True Lateral Projection Research Articles

Correction to: Development of non-contact patient head alignment device (HEAD) for X-ray imaging for skull true lateral projection

Correction to: Development of non-contact patient head alignment device (HEAD) for X-ray imaging for skull true lateral projection

Development of non-contact patient head alignment device (HEAD) for X-ray imaging for skull true lateral projection

The purpose of this study was to evaluate the accuracy of the developed auxiliary head alignment device for true X-ray skull lateral projection and evaluate the accuracy of skull true lateral imaging according to the use of this device by applying a skull phantom. The developed non-contact patient head alignment device (HEAD) for radiography was intended to enable someone with minimal experience with X-ray imaging to inspect an accurate skull true lateral projection and ensure the reproducibility of the inspection. The tilting and rotation of the skull X-ray images were evaluated by comparing the positions of the mandibular condylar processes observed from both sides. A paired t test was performed for the differences in tilting and rotational changes before and after using the HEAD for skull lateral projection. In addition, the interclass correlation coefficient (ICC) was used for reliability evaluation according to the use of the HEAD at different times. The mean length of the left and right intervals of both intercondylar processes indicating rotation before and after the use of the HEAD was 7.25 ± 2.62 and 2.24 ± 1.32, respectively (p < 0.01). The upper and lower intervals of both intercondylar processes indicating tilting of the head were 8.18 ± 2.24 without the HEAD and 2.60 ± 1.92 using the device (p < 0.01). Using the developed HEAD, a skull lateral X-ray image with very accurate information for the patient’s diagnosis can be acquired

Real 3D Visualization of the Circumflex Artery Surrounding the Mitral Annulus.

The circumflex coronary artery is located close to the mitral annulus. Consequently, it is not immune to iatrogenic damage during mitral valve procedures. Our objective was to visualize the circumflex artery from a surgeon's point of view, emphasizing its proximity. Furthermore, comparing it to coronary angiograms might support preoperative planning. Ten adult human hearts preserved in 4% formaldehyde solution were investigated (left coronary artery injected with contrast agent). After performing coronary angiographies from LAO (left anterior oblique) 40/cranial 20, RAO (right anterior oblique) 10/cranial 40, and true lateral projections, anatomical preparations were performed. Images were captured throughout the full course of the circumflex coronary artery from multiple angles. Finally, the mean distances were measured in every 5 mm between the investigated artery and the annulus of the mitral valve. Three-dimensional model of the circumflex coronary artery and its surroundings was successfully achieved from a left atrial surgical viewpoint. The main branches were identified on the coronary angiograms. The closest distance was measured under the region of the left auricle (2.02 ± 0.69 mm; 1-3.1 mm). Afterward, the circumflex artery was observed to make a loop away from the annular region. Our observations show correlation with previous anatomical studies and case reports addressing iatrogenic lesions on the circumflex coronary artery. Based on all these, we could determine a "danger zone" on the vessel. The simultaneous evaluation of the anatomical preparations and the angiograms might improve the acknowledgment of this vulnerable region serving to avoid any damage to the coronary artery.

Tangential View and Intraoperative Three-Dimensional Fluoroscopy for the Detection of Screw-Misplacements in Volar Plating of Distal Radius Fractures.

