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PubMed2000

Evaluation of bifid median nerve with sonography and MR imaging.

Bifid median nerve is an anatomic variation that may be associated with carpal tunnel syndrome. It is important for the surgeon to be aware of the existence of this condition preoperatively in order to plan the carpal tunnel release. We report the correlation between ultrasonographic findings and magnetic resonance imaging results in six patients with bifid median nerve, selected from a population of 294 patients with carpal tunnel syndrome, who were studied by ultrasonography using a high frequency transducer. Sonography showed two structures inside the carpal tunnel with the same pattern as the median nerve in all six patients. Magnetic resonance imaging confirmed the sonographic findings. The patients underwent open surgery, and a bifid median nerve was found. In conclusion, bifid median nerve is an anatomic variant that can be demonstrated ultrasonographically. It is important to be aware of this anomaly when planning carpal tunnel release surgery.

Adolescent↗

PubMed1997

Liver of the "visible man".

Endoscopic surgery, also called minimally invasive surgery, is presumed drastically to reduce postoperative morbidity and thus to offer both human and economic benefits. For the surgeon, however, this approach leads to a number of gestural challenges that require extensive training to be mastered. In order to replace experimentation on animals and patients, we developed a simulator for endoscopic surgery. To achieve this goal, a first step was to develop a working prototype, a "standard patient," on which the informatic and microengineering tools could be validated. We used the visible man dataset for this purpose. The external shape of the visible man's liver, his biliary passages, and his extrahepatic portal system turned out to be fully within the standard pattern of normal anatomy. Anatomic variations were observed in the intrahepatic right portal vein, the hepatic veins, and the arterial blood supply to the liver. Thus, the visible man dataset reveals itself to be well suited for the simulation of minimally invasive surgical operation such as endoscopic cholecystectomy.

Adult↗

PubMed1988

Distribution pattern of the deep branch of the ulnar nerve in the hypothenar eminence.

The deep branch of the ulnar nerve (DBUN) was carefully dissected, using gross and microtechniques, in 21 fresh frozen cadaver upper extremities. This study emphasized branching patterns of the DBUN to the hypothenar muscles and the interrelationship of variations in hypothenar muscle anatomy and DBUN branching patterns. The DBUN generally passed between the abductor digiti minimi and the flexor digiti minimi, and then through the interval between superficial and deep layers of the opponens digiti minimi on its course to the deep palm. Innervation of the hypothenar muscles was by one to four branches of the DBUN. The most common distribution pattern was two major branches, which occurred in 14 (66%) of the specimens. Of these 14 specimens, nine exhibited normal hypothenar muscle anatomy, suggesting a prevalent relationship between three normal muscles and two nerve branches. One main branch occurred in four (19%) specimens, three branches occurred in two (9%) specimens, and four branches occurred in one (4%) specimen. Anatomic variations in the hypothenar muscles were significant, the most notable being the absence of flexor digiti minimi in eight (38%) of the specimens.

Hand↗

PubMed1982

Prosthetic hip range of motion and impingement. The effects of head and neck geometry.

Two major design parameters to total hip arthroplasty which can be selected to optimize for anatomical variation are head diameter and neck length. By using a cadaveric pelvis mounted in a three-dimensional protractor, it was shown that increased head-neck diameter ratio results in increased range of motion, with decreased prosthetic impingement, and that increased neck-length results in increased range of motion, with increased prosthetic impingement. Head diameter has no range of motion effect in arcs characterized exclusively by bony impingement, and neck length has no range of motion effect in arcs characterized exclusively by prosthetic impingement. The surgeon is currently confronted with a variety of prostheses with different head-neck diameter ratios and neck lengths. When choosing the optimal prosthesis for a particular patient, the surgeon is often restricted by various anatomical constraints. While a large head diameter cannot always be chosen, an adequate range of motion without prosthetic impingement can still be achieved by ensuring that head-neck diameter ratio is optimum. A sufficient neck length to ensure adequate range of motion is desirable, but the neck should not be so long that neck-socket impingement is of concern. Optimum clinical range of motion, with minimal prosthetic impingement, may be achieved with a large head size and a medium neck length.

