SEARCH · PubMed Health

Results for “Anatomic Variation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources

PubMed1995

Ultrasonographic anatomy of the anterior neck: implications for tracheostomy.

PURPOSE: Tracheostomy is the preferred intervention for surgical establishment of an upper airway in the treatment of certain elective maxillofacial procedures. Complication rates associated with surgical tracheostomy are largely related to the restricted possibilities in diagnosis of anatomic variations. Therefore, endoscopic-guided tracheostomy is increasingly being used to enhance precision and safety. The purpose of this study was to assess the ultrasonographic anatomy of the anterior neck with regard to the performance of tracheostomy. PATIENTS AND METHODS: Fifty patients underwent ultrasonographic investigation to analyze the relationship of anatomic structures lying in the immediate vicinity of the tracheostomy site. RESULTS: The data presented demonstrate the feasibility and advantage of preoperative ultrasonography to visualize the structures of the infrahyoid region. CONCLUSION: Preoperative ultrasonography may be of great importance in diagnosing individual anatomic variations at the site of tracheostomy and in avoiding complications.

Humans↗

PubMed1998

The role of anteromedial foraminotomy and the uncovertebral joints in the stability of the cervical spine. A biomechanical study.

STUDY DESIGN: The biomechanical role of the cervical uncovertebral joint was investigated using human cadaveric spines. Sequential resection of cervical uncovertebral joints, including clinical anteromedial foraminotomy, was conducted, followed by biomechanical testing after each stage of resection. OBJECTIVES: To clarify the biomechanical role of uncovertebral joints and clinical anteromedial foraminotomy in the cervical spine and their effects on interbody bone graft stability. SUMMARY OF BACKGROUND DATA: Although the biomechanical role of the cervical uncovertebral joints has been considered to be that of a guiding mechanism in flexion and extension and a limiting mechanism in posterior translation and lateral bending, there have been no studies quantifying this role. According to results in quantitative anatomic studies, anatomic variations exist in uncovertebral joints, depending on the vertebral level, articular angulation, and relative height of the joints. METHODS: Fourteen human functional spinal units at C3-C4 and C6-C7 underwent sequential uncovertebral joint resection, with each stage of resection followed by biomechanical testing. The uncovertebral joint was divided anatomically into three parts on each side: the posterior foraminal part, the posterior half, and the anterior half. The loading modes included torsion, flexion, extension, and lateral bending. A simulated anterior bone graft construct was also tested after each uncovertebral joint resection procedure. RESULTS: Significant changes in stability were observed after sequential uncovertebral joint resection in all loading modes (P < 0.05). The biomechanical contribution of uncovertebral joints decreased in the following order: the posterior foraminal part, the posterior half, and the anterior half. Unilateral and bilateral foraminotomy most affected the stability of the functional spinal unit during extension, causing a 30% and 36% decrease in stiffness of the functional spinal unit, respectively. The effect was less in torsion and lateral bending. After sequential resection, there was a statistically significant difference between decreases in torsional stiffness at C3-C4 and C6-C7 (P < 0.05). The stiffness of the simulated bone graft construct decreased progressively during flexion and lateral bending after each foraminotomy (P < 0.05). Increased bone graft height of 79% returned stability to the preforaminotomy level. CONCLUSIONS: This is the first study to quantitate the biomechanical role of uncovertebral joints in cervical segmental stability and the effect at each intervertebral level. The effect differs because of anatomic variations in uncovertebral joints. The major biomechanical function of uncovertebral joints includes the regulation of extension and lateral bending motion, followed by torsion, which is mainly provided by the posterior uncovertebral joints. This study highlights the clinical assessment of additional segmental instability attributed to destruction of the uncovertebral joints during surgical procedures or by neoplastic lesions.

Biomechanical Phenomena↗

PubMed2006

Nonhepatic arteries originating from the hepatic arteries: angiographic analysis in 250 patients.