Background:Volar locking plate fixation has become the gold standard in the treatment of unstable distal radius fractures. Juxta-articular screws should be placed as close as possible to the subchondral zone, in an optimized length to buttress the articular surface and address the contralateral cortical bone. On the other hand, intra-articular screw misplacements will promote osteoarthritis, while the penetration of the contralateral bone surface may result in tendon irritations and ruptures. The intraoperative control of fracture reduction and implant positioning is limited in the common postero-anterior and true lateral two-dimensional (2D)-fluoroscopic views. Therefore, additional 2D-fluoroscopic views in different projections and intraoperative three-dimensional (3D) fluoroscopy were recently reported. Nevertheless, their utility has issued controversies.Objectives:The following questions should be answered in this study; 1) Are the additional tangential view and the intraoperative 3D fluoroscopy useful in the clinical routine to detect persistent fracture dislocations and screw misplacements, to prevent revision surgery? 2) Which is the most dangerous plate hole for screw misplacement?Patients and Methods:A total of 48 patients (36 females and 13 males) with 49 unstable distal radius fractures (22 x 23 A; 2 x 23 B, and 25 x 23 C) were treated with a 2.4 mm variable angle LCP Two-Column volar distal radius plate (Synthes GmbH, Oberdorf, Switzerland) during a 10-month period. After final fixation, according to the manufactures' technique guide and control of implant placement in the two common perpendicular 2D-fluoroscopic images (postero-anterior and true lateral), an additional tangential view and intraoperative 3D fluoroscopic scan were performed to control the anatomic fracture reduction and screw placements. Intraoperative revision rates due to screw misplacements (intra-articular or overlength) were evaluated. Additionally, the number of surgeons, time and radiation-exposure, for each step of the operating procedure, were recorded.Results:In the standard 2D-fluoroscopic views (postero-anterior and true lateral projection), 22 screw misplacements of 232 inserted screws were not detected. Based on the additional tangential view, 12 screws were exchanged, followed by further 10 screws after performing the 3D fluoroscopic scan. The most lateral screw position had the highest risk for screw misplacement (accounting for 45.5% of all exchanged screws). The mean number of images for the tangential view was 3 ± 2.5 images. The mean surgical time was extended by 10.02 ± 3.82 minutes for the 3D fluoroscopic scan. An additional radiation exposure of 4.4 ± 4.5seconds, with a dose area product of 39.2 ± 14.5 cGy/cm2 were necessary for the tangential view and 54.4 ± 20.9 seconds with a dose area product of 2.1 ± 2.2 cGy/cm2, for the 3D fluoroscopic scan.Conclusions:We recommend the additional 2D-fluoroscopic tangential view for detection of screw misplacements caused by overlength, with penetration on the dorsal cortical surface of the distal radius, predominantly observed for the most lateral screw position. The use of intraoperative 3D fluoroscopy did not become accepted in our clinical routine, due to the technical demanding and time consuming procedure, with a limited image quality so far.

Biomechanical Characteristics of Hemi-Hamate Reconstruction Versus Volar Plate Arthroplasty in the Treatment of Dorsal Fracture Dislocations of the Proximal Interphalangeal Joint

To compare stability and range of motion after hemi-hamate reconstruction versus volar plate arthroplasty in a biomechanical proximal interphalangeal (PIP) joint fracture-dislocation model. Eighteen digits from 6 cadaver hands were tested. We created defects of 40%, 60%, and 80% in the palmar base of each digit's middle phalanx, simulating an acute PIP joint fracture-dislocation. Each defect scenario was reconstructed with a hemi-hamate arthroplasty followed by a volar plate arthroplasty. A computer-controlled mechanism was used to bring each digit's PIP joint from full extension to full flexion via the digital tendons in each testing state, and in theintact state. During each testing scenario we collected PIP joint cinedata in a true lateral projection using mini-fluoroscopy. A digital radiography program was used to measure the amount of middle phalanx dorsal translation (subluxation) in full PIP joint extension. We recorded the angle at which subluxation, if present, occurred during each testing scenario. Average dorsal displacement of the middle phalanx in relation to the proximal phalanx was 0.01 mm for the hemi-hamate reconstructed joints and -0.03 mm for the volar plate arthroplasty, compared with the intact state. Flexion contractures were noted in each of the specimens reconstructed with volar plate arthroplasty. Degree of contracture was directly correlated with defect size, averaging 20° for 40% defects, 35° for 60% defects, and 60° for 80% defects. We observed no flexion contractures in the hemi-hamate reconstructions. Surgeons can use both hemi-hamate and volar plate arthroplasty to restore PIP joint stability following a fracture dislocation with a large middle phalanx palmar base defect. Use of volar plate arthroplasty led to an increasing flexion contracture as the middle phalanx palmar base defect increased. Clinicians can use the information from this study to help with surgical decision-making and patient education.

