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PubMed1994

Anatomic variations of the deep palmar arteries in man.

The deep palmar circulation is constituted by the deep palmar arch. In most cases this is a complete arch formed by the radial artery and its continuation to a deep branch of the ulnar artery. In a few cases, the deep palmar circulation is formed only by the radial or the ulnar artery. Only rarely is there a complete absence of the deep palmar arch. A series of 60 vascular casts was examined in order to identify the primary variants of the deep palmar arterial supply. Four anatomic patterns were identified: (1) radioulnar (66.67%); (2) radial-anastomotic (21.67%); (3) radial (8.33%), and (4) ulnar (3.33%). Two distinct types of the radioulnar variant were observed, a proximal and a distal one, named according to the origin of the deep palmar branch.

Corrosion Casting↗

PubMed1992

Human gut mucosal mast cells: ultrastructural observations and anatomic variation in mast cell-nerve associations in vivo.

One hundred and seventeen coded intestinal biopsy specimens were examined by electron microscopy. All surgical biopsies were obtained from uninvolved sites of patients with two inflammatory bowel diseases (ulcerative colitis or Crohn's disease) and from patients with preneoplastic and neoplastic diseases (adenocarcinoma, rectal polyp, familial polyposis). Biopsy sites included normal ileum, colon, and rectum as well as conventional ileostomies and continent pouches constructed from the ileum. The data reported here describe the ultrastructural anatomy of human gastrointestinal tract mucosal mast cells in vivo and their anatomic associations with enteric nerves.

Adenocarcinoma↗

PubMed2003

Vestibular surgical access to the palatine root of the superior first molar: "low-dose cone-beam" CT analysis of the pathway and its anatomic variations.

Apicoectomy of the superior first molar palatine root until recently involved relatively destructive and laborious surgery because of the palatal access route, which not only necessitates an extensive flap, but also the readying of procedures required to deal with a possible hemorrhage from the palatine artery. With the advent of operative microscopy, endodontic surgery has become more precise and less invasive and its technical potential has increased; a possible innovative surgical technique may entail vestibular root access. The possibility of using low-dose, low-cost computed tomography (CT) dedicated to the jaw to obtain anatomic information to plan apicoectomy via the vestibular approach was evaluated; 31 patients were referred to CT with the NewTom apparatus. In 43 superior first molars, the mean distance of the palatine root from the external vestibular cortex was measured, and the frequency that the maxillary sinus lateral recess lay between the roots was determined. The mean root apex-vestibular cortex distance was 9.73 mm. In 25% of cases the maxillary sinus recessus lay between vestibular and palatine roots. CT may play an important role in optimizing palatine root apicoectomy through vestibular access, with regard to precision and preventing complications, with relatively low biological and economic cost, also possibly contributing to the affirmation of this new surgical procedure.

Adolescent↗

PubMedDate not supplied

Anatomic variation of the mechanical properties of the glenoid.

Finite element analysis modeling is an important tool in the design of total joint replacements. However, to use a finite element analysis the material properties of the studied bone must be known. The aim of the study was to measure the elastic properties of the glenoid bone in the axial, coronal, and sagittal planes with an ultrasound transmission technique. The relative density and Houndsfield computed tomography numbers were also assessed. Three pairs of scapulas were obtained from unembalmed human cadavers. Seventy-four cubic cancellous bone specimens of 6 mm were used for ultrasonic measurements. The study showed significant differences with anatomic location. Mechanical properties of cancellous bone were found to be higher near the direction of application of the resultant force, perpendicular to the articular surface of the glenoid. Mechanical properties were found to be significantly higher at the center and posterior edge of the glenoid (p < 0.01). Significant differences were also found in the three planes studied. The lateromedial Young's modulus (E1) was higher than the anteroposterior modulus (E2) and the superoinferior modulus (E3) (E1 = 372 +/- 164 MPa, E2 = 222 +/- 79 MPa, E3 = 198 +/- 75 MPa).

Analysis of Variance↗

PubMedDate not supplied

Cervical transforaminal injection and the radicular artery: variation in anatomical location within the cervical intervertebral foramina.