PURPOSE: To investigate the prevalence and patterns of origin of nonhepatic arteries originating from the proper hepatic artery (PHA) or its distal branches and to assess their relation to anatomic variations. MATERIALS AND METHODS: Digital subtraction celiac arteriography and selective left hepatic arteriography was performed in 250 patients with hepatocellular carcinoma. Three interventional radiologists interpreted the angiograms on the monitor by consensus. If necessary, further superselective arteriography was performed. The prevalence of nonhepatic arteries, their sites of origin, and the influence of underlying anatomic variants were analyzed. RESULTS: Nonhepatic arteries were found in 205 patients. The most common nonhepatic artery was the right gastric artery (RGA; n = 196), followed by the hepatic falciform artery (HFA; n = 129), accessory left gastric artery (LGA; n = 43), posterior superior pancreaticoduodenal artery (PSPDA; n = 18), and left inferior phrenic artery (LIPA; n = 5). The left hepatic artery (LHA) was the most frequent origin of nonhepatic arteries (170 of 250). Regardless of anatomic variation, the most common origins of the RGA and HFA were the PHA and the segment IV hepatic artery, respectively. In patients with an aberrant LHA from the LGA, no accessory LGAs or LIPAs were found. PSPDAs preferentially arose from variant hepatic arteries arising from the gastroduodenal artery. CONCLUSIONS: Nonhepatic arteries commonly arise from the hepatic arteries, especially the LHA and PHA. Moreover, variants of the celiac and hepatic arteries influence the prevalence and sites of origin of nonhepatic arteries.

Adult↗

PubMed1985

Ultrasonographic anatomy and physiology of the fetal kidney.

The aim of this work was to demonstrate the impact of ultrasonography in utero to gain a better understanding of the anatomy, growth, anatomical variations and function of the fetal kidney and urinary tract. Three main topics are discussed in this paper based on the authors' personal experience and data from the literature: 1) the technique of ultrasonography in utero, including the main difficulties encountered and limitations of this technique; 2) ultrasonographic study of the morphology, growth and anatomical variations of the fetal kidney. The length of the fetal kidney was found to be the most significant parameter for assessment of its growth. At term, the kidney measures slightly more than 4 cm in length, while the renal pelvis is usually no more than 10 mm thick; 3) current knowledge of the physiology of the fetal urinary apparatus especially the kidney. Excretory function of the kidney begins in the third month of gestation and its main role involves the regulation of the amniotic fluid.

Embryonic and Fetal Development↗

PubMed1989

The inguinal region: anatomic differences in men and women with reference to hernia formation.

Fifty inguinal regions were dissected in anatomic human adult specimens, of which 26 were males and 24 females. The comparison of anatomic variations in both sexes showed that the distance between the public tubercle and the internal ring was larger, and the rectus muscle significantly wider in females. The diameter of the internal ring was larger in males, however, with significant variability. No differences were found regarding the presence or absence of the conjoint tendon. The anatomic variations may explain the sex differences in hernia formation.

Anatomy↗

PubMed2006

[Analysis on the long-term curative effect of endoscopic sinus surgery].

OBJECTIVE: To analyze the long-term curative effect of endoscopic sinus surgery. METHOD: One hundred and twenty-eight cases (180 sides) of chronic sinusitis and nasal polyps were treated with FESS, 80 side (64 cases) were elected randomly to deal with the anatomical variation of middle and inferior turbinate and nasal septum during the operation (rectification group), comparing the curative effects with other 100 sides (64 cases) (contrast group). RESULT: Following up survey from 12 months to 24 months postoperatively, the curative effect in the rectification group was better than that in the contrast group. CONCLUSION: Dealing with anatomical variation that influence the nasal cavity function in FESS can significantly improve the healing rate of sinusitis and ventilation function and decrease the adhesions rate.

Adolescent↗

PubMedDate not supplied

Imaging in pediatric liver transplantation.

In liver transplantation, the role of the imaging study in the evaluation of transplant candidacy is to define the conditions in which transplantation is contraindicated and to identify anatomic variations that may alter the surgical approach. Among pediatric recipients, the largest numbers of patients were suffering from biliary atresia, and metabolic diseases. Acquired and congenital vascular anomalies are usually associated with biliary atresia which may be hazardous to liver transplantation requiring a modification of standard surgical procedure. Therefore, confirmation of the patency of the vascular structure is the most essential prerequisite especially in living related liver transplantation. From June 17, 1994 to November 30, 1996, eleven living related liver transplantations were performed at Chang Gung Memorial Hospital, Kaohsiung Medical Center. The left liver or the left lateral segment of the liver was used as the graft. It is necessary to keep patency of the inflow and outflow of hepatic vessels and biliary trees of both donor and recipient. Both resected and remnant livers have to function well postoperatively. In order to achieve parenchyma dissection with minimal hepatic damage, various anatomical variations of the liver size, portal vein, hepatic veins and bile duct of the donor cannot be ignored. Therefore, the precise preoperative anatomical evaluation of the donor using various imaging modalities is mandatory for the safe partial liver transplantation. Ultrasound, computed tomography, magnetic resonance image and three dimensional computed tomographic cholangiography are the method of choice in demonstrating the anatomical structures. After the complex anatomical factors can be well evaluated we can assess the appropriateness and feasibility of the procedure that may correct problems during or after transplantation. Finally, noninvasive and safe examination procedures are our outmost concern and policy in doing this survey.