Defining the Lateral and Accessory Views of the Patella

The majority of orthopaedic surgeons rely on a lateral fluoroscopic image to assess reduction during patella fracture osteosynthesis. However, a comprehensive radiographic description of the lateral view of the patella has not been performed previously, and no accessory views to better visualize specific anatomic features have been developed. The purpose of this study was to provide a detailed anatomic description of all radiographic features of the true lateral of the patella, describe reproducible accessory views for assessing specific features of the patella, and demonstrate their utility in a fracture model. Twelve cadaver knee specimens free of patellofemoral pathology were used, and imaging was performed using standard C-arm fluoroscopy. For each specimen, a true lateral radiographic projection of the patella was obtained and distinct features were noted. Next, an arthrotomy was made and steel wire was contoured and fixed to various anatomic regions of the patella so as to obliterate the radiographic densities on the true lateral projection, thus confirming their anatomic correlation. Ideal views of the lateral and medial facets themselves were determined using radiographic markers and varying amounts of internal or external rotation of the specimen. Last, a transverse osteotomy was created in each patella and the ability of the true lateral and accessory views to detect malreduction was assessed. The true lateral projection of the patella was obtained with the limb in neutral alignment. Constant radiographic features of the lateral view of the patella include the articular tangent, a secondary articular density of variable length, and a dorsal cortical density. The articular tangent was produced by the central ridge between the medial and lateral facets in all specimens. The secondary articular density was created by a confluence of the edge of the lateral and edge of the medial facets in 5 patellas, a confluence of the edge of the lateral facet and the intersection of the odd and medial facets in 6 patellas, and the edge of the lateral facet alone in 1 patella. The edge of the lateral facet gave a constant contribution to the appearance of the secondary articular density in all cases. A distinct accessory view of the tangent of the lateral facet could be seen with an average of 17 degrees of patella external rotation (range, 12-35 degrees), and the tangent of the medial facet with an average of 26.5 degrees of internal rotation (range, 15-45 degrees). These accessory views were better able to visualize malreduction than the single lateral projection in a fracture model in all specimens. Described here is a comprehensive description of the true lateral radiographic view of the patella and accessory views. These views can be used in the evaluation of minimally displaced patella fractures if a computerized tomography is not desired to better assess the true amount of displacement and when assessing intraoperative reduction during patella fracture osteosynthesis.

Stability of Acute Dorsal Fracture Dislocations of the Proximal Interphalangeal Joint: A Biomechanical Study

We performed a cadaveric biomechanical study to characterize proximal interphalangeal joint stability after an injury to different amounts of the volar articular base of the middle phalanx (intact, 20%, 40%, 60%, and 80% volar defects). Eighteen digits on 6 hands were tested through full proximal interphalangeal joint range of motion using computer-controlled flexion and extension via the digital tendons. We collected proximal interphalangeal joint kinematic cine data in a true lateral projection with mini-fluoroscopy. We measured the amount of dorsal middle phalanx translation in full proximal interphalangeal joint extension. As we cycled the joint from full flexion into extension, we recorded the angle at which subluxation occurred. No specimens with 20% volar bony defect subluxated. All specimens in the 60% and 80% groups subluxated at an average flexion angle of 67° (range, 10° to 90°) in the 60% group and at all degrees of flexion in the 80% group. In the 40% group, 28% of specimens demonstrated subluxation at an average flexion angle of 14° (range, 4° to 40°). Mean dorsal translation of the middle phalanx in relation to the proximal phalanx at full digital extension was 0.2 mm in the 20% group, 0.8 mm in the 40% group, 3.2 mm in the 60% group, and 3.1mm in the 80% group. Simulated volar articular bony defects of 20% were stable, whereas those with 60% and 80% defects were unstable during digital motion. Stability in the 40% group was variable and appeared to be the threshold for stability. Knowledge of the typical amount of middle phalanx defect and degree of proximal interphalangeal joint extension that can lead to joint instability may improve management of mechanically important proximal interphalangeal joint fracture dislocations.