BACKGROUND: Recent articles have detailed the adverse events associated with transforaminal steroid injections into the radicular arteries. Guidelines on strict transforaminal epidural techniques have been described to limit complications. There remains limited information regarding the cervical level of entry, location within the intervertebral foramina, and prevalence of the radicular arteries within the population. METHODS: With the aid of premortem angiography and postmortem latex-injected vasculature, a single detailed cadaveric dissection was performed to elucidate the specific anatomic location of the radicular arteries within the intervertebral foramina and the anastomoses of the arteries to the anterior spinal artery. RESULTS: Five radicular arteries (C5, C6, two at C7, C8) were traced entering the foramina either anteriorly or posteriorly to supply the anterior and posterior spinal arteries. Radicular arteries received blood supply from either the deep cervical (C8) or vertebral arteries. The C8 radicular artery entered the lateral aspect of the foramen and penetrated the dural sleeve within the inferior portion of the foramen, directly inferior to the exiting spinal nerve, to supply the anterior spinal artery. This artery was of a large enough caliber to be entered by a 22-gauge needle. CONCLUSIONS: A larger population is necessary to characterize the range of anatomic variations in arterial supply within the foramina. Available studies support the current technique of fluoroscopic needle insertion. Yet, there is wide anatomic variation in the origin and location of these vessels, and even with strict adherence to technique, it is feasible that a properly placed needle could penetrate a radicular artery.

Arteries↗

PubMed2004

Superficial branch of the radial nerve piercing the brachioradialis tendon to become subcutaneous: an anatomical variation with clinical relevance.

We dissected 20 preserved Caucasian cadaveric upper limbs looking at the relation of the superficial branch of the radial nerve (SBRN) to the brachioradialis tendon. SBRN emerged from deep to superficial position by piercing the brachioradialis tendon near its dorsal border in four limbs. The resulting dorsal tendinous band compressed the nerve and prevented longitudinal gliding movement during ulnar flexion. This is likely to increase the risk of chronic compression neuropathy (Wartenberg's syndrome). In two of these four limbs, there was a communication between the SBRN and lateral cutaneous nerve of the forearm. No such communication was found in the remaining 16 forearms. This communication could contribute to the minimal area of sensory loss observed in Wartenberg's syndrome. We recommend that this anatomical anomaly is looked for and if present dealt with during surgical treatment of Wartenberg's syndrome, as it is likely to predispose to chronic compression neuropathy.

Cadaver↗

PubMed1992

Anatomic variations of surgical importance in ethmoid labyrinth and sphenoid sinus. A study of radiological anatomy.

The present study was performed on axial and coronal CT scans of 100 patients, most of whom were affected by nasal polyposis. Five observers had to analyse the radiograms and answer a questionnaire including the following items: presence of a supraorbital recess; identification of anterior and posterior ethmoidal canals; dehiscences in the lamina papyracea; pneumatized middle turbinate; presence of a sphenomaxillary plate; presence of Haller's cells; presence of Onodi's cells; relationships of the optic canal; relationships of the internal carotid artery; relationships of the maxillary nerve; relationships of the vidian nerve; level difference between the ethmoid roof and nasal vault; depth of the sphenoethmoidal recess. The data obtained were compared with those drawn from anatomical studies. The fair agreement between them proves the value of CT as an alternative method for studying paranasal sinuses anatomy.

Ethmoid Bone↗

PubMed1992

Lateral arcuate ligaments of the diaphragm: anatomic variations at abdominal CT.

The authors have occasionally observed nodular areas abutting the lateral diaphragmatic surface and extending into the posterior pararenal space on computed tomographic (CT) scans. Review of the anatomy literature revealed that this finding represents inferolateral extension of the lateral arcuate ligaments, which reflect over the quadratus lumborum muscles to fuse with the diaphragm. CT scans from 100 consecutive patients were reviewed to determine the frequency, relationship to habitus, and appearance of this finding. Nodularity was found in five patients (bilateral in three, unilateral in two). The average size was 9.4 mm in the transverse plane, 6.3 mm in the anteroposterior plane, and 4.3 cm in the cephalocaudal plane. The extent of retroperitoneal fat was normal in all five patients. In one patient, there were easily visible lobulations; three patients had prominent lobulations, and one patient had few lobulations. It is important to recognize this anatomic variant to avoid confusion with disease.

Adult↗

PubMedDate not supplied

Anatomic variations of the human cochlear aqueduct. A radioanatomic investigation.

The cochlear aqueduct follows a course through the petrous pyramid that varies from straight and steeply vertical to a curvilinear and horizontal. Its course and length are correlated to the pneumatization of the pyramid and also to the volume of the jugular fossa. These two factors influence the radiographic reproduction of the cochlear aqueduct, especially in computed tomography in the axial transverse projection but to a far lesser degree in multidirectional tomography.

