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PubMed1999

Anatomic variation of the extensor tendons to the ring and little fingers: a cadaver dissection study.

We found an anatomic variation of the extensor digiti minimi (EDM) and extensor digitorum communis (EDC) in a cadaveric dissection. The EDM had three tendon slips; two slips to the little finger and one to the ring finger metacarpophalangeal (MP) joint. The ring finger slip inserted in the extensor hood with the EDC. The EDC had a separate tendon to the little finger extensor hood. The EDM had an additional pulley distal to the extensor retinaculum. The MP joints of the little and ring fingers extended simultaneously upon pulling the EDM or the EDC. The third slip of the EDM could provide an extra donor site and possibly poses a unique clinical presentation.

Aged↗
PubMed2005

Anatomic variations of the hook of hamate and the relationship to carpal tunnel syndrome.

PURPOSE: To determine the incidence of anatomic variations of the hook of hamate and to evaluate its association with the development of carpal tunnel syndrome (CTS). METHODS: Radiographs of 3,218 hands (2,070 patients) were evaluated. This group included 2,866 hands diagnosed with CTS and 352 hands without the diagnosis of CTS. Using the carpal tunnel view variations of the hook of hamate were identified. Variants were classified based on appearance and measurements. Patients having variant hooks of hamate who were diagnosed with CTS then were compared with patients with variant hooks of hamate who had no evidence of CTS. Endoscopic carpal tunnel release using the Chow technique was performed on all patients with CTS who had a known variation of the hook of hamate without difficulty or complication. RESULTS: Variations of the hook of hamate were found in 96 hands: 42, bipartite hook; 50, hypoplastic hook; and 4, aplastic hook. Ninety-three hands with variant hooks of hamate were diagnosed with CTS. The remaining 3 hands identified with variants had no evidence of CTS. After comparing the 2 groups, we found that the incidence of a variant hook of hamate in the group with CTS was significantly greater than the incidence of variations in the group without CTS. CONCLUSIONS: Three variations of the hook of hamate were identified with radiographic evaluation using the carpal tunnel view. Variations are more prevalent than once thought. There was a significant increase in the incidence of variation in the hook of hamate in the group with CTS compared with the group without CTS.

Adolescent↗
PubMed1997

Anatomical variations in the dentition of the domestic cat.

Skulls (n = 155) of adult domestic cats were examined macroscopically and anatomical variations were documented. The maxillary second premolar tooth was absent in 7.9% of cases, and was found to have a single root in 27.7%, partly fused roots in 55.1% and two fully formed roots in 9.2% of cases. The maxillary first molar tooth was absent in 2.3% of cases; a single root was present in 35.0%, a partly fused root in 34.7%, and two roots in 28.0% of cases. Supernumerary roots were found on the maxillary third premolar teeth in 10.3% of cases. Other variations were found to be extremely rare.

Animals↗
PubMed1981

[Anatomical variations of the nervus alveolaris inferior and their importance for the practice (author's transl)].

The authors have studied the anatomic variations of the inferior alveolar nerve (N. alveolaris inferior) in 18 human heads. The mandibular nerve being free by medial abord. At about half of the studied cases the M. pterygoideus medialis presents a widened insertion extending on the posterior border of the Ramus mandibulae. Before entering into the mandibular channel the inferior alveolar nerve separated from the next elements by expansion of "aponévrose interptérygoidienne". At this level gets sympathic branches from the plexus caroticus externus et internus, making a plexiform structure interfering sometimes a vegetative ganglion formation. At 16.6% of the cases between the alveolar inferior nerve and the lingual nerve are established connection bridges more or less developed. They have an asymetric aspect. There were observed evident connections between the inferior alveolar nerve and the auriculotemporal nerve taking a mono- or pluriradicular form. The mylohyoidian nerve on his homonymous way gives 2--3 sensitive, or vegetative branches to the bone. Practically speaking are important the branches coming from the precanalicular portion of n. alveolaris inferior perforating the periost and penetrating independently in to mandibula through separated vents. These results are practically useful in Stomatological technique explaining from an anatomically point of view the inefficiency of mandibular anaesthesia in some cases although it is correctly applied.

Humans↗
PubMed2001

Anatomical variations of the extrahepatic biliary tree: review of the world literature.