Radiographic recognition of the sacral alar slope for optimal placement of iliosacral screws: a cadaveric and clinical study.

Malpositioning of iliosacral screws happens more often when common variations in the morphology of the upper sacral segments are unrecognized. Radiological-anatomic correlations of sacral anatomy were studied in 10 fresh-frozen cadaveric pelvises without evidence of skeletal disease, obtained from six male and four female donors. Eighty consecutive patients with complicated pelvic fractures treated operatively by the same surgeon using percutaneously placed iliosacral screws were evaluated. Variations in the sacral alar anatomy and slope found in upper sacral segmentation anomalies are common. Surgically important and predictable abnormal morphological patterns can be easily identified using pelvic outlet and lateral sacral plain radiographs along with computed tomographic scans. On the true lateral projections, the iliac cortical density adjacent to the sacroiliac joint parallels the sacral alar slope and is almost always caudal and posterior to it; it delineates the anterior extent of the "safe zone" for iliosacral screw insertion. Thus, the lateral sacral image provides the surgeon with a better understanding of the sacral alar slope and can help prevent iliosacral screw placement errors. The lateral sacral image should always be used intraoperatively with the inlet and outlet images to guide iliosacral screw placement.

Osteoarthritis of the knee: comparison of radiography, CT, and MR imaging to assess extent and severity.

Although conventional radiography is the method most frequently used for monitoring progression of osteoarthritis, it may not show osteoarthritic changes of the knee until late in the disease, and it may show involvement of only one or two compartments in patients who have tricompartmental disease. We compared radiography, CT, and MR imaging for assessing the extent and severity of osteoarthritis of the knee in 20 patients. Radiography included posteroanterior weight-bearing, true lateral, and sunrise patellar projections. Axial CT scans were reformatted in sagittal and coronal planes. MR imaging consisted of spin-echo (600-800/20; 2000/60, 120 [TR/TE]), and gradient-echo (600/30, theta = 30 degrees) sequences. The severity of osteoarthritic changes was graded from 0 to 3. MR frequently showed tricompartmental cartilage loss when radiography and CT showed only bicompartmental involvement in the medial and patellofemoral compartments. In the lateral compartment, MR showed a higher prevalence of cartilage loss (60%) than radiography (35%) and CT (25%) did. In the medial compartment, CT and MR showed osteophytes in 100% of the knees, whereas radiography showed osteophytes in only 60%. Notably, radiography often failed to show osteophytes in the posterior medial femoral condyle. On MR images, meniscal degeneration or tears were found in all 20 knees studied. Partial and complete tears of the anterior cruciate ligament were found in three and seven patients, respectively. MR is more sensitive than radiography and CT for assessing the extent and severity of osteoarthritic changes and frequently shows tricompartmental disease in patients in whom radiography and CT show only bicompartmental involvement. MR imaging is unique for evaluating meniscal and ligamentous disease related to osteoarthritis.

Disruption of the radiocapitellar line in the normal elbow

Disruption of the radiocapitellar line (RCL) can be a useful sign in injured elbows in children. Although originally described only in the true lateral projection, it has become generally accepted to apply the sign to any radiographic projection. However, it is not clear how to draw the line in the anteroposterior projection when there is prominent bowing of the radial shaft. Five cases are presented where the RCL, when drawn on radiographs of uninjured elbows, either did not pass through the capitellum (one case) or only passed tangential to it (four cases). In these cases, the elbow was not in the standard anteroposterior or lateral position. Radiologists and clinicians involved in trauma should be aware that radiographic positioning and normal bowing of the radial shaft can affect the validity of this sign and that it is best applied only to the true lateral projection as originally described.