Cochlea↗

PubMed1999

Anatomic variation in the origin of the main renal arteries: spiral CTA evaluation.

The aim of this study was to provide quantitative data on the origin and trajectory of the main renal arteries using spiral CT angiography and arteriography. Normal renal artery anatomy was assessed on spiral CT angiography (axial transverse sections and shaded-surface-display reconstructions) in 100 patients referred for renal arteriography who had no significant renal artery stenosis. Two hundred major renal arteries were studied. The vast majority of right (88 %) and left (87 %) renal arteries originated between the lower third of the first lumbar vertebra and the lower border of the second lumbar vertebra. In 50 patients both ostia were at the same level; in the remaining 50 patients, the right ostium was located above the left in 37 patients. On the right, the angle of origin varied from -10 to + 55 degrees (mean + 24 degrees ). On the left, the angle of origin varied from + 30 to -55 degrees (mean -11 degrees ). Spiral CT angiography provides additional anatomic data, notably regarding the angle of origin of the renal arteries, that is potentially useful for planning interventional procedures.

Aged↗

PubMed1976

Anatomic variations in underdeveloped right ventricle related to tricuspid atresia and stenosis.

In the anatomy of 416 hearts, the seat of tricuspid stenosis or atresia is examined, with special reference to Fontan-like surgical procedures. A classification is offered which includes cases with and without regular or inverted transposition, and with decreased or increased pulmonary flow. The size and thickness of the right atrium, the size and architecture of the right ventricle, the size of the pulmonary tree, the types of atrial and ventricular septal defects, the condition of the mitral valve, and the size and thickness of the left atrium and left ventricle are analyzed. In addition the various intracardiac and extracardiac abnormalities are enumerated. Reference is also made to the tendency of the aorta and pulmonary trunk to override the septum, in some cases producing double-outlet left ventricle. It is considered that many cases of tricuspid valve atresia and stenosis with or without transposition may be amenable to Fontan-like procedures in the proper age group. All the above anatomic considerations have a bearing on the suitability and type of operative tricuspid bypass procedures, and they may influence the prognosis of surgical therapy.

Abnormalities, Multiple↗

PubMed1995

The pineal gland: a comparative MR imaging study in children and adults with respect to normal anatomical variations and pineal cysts.

This study was undertaken to evaluate the variations in appearance of the normal pineal gland. The findings of 1000 consecutive MR imaging examinations obtained at 0.5 T were studied. The age of the patients ranged from 1 day to 83 years, and findings in children and adults were compared. In all age groups the pineal gland appeared mainly in three forms: (1) nodule-like, (2) crescent-like and (3) ring-like. Overall prevalences of these forms were 52%, 26% and 22%, respectively. Apparent differences in frequencies were evident in children and adults with respect to the crescent- and ring-like types. Cystiform pineal lesions 5 mm or larger in one diameter (anteroposterior, sagittal or transverse) were taken to be true pineal cysts, when compared with the gland's ring-like appearance (less than 5 mm). Pineal cysts had a prevalence of 0.6% in children and 2.6% in adults. No symptomatic pineal cyst with mass effect on the lamina tecti was detected in the series. Besides identifying the three anatomical types of the pineal gland as seen on MR imaging and addressing the potential significance of differences in their frequencies in children and adults, the author tries to explain the previous discrepancy between the MR imaging and autopsy series findings with respect to frequencies of the pineal cysts.

Adolescent↗

PubMed2003

[An ischemic syndrome of the oculumotor nucleus: associated clinical and anatomical variations on a theme].

