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 109 records · Page 6Linked to original sources

PubMedDate not supplied

Anatomic variations of the human semicircular canals. A radioanatomic investigation.

The anatomic variations of the semicircular canals were investigated in a series of 95 plastic temporal bone preparations. The results showed a wider range of variability than has been assumed previously. An intraindividual correlation was found between the sizes of the superior and lateral semicircular canals. Observations indicate why a semicircular canal is not invariably delineated on one tomographic plane despite correct positioning for its optimum reproduction.

Humans↗

PubMed1999

Anatomic variations in patients operated for bladder substitution.

Authors review the anatomic variations observed throughout orthotopic ileal neobladder formation in 38 cases following radical cystectomy. A part of the variations was necessitated because of deviation from the classic Hautmann-type surgical technique: in 6 cases the site of ileal resection was modified due to abnormal mesenterial art. course, on 2 occasions Meckel diverticules were detected while cutting the ileal neobladder, in 13 cases the laterally adhered sigma bladder necessitated the left-sided ureter to be pulled through beneath the mesosigma for the purpose of making sure the ureter--ileal neobladder anastomosis became free of any tension, while on 1 occasion the left ureteral preparations went with some injury. Since the left ureter became short, ureter replacement variation was needed, similar to the Studer method of ileal neobladder formation. All these variations, however, did not implicate the essence of the Hautmann technique. Follow-up of the patients did not reveal high frequency of occurrence of any complications.

Aged↗

PubMed1989

Unusual anatomic variation of bilateral ectopic ureters in a dog.

An unusual anatomic variation of bilateral ectopic ureters was diagnosed in a 6-week-old female Siberian Husky with urinary incontinence. Assessment during surgery revealed bilateral ectopic ureters with a common opening in the proximal portion of the urethra. Ureteroneocystostomy was performed bilaterally. After surgery, intermittent urinary incontinence continued, but was less severe. After resection of a persistent hymen in the 6-month-old dog, incontinence appeared to resolve, but then recurred, and has been controlled by phenylpropanolamine administration.

Animals↗

PubMed1993

[Endoscopic paranasal sinus surgery. The most important anatomic variations of the main paranasal sinus and accessory paranasal sinus].

Anatomic variations of the nasal cavity and paranasal sinuses are described in order of their appearance in endoscopy. Variations of the pyriform aperture are followed by variations of the agger nasi, inferior and middle conchas, inferior and middle nasal meati, and variations of the bulla ethmoidea, uncinate process and fontanelles. Variations of the maxillary sinus are described from their anterior and lateral views. Partial and total septation of the maxillary sinus, variations of its dimensions and its relation to dental roots are stressed. The dimensions of the frontal sinus, frontal bulla or bullae are noted. The variation of the sphenoid sinus and its dimensions and relationships to the structures of the cavernous sinus and the endocranium are described. Pneumatization of the anterior clinoid process and the region around the optic canal by the frontal sinus, ethmoid labyrinth or sphenoid sinus is discussed. Knowledge of these different variations will help the rhinologic surgeon in his orientation during endoscopic surgical interventions.

Adolescent↗

PubMed2001

[Differences of anatomic variations in ostiomeatal complex between two sides of the deviated septum].

OBJECTIVE: To explore the influence of the deviated septum on the development of ostiomeatal complex (OMC). METHODS: Nasal endoscopic examination and CT scan of the paranasal sinuses of 103 patients with nasal septal deviation were analyzed. The differences of anatomic variations in OMC between ipsilateral and contralateral sides in relation to the direction of septal deviation. The incidence of sinusitis on either side of the deviated septum was evaluated. RESULTS: On the side opposite to the deviated septum, the incidence of middle and inferior turbinate hypertrophy was higher than that of the deviated side(P < 0.05). The width of agger nasi and ethmoid bulla was on the contralateral side larger than that of the ipsilateral side (P < 0.01). The incidence of paradoxical curvature of middle turbinate on the ipsilateral side was higher than that of contralateral side (P < 0.01). Other anatomic variations showed no significant differences between two sides of the deviated septum (P > 0.05), nor was there any difference between the incidence of sinusitis on the two sides. CONCLUSION: Some compensatory changes in middle and inferior turbinates and lateral nasal-wall on the opposite side to the deviation might be caused by the deviated septum.

Adolescent↗

PubMed2004

Anatomical variations within the deep posterior compartment of the leg and important clinical consequences.

