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PubMed1993

Retrogastric colon: CT demonstration of anatomic variations.

In a series of 9,400 body computed tomographic (CT) scans of adult patients, a retrogastric course of the transverse colon with interposition of colon between the pancreatic body-tail and stomach was identified in 18 patients (0.2%). Three other patients (0.03%) had retrosplenic, retrogastric colon with transverse colon interposed between the spleen and posterior diaphragm. Three of the 18 patients with pancreaticogastric interposition also had small bowel malrotation. Clinically, no symptoms attributable to retrogastric colon were found. Retrogastric colons probably result from mild embryologic abnormalities of bowel rotation and fixation. Radiologically, colon in the area of the lesser sac must be differentiated from the normal duodenojejunal flexure, a perforated viscus, and abscess.

Adult↗
PubMed1996

Anatomic variation of extrahepatic biliary tree structures: importance in treatment planning for radiation therapy.

PURPOSE: To demonstrate the variable location of biliary tree components and to assess two treatment planning rules of thumb used for locating porta hepatic nodes for radiation therapy. MATERIALS AND METHODS: The distance of the common hepatic duct bifurcation and duodenal papilla from adjacent vertebral bodies was measured on 34 cholangiograms, and their relationships to particular vertebral body levels were recorded. Adequacy of treatment volume to encompass porta hepatic lymph nodes was evaluated in 30 of these cholangiograms by constructing radiation portals according to the two rules of thumb. RESULTS: Location of the common hepatic duct bifurcation and duodenal papilla varied widely. The treatment portal encompassed 13% (four of 30) of cases when the first rule of thumb was used and 80% (24 of 30) of cases when the second rule of thumb was used. CONCLUSION: The wide variability of location of extrahepatic biliary tree structures suggests the need for individualized treatment planning so that sensitive and dose-limiting healthy tissues can be optimally excluded from radiation treatment portals. Computed tomography and other imaging modalities enable precise location of biliary tree components for radiation treatment planning.

Ampulla of Vater↗
PubMed1999

Anterior chest wall: frequency of anatomic variations in children.

PURPOSE: To evaluate the frequency of anterior chest wall variations in children. MATERIALS AND METHODS: The computed tomographic (CT) images of 200 consecutive infants and children (114 boys and 86 girls; mean age, 10.5 years; age range, 3 months to 19 years) who underwent chest CT during a 20-month period were evaluated for chest wall variations. Children who had undergone chest wall surgery or were suspected of having a chest wall abnormality were excluded. The frequency of chest wall anomalies was compared with age and sex (Fisher exact test). RESULTS: The CT scans of 65 children (33%) depicted one or more variations in the anterior chest wall: titled sternum (n = 29), prominent convexity of anterior rib or costal cartilage (n = 19), prominent asymmetric costal cartilage (n = 20), well-defined paracostal subcutaneous nodule (n = 4), mild pectus excavatum (n = 4), or mild pectus carinatum (n = 4). The frequency of these findings did not vary significantly with age (P = .96) or sex (P = .36). CONCLUSION: Variations in the anterior chest wall are common, occurring in one-third of children, and should be considered normal. These asymptomatic variations should not be considered alarming when palpated at physical examination.

Adolescent↗
PubMed1981

Anatomic variations of efferent duct from caudal mediastinal lymph node in sheep.

Collection of lymph from the efferent duct of the caudal mediastinal node in sheep is accepted as a reliable method for following lung microvascular fluid and protein filtration. There are significant variations in the efferent duct anatomy, which can complicate the cannulation procedure and, therefore, the success of the preparations. We analyzed the major variations in the efferent duct in 75 consecutive sheep. The majority (59%) had a single efferent duct varying in length, course, and origin fom the caudal mediastinal node; 41% had multiple ducts, often with confluences or bifurcations, making successful cannulation more difficult. It is important to recognize the potential variations in the efferent duct to facilitate useful cannulation.

Animals↗
PubMed2006

Anatomic variations in the circle of Willis in patients with symptomatic carotid artery stenosis assessed with multidetector row CT angiography.

PURPOSE: To assess the presence of anterior and posterior collateral pathways in the circle of Willis in patients with symptomatic carotid artery stenosis (SCAS) and to compare this to patients without carotid artery stenosis. MATERIALS AND METHODS: Multislice CT angiography was performed in 91 patients and 91 control subjects. Using consensus reading, 2 observers evaluated the presence and diameter of the anterior communicating artery (AcomA), the A1 segments of the anterior cerebral arteries, the posterior communicating arteries (PcomA) and the P1 segments of the posterior cerebral arteries. Anterior or posterior pathways were assumed to be present if the diameter of continuous arterial segments was >1 mm; both A1 segments and AcomA anterior, and ipsilateral P1 segment and PcomA posterior. Comparison between patients and controls was performed using the chi(2) test. RESULTS: In the patients we found significantly more hypoplastic (<1 mm) or invisible A1 segments (16 and 14 vs. 4 and 1, respectively, p < 0.01). The AcomA was invisible in 4 patients versus 1 control. An isolated compromised anterior pathway and a combined compromised anterior and posterior pathway occurred more frequently in the patients as compared to the controls; 9 versus 1% (p < 0.01) and 26 versus 4% (p < 0.01). CONCLUSION: A compromised anterior collateral pathway, usually combined with a compromised posterior pathway, occurs more frequently in patients with SCAS as compared to controls, which suggests a relation between symptomatic carotid stenosis and an incomplete circle of Willis.