Angiography↗

PubMed2003

Redefining the "Arcade of Struthers".

PURPOSE: To define the anatomy and presence of the arcade of Struthers, its anatomic variations, and potential sites of compression of the ulnar nerve. METHODS: In 11 fresh specimen dissections, the ulnar nerve was followed from the brachial plexus through the anterior compartment into the posterior compartment through the intermuscular septum and the arcade of Struthers on to the cubital tunnel. The arcade was identified, dissected, measured, and photographed. All anatomic variations were documented. RESULTS: The arcade of Struthers and intermuscular septum were present in all 11 specimens. The arcade was not merely an opening in the septum nor was it a short band as typically described: the arcade was better described as a fibrous canal with an average length of 5.7 cm. Its openings at either end were 3.9 and 9.6 cm proximal to the medial epicondyle. The structural components of the canal consisted of the fibrous tissue of the intermuscular septum, the internal brachial ligament, the deep fascia of the triceps, and the epimysium of the triceps muscle itself. The ulnar nerve was bound tightly within the entire canal in one case. In all specimens the nerve had an hourglass indentation at the proximal opening of the canal between the intermuscular septum and the internal brachial ligament. CONCLUSIONS: The arcade of Struthers consists of a fibrous canal. The tightest point is the proximal end of the canal at the intermuscular septum that represents the clinically relevant site of entrapment or compression of the ulnar nerve.

Dissection↗

PubMedDate not supplied

An anatomic study of the sacral hiatus: a basis for successful caudal epidural block.

STUDY DESIGN: An anatomic study of the sacral hiatus using isolated sacra. OBJECTIVES: To clarify the anatomic variations of the sacral hiatus using the bony landmarks of the sacrum for improving the reliability of caudal epidural block (CEB). BACKGROUND DATA: The CEB has been widely used for the diagnosis and treatment of lumbar spinal disorders. The reliability of CEB is 70%-80% in the literatures. The cause of failure of CEB may depend on anatomic basis. METHODS: A total of 92 isolated sacra were used in this study. The bony landmarks were sacral hiatus and sacral cornua. Morphologic types of the sacral hiatus were classified using these landmarks. Also, location of the apex of sacral hiatus, diameter of the sacral canal at the apex of sacral hiatus, and the distance between bilateral cornua were measured. Two orthopedic surgeons performed measurements independently. RESULTS: Forty-two percent of the cases have both hiatus and cornu. Four percent of the cases showed the absent hiatus. The apex of sacral hiatus existed at the level of S4 vertebrae in 64% of the cases. The average diameter of the sacral canal was 6.0 +/- 1.9 mm. The average distance of bilateral sacral cornua was 10.2 +/- 0.35 mm. There were closed hiatus in 3% of cases. CONCLUSIONS: The sacral hiatus has anatomic variations. Understanding of these variations may improve the reliability of CEB.

Adult↗

PubMed1997

[Nonrecurrent recurrent nerve. Danger in thyroid and parathyroid surgery. Apropos of 9 cases].

Main difficulties in thyroid surgery are represented by recurrent nerve anatomy and parathyroid glands. Nerve injury or accidental truncation cause definitive impairment. Risk of recurrent paralysis is 0.5 to 3% for advanced teams. Early investigation and dissection of this nerve are considered mandatory for preservation. This practice is also highly indicated due to anatomical variations, cause for accidental truncation. The most difficult case is encountered when there is nerve non recurrence, due to variations in origin and path of the nerve. Inferior laryngeal nerve non recurrence can be present on the right side, it is uncommon but possible on the left side. We have evaluated a series of 1165 cervicotomies undertaken for thyroidectomy or parathyroid gland approach. There were 9 cases of non recurrence. Literature review allowed us to study anatomical variations and nerve relationships.

Humans↗

PubMed2003

[Evaluation of the lower leg vessels before microsurgical fibula transfer. Magnetic resonance angiography versus digital subtraction angiography].