Idiopathic scoliosis in three dimensions. A radiographic and morphometric analysis.

Eleven articulated scoliotic spines were examined radiographically and morphometrically. Measurement of the curve on anteroposterior radiographs of the specimens gave a mean Cobb angle of 70 degrees, though true anteroposterior radiographs of the deformity revealed a mean Cobb angle of 99 degrees (41% greater). Lateral radiographs gave the erroneous impression that there was a mean kyphosis of 41 degrees while true lateral projections revealed a mean apical lordosis of 14 degrees. Morphometric measurements confirmed the presence of a lordosis at bony level, the apical vertebral bodies being significantly taller anteriorly (P less than 0.02). There were significant correlations (P less than 0.01) between the true size of the lateral scoliosis, the amount of axial rotation and the size of the apical lordosis. This study illustrates the three-dimensional nature of the deformity in scoliosis and its property of changing in character and magnitude according to the plane of radiographic projection.

The role of radiography and computerized tomography in the diagnosis of subluxation and dislocation of the distal radioulnar joint

The diagnosis of an isolated subluxation or dislocation of the distal radioulnar joint (DRUJ) may be extremely difficult to make from the standard radiographic examination. Radiographs and computerized tomographic (CT) scans of cadaver wrists were used to evaluate subluxation and dislocation of the DRUJ. Both subluxation and and dislocation could be accurately diagnosed from a true lateral radiographic projection of the wrist with the forearm in neutral rotation. Minimal supination or pronation of the forearm led to inaccurate diagnosis. A single CT scan through the DRUJ was diagnostic for subluxation and dislocation in all positions of forearm rotation. Wrist pain, plaster immobilization, or suboptimal wrist positioning may make it impossible to obtain a perfect lateral view of the wrist, thereby precluding the radiographic diagnosis of DRUJ subluxation and dislocation. In this instance, a single CT scan through the DRUJ is recommended.

Gonad dose in cineurethrocystography.

The technical factors used for cineurethrocystography for the true lateral projection in females are given. The midline radiation dose has been measured with LiF TLD inserted into the vagina in 19 examinations. The average dose recorded was 148 mrad, the range being 50 to 306 mrad; the average number of cine frames exposed was 96. Data obtained using a Rando phantom indicated that the average ovary dose would be 30% greater than the mid-line dose since the near ovary receives a higher dose than the more distant one. The technique used for men is also given, the average gonad dose in six men being 123 mrad, range 56 to 243 mrad when simple lead foil gonad protection was used; the average number of cine frames was 107. The dose in one man without gonad protection was 1575 mrad for 112 cine frames. The results for both sexes compare favourably with those of others reported in the literature and with gonad doses recorded in typical IVP examinations.

Multidirectional tomography in reconstructive middle ear surgery.

The tomographic demonstration of essential structural details before reconstructive middle ear surgery with osseous auto- and homografts is described, and the preoperative information requirements are briefly discussed. The tomographic appearance of the different types of reconstruction is presented. The halfaxial and true lateral projections are to be preferred, if necessary complemented by the axial-pyramidal projection. Tomography may disclose obvious morphologic causes of absence of postoperative hearing improvement or secondary hearing impairment.

Lateral projections with inclined head for angiography of basal cerebral aneurysms.

Inclined lateral projections prove useful in defining aneurysms situated about the circle of Willis. For these projections, the x-ray tube and film changer are positioned as for a true lateral projection. The MCA lateral projection (patient's head inclined away from the side of injection) is valuable in investigating aneurysms of the internal carotid artery, posterior communicating artery and middle cerebral artery trifurcation. The ACA lateral projection (head inclined toward the side of injection) may be used to define aneurysms in the region of the anterior communicating artery.