Adult↗
PubMed1993

Anatomic variation of the middle cerebral artery in the Sprague-Dawley rat.

BACKGROUND AND PURPOSE: The aim of this study was to record and analyze the anatomy of the middle cerebral artery in the rat in an attempt to identify a potential source of variation of quantitative infarct measurements in commonly used models of focal cerebral ischemia. METHODS: Over a period of 22 months, as part of ongoing studies, we routinely induced focal cerebral ischemia in 263 Sprague-Dawley rats. This was achieved by permanent occlusion of a length of the right middle cerebral artery approximately 1 to 5 mm distal to the point at which it traverses the rhinal fissure combined with 60 minutes of bilateral common carotid occlusion. The branching pattern of the middle cerebral artery was recorded for each animal by drawing and photography before occlusion and at the time of death. RESULTS: Six distinct branching patterns were observed. The majority (82.9%) of middle cerebral arteries studied conformed to the typical bifurcating vessel commonly referred to in the literature. However, the remaining 17.1% were far more variable with major, atypical branching, introducing, we believe, unnecessary and avoidable variation into quantitative measurements of ischemia in this and similar models. CONCLUSIONS: Middle cerebral artery anatomy should be routinely recorded in models of focal cerebral ischemia in which this artery is occluded distal to the olfactory tract, thus allowing improved analysis of data.

Animals↗
PubMed1981

Pathologic anatomic variations in the sesamoids.

This paper reviews 26 patients who presented with disorders of one or both sesamoids of the foot. There is a high association between long-distance running and chondromalacia or stress fractures in these bones. Thirty-eight per cent of these patients had variations in the anatomy at this articulation, including asymmetry in sesamoid size, symmetrical sesamoid enlargement, metatarsal condylar hypoplasia, and metatarsal rotational abnormalities.

Athletic Injuries↗
PubMed1993

Digital nerves of the foot: anatomic variations and implications regarding the pathogenesis of interdigital neuroma.

Seventy-one cadaveric feet were dissected, with attention to communicating branches of the digital nerves, the diameters of the digital nerves, the distance between the metatarsal heads, and the presence or absence of interdigital neuromas. A communicating branch was absent in 52 feet (73.2%) and present in 19 specimens (26.8%). The communication was from the fourth to the third web space common digital nerve (i.e., from the lateral to the medial plantar nerve) in 11 specimens. A reverse communication, from the third to the fourth web space common digital nerve (i.e., from the medial to the lateral plantar nerve), was present in eight specimens. Neuromas were identified in the second web space in 26 specimens and in the third web space in 32 feet. The common digital nerve to the third web space was not thicker in feet with a contribution from the fourth to the third web space nerve. Additionally, the incidence of third web space neuroma in feet with this type of communication was not significantly greater than in those feet without an internervous communication. However, the intermetatarsal head distances and the ratios of the intermetatarsal head distance to the digital nerve diameter in web spaces 2 and 3 were significantly smaller in comparison to spaces 1 and 4 (P < .05). The morphometric data lend support to theories that explain the propensity for neuroma formation in both the second and third web spaces on a mechanical basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1997

Pathologic anatomic variations in subtalar anatomy.

Thirteen patients presenting with symptomatic pathologic variations or congenital deformities of the subtalar joint are presented. These variations included: four abnormal posterior talar processes, five patients with asymmetric subtalar joint development, and four congenital complete subtalar coalitions with a secondary ball-and-socket joint. In each case these adult patients had been unaware of the variation and had been symptom free until "awakening" sprain or fracture trauma brought about symptoms. The nonoperative and operative management of these variations is reviewed.

Adult↗
PubMed2004

Anatomical variations in termination of the axillary artery and its clinical implications.

Variations in the termination of the axillary artery (AA) were observed in 51 out of 356 axilla during routine dissections. The incidence of variation was higher on the right axilla in 17.42% cases (CI: 11.60-22.51) than the left axilla 11.24% cases (CI: 6.46-15.55) and was found to be 12.33% in male and 40.63% in female cadavers. The variations were divided into four groups. The first group showed that the terminal end of the AA divided into lateral and medial divisions in 6.16% (CI: 2.21-9.82) male and in 15.63% (CI: 2.76-25.25) female cadavers. The second group variation showed that the terminal end of the axillary artery divided into deep and superficial divisions in 2.74% (CI: 0.10-5.27) male and in 6.25% (CI: -1.87-13.13) female cadavers. The third group showed that the terminal end of the AA divided into three branches in 2.74% (CI: 0.10-5.27) male and in 6.25% (CI: -1.87-13.13) female cadavers. The fourth group showed the tapering of the terminal end of AA in 0.68% (CI: -0.63-1.99) male and 12.50% (CI: 0.97-21.46) female cadavers. The variable origin of the circumflex humeral, subscapular and profunda brachii arteries was also observed. These variations in the terminal end of the axillary artery are not only of significant clinical importance to orthopaedic and reconstructive surgeons but also have very significant medico-legal implications.

Axilla↗
PubMed1985

Real time ultrasonic evaluation of the paediatric abdomen: technique and anatomical variations. A personal view.

Most of the paediatric abdomen can be evaluated ultrasonically by a real-time subcostal approach. A basic technique is given using four standard sites. The anatomy that is visualised at these sites is described in simple detail. The major differences between adults and children are listed. Problems of recognition between normal and paediatric variations are commented on, and size measurements of various organs at different ages are tabulated.

Abdomen↗