The management of musculoskeletal conditions makes up a large part of a sports medicine practitioner's practice. A thorough knowledge of anatomy is an essential component of the armament necessary to decipher the large number of potential conditions that may confront these practitioners. To cloud the issue further, anatomical variations may be present, such as supernumerary muscles, thickened fascial bands or variant courses of nerves and blood vessels, which can themselves manifest as acute or chronic conditions that lead to significant morbidity or limitation of activity. There are a number of contentious areas within the literature surrounding the anatomy of the leg, particularly involving the deep posterior compartment. Conditions such as chronic exertional compartment syndrome, tibial periostitis (shin splints), peripheral nerve entrapment and tarsal tunnel syndrome may all be affected by subtle anatomical variations. This paper primarily focuses on the deep posterior compartment of the leg and uses the gross dissection of cadaveric specimens to describe definitively the anatomy of the deep posterior compartment. Variant fascial attachments of flexor digitorum longus are documented and potential clinical sequelae such as chronic exertional compartment syndrome and tarsal tunnel syndrome are discussed.

Aged↗

PubMed2002

Anatomical variations of the inguinal nerves and risks of injury in 110 hernia repairs.

The aim of this study was to identify the anatomical variations in the inguinal course of the ilioinguinal nerve (IIN) and the iliohypogastric nerve (IHN) during operative repair of inguinal hernias. A consecutive series of 110 primary inguinal hernias were repaired by the mesh technique. Particular attention was paid to early identification and recording of the course of both the IIN and IHN and preserving them throughout the operative procedure. The course of both nerves was found to be consistent with that described in anatomical texts in only 46 of 110 explorations (41.8%). The course of one or both nerves was found to be a variant in the other 64 of 110 (58.2%) explorations and often rendered them susceptible to injury. These variations included: (1) acute infero-lateral angulation of the IIN at its exit behind the superficial inguinal ring (SIR) fibers in 20 of 64 cases; (2) similar direction of the IIN but in a plane superficial to the external oblique aponeurosis (EOA) and proximal to the SIR in 18 of 64 cases; (3) a single stem for both nerves over the spermatic cord in 24 of 64 cases, with variation in the subsequent course; (4) absence of one or both nerves in 8 of 64 cases; (5) accessory IIN or IHN in 3 of 64 cases; and (6) aberrant origin of the IIN from the genitofemoral nerve (GFN) in 2 of 64 cases. None of 68 of 105 patients seen at 3 months postoperatively (compliance rate 65%) complained of sensory disturbances or pain in a dermatome distribution of the IIN or IHN. It is concluded that anatomical variations in the inguinal course of the IIN and the IHN are extremely common but readily identifiable. Their early identification and preservation is likely to abolish, or considerably decrease, the incidence of postoperative sensory changes and/or neuralgia pain.

Adult↗

PubMed2000

The prevention of bile duct injury during laparoscopic cholecystectomy from the point of view of anatomic variation.

The aim of this study was to evaluate ways to prevent bile duct injury during laparoscopic cholecystectomy in patients with anomalous biliary tract anatomy. The biliary tract was studied using cholangiograms of 511 patients who had gallbladder disease and was dissected in 92 cadaveric specimens. The authors classified confluent forms of the cystic duct and the bile duct into five different types, including four anomalous types. Sixteen instances (3.13%) of anatomic variation of the biliary tract were found among the patients, and four cases (4.35%) were found in the cadavers. Among the 511 patients, there were 495 cases of type C anatomy, three cases of type A, seven cases of type R, six cases of type P, and zero cases of type L; among the 92 cadaveric specimens, there were 88 cases of type C anatomy, one case of type R, two cases of type P, and one case of type L. For anatomic types A, P, and R, there is a high probability of risk of cutting the wrong duct. Therefore, it is important to clarify the anatomy of the biliary tract by preoperative examination and to carefully dissect the cystic duct close to the neck of the gallbladder during laparoscopic cholecystectomy. Anatomic variation of the biliary tract is common and can create a rare pitfall during laparoscopic cholecystectomy.

Adolescent↗

PubMed1989

Anatomical variation of orthotropic elastic moduli of the proximal human tibia.

The anatomical variation of orthotropic elastic moduli of the cancellous bone from three human proximal tibiae was investigated using an ultrasonic technique. With this technique, it was possible to measure three orthogonal elastic moduli and three shear moduli from cubic specimens of cancellous bone as small as 8 mm per side. Correlation with mechanical tensile testing has shown this technique to offer a precise measure of cancellous modulus (Eten = 0.94Eult + 144.6 MPa, r2 = 0.96, n = 34). The cancellous bone of the proximal tibia was found to be very inhomogeneous, with the axial modulus ranging between 340 and 3350 MPa. A course map is presented, showing measured Young's moduli as a function of anatomical position. The anisotropy of the cancellous bone, determined by the relative differences between the three orthogonal moduli, was shown to be relatively constant over the entire range of cancellous densities tested. The relationship between the axial elastic modulus and the apparent density was found to be approximately linear, as reported by others for proximal tibial cancellous bone.