BACKGROUND: Since the introduction of the fibula flap by Taylor in 1975, and its first application in the lower jaw by Hidalgo in 1989, it has become an option of first choice in mandibular reconstruction of large oromandibular defects. Perfusion of the osteomyocutaneous fibula transplant is based on the peroneal artery. To avoid postoperative ischaemia of the lower leg after sacrificing this artery, especially in smokers, adequate perfusion must be guaranteed preoperatively by radiological evaluation. Progress in the field of magnetic resonance angiography (MRA) enables an increasing number of primary non-invasive evaluations of vessels. The aim of this prospective study was to answer the question of whether MRA enables a accurate representation of anatomical variation and pathological stenoses of the lower leg vessels and can therefore replace conventional digital subtraction angiography (DSA). MATERIALS AND METHODS: We carried out conventional DSA of the lower leg before raising a fibula transplant and postoperative MRA with contrast medium in a prospective study with 15 patients. Vessels were assessed for atherosclerotic, occlusive or hypoplastic changes and anatomical variations by three radiologists. RESULTS: High resolution of MRA enables a reliable judgement of the lower leg vessels. Hypoplastic vessels, stenoses, occlusion or atherosclerotic changes of the vessels could definitely be detected by MRA just as by DSA. Thus, all patients without these diagnosed contraindications could be operated successfully. CONCLUSION: MRA of the lower leg enables a definitive determination of the vessel quality and the site of preference for harvesting the flap. Because MRA is a low risk procedure, can be carried out on an outpatient basis and causes no radiation load, it should be preferred to conventional DSA.

Adult↗

PubMed1998

Normal and variant anatomy of hepatic arteries: angiographic experience.

BACKGROUND: Anatomic variation of hepatic arteries is reported to occur in 25-50% of the general population. Knowledge of the existing variations is important in planning and conducting surgical or radiologic procedures in the upper abdomen, such as liver transplantation and transarterial chemo-embolization (TACE). METHODS: Based on data from 321 patients undergoing upper abdominal arteriography, hepatic artery anatomy was analyzed and classified into three groups (single, double and multiple hepatic arteries at hepatic hilum) according to Suzuki's classification. Each group was subdivided into three types (celiac, mesenteric and mixed types) according to the origin of the hepatic arteries. The variations within each type were recorded. RESULTS: Two hundred and sixty one patients (68.%) had single hepatic arteries. One hundred and five patients (27.6%) had double hepatic arteries and only fifteen patients had multiple hepatic arteries. All of these variants, including twenty subtypes, were identified. CONCLUSIONS: This study, based on Suzuki's classification, provides basic data for the anatomic variations of hepatic arteries for the Chinese population in Taiwan.

Female↗

PubMed2005

Long-term ovariectomy decreases ovine compact bone viscoelasticity.

Changes in bone mineral density associated with estrogen depletion in humans do not account for all of the associated change in fracture risk, and it is possible that some of this variation may lie in changes of other aspects of bone quality. The purpose of this study was to investigate changes in viscoelastic behavior of compact bone that may be associated with estrogen depletion. Changes in compact bone viscoelastic properties associated with three years of ovariectomy were investigated with dynamic mechanical analysis (low-amplitude 3-point bending at frequencies of 1-20 Hz) using beams milled from the diaphysis of the ovine radius. The viscoelastic storage modulus was significantly (5.2%) lower at the higher frequencies for the ovariectomized animals. The general anatomic variation in storage modulus, in which cranial sectors had higher values than caudal sectors, did not change with ovariectomy. The loss tangent (tandelta, a measure of damping) was also greatly decreased (up to 83%) at high frequencies in the ovariectomized animals. Anatomic variation in tandelta at low (6-12 Hz) frequencies (cranial and caudal sectors having higher values than lateral or medial sectors) was enhanced with ovariectomy. Changes in viscoelastic properties associated with long-term estrogen depletion could be responsible for a significant reduction in the toughness or strength of a bone without concomitant changes in screening modalities used to evaluate bone quality (e.g., DXA, QCT, QUA).

Animals↗

PubMedDate not supplied

Arteriographic study of variant arterial anatomy of the upper extremities.

Anatomic variations in the major arteries of the upper extremities have been reported in 11-24.4% of individuals. In a review of 100 upper extremity arteriograms, we found an overall incidence of 9%. High origin of the radial artery from the brachial artery was the most frequently encountered anomaly occurring in 7% of individuals and accounting for 78% of all anatomic variations. Origin of the radial and ulnar arteries from the axillary artery was an infrequent finding occurring in only 2% of extremities.

Adult↗

PubMedDate not supplied

[Experiences with the en bloc multiorgan procurement technique].