Biomechanical Phenomena↗

PubMed1997

[MRI: incidence and evaluation of size and form criteria in hypophysis-healthy probands and in patients with detectable microadenomas].

Magnetic resonance imaging (MRI) was performed in 42 patients with proven microadenomas and in 42 patients with normal pituitary hormone analysis. The normal MRI--anatomy of the pituitary gland and its possible variations with measurement of the volume and comparison of the anatomy with that of the gland after changes caused by microadenomas has to our knowledge not yet described. In this study we measured the height, coronary and sagittal diameter of the pituitary gland in both groups as well as other indirect signs of microadenomas (asymmetry of the gland, sella turcica, and the stalk). The pituitary volume indicates the expansion of microadenomas much better than the gland height (and the other diameters). Normal pituitary glands showed a significant lower volume (525 +/- 137 mm3 [R = 225-800 mm3]) than patients with proven microadenomas (734 +/- 393 mm3 [R = 335-2800 mm3], p < 0.001). The normal pituitary gland and sella turcica show a large variety of anatomic variations. These variations are less frequent in healthy subjects (10-21%) than in patients with microadenomas (48-71%). The described criteria are of some value in diagnosis of a suspected gland hypertrophy or microadenoma. In 75% of the patients with normal pituitary parameters and in 12% of the patients with microadenomas no indirect adenoma criteria was found in our study.

Adenoma↗

PubMed1988

[Relationship between angiographical manifestations and operative findings in 100 cases of hemifacial spasm].

Relationship between angiographical manifestations and operative findings of hemifacial spasm was studied in 100 cases. Vertebral angiography was performed, and Towne, straight AP, and lateral projections were routinely studied. The anterior inferior cerebellar artery (AICA) directly compressed the facial nerve root exit zone in 54 instances, the posterior inferior cerebellar artery (PICA) in 38, and the vertebral artery (VA) in 11. Compressions by multiple vessels were observed in 3 cases. Anatomical variations of the AICA and the PICA were classified into 3 groups according to their origins and their distributions of blood supply: Type I, normal distribution of AICA and PICA; Type II, common trunk anomaly with dominant AICA (basilar artery origin); and Type III, common trunk anomaly with dominant PICA (vertebral artery origin). In our cases, 35% of them showed normal distribution, 34% dominant AICA, and 35% dominant PICA. Analyses of the angiograms revealed significantly increased numbers of common trunk anomalies when compared with normal angiograms studied by Takahashi. In 60 of the 65 cases with common trunk anomalies, facial nerves were compressed by the main trunk or the branches of the dominant artery. There were 35 cases which belonged to Type I anatomical classification. They were subdivided into 2 groups according to the size of the AICA and PICA: 1. AICA greater than PICA, and, 2. PICA greater than AICA. In the AICA greater than PICA subgroup, the AICA was the offending artery in all but one case. In the PICA greater than AICA subgroup, the PICA was responsible in 9 of 17 cases. In 31 cases, angiograms showed a redundant VA with lateral elongation into the cerebellopontine angle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2003

Myometrial hyperplasia in pediatric, adolescent, and young adult uteri.

OBJECTIVES: To evaluate if myometrial hyperplasia is a congenital variation in myometrial differentiation, or an acquired structural disorder of the myometrium, this study evaluated whether myometrial hyperplasia was present in uteri of children, adolescents, and young adults. METHODS: We studied 19 pediatric/young adult uteri in cases with no clinical history of uterine disease. Random photomicrographs at 100x, taken at 1, 5, and 10 mm beneath the endometrium, were assessed for increased cellularity and nucleus/cell ratio, as compared to normal myometrium in the outer third of the same uterus. RESULTS: Myometrial hyperplasia was generally absent in prepubertal uteri, first appeared in adolescent uteri just beneath the endometrium, and was found at 5 mm depth only after age 18. It decreased with depth beneath the endometrium (P<0.05). CONCLUSIONS: Myometrial hyperplasia is not a congenital anatomic variation in myometrial differentiation, but rather an age-related acquired structural variation. Its relationship to common adolescent symptoms of dysmenorrhea and anovulatory bleeding remains unknown and unexplored.