The anatomy facing a surgeon during cholecystectomy involves complex relationships between the hepatic artery, extrahepatic biliary tree, and gallbladder. A sound knowledge of the normal anatomy of the extrahepatic biliary tract is thus essential in the prevention of operative injury to it. Equally important, however, is an understanding of congenital variation of biliary and vascular anatomy, as the literature abounds with reports of specific anatomical variations, and their operative implications. This article reviews the world literature on congenital variation of extrahepatic biliary anatomy.

Bile Ducts↗
PubMed1998

Anatomical variation of cerebral venous drainage: the theoretical effect on jugular bulb blood samples.

Recent studies have demonstrated significant variation in bilateral jugular venous oxygen saturation measurements which may be of clinical significance. We have therefore measured variations in normal dural sinus venous drainage to assess the possible effects of normal anatomical variations on measured jugular venous oxygen saturation. Normal volunteers (n = 25) were imaged using magnetic resonance venography to demonstrate variations in venous anatomy. Flow was measured in the superior sagittal sinus and bilaterally in the transverse sinus, sigmoid sinus proximal to the jugular bulb and proximal jugular vein using phase difference magnetic resonance imaging. Examination of magnetic resonance venogram images showed considerable variability in the symmetry of transverse sinus flow. Complete absence of one transverse sinus was seen in four cases and significant asymmetry in the size of the transverse sinuses was present in 13. Quantitative flow studies demonstrated that the ratio of superior sagittal sinus to combined jugular bulb flow showed remarkably little variation (0.46 +/- 0.06). Measurements of transverse sinus flow showed significant asymmetry (< 40% of superior sagittal sinus flow in one transverse sinus) in 21 of 25 volunteers. The effect of the observed asymmetry on jugular venous oxygen saturation was modelled based on the assumption of either a supratentorial or infratentorial lesion. This model predicted significant asymmetry in jugular venous oxygen saturation measurements (> 10%) in 65% of cases with a supratentorial lesion which is in close agreement with clinical observations. This study suggests that normal variations in venous drainage may account for observed asymmetry in jugular venous oxygen saturation measurements.

Adult↗
PubMed2005

Anatomical variations as potential risk factors for ulnar tunnel syndrome: a cadaveric study.

The aim of this study was to assess the anatomical variations, especially the anomalous muscles passing through Guyon's canal and the fibrous arch forming the piso-hamate hiatus, which may play a role in ulnar tunnel syndrome. We have also focused on the relation of these structures with specific concern to the ulnar nerve. Nineteen embalmed cadavers (37 hands and forearms) were dissected. A fibrous arch extending between the pisiform and the hook of the hamate was observed in 21 hands. In majority of the cases flexor digiti minimi muscle was found to originate only from this arch. An anomalous muscle was disclosed in six hands with four of them passing through the piso-hamate hiatus with the deep branch of the ulnar nerve. In two of four cases, the superficial branch of the ulnar nerve was also accompanying the deep branch of the ulnar nerve beneath the anomalous muscle and through the piso-hamate hiatus. Because these anomalous muscles were generally found to course through the piso-hamate hiatus with the branches of the ulnar nerve, we conclude that the distal portion of the Guyon's canal has a relatively higher risk for ulnar nerve entrapment. We believe that surgeons operating on this region should take into account these various anatomic structures.

Cadaver↗
PubMedDate not supplied

Anatomical variation of maxillary sinus mimicking a periapical cyst: a case report.

Maxillary sinus can pose diagnostic dilemma radiographically because of its anatomical variation which can mimic a periapical pathosis. This case report deals with one such diagnostic problem, where a maxillary sinus was interpreted in an intraoral periapical radiograph as a periapical cyst. With the advances in imaging techniques, the use of an Ultrasound imaging together with application of Colour Power Doppler helped in revealing the contents of the radiolucent area and come up with an accurate diagnosis. Thus a thorough knowledge about the normal anatomy and its variations and proper diagnostic aids are essential in the diagnosis of periapical pathology.

Adult↗
PubMed2006

A neurosurgical view of anatomical variations of the distal anterior cerebral artery: an anatomical study.

OBJECT: The vascularization pattern of the anatomy of the distal anterior cerebral artery (ACA) remains a subject of debate. The authors provide detailed information about the distal ACA and shed light on issues concerning it that have not previously been adequately discussed. METHODS: Fifty adult human brains (100 hemispheres) were obtained during routine autopsies. Cerebral arteries were separately cannulated and injected with latex. The vascularization patterns of the cortical branches and the variations of the arteries were investigated. The authors found that the distal ACA supplied all the inner surfaces of the frontal and parietal lobes and a median of one third of the outer surfaces. The origin of the arteries from the main trunk and their exit angles affected the vascularization patterns of the hemispheres. The authors redefine controversial terminology regarding the callosomarginal artery. CONCLUSIONS: In each hemisphere, the vascularization pattern of the distal ACA is different to a greater or lesser extent. An awareness of this fact will contribute significantly to surgical interventions.

