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PubMed2004

Anatomical variations of the extensor tendons to the fingers over the dorsum of the hand: a study of 50 hands and a review of the literature.

The extensor tendons to the fingers were studied in dissections of 50 fresh cadaveric hands, and the divisions of the tendons, as well as the communications (juncturae), were analyzed. The pattern of distribution most frequently observed was as follows. The extensor digitorum communis provided one tendon to the index finger, one to the middle finger, two to the ring finger, and none to the little finger. The extensor indicis exhibited one tendon, whereas the extensor digiti minimi exhibited two tendons. The extensor indicis tendon was always observed to lack a junctura tendinum. The extensor indicis was absent in both hands of one cadaver. A tendon slip from the extensor digiti minimi to the ring finger was observed in one hand. All surgeons must bear in mind the existence of these variations when performing common tendon transfers.

Aged↗
PubMed2003

Approach to anatomic variations of the graft portal vein in right lobe living-donor liver transplantation.

Right lobe living-donor liver transplantation (LDLT) is often not attempted in donors with anomalous portal venous branching (APVB). The authors describe their experience with portal vein (PV) reconstruction in 17 cases of APVB in right lobe LDLT. From July 1997 to December 2001, 214 right liver LDLT were performed at the Asan Medical Center. Seventeen of the donors had APVB and successfully underwent right lobectomy. The APVB were type II (trifurcation) in nine cases, type III (independent posterior segmental branching from main PV trunk) in seven, and unclassified in one. All 17 donors and recipients are alive, with good liver function. In type II APVB, the donor PV branches were obtained with separate openings that were joined as a common orifice at the back table in two, with a discoid-patch single opening in four, and with one common opening in three. In type III APVB, the donor PV were divided with two openings in four and with a discoid-patch single opening in three. The discoid-patch defect in the remnant PV was repaired with a vein patchplasty in two donors and resected with end-to-end anastomosis in five. However, one donor developed portal vein thrombosis (PVT) that was managed successfully by re-exploration and insertion of a metallic vascular stent. Of the four type III APVB obtained with two separate PV openings, the first two liver grafts were each reconstructed as double PV anastomoses. One of them required re-exploration because of PVT. In the two succeeding cases, a Y-graft interposition technique using a cryopreserved cadaveric iliac vein or the recipient's own portal confluence was successfully applied. To minimize the risk of PVT in donors with APVB, discoid-patch excision followed by repair with vein patchplasty or segmental resection should be avoided. Individual division of the PV branches creating two separate openings instead is recommended. To decrease the recipient's risk of PVT, interposition Y-graft venous reconstruction at the back table is superior to double PV anastomoses.

Anastomosis, Surgical↗
PubMed2006

Anatomical variations of the internal jugular veins and their relationship to the carotid arteries: a CT evaluation.

The right internal jugular vein (IJV) is a common vessel to obtain venous access. It is important to have a clear understanding of the anatomy of the IJV and its relationship to the common carotid arteries (CCA) to avoid inadvertent arterial puncture. This study aims to objectively evaluate the variations in the anatomy of IJV and its relation to the CCA. A total of 176 right and left IJV were retrospectively evaluated using CT imaging with the CentraRad Diagnostic Viewer Version 4.09.0190 (CDN Telemedicine Solutions, Wollongong, Australia). The data were recorded and analysed. The right IJV (80.5%) was more often larger than the left IJV. With reference to the CCA, 85.2% of the IJV were found in the lateral position, 12.5% anteriorly, 1.1% medially and 1.1% posteriorly. Seven IJV were found to be hypoplastic, and in one case this was seen bilaterally in both the right and left IJV. The maximum depth of IJV from the skin was 27.9 mm. More than half (69.5%) of the IJV were less than 1 mm from the carotids. Computed tomography is an excellent method to delineate the anatomy of IJV. Variations in the anatomy of the IJV and their correlation to the CCA are common.

Adult↗
PubMed2006

Anatomical variations of the common carotid artery bifurcation.