Nuclear syndrome of the oculomotor nerve was first described in 1981, it is characterized by the association of an ipsilateral third nerve palsy with a paresis of elevation in the contralateral eye. This syndrome can be caused by vascular or tumoral lesions in the upper midbrain. It is rarely due to ischemic unilateral mesencephalic lesions, because ischemic lesions of the midbrain are usually integrated in a diffuse involvement of the brainstem and the thalamo-sub-thalamic region. In case of nuclear syndrome of the third nerve due to isolated upper midbrain infarct in the paramedian territory, dependent on branches of the basilar artery, oculomotor symptoms are frequently isolated. On the contrary, in fascicular syndromes of the third nerve, resulting from stroke in more lateral territories upon branches of the posterior cerebral artery, many neurological symptoms are associated with the oculomotor signs. We describe 3 patients presenting with a characteristic nuclear syndrome of the third nerve, resulting from a unilateral paramedian ischemic stroke in the upper midbrain, confirmed by cerebral CT scan or MRI examination. Clinical presentation differed in each case, and marked contralateral hemiparesia, cerebellar syndrome and focal asterixis were associated in various ways with the stereotyped oculomotor disorders. In the 3 cases, the nuclear syndrome of the third nerve was associated with fascicular involvement of the nerve, in an unusual clinical picture. The theoretical distinction between nuclear and fascicular syndromes is supported by the anatomical description of the arterial segmentation in the upper midbrain, which remains debated since the first description. According to the variability of clinical presentations, it seems that the arterial territories may be more variable than initially described. Therefore, ischemic lesions of the upper midbrain may involve some vascular borderzones with a high inter-individual variability. Upper midbrain strokes may thus lead to variable clinical pictures.

Aged↗

PubMed1999

Anatomical variations in the origin of the human ophthalmic artery with special reference to the cavernous sinus and surrounding meninges.

The origin of the human ophthalmic artery (OA) and surrounding structures was investigated in 109 cadavers by three different methods: macroscopic, stereomicroscopic, and histological observations. The following results were obtained. (1) Macroscopic observation: In 39% of the specimens the origin of the OA was observable in the cranial cavity and defined as the intradural (i.d.) type. The other 61% were named the extradural (e.d.) type. (2) Stereomicroscopic observation: In 59% of the cases, the OA originated from the internal carotid artery over or on the cavernous roof and at least a part of the OA was exposed within the cranial cavity. In the other 41% the OA originated within the cavernous wall or cavity and entered directly the optic dural sheath, thus no part of the OA was visible in the cranial cavity. Therefore, approximately 20% of the origins of the OA might be of the i.d. type, although they could not be macroscopically identified in the cranial cavity since they might emanate from the internal carotid artery between the optic canal and the optic nerve, even above the cavernous roof. (3) Histological observation: The proximal portion of the OA runs alongside the optic nerve within the subarachnoid space in the cases of the i.d. type. In contrast, the corresponding portion of the e.d. type was embedded in the dense fibrous tissue which was continuous both with the dura mater of the cavernous wall and the periosteum of the sphenoid. These anatomical data may provide important information for understanding the variety of the pathology in this region and is also useful for designing operative strategies.

Adolescent↗

PubMed2006

Anatomic variations and MRI of the intermalleolar ligament.

OBJECTIVE: The purpose of this study was to identify the intermalleolar ligament morphologically and to correlate its shape with MR images. MATERIALS AND METHODS: Seventy-seven ankles were used in this study. After the intermalleolar ligament had been located in the posterior ankle space, its medial and lateral attaching sites were identified, and its length, width, and thickness were measured. MRI was performed on 26 ankles before they were dissected (20 specimens) or serially sectioned (six specimens). The serial sections were taken at a thickness of 2 mm in the sagittal and horizontal directions. RESULTS: The intermalleolar ligament was observed in 81.8% of the specimens and was composed of more than two bundles of fibers in all cases. The medial arising sites of the ligament were diverse (e.g., from the medial malleolus to the floor of the fibrous tunnel of the flexor hallucis longus). The ligament narrowed laterally and attached with the posterior talofibular ligament to the medial fossa of the lateral malleolus. Their morphologic shapes were also diverse, depending on their medial arising sites, the number of the composing fiber bundles, and the degree of bundle compactness. The intermalleolar ligament appeared as a thick string or as more than two fine parallel stripes on coronal MR images and as a linear structure on axial images. On sagittal images, the ligament appeared as scattered dots in the medial part and as a thin flat or nodular structure in the lateral part. CONCLUSION: The intermalleolar ligament seemed to be an almost invariably present anatomic entity with diverse morphologic features on MR images.

Adult↗

PubMed2006

The cochlear-carotid interval: anatomic variation and potential clinical implications.