Anterior Cerebral Artery↗
PubMedDate not supplied

Effects of anatomical variations of the nasal cavity on acoustic rhinometry measurements: a model study.

BACKGROUND: The goal of this study was to assess how anatomic variations of the nasal cavity affect the accuracy of acoustic rhinometry (AR) measurements. METHODS: A cast model of a human nasal cavity was used to investigate the effects of the nasal valve and paranasal sinuses on AR measurements. A luminal impression of a cadaver nasal cavity was made, and a cast model was created from this impression. To simulate the nasal valve, inserts of varying inner diameter were placed in the model nasal passage. To simulate the paranasal sinuses, side branches with varying neck diameters and cavity volumes were attached to the model. RESULTS: The AR measurements of the anterior nasal passage were reasonably precise when the passage area of the insert was within the normal range. When the passage area of the insert was reduced, AR measurements significantly underestimated the cross-sectional areas beyond the insert. The volume of the paranasal sinus had limited effect on AR measurements when the sinus ostium was small. However, when the ostium size was large, increasing the volume of the sinus led to significant overestimation of AR-derived areas beyond the ostium. CONCLUSION: The pathologies that narrow the anterior nasal passage result in the most significant AR error by causing area underestimation beyond the constriction. It also appears that increased paranasal sinus volume causes overestimation of areas posterior to the sinus ostium when the ostium size is large. If these physical effects are not considered, the results obtained during clinical examination with AR may be misinterpreted.

Computer Simulation↗
PubMed2004

[Inferior orbital fissure and groove: axial CT findings and their anatomic variation].

OBJECTIVE: To show imaging findings of inferior orbital fissure (IOF) and groove (IOG) on axial CT scans and to discover their anatomic variations, so as to avoid misdiagnosing them as orbital fracture. METHODS: 25 normal skull were used to investigate the configurations of IOF and IOG. Five skulls were performed axial CT scans. 20 normal orbital axial scans were studied as well. MPR and RT-3D reconstructions were used in this study. RESULTS: Skulls scans and normal orbital images on axial CT showed three sorts of findings: (1) single bony dehiscence between lateral and inferior walls; (2) first type of double bony dehiscence between lateral and inferior walls, among the dehiscence interposing a small bone. The long axis of the small bone was parallel to orbital wall; (3) second type of double bony dehiscence between lateral and inferior walls, but the long axis of the small bone was in anteroposterior direction. Anatomy and variation of three sorts of CT findings were corresponded respectively to: (1) a baseball club-shaped IOF; (2) a "V"-shaped IOF, that is composed of both of lateral and internal ramus, lateral ramus situates between the zygoma and the lateral portion of greater wing of sphenoid, and internal ramus between the maxilla and the internal portion of greater wing of sphenoid, both rami intercross caudally and open upwards in a "V"-shaped configuration; (3) a deep IOG with a protuberant lateral wall. CONCLUSION: Familiarity of imaging features on the axial CT scans and understanding of their anatomy of IOF and IOG would be helpful for avoiding misdiagnosis of orbital fracture.

Cadaver↗
PubMed1998

[The role of transesophageal echocardiography in the detection of coronary anomalies and anatomical variations].

OBJECTIVES: The aim of the study is to examine the role of transesophageal echocardiography (TEE) in the diagnosis of anomalies and anatomic variations of the coronary arteries. BACKGROUND: In the past, coronary angiography was the only method for diagnostic confirmation in all cases with coronary anomalies, but even during invasive procedures diagnostic difficulties could and can emerge. The different, varying origin of aberrant coronary arteries can prolong the diagnostic procedure, therefore can increase the irradiation time. So every method which seems to be suitable for diagnosis of suspected coronary anomalies can be helpful. METHODS: The origin and course of anomalous coronary arteries were studied by TEE and coronary angiography during a six-month period. RESULTS: We found 16 patients (2.8%) with coronary anomalies or variations by angiography, the diagnosis of which was technically difficult. Seven of these had TEE examination too. All seven anomalous origins proven angiographically and 2 of the 2 anomalous courses in the relation to the great vessels were diagnosed by TEE. (In two, the left circumflex originated from the right sinus of Valsalva, in two we found anomalous separate origin of left circumflex coronary artery from the left sinus, in another two a common ostium of the left anterior descending and circumflex artery from the left sinus and in one an accessory artery from the non-coronary sinus.) CONCLUSIONS: TEE in a useful test to diagnose the origin of anomalous coronary arteries and confirming their course in relation to the great arteries.