Adolescent↗

PubMed2003

Variations in lower limb venous anatomy: implications for US diagnosis of deep vein thrombosis.

PURPOSE: To retrospectively review bilateral venograms free of thrombus to evaluate the frequency and types of variations seen in venous anatomy. MATERIALS AND METHODS: A retrospective review of 404 bilateral (808 limbs) lower limb venograms obtained from medical patients participating in a thromboprophylaxis clinical trial and found to be free of thrombus was performed. Venograms were evaluated according to predetermined criteria for the presence of duplication of vessels and inter- and intraindividual variations in venous anatomy. Variations were assessed with analysis of variance and chi2 tests. RESULTS: Two vessels were seen in the popliteal fossa on 337 (42%) of 808 venograms, and 41 (5%) were true duplicated popliteal veins. There were 253 (31%) duplicated superficial femoral veins (SFVs), with 12 (1.5%) being complex duplicated systems. Of 265 duplicated SFVs, 138 (52%) began in the midthigh region and 80 (30%), in the adductor canal region. The duplicated vessel was medial to the main SFV in 122 (46%), lateral in 131 (49%), and both (ie, triplications) in 12 (4.5%). The length of the duplicated SFV ranged from 1 to 35 cm; 6-15 cm was the most common length in 162 (62%) SFVs. There was no significant association between the incidence of anatomic variations and age or sex (P >.1). The presence of multiple vessels in one leg was strongly correlated with the probability of occurrence in the other leg (P <.001). CONCLUSION: Variations in lower limb venous anatomy are common and have important implications for the US diagnosis of deep vein thrombosis.

Adult↗

PubMed1989

[Computer-assisted geometric measuring technic in coronary angiography interval studies: results of initial angiograms of the International Nifedipine Trial of Anti-atherosclerotic Therapy (INTACT) study].

In 396 of 423 (93.6%) patients with mild to moderate coronary artery disease participating in a coronary angiographic follow-up trial, diameters of the epicardial coronary arteries were measured with an automatic contour detection system (CAAS). The underlying INTACT study (International Nifedipine Trial on Antiatherosclerotic Therapy), a prospective, placebo-controlled, randomized, double-blind multicenter trial, investigates the influence of the calcium antagonist nifedipine (80 mg/day) on the progression of coronary atherosclerosis over a three-year interval. The study is based on coronary angiograms repeated in identical projections after premedication with 10 mg isosorbide dinitrate sublingually. For quantitative analysis the coronary artery system was, in consideration of all anatomical variations, subdivided into 25 segments. In the first angiograms of the 396 patients evaluated up to April 1, 1988, altogether 5,425 different coronary segments could be analyzed over their entire length in one or more angiographic projections--on the average 13.7 +/- 2.8 segments per patient. Analysis parameters were the mean diameters of the entire segments and of the individual subsegments (about 5 mm in length). The 10 major proximal segments could be evaluated in 76-94% of patients respectively in more than two different angiographic projections on the average; in 0-13% of patients the respective segments were occluded. In 1-4% of patients the evaluation of these segments was prevented by poor film quality and in 1-16% of patients prevented by anatomical abnormalities (e.g., segment too short or too small). 184 segments were found occluded (RCA 42%, LAD 30%, CX 28%) and 909 mostly low-grade to moderate stenoses (RCA 34%, CX 32%, LAD 30%, left main 4%) were analyzed with a special algorithm. The following obstruction parameters were derived: minimal diameter, percentage severity, length, and plaque area. The present data demonstrate that in an angiographical multicenter follow-up study such as INTACT a nearly complete quantitative morphometric analysis of the visualized coronary artery system can indeed be obtained in virtually all angiograms when a computer-assisted contour detection system is applied.