BACKGROUND AND PURPOSE: A temporal bone CT study in a patient with episodic mid-tone sensorineural hearing loss and tinnitus demonstrated absence of bone between the petrous internal carotid artery and the basal turn of the cochlea. The potential implications with respect to increasingly popular cochlear implant surgery compelled us to retrospectively analyze a series of temporal bone CT scans to establish typical measurements for this region, which we termed the "cochlear-carotid interval" (CCI). METHODS: After IRB exemption, 2 observers independently measured the bony interval between the cochlea and the petrous internal carotid artery canal on coronal images from 30 consecutive temporal bone CT studies. The 1-mm thick coronal images were either acquired directly or were reconstructed from an axial dataset acquired at 0.75 or 0.6 mm section thickness. All measurements were performed by using electronic calipers on a Sienet MagicView VE 42 Siemens PACS station. Mixed model analysis of variance was used to evaluate differences between readers and sides with respect to the mean CCI but adjusted for age and accommodating the correlation among observations generated for the same subject. RESULTS: The patient in our case report had a right CCI of 0.2 mm and left CCI of 0.0 mm. In the other 30 patients, the right CCI ranged from 0.2 to 3.8 mm (mean, 1.2 +/- 0.8 mm; median, 0.9) and the left CCI from 0.2 to 5.0 mm (mean, 1.1 +/- 0.9 mm; median, 0.8). The CCI did not exhibit a significant association with subject age (P = .1336), and there were no significant differences between readers (P = .824) or sides (P = .350) in terms of mean CCI. CONCLUSION: The CCI varies widely between patients and may be as small as zero. Analysis of anatomic relationships suggests a potential relationship between small CCI and mid-tone sensorineural hearing loss, as in our reported patient. Preoperative knowledge of thin or absent bone between the cochlea and petrous carotid canal may help prevent inadvertent penetration of the carotid canal during cochlear implant surgery.

Adolescent↗

PubMed2002

Anatomical variations of the arterial pattern in the right hemiliver.

The arterial supply to the right hemiliver was studied in 80 liver casts. The arteries were divided into 10 groups according to their origin and branching pattern. The right hemiliver was supplied by one artery in 96% of cases and by two arteries in 4%. When there was only one artery it originated from the proper hepatic artery in 73/77 cases and from the superior mesenteric artery in 4/77 cases. The replacing right hepatic artery which originated from the superior mesenteric vessel supplied the whole right hemiliver in 5% of cases. The incomplete replacing right hepatic artery which supplied only a part of the right hemiliver was found in 4% of cases. The anterior section (segments 5 and 8) was supplied by one artery in 61%, by two arteries in 30% and by three arteries in 9% of cases. The posterior section (segments 6 and 7) was supplied by one artery in 66%, by two arteries in 31% and by three arteries in 3% of cases. Segments 5 and 7 were predominantly supplied by one artery, whereas segments 6 and 8 by two arteries.

Autopsy↗

PubMed2002

Anatomic variation of prescription points and treatment volume with fractionated high-dose rate gynecological brachytherapy.

The purpose of this report is to evaluate the geometric movement (relative to the bony pelvis) and dose variation of brachytherapy reference points in the same patient at repeated high-dose rate (HDR) intracavitary implants. A study was also concluded to find the variation in treatment volume from repeated fractions. Twenty-five consecutive cervical cancer patients (all stages) treated with external beam and fractionated HDR intracavitary implants at the University of Wisconsin were reviewed. Each brachytherapy insertion had a different plan generated prior to treatment delivery. ICRU #38 prescription points (A, B, P, bladder, and rectum) were used. Dose volume histogram was generated and treated volume to the prescription dose was recorded for each fraction. Motion analysis of the various points (from a common origin) in subsequent fractions relative to the first fraction revealed a shift of 2-9 mm in a single plane. Vector analysis revealed the magnitude of the average shift ranged from 10-13 mm. These shifts resulted in a dose difference of >20% for the bladder and rectum points, but < than 8% for the other points. Dose volume histograms revealed that with the change in the anatomy of the cervix and upper vagina during a patient's course of treatment, the treatment volume changes considerably. Thirty-six percent of all patients (9/16) had a reduction in the size of the ovoid during the treatment course. Sixty percent of all patients (15/25) had volume changes <10%. Sixty-two and one half percent of patients (10/16) who did not undergo a reduction of avoid size during the entire course of the treatment had volume change <10%. Since there is a change in the anatomy of the cervix and upper vagina during the course of a treatment along with the irreproducibility of the packing, there is movement of the absolute position of the prescription points between fractions, thus emphasizing the importance of individual dosimetry. Moreover, due to the same reasons, there are significant changes in the treatment volume among implants for the same patient. Volume reduction caused by reduction in ovoid size alone could not be extracted from this study.

Brachytherapy↗