Autotomography of the upper dorsal region.

Adequate visualization of the cervical and thoracic vertebrae is essential to correct diagnosis. The greater portion of this part of the spine can be fairly easily examined by any of a number of projections. Unfortunately, one of the most useful, the lateral projection, is difficult to obtain in the region lying between the seventh cervical vertebra and the third thoracic vertebra. Autotomography yields good to excellent visualization of this area in the true lateral projection. The method of autotomography is applied generally to the head and upper neck region and has been used more extensively in Europe than in this country. We have applied the principle of rotation to the upper thoracic and lower cervical spine regions. We have found the best method to date to be as follows. The patient is seated on a fairly rigid structure in the true lateral position with arms extended at right angles to the spine and crossed so that the hands grasp the elbows (Fig. 1). The elbows are then moved horizontally back and...

Changes due to trauma in the fat plane overlying the supinator muscle: a radiologic sign.

Aradiolucent fat plane may be recognized parallel to the ventral aspect of the proximal one third of the radius in virtually all normal lateral radiographs of the elbow. Alterations are seen in trauma or inflammatory disease processes. Recognition of widening, blurring, and ventral displacement is often useful in interpretation. It has been found to be particularly helpful in subtle fractures of the.head and neck of the radius. Anatomic Observations A twenty-three year old male fell on his outstretched hand (Case I). The lateral view of the opposite normal elbow, Figure 1, A, illustrates a well defined radiolucent line (arrowheads). It arises from the elbow joint and runs distally in a gentle ventral curve parallel to the proximal third of the radius. In contrast, the usual distortion associated with radial head and neck fracture is demonstrated in Figure 1, B with the fat line widened, blurred, and ventrally displaced. Figure 1, C is an oblique view, obtained because of the soft-tissue findings, which illustrates a fissure fracture of the radial head which was not evident in the frontal film. The location of the fat line was established by anatomic dissection of the cadaver elbow joint in which the fat plane was observed radiologically in the true lateral projection prior to the dissection. The immediate posterior relations of the fat plane are the supinator muscle and the proximal end of the radius. The principal anterior relations are the pronator teres and the brachioradialis muscles. In the majority of adults, the fat plane lies within one cm from the ventral margin of the radius. In patients with very muscular arms, this distance may range up to 1.3 cm. The variation between two normal sides is usually only 1 to 2 mm, whereas the difference noted with a fracture is invariably much greater. Radiologic Observations Two hundred and fifty consecutive cases of elbow trauma were reviewed. During the period of study a lateral film of the opposite normal elbow was obtained for comparison. The records of an additional 50 adult patients with nontraumatic conditions, principally arthritides and infections of the elbow joint, were also reviewed. Fifty pediatric cases of elbow injury from Winnipeg Children's Hospital and Montreal Children's Hospital were also assessed in a similar manner. Radial head and neck fractures constitute the group of greatest interest because this type of fracture may be overlooked in the initial radiologic assessment. In all radial head and neck fractures observed, supinator fat plane changes were present. Another constant feature was the radiologic sign of elbow joint effusion. Several fractures were not initially recognized by experienced radiologists due to subtle fracture lines and the absence of displacement of the fragments. However, because of both supinator fat plane changes and joint effusion, oblique films were obtained and established a radial head and/or neck fracture.

The tilted left anterior oblique position in the study of congenital cardiac anomalies.