BACKGROUND: The correlation of the common carotid artery (CCA) bifurcation and its surrounding structures is poorly described. The aim of this study was to describe the anatomy of the CCA bifurcation relative to its surrounding structures. METHOD: We dissected a total of 67 carotid specimens from 36 embalmed cadavers. CCA bifurcation occurred at the superior border of thyroid cartilage in 39% and at the body of hyoid bone in 40% of specimens. RESULTS: The superior thyroid artery arose more commonly from the CCA (52.3%) than the external carotid artery (46.2%). The vagus nerve was posterior to the carotid bifurcation in 40 (60%), posterior-lateral in 24 (36%), posterior-medial in 2 (3%) and anterior-lateral in 1 specimen (1.5%). The hypoglossal nerve was closer to the CCA bifurcation when the CCA bifurcated at the level of the hyoid bone than when it bifurcated at the superior border of the thyroid cartilage (P < 0.05). The correlation of the common facial vein and the carotid artery was highly variable. CONCLUSION: The presence of a high CCA bifurcation should caution surgeons that the hypoglossal nerve lies in closer proximity and is more vulnerable. Preoperatively documenting the level of the CCA bifurcation may be helpful in identifying those patients at increased risk of iatrogenic injury.

Aged↗
PubMed2005

Interfractional anatomic variation in patients treated with respiration-gated radiotherapy.

As quality assurance for respiration-gated treatments using the Varian RPM system, we monitor interfractional diaphragm variation throughout treatment using extra anterior-posterior (AP) portal images. We measure the superior-inferior (SI distance between one or more bony landmarks and the ipsilateral diaphragm dome in each such radiograph and calculate its difference, D, from the corresponding distance in a planning CT scan digitally reconstructed radiograph (DRR). For each patient, the mean of D represents the systematic diaphragm displacement, and the standard deviation of D represents random diaphragm variations and is a measure of interfractional gating reproducibility. We present results for 31 sequential patients (21 lung, 10 liver tumors), each with at least 8 such portal images. For all patients, the gate included end-exhale. The patient-specific duty cycle ranged from 30% to 60%. All patients received customized audio prompting for simulation and treatment, and 14 patients also received visual prompting. Respiration-synchronized fluoroscopic movies taken at a conventional simulator revealed patient-specific diaphragm excursions from 1.0 cm to 5.0 cm and diaphragm excursion within the gate from 0.5 cm to 1.0 cm, demonstrating a significant reduction of intra-fractional diaphragm (and by inference tumor) motion by respiratory gating. One standard deviation of the systematic displacement (the mean of D) was 0.63 cm and 0.48 cm for the lung and liver patient groups, respectively. The average +/-1 SD of the random displacements (i.e., the average of the standard deviations of D) was 0.42 +/- 0.11 cm and 0.50 +/- 0.19 for the two groups, respectively. The similar magnitude of the systematic and random displacements suggests that both derive from a common distribution of interfractional variations. Combining visual with audio prompting did not significantly improve performance, as judged by D. Guided by these portal images, field changes were made during the course of treatment for 6 patients (1 lung, 5 liver).

Artifacts↗
PubMed1990

Anatomic variations and abnormalities in the diaphragm seen with US.

The authors report their experience with diaphragmatic structures that simulate intrahepatic masses at abdominal ultrasonography (US). In a series of 74 patients, diaphragmatic slips were the most common finding (34 patients). The slips could be differentiated from masses by scanning along their long axis to demonstrate elongated structures with multiple linear echoes. Scalloping of the diaphragm, associated with multiple slips, was seen in 10 patients. Partial eventration was found in 23. Inversion of a hemidiaphragm, caused by a large pleural effusion or intrathoracic mass, was seen in 13 patients. Pleural masses affecting the diaphragm were seen in 13 patients; focal hypertrophy of a diaphragmatic crus simulated a mass in three. Real-time US allowed the differentiation of diaphragmatic abnormalities from lesions.

Adolescent↗
PubMed1994

Labrocapsular ligamentous complex of the shoulder: normal anatomy, anatomic variation, and pitfalls of MR imaging and MR arthrography.

Magnetic resonance (MR) imaging is a useful modality for evaluating the labrocapsular ligamentous complex (LCLC) of the shoulder. MR arthrography is an important and occasionally indispensable supplementary modality for accurate differentiation between normal and deranged glenohumeral joints. Because of the joint distention that occurs during MR arthrography, it is especially helpful in detecting subtle capsular derangement, as occurs in patients with atraumatic instability. Also, some of the pitfalls associated with MR imaging of the LCLC are less likely to occur with MR arthrography. Radiologists should look for several key abnormalities when evaluating MR images of the shoulder: an anterior or posterior Bankart lesion; a Hill-Sachs defect; a tear of the rotator cuff, glenoid labrum, or superior labrum-biceps tendon attachment; and loose bodies. Knowledge of normal anatomy, normal variations, and pitfalls in image interpretation related to evaluation of the LCLC will help the radiologist accurately detect debilitating derangements associated with glenohumeral instability.

Humans↗