Coronary Disease↗
PubMed1998

Interpretation of anatomic variations of computed tomography scans of the sinuses: a surgeon's perspective.

Four hundred computed tomography (CT) scans of patients undergoing endoscopic sinus surgery were studied with particular attention to anatomic variations. Six specific variations were identified that may predispose the surgeon to inadvertent penetration of the orbit or anterior cranial cavity. These anatomic variants are: 1. lamina papyracea lies medial to the maxillary sinus ostium; 2. maxillary sinus hypoplasia; 3. fovea ethmoidalis abnormalities, such as low or sloping fovea and encephaloceles; 4. lamina papyracea dehiscence resulting in herniation of orbital content into the ethmoids; 5. sphenoid sinus wall variations such as septa attached to the carotid covering, and penetration of the sphenoid by the internal carotid artery or optic nerve; 6. sphenoethmoid cells (Onodi cells), the most posterior ethmoid cells pneumatizing lateral and superior to the sphenoid and intimately associated with the optic nerve.

General Surgery↗
PubMed2001

Anatomical variations of internal jugular vein as seen by "Site Rite II" ultrasound machine--an initial experience in Pakistani population.

OBJECTIVE: To determine the anatomical variations of the internal jugular vein (IJV) in Pakistani adult population with the help of Site Rite II ultrasound machine. MATERIAL AND METHOD: The right IJV relation to the carotid artery was visualized at four different landmarks (angle of the mandible, thyroid cartilage, cricoid cartilage, and the supraclavicular area). Size of IJV in comparison to carotid artery was also seen. RESULTS: In 49 cases the IJV was found in aberrant relation to carotid artery at the angle of the mandible (p value < 0.05), 22 at the thyroid cartilage, 20 at the cricoid cartilage, and 46 at the supraclavicular area (p value < 0.05). In 93% of cases the IJV was found to be larger than the carotid artery. CONCLUSION: Care should be taken while cannulating IJV at the angle of the mandible and supra clavicular area by external landmark guided technique. Ultrasound guided technique should be used in every anticipated difficult case.

Adolescent↗
PubMed1983

Anatomical variations in hiatal and upper gastric areas and their relationship to difficulties experienced in operations for reflux esophagitis.

We have seen a number of patients whose initial operations for reflux esophagitis or hiatal hernia or both have failed. During the course of reoperation, the authors have been impressed that anatomic variation contributed to these failures. Therefore, a formal anatomic study was undertaken in 36 fresh cadavers without hiatal hernias or factors pertinent to operative maneuvers. The data from this study suggest that 1) mobilization of the left lobe of the liver is difficult in 30% of normal specimens; 2) the hiatal crura are very thin in early half of the specimens; 3) a "tethering ligament" (the gastrolienal ligament) between fundus and superior pole of the spleen is present in half of the specimens, but there is ample space (7-8 cm) "above" the highest short gastric artery; 4) the angle of His is highly variable in normal subjects; 5) the bare area of the stomach requires deliberate exposure and division in more than half of the subjects to obtain a wrap without tension; 6) the posterior gastric vessels can be a hazard in such mobilization. Attention to these matters should enhance the safety and success of transabdominal operation for reflux esophagitis.

Esophagitis, Peptic↗
PubMed2006

An aberrant anatomic variation along the course of the ulnar nerve above the elbow with coexistent cubital tunnel syndrome.

We report on a patient with an unusual anatomic variation along the course of ulnar nerve above the elbow who had cubital tunnel syndrome. The variation consisted of a cutaneous neural branch that was originating at a distance of approximately 40 mm proximal to the medial epicondyle, and from the radial aspect of the main trunk of ulnar nerve. The branch had a superficial course and it was passing distally, anterior to the medial epicondyle without penetrating the fascia of the flexor muscles origin. Anterior intramuscular transposition of the ulnar nerve was performed leaving the newly found branch over the fascia between the muscles and the adipose subcutaneous tissue.

Cubital Tunnel Syndrome↗