Aged↗

PubMed2006

Anatomical variations in the human sinuatrial nodal artery.

OBJECTIVE: To analyze the anatomical variations of sinuatrial nodal branch(es) of the coronary artery mainly regarding their number; a recent report from Japan claims the presence of 2 branches in up to 50% of cases, an occurrence that would permit adequate flow compensation in case of occlusion or section of 1 of these branches. METHODS: The sinuatrial nodal branch(es) of 50 human hearts fixed in formol solution were dissected with the aid of a Normo Health 3.0 degree visor magnifying lens, measured, and classified as to the origin, route, and number of branches. RESULTS: In 94% (n = 47) of cases, a single sinuatrial nodal branch was found. classified: (A) two right side types, R1 (in 46% of cases, n = 23), situated medial to the right auricle and R2 (in 4% of cases, n = 2), situated on the posterior surface of the right atrium; (B) three left side types, L1 (in 24% of cases, n = 12), situated medial to the left auricle, L2 (in 16% of cases, n = 8), situated posterior to the left auricle, and L3 (in 4% of cases, n = 2), situated on the posterior surface of the left atrium. Except for R2, each type was subdivided into 'a' or 'b' types, according to whether the sinuatrial nodal branch(es) occurred in a clockwise or counterclockwise orientation around the base of the superior cava vena. In 4% of cases (n = 2), 2 sinuatrial nodal branch(es) were observed with 1 branch originating from each of the coronary arteries. In 1 case (2%), 3 sinuatrial nodal branch(es) were found, 2 from the right coronary artery and the third probably from the bronchial branch of the thoracic aorta. In 30% of the cases, the sinuatrial nodal branch(es) formed a ring around the base of the superior cava vena. In all cases, the sinuatrial nodal branch(es) supplied collateral branches to the atrium and/or the auricle of the same side as its origin and/or to the opposite side. CONCLUSION: The low frequency of 2 sinuatrial nodal branch(es) in Brazilian individuals, compared to the higher frequency found among the Japanese, is probably due to a variation associated with ethnic group origin.

Adult↗

PubMed2000

Anatomical variation of the posterior interosseous nerve: a cadaver dissection study.

An anatomical variation of the posterior interosseous nerve was found in a cadaver. The posterior interosseous nerve entered the supinator muscle 3 cm distal to the radiohumeral joint, but exited from two sites. Fifty percent of the nerve exited under the distal edge of the supinator muscle. The other 50% of the nerve pierced through the supinator muscle, 4.2 cm distal to the articular surface of the radial head and then joined the remaining posterior interosseous nerve as it emerged from the supinator muscle distally. Variations were not found concerning the order and the manner of branches to the muscles. This variation in the posterior interosseous nerve could be an additional compression site for this nerve and therefore responsible for some of the atypical presentations of symptoms and for partial recovery after surgical decompression. Careful surgical dissection is recommended to avoid injury to this branch.

Aged↗

PubMed2004

Anatomical variations of the median nerve distribution and communication in the arm.

Anatomical variations of peripheral nerves constitute a potentially important clinical and surgical issue. The aim of this work is to study the variations of the median nerve in the arm with respect to its branching pattern and distribution as well as its possible communication with the musculocutaneous and/or ulnar nerves. Sixty arms pertaining to 30 preserved human cadavers, ranging in age from 30 to 67 years, were dissected in pursuit of this aim. In one limb out of 60 (1.7%) the median nerve gave off muscular branches to the brachialis muscle as well as a branch from its lateral root to supply both heads of the biceps brachii muscle. Concomitantly the musculocutaneous nerve was absent. The same limb demonstrated a branch from the lateral cord of the brachial plexus supplying the coracobrachialis muscle. Three limbs (5%) showed a communicating branch between the median and the musculocutaneous nerves. These observations should be considered when a high median nerve paralysis is shown to originate in the axilla or proximal arm in a patient presenting with weakness of forearm flexion and supination. Similarly, it can explain weakness of the arm flexor muscles in thoracic outlet syndrome with median nerve affection.

Adult↗

PubMed2004

Fossa navicularis: anatomic variation at the skull base.

