. The basics of our understandings were established by the brilliant work of Pick, Langendorf, and Katz who by using careful deductive analysis of ECGs were able to define the basic pathophysiological processes. Subsequently, Wellens and Durrer applied invasive electrical stimulation to the heart in order to confirm the pathophysiological processes. Sealy and his colleagues at Duke University Medical Center were the first to successfully surgically divide an accessory pathway and ushered in the modern area for curative therapy for these patients. Morady and Scheinman were the first to successfully ablate an accessory pathway (posteroseptal) using high-energy direct-current shocks. Subsequently, Jackman, Kuck, Morady, and a number of groups proved the remarkable safety and efficiency of catheter ablation for pathways in all locations using radiofrequency energy. More recently, Gallob et al. first described the gene responsible for a familial form of WPW. The current ability to cure patients with WPW is due to the splendid contributions of individuals from diverse disciplines from throughout the world.

Cardiology↗

PubMed2005

The history of AV nodal reentry.

Though patients with AV nodal reentry are now routinely cured by catheter ablation, the basic mechanism of this disorder is still under debate. The putative mechanism of AV node reentry was first discovered by the elegant work of Gordon Moe. He demonstrated the existence of dual pathways and echo beats in rabbits. Building on these seminal observations, the mechanism of AVNRT has burgeoned to include the possibility of left atrial input into the node. The first curative nonpharmacologic procedures involved surgical dissection around the AV node and the procedure was rapidly supplanted by catheter ablation procedures. The initial ablative procedure targeted the fast pathway, but later observations showed that ablation of the slow pathway was more effective and safer. Cure of AV nodal reentry which is the most common cause of paroxysmal supraventricular tachycardia became possible through the cooperative efforts of anatomists, physiologists, surgeons, and clinical electrophysiologists.

Cardiology↗

PubMed2000

How constant anatomically is the tendon of Todaro as a marker for the triangle of Koch?

INTRODUCTION: Although well recognized by anatomists as a border of the triangle of Koch demarcating the location of the AV node, the tendon of Todaro is not visible in the operating room or in the catheterization laboratory. Instead, clinicians use as surrogate a projected line between the eustachian valve and the central fibrous body. The constancy of the tendon of Todaro within this border remains to be determined. MATERIALS AND RESULTS: We reexamined serial histologic sections from 25 adults and 50 infants and gross dissections in four normal hearts. The tendon of Todaro was identified in all cases and traced to the central fibrous body in all but one case. It tended to be thicker in the hearts of infants cases (0.2 to 0.8 mm vs 0.1 to 0.6 mm). The tendon and the hinge-line of the septal leaflet of the tricuspid valve were consistent as landmarks for location of the compact AV node in all the cases studied by histology. Gross dissections traced the tendon to the free edge of the eustachian valve. CONCLUSION: The tendon of Todaro is present in hearts obtained from both adults and infants. It, or its surrogate, is a reliable border for the triangle of Koch and serves as a landmark to location of the atrial components of the AV conduction axis.

Adolescent↗

PubMed1995

Mechanisms of AV node modulation in AV node reentry tachycardia.

Atrioventricular nodal reentrant tachycardia has been recognized for many years as a very common cause of supraventricular tachycardia. First curable by surgery, this tachycardia is now successfully approached by selective radiofrequency current application to the slow pathway of the reentrant circuit. Importantly, these curative treatments brought evidence that the reentrant circuit of this arrhythmia was not confined to the compact atrioventricular (AV) node. These findings stimulate anatomists and basic and clinical electrophysiologists to fundamentally reconsider the atrioventricular junction in order to better understand the mysteries of atrioventricular junctional reentrant tachycardia, as we still do not know exactly what we are doing in AV node region procedures. This article will focus on the different hypotheses regarding the effect of selective slow AV pathway ablation in AV junctional reentrant tachycardia.

Atrioventricular Node↗

PubMed2006

William Osler: slow pulse, stokes-adams disease, and sudden death in families.

In 1903, William Osler, then at Johns Hopkins University, published "On the So-Called Stokes-Adams Disease (Slow Pulse with Syncopal Attacks, etc.)" in The Lancet, classifying a syndrome in evolution. There are thinly disguised references to a brother and to himself in the article, suggesting that Osler was concerned about a family and personal predisposition. Osler's decision to move to Oxford was triggered in part by his personal concerns about cardiac disease. Then, in 1909, Osler contributed a chapter on Stokes-Adams disease to Allbutt and Rolleston's A System of Medicine, complemented by a brilliant pathologic section by the renowned anatomist-morphologist, Arthur Keith. Osler's original contributions involved his emphasis on the importance of family history, his careful clinical and natural history observations, and his recognition of the familial occurrence of bradycardia, Stokes-Adams disease, sudden death, and cardiomyopathy.

Adams-Stokes Syndrome↗

PubMed2004

Pacinian corpuscle in the juxtaoral organ of Chievitz.

The juxtaoral organ of Chievitz (JOOC) is a normal permanent anatomical structure located within the soft tissue overlying the angle of the mandible in the buccotemporal space. Although the sensory organ nature of JOOC, repeatedly mentioned in German publications, has been neglected in the last decade by the American anatomists and pathologists, we incidentally found JOOC-type squamous epithelium accompanied by Pacinian corpuscles. This fortuitous finding appears to be the first report of the authentic Paciniform nerve endings within JOOC, supporting its mechanosensory function.

Adult↗

PubMed2003

Andreas Vesalius (1514-1564), Padua, and the fetal "shunts".

Three remarkable medical anatomists working in Padua during the 16th century described the anatomy of the fetal cardiovascular system, thus laying the foundation for William Harvey's discovery and description of the fetal circulation in the following century.

Embryology↗