Clinical Trials as Topic↗

PubMed2005

A common hepatic artery passing in front of the portal vein.

A variation in liver vascularization was discovered in a 50-year-old man. A single common hepatic artery was found to be responsible for vascularization of the entire liver. This artery was unusual in that it formed the first branch of the superior mesenteric artery, crossing the portal trunk shortly after its origin, and passed in front of the portal vein to reach the hilum of the liver, where it divided into a right and a left branch. This artery was a true common hepatic artery because a gastroduodenal artery emerged from it 2 cm after its origin. A common hepatic artery originating from the mesenteric artery and passing in front of the portal vein has never been described before. The patient had a second anatomical variation: the left gastric artery and the splenic artery arose directly from the aorta, without celiac trunk separation. This observation confirms the importance of carrying out a precise vascular assessment before all types of hepatic or pancreatic surgery, to identify possible variations in the number or trajectory of hepatic arteries.

Catheterization, Peripheral↗

PubMed2000

[Facial artery. Embryological review, descriptive and functional anatomy based on a review of the literature].

After a summary of the embryology and anatomy of the arterial blood supply of the face, the authors present the descriptive anatomy of the facial artery and its eight most frequent branches. Variations of the origin, course and division of the artery are then described. The literature contains 3 to 5 different descriptions of the course of the artery. The authors considered 4 of these descriptions to be relevant: I (angular), II (nasal), III (superior labial), IV (hypoplastic). Seventeen different branches have been described, many of which are inconstant. The superficial and deep anastomotic network is described, with emphasis on the subdermal network and that of the transverse facial artery. The various vascular regions of the face, first described by Mitz and Whetzel, are described. Based on these observations, and on Lasjaunias'theory of the triple hemodynamic balance, the authors propose a functional analysis of the arterial blood supply of the face. According to this analysis, the anatomic variations observed are determined by regional hemodynamic balances. These observations influence the design and creation of certain local facial flaps, such as the submental, nasolabial and buccinator flap. They may also influence present concepts concerning the hemodynamics of arteriovenous malformations of the face.

Arteries↗

PubMed1991

Variations in anatomy of the ulnar nerve at the cubital tunnel: pitfalls in the diagnosis of ulnar neuropathy at the elbow.

Two processes account for most instances of ulnar neuropathy at the elbow: compression in the retroepicondylar groove, and compression by the humeroulnar aponeurotic arcade joining the two heads of the flexor carpi ulnaris. While conventional electrodiagnostic criteria may localize an ulnar neuropathy to the elbow, separating retroepicondylar compression from humeroulnar arcade compression is more difficult. In 130 cadaver elbows, we examined the relationships between the medial epicondyle, flexor carpi ulnaris, and ulnar nerve. The humeroulnar arcade lay from 3 to 20 mm distal to the medial epicondyle, the intramuscular course of the nerve through the flexor carpi ulnaris ranged from 18 to 70 mm, and the nerve exited the flexor carpi ulnaris 28 to 69 mm distal to the medial epicondyle. In 6 specimens, dense fibrous bands bridged directly between the medial epicondyle and the olecranon proximal to the cubital tunnel proper; accessory epitrochleoanconeus muscles were present in 14 specimens: both may cause ulnar neuropathy at the elbow. Anatomical variations may contribute to the difficulty in separating causes of ulnar neuropathy at the elbow.

Cadaver↗

PubMed2004

First two cases of living related liver transplantation with complicated anatomy of blood vessels in Beijing.