The fossa navicularis is a relatively rare anatomic variation of the skull base. Awareness of its existence will avoid misinterpretations of radiological images and unnecessary investigations. This study describes the appearance of the fossa navicularis, and investigates its incidence and whether it is related to pathology at the basiocciput. We studied 492 dry human skulls and 525 computer tomography (CT) images of patients. Dry skulls showing a fossa navicularis were investigated by CT scan, whereas patients identified as having a fossa navicularis were further examined with magnetic resonance imaging (MRI). To document the position of the fossa more precisely, measurements were made between the fossa navicularis and certain anatomic landmarks such as the foramen ovale, the pharyngeal tubercle, the posterior border of the vomer, the foramen lacerum, the carotid canal, and the occipital condyle. Upon examination, 26 of 492 skulls (5.3%) were found to have a fossa navicularis. Twelve were <2 mm in depth and the other 14 had a depth of >/=2 mm. Of the 525 patients, 16 (3.0%) were identified as having a fossa navicularis in CT images. Evaluation of MRIs showed no soft tissue lesions in any of these patients. Comprehensive anatomic details of the fossa navicularis have not been reported in the literature. The results of this study may be useful to radiologists, anatomists, and surgeons interested in the skull base.

Bone Cysts↗

PubMed2007

Anatomical variations of the cords of brachial plexus and the median nerve.

The variations in formation, location, and courses of the cords of brachial plexus and the median nerve were studied in both axillae of 172 cadavers. The total prevalence of variation was 12.8% (CI, 7.6-17.4) and it was found in 13.2% (CI, 7.5-18) of male and in 10.7% (CI, -0.6-19.6) of female cadavers. These variations were divided into three groups. The first group was abnormal location of the cords, which was either posterolateral or anteromedial in relation to the axillary artery in 2.3% (CI, 0.1-4.5) cadavers. The lateral cord and the medial root of the median nerve had received communicating branches from the posterior cord in most of the cases of this group. The second group was absence of the posterior cord in 3.5% (CI, 0.7-6.1) of cadavers. The lateral and medial cords of this group were connected with the communicating branches, which had a course in front of the axillary artery. The third group was abnormal formation and course of the median nerve in 7% (CI, 3.1-10.6) of cadavers. In all cases of this group the medial root received communicating branch/branches either from the lateral or posterior cord. In eight (4.7%) cadavers, both roots of the median nerve were joined on medial side of the axillary artery to form a median nerve, which traveled medial to the artery. In four (2.3%) cadavers the roots of the median nerve did not join and both traveled separately anteromedial to the axillary and brachial arteries. This study indicates that all three cords and median nerve vary considerably in levels of origin, location and course in relation to the axillary artery and these variable cases were joined with the communicating branch/branches. The observed variations are of anatomical and clinical interest. These kinds of variations are more prone to injury in radical neck dissection and in other surgical operation of the axilla.

Aged↗

PubMed1986

[Anatomical variations at the level of the muscles of the arm].

The muscular anatomical variations of the thoracic member are recorded in a series of 180 subjects. Two muscles are supernumerary: a bilateral accessory coraco-brachialis and a unilateral accessory palmaris longus. Two muscles have additional tendons: the extensor carpi radialis brevis and the extensor digitorum.

Aged↗

PubMed1986

Intrahepatic termination of the left gastric vein (vena gastrica sinistra): a new case of this unusual anatomic variation.

The intrahepatic termination of the left gastric vein is an unusual anatomic variation. A new case studied after dissection is described. The left gastric vein is divided in 2 terminal branches which enter the left liver lobe after flowing through the pars condensa of the lesser omentum. One is a terminal branch which contributes to the portal irrigation of the superior lateral subsegment. The other anastomoses to the ramus cranialis of the left branch of the portal vein. The diameter of the left gastric vein, portal vein and splenic vein obtained after morphometric study can be considered normal. The existence of portal hypertension prior to death is discarded.

Aged↗

PubMed2006

Intracranial aneurysms associated with other lesions, disorders or anatomic variations.

Intracranial aneurysms (IAs) can be related to or associated with some vascular anatomic variations, lesions, diseases, or systemic disorders in which a causative or predisposing factor(s) in aneurysm formation can be identified. This article includes flow-related, infectious, traumatic iatrogenic, and neoplastic aneurysms and aneurysms related to systemic disorders and drug abuse. In some conditions, IAs associated with other disorders are true aneurysms. Most of them, however, are false aneurysms. Characteristics and management of these unusual aneurysms are discussed.

Brain↗

PubMed1991

Anatomical variation of the superficial preprostatic veins with respect to radical retropubic prostatectomy.

The anatomical variations of the veins within the retropubic adipose tissue anterior to the prostate in 160 patients undergoing radical retropubic prostatectomy are described. A single midline vein was present in approximately 60% of the cases. In another 20% there was bifurcation of the single midline vein with the majority having a right or left pelvic sidewall branch. Various anomalous distributions were present in 10% of the cases and the superficial veins were completely absent in the remaining 10%.

Adipose Tissue↗