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At least 487 records · Page 27Linked to original sources
PubMed1992

Anatomical variations of the median nerve at the wrist.

A comprehensive review of reported median-nerve variations at the wrist is presented. This includes motor-branch anomalies, multiple divisions of the median nerve, neural loops, and variations in association with aberrant muscles. Inadvertent injury to the median nerve during carpal tunnel surgery can be minimized if the anatomy is understood, variations are recognized, and adequate exposure is achieved.

Hand↗
PubMed2004

Anatomic variations of the root canal of the rat according to age.

The mesial canal of the first lower molar of the rat has been used as an experimental model in Endodontics. The present study involves a detailed analysis of its structural variations as a function of age and thus contributes to its characterization and adequate use as an experimental model. We evaluated 60 molars of Wistar rats of different body weight: (group 1: 300-399 g, n=22; group 2: 400-499 g, n=16; group 3: 600-700 g, n=22). The samples were radiographed employing a standardized system. Total canal length and volume were measured on enlarged projections of the radiographs. Canal diameter was measured at coronary, middle and apical levels and employed to estimate the area of canal cross-section as an indicator of potential flow or metabolic interchange. From the second age group onwards, we detected radicular hypercementosis that increased canal length and resulted in the formation of a complex apical delta. The canal diameter decreased very significantly in the apical third. The estimated flow expressed in terms of the area of cross-section on the projection decreased from 1.2 mm2 in Group 1 to 0.05 mm2 in Group 2. Group 3 did not differ significantly from Group 2. The present results reveal that the spontaneous, age-related variations in canal anatomy described herein must be considered when performing experimental endodontics in rats.

Aging↗
PubMed2005

Anatomical variations of the superficial and deep palmar arches.

The use of radial arteries as an arterial bypass conduit is an invasive procedure which is becoming popular among various medical centres. The greatest risk associated with harvesting the radial artery is ischaemia of the soft tissues of the hand. In this study we dissected 200 hands derived from 100 formalin-fixed cadavers in order to identify arterial patterns that will allow safe removal of the radial artery for use in bypass procedures. A complete superficial palmar arch (SPA) was found in 90% of the cases and divided into 5 types, while the remaining 10% possessed an incomplete palmar arch. Types of SPA are designated by the letter S. In type S-I (40%), the SPA is formed by anastomosis of the superficial volar branch of the radial artery to the ulnar artery. Type S-II (35%) is formed entirely of the ulnar artery. Type S-III (15%) is formed by anastomosis of the ulnar and median arteries. Type S-IV (6%) is formed by anastomosis of the ulnar, radial, and median arteries and Type S-V (4%) is formed by a branch of the deep palmar arch (DPA) communicating with the SPA.DPA was identified in all specimens and classified into three types, all designated by the letter D. Type D-I (60%) is formed by anastomosis of the deep volar branch of the radial artery and the inferior deep branch of the ulnar branch. Type D-II (30%) is formed by anastomosis of the deep volar branch of the radial artery and the superior deep branch of the ulnar artery. Type D-III (10%) is formed by anastomosis of the deep volar branch of the radial artery with both deep branches of the ulnar artery. This data could provide an important source of information for vascular surgeons harvesting radial arteries.

Aged↗
PubMed2005

Anatomical variations in the branches of the human aortic arch: a recent study of a South Australian population.

Variations of the branches of the aortic arch are likely to occur as a result of the altered development of certain branchial arch arteries during the embryonic period of gestation. In the present investigation the pattern of branches of the aortic arch was studied in 81 cadavers from a recent South Australian population of European descent, who have migrated to (n = 38) or were born and lived in (n = 43) South Australia during the twentieth century. Two principal variations were noted in the present study. Firstly, in 6 cadavers, the left vertebral artery originated directly from the arch of the aorta, between the left common carotid and the left subclavian arteries. The 6 subjects were among the subgroup born in South Australia, giving an incidence of 13.95%, which is much higher than in previous reports. The overall incidence of 7.41%, when related to the whole group, is also higher than incidences reported in other populations. The presence of this variation suggests that in some individuals part of the aortic arch is formed from the left 7(th) inter-segmental artery. Secondly, none of the cadavers examined had the thyroidea ima artery, contrasting with previously reported incidences that varied between 4% and 10%. Since all 6 cadavers with the left vertebral artery variant were born in South Australia, it is suggested that environmental factors may have contributed to this variation. Significant environmental changes in South Australia around the turn of the twentieth century are discussed. This study represents the first systematic investigation of the branches of the aortic arch in a South Australian population and provides data relevant to the practice of medicine.

Aorta, Thoracic↗
PubMed1992

Anatomic variations of the nasolabial fold.

The nasolabial fold varies considerably from person to person. Three main groups may be distinguished: convex, concave, and straight. It is the muscles of smiling that are directly responsible for the shape and depth of the fold, and in their absence of function, as in facial palsy, the nasolabial fold disappears. Cadavers were selected in accordance with the nasolabial fold they presented and were dissected to analyze the difference in underlying anatomy between one fold shape in one cadaver and another fold shape in another. The study demonstrates that the nasolabial fold is the result of a conflict between soft and dynamic tissues of the middle face or an interaction between the skin and fat envelope on one side and the underlying muscles on the other. The greater this conflict, the more excess there is of cheek skin and the more pronounced a nasolabial fold. The mechanism that creates the nasolabial fold and the anatomy of the fold are described in this paper.

Cadaver↗
PubMed1991

Anatomic variations and anomalies involving the facial canal.

Congenital bony dehiscences in the facial canal result from incomplete closure during development and are observed in approximately 55% of temporal bones. Anomalies involving the facial canal frequently are encountered in malformations of the temporal bone. These anomalies include aberrations of the course of one or all of the segments of the canal; abnormal relation to the oval and round window; bifurcations and trifurcations of the nerve; and associations with dysplasia of the stapes, oval window, external ear canal, and auricle. Rarely, the facial nerve may be hypoplastic or totally absent. Two abnormal vessels occasionally may accompany the facial nerve in the Fallopian canal: a persistent stapedial artery and a persistent lateral capital vein.

Chorda Tympani Nerve↗
PubMed1991

[Anatomic variations in the course of the left hepatic artery. A problem for systematic lymphadenectomy in gastrectomy or proximal stomach resection before stomach tube formation].

In 21 patients resected for gastric or esophageal malignancy an aberrant left hepatic artery from the left gastric artery was found. The study shows that in systematic lymphadenectomy ligation of the left gastric artery distally from the origin can safely preserve an aberrant hepatic artery without impairment of oncological quality. Related to a control group no difference in the number of resected lymph-nodes and the operation time was observed. Postoperatively there was no problem concerning liver function and surgical morbidity. In real-time sonography the aberrant artery could be postoperatively seen precisely in 19%, but duplex signal was found in 63%. Limited visualization in sonography may be caused by technical problems due to anatomy and overlying air from small-bowel reconstruction after gastrectomy.

Aged↗