AIM: Living related liver transplantation (LRLT) has been developed in response to the paediatric organ donor shortage. Though it has been succeeded in many centers worldwide, the safety of the donor is still a major concern, especially in donors with anatomy variation. We succeeded in performing the first two cases of living related liver transplantation with complicated anatomy of blood vessels as a way to overcome cadaveric organ shortage in Beijing. METHODS: Two patients, with congenital liver fibrosis and congenital biliary atresia were performed with living donor liver transplantation in our hospital and then followed up from November 12 to December 13, 2001. The two living donors, mother and father, were healthy aged 34 and 35 years. One right lobe (segment V, VI, VII, VIII) and one left lateral lobe (segment II and III) were used. The grafts weighed 394 g and 300 g. The ratio of graft weight to the standard liver volume (SLV) of donors was 68% and 27%. The graft weight to recipient body weight ratio was 3.2% and 4.4%. The graft weight to recipient estimated standard liver mass (ESLM) ratio was 63% and 85%. The two donors had complicated blood vessel variation. RESULTS: Two patients undergone living donor liver transplantation had good results. Abnormal liver function with high bilirubin level appeared in a few days after operation, but liver function returned to normal one month after operation with bilirubin level almost decreased to near normal. No bleeding, thrombosis, infection and bile leakage occurred. One had an acute rejection and recovered. The two donors recovered in two weeks. One had slight fever because of a little collection in abdomen and recovered after paracentesis and drainage. CONCLUSION: Living donor liver transplantation has been proved to be a good way that offers a unique opportunity of getting a timely liver graft as a response to shortage of pediatric donors, though it could be a technically difficult operation if there is anatomical variation.

Adult↗

PubMed2006

[Ultrasound evaluation of the acromioclavicular joint--a correlation of anatomical and sonographical findings].

AIM: To compare ultrasound imaging to the anatomy of the acromioclavicular joint. METHODS: 13 cadaveric acromioclavicular joints were examined by ultrasound (11 MHz linear array transducer) to determine the limits of the joint capsule and the width of the joint space. The results were compared to macroscopic sections. RESULTS: Anatomical variations were observed. The joint space of one specimen was completely filled by fibrous tissue, leaving 12 specimens for a complete study. A hypoechoic meniscoid disc was attached to the superior joint capsule, resulting in a convex curvature of the cranial part. The mean sonographic width of the joint space was 3.9 mm +/- 1.7 mm standard deviation (SD). The mean distance of the joint capsule from the articular bone rim of the clavicle, the acromion, and from the middle of the joint space was 1.1 +/- 1.0 mm, 1.3 +/- 0.7 mm, and 2.1 +/- 0.9 mm, respectively. The distance from the joint space to the capsular insertion on the clavicle and on the acromion was 4.4 +/- 1.4 mm and 5.3 +/- 2 mm, respectively. The mean difference between ultrasound and anatomical measurements in the vertical (cranio-caudal) plane was 0.5 +/- 0.5 mm (SD), whereas the mean difference between measurements in the horinzontal (medio-lateral) plane was 1.3 +/- 1.1 mm (SD). CONCLUSION: Due to low cost, safety and wide availability, sonography is suited for the evaluation of the acromioclavicular joint. However, when interpreting the results, errors in measuring, limitations in resolution of the system used, and the anatomy of the acromioclavicular joint and its anatomical variants have to be taken into consideration.

Acromioclavicular Joint↗

PubMed1995

Intraoperative measurement of colonic anatomy and attachments with relevance to colonoscopy.

This study examined the variations in colonic length and mesenteric attachments in 118 patients undergoing laparotomy. Measurements were taken according to a set protocol with the bowel pulled medially, or towards the pubic symphysis or the xiphisternum, mimicking the possible displacements that may occur during colonoscopy. A free sigmoid loop was not present in 20 patients (17 percent) because of adhesions. A descending mesocolon of 10 cm or more in length was recorded in ten patients (8 percent) and an ascending mesocolon 10 cm or greater in 11 (9 percent). Some 24 patients (20 percent) had mobile splenic flexures and in 34 (29 percent) the mid-transverse colon reached the symphysis pubis or lower when pulled downwards. Mean (range) total colonic length was 114.1 (68-159) cm. This study helps define anatomical variations that may affect the facility, or otherwise, of colonoscopy.

Adult↗

PubMed1995

Anatomic relationships of the cervicothoracic junction.