INTRODUCTION: The pressing need to obtain organs for transplantation demands an optimal usage of donors. Surgical techniques based on rapid multiorganic retrieval gain vital importance especially when hemodynamically unstable donors are involved. OBJECTIVE: To highlight the advantages of this technique and evaluate our experience after 2 years of implementation. MATERIAL AND METHODS: A longitudinal, prospective non-controlled study was performed, including 34 multiorganic retrievals using the Total Abdominal Evisceration (TAE) technique. Information on demographic characteristics, surgical times, anatomical variations and final fate of organs is gathered. RESULTS: Thirty four organ retrievals were performed using TAE techniques. Included donors had a mean age of 47 years and a mean weight of 66 kg. Dissection time range was 35 +/- 10 min, bloc retrieval was performed in 20 +/- 8 min and dissection at backbench range was 100 +/- 30 min. All anatomic variations were detected and were present in 46.9% of cases. Over 70% of livers retrieved by TAE resulted in minimal preservation injury. Only one presented primary non-function after transplantation, directly related to hemodynamic instability. CONCLUSIONS: The TAE technique for multiorgan retrieval allows adequate harvesting of organs for transplantation with favorable preservation. It is a valid alternative for transplant groups in our country, especially when dealing with unstable donors.

Adult↗

PubMed2006

Anatomy of ligamentous structures in the tarsal sinus and canal.

BACKGROUND: The descriptive morphology of the interosseous talocalcaneal ligament and other structures in the tarsal sinus and canal vary. An anatomical investigation of the ligamentous structures in the tarsal sinus and canal identified two distinct ligaments, the interosseous talocalcaneal ligament and the anterior capsular ligament, and three components of the medial root of the inferior extensor retinaculum. METHODS: Forty embalmed cadaver feet were examined. After disarticulation of the ankle joint, the posterior half of the talus was removed. The length, width, and thickness of the two ligaments and the three components of the extensor retinaculum in the tarsal canal and sinus were measured with calipers. Anatomical variations were recorded. RESULTS: The interosseous talocalcaneal ligament was band-like in 92.5% (38 of 40) of examined specimens, and the anterior capsular ligament was present in 95% (39 of 40) of specimens. The interosseous talocalcaneal ligament, the medial component of the inferior extensor retinaculum, and the talar component of the inferior extensor retinaculum had one or two distinct anatomical variations of morphology and attachments. The interosseous talocalcaneal ligament and the medial component of the extensor retinaculum formed a V shape in the tarsal sinus and canal. CONCLUSION AND CLINICAL RELEVANCE: We demonstrated the morphology and dimensions of the ligaments and components of the extensor retinaculum in the tarsal sinus and canal. Precise anatomy of the structures in the tarsal sinus and canal will strengthen our understanding of their function in the motion or stabilization of the subtalar joint. There may be a functional link between the medial component of the inferior extensor retinaculum and the interosseous talocalcaneal ligament.

Aged↗

PubMed1991

[Free toe transfer with plantar metatarsal arteries and dorsal venous pedicle. Report of 18 cases].

Eighteen free second toe were used for pollicization other than the conventional method. From the first and second plantar metatarsal arteries junction of the both digital arteries of the second toe were dissected retrogradely and anastomosed to the deep of superficial palmar arch or terminal branch of the radial artery. The venous return was established between the dorsal venous arch and cephalic vein. These vessels were found to have much bigger diameters and less anatomical variation than those used by conventional methods. Seventeen transplantation were considered successful both functionally and cosmetically. One cases had persistent spasmodic contraction of the recipient arteries, so the transplant was salvaged by subclavicular pedicle including the sutured nerves and the attached soft tissues as introduced by Lu in 1964. Our method for reconstruction of the thumb or finger can avoid frequent anatomical variation and smaller diameter of the anastomosed vessels.

Adult↗

PubMedDate not supplied

Evaluation of cross-circulation through circle of Willis using an ultrasonic Doppler technique. Part I. Comparison between blood flow velocity by ultrasonic Doppler flowmetry and angiogram.

In 24 patients with cerebrovascular disease and 6 without organic brain lesions, the increased velocity of blood flow in both the internal carotid and vertebral arteries during a contralateral carotid compression was compared with the angiographic appearance of the circle of Willis. The flow velocity was measured using ultrasonic Doppler flowmetry. It was not possible to investigate fully the relationship between the increase of velocity of blood flow in the internal carotid artery and the anatomical variations of the circle of Willis, specifically the anterior cerebral and communicating arteries. The velocity of flow in the patients with an aplastic proximal portion of the anterior cerebral artery showed no increase. There were no differences in the increase of velocity of flow in the vertebral artery in patients with hypoplastic, normal and fetal posterior communicating arteries. It is considered that although anatomical variations of the circle vessels influence the cross-circulation via the circle of Willis, peripheral vascular factors distal to the circle also play an important role in the quantity of cross-circulation through the circle.

Adolescent↗