Selective cineangiocardiography is widely used for the demonstration of congenital cardiac anomalies. Selective opacification of a cardiac chamber is performed after a diagnosis has been proposed or established by physical examination, radiographic and fluoroscopic examination of the chest, and study of data derived from external electrocardiography and cardiac catheterization. The selection of the injection site is determined by (a) the diagnosis established from the data and (b) the ability to introduce a catheter into the desired chamber. The roentgenographic positions chosen for selective angiocardiography depend upon the type of available equipment and the nature of the presumed cardiac anomaly. In the use of biplane rapid film changers, Kjellberg et al. (2) first called attention to the advantages and disadvantages of conventional positions for examination of congenital cardiac anomalies. Because of the complexities of cardiac anatomy, these investigators experimented with various positions of the patient. In addition to rotating the patient, Kjellberg tilted the x-ray tube so that the atrial and ventricular septa could be optimally outlined. Routine use of this maneuver was abandoned because of distortion projected on the biplane angiocardiograms. Kjellberg, therefore, recommended conventional postero-anterior and lateral projections for examination of virtually every cardiac lesion. These projections are the usual ones when biplane rapid film-changers are employed. On the other hand, the use of oblique positions is required for most examinations performed with a single-plane rapid film-changer or a cine unit. The right anterior oblique position is useful in the demonstration of atrioventricular valves (i.e., mitral stenosis) and in the separation of aorta and pulmonary artery (i.e., tetralogy of Fallot). The left anterior oblique position is preferred in study of the atrial and ventricular septa in presence of intracardiac shunts. Rationale for Use of Tilted Left Anterior Oblique Position In the postero-anterior and true lateral projections of the angiographic image, there is inevitable overlap of the central portions of the atrial and ventricular chambers and the atrioventricular valves. With atrial septal defects, the overlap of the cardiac chambers precludes precise localization of a defect site (2). Correlation of the frontal projection with the lateral is necessary for localization of high ventricular septal defects (1). In the conventional left anterior oblique position, the ventricles lie nearly directly in front of their respective atria. As a result, the interventricular septum is foreshortened and superimposed on the atrial septum. The atrioventricular valves are not visible when the atria are opacified because the contrast medium overlaps the valvular plane.

CHANGES DUE TO TRAUMA IN THE FAT PLANE OVERLYING THE PRONATOR QUADRATUS MUSCLE: A RADIOLOGIC SIGN.

The radiologist usually has no difficulty identifying fractures of the lower ends of the radius and ulna. There are instances, however, in which there is no displacement of fragments and subtle fractures may be overlooked. It has been observed that a fat plane just anterior to the lower ends of the radius and ulna consistently undergoes alterations from trauma, and sometimes it is easier to appreciate the changes in this fat plane than in the bones themselves. This report concerns identification of the fat plane and a review of the author's experiences in children and adults. The Pronator Plane Radiologic Sign Figure 1, A illustrates a normal lateral projection of the wrist of a twelve-year-old boy, with arrows outlining a linear fat plane. This fat has a gentle convex curve just anterior to the lower one-sixth of the radius and ulna and is seen in true lateral projections of the wrist in almost all normal subjects from premature infants to persons of advanced age. The right and left sides are usually symmetrical, and there is no relationship to handedness. Figures 1, B and C show a transverse fracture of the lower end of the radius caused by a fall on the outstretched hand the day before. In comparison with the normal lateral view (Fig. 1, A), the fat plane is displaced anteriorly and is more bowed. Furthermore, the fat is less well defined, with blurring and irregularity. It is postulated that the fracture has led to bleeding into and swelling of the pronator quadratus muscle. These cause it to expand and displace the overlying fat. Also, edema and∕or hemorrhage in the fat plane itself have increased its radiographic density, giving it a blurred and irregular appearance on the film. No operative findings or postmortem studies of recent injuries were available to test the observation, but the limb of a cadaver was dissected and radiologic and clinical observations suggest that the postulate is true. Anatomical Description The forearm of a cadaver was obtained for study and it is illustrated before dissection in Figure 2, A. What appears to be the fat plane (arrow) is actually fat, plus a small amount of air which has tracked down from the elbow region where the forearm was disarticulated. Dissection revealed the plane of the fat to lie just over the pronator quadratus muscle. Another fat plane just anterior to this was found to be between the tendons of the flexor digitorum profundus muscle and the tendons and muscle masses of the flexor digitorum sublimis muscle. This thin fat