STUDY DESIGN: This study analyzed the anatomic relationships between bony structures and soft tissues of the cervicothoracic junction. OBJECTIVES: To provide composite reference data for intrasegmental and intersegmental gradients of anatomic variation within the cervical-thoracic junction. SUMMARY OF BACKGROUND DATA: Because the risk of soft tissue damage during posterior spinal stabilization, an understanding of bony and soft tissue changes in the cervicothoracic junction is necessary. METHODS: Three-hundred-twenty-four cross-sectional spinal segments from nine spines were analyzed to characterize cervicothoracic junctional anatomy. RESULTS: There were predictable cranial-to-caudal alterations in both bone and soft tissue anatomy of the cervicothoracic junction. Neural and vascular structures directly anterior to the lateral mass or transverse process and lateral to the pedicle tend to decrease in frequency, whereas measured parameters of the vertebrae increase in size from C5-T3, except for pedicle dimensions that tend to increase at the C7-T1 junction. CONCLUSION: The anatomic changes that occur within the cervicothoracic junction are consistent and predictable, and their recognition should lead to a better appreciation of their clinical implications.

Aged↗

PubMed2003

Developmental anatomy of the heart: a tale of mice and man.

Because of the increasing availability of tools for genetic manipulation, the mouse has become the most popular animal model for studying normal and abnormal cardiac development. However, despite the enormous advances in mouse genetics, which have led to the production of numerous mutants with cardiac abnormalities resembling those seen in human congenital heart disease, relatively little comparative work has been published to demonstrate the similarities and differences in the developmental cardiac anatomy in both species. In this review we discuss some aspects of the comparative anatomy, with emphasis on the atrial anatomy, the valvuloseptal complex, and ventricular myocardial development. From the data presented it can be concluded that, apart from the obvious differences in size, the mouse and human heart are anatomically remarkably similar throughout development. The partitioning of the cardiac chambers (septation) follows the same sequence of events, while also the maturation of the cardiac valves and myocardium is quite similar in both species. The major anatomical differences are seen in the venous pole of the heart. We conclude that, taking note of the few anatomical "variations," the use of the mouse as a model system for the human heart is warranted. Thus the analysis of mouse mutants with impaired septation will provide valuable information on cellular mechanisms involved in valvuloseptal morphogenesis (a process often disrupted in congenital heart disease), while the study of embryonic lethal mouse mutants that present with lack of compaction of ventricular trabeculae will ultimately provide clues on the etiology of this abnormality in humans.

Anatomy, Comparative↗

PubMed1987

Comparative microvascular anatomy of mammalian ciliary processes.

Methylmethacrylate lumenal castings of the ciliary body microvasculature were prepared from eight mammalian species and studied with the scanning electron microscope. In all of these species, the ciliary body is supplied by the major arterial circle, which originates solely from the long posterior ciliary arteries without contribution from the anterior ciliary circulation. In contrast to primates and rabbits, the ciliary processes of the eight species we studied are supplied by only one type of arteriole, which travels posteriorly from the major arterial circle to the iris root, where it gives rise to ciliary process arterioles. Using precise microdissection techniques, we found marked interspecies variations in ciliary process angioarchitecture among the mammalian eyes examined. Rodents (rat and guinea pig) demonstrated several interesting similarities to primates, with extensive interprocess connections and irregularly dilated, concentrically parallel capillaries traveling posteriorly to empty into the choroidal veins. In addition, rat ciliary process arterioles displayed marked focal constrictions suggestive of precapillary "sphincter" agonal activity. The carnivore ciliary process (cat and dog) is supplied by a single arteriole traveling posteriorly throughout its length and sending capillary arcades to its margin from where they drain outward into venous sinuses at the base of the process. Ungulate processes (sheep, goat, pig and cow) receive blood from multiple arterioles that occupy the process core along with veins that empty into the choroidal circulation. These vessels serve delicate capillaries lying on the sides, margin and head of each process. The anatomic variations described here should be considered in the design and interpretation of physiologic and immunohistochemical studies of ciliary body vascular perfusion in non-primate animal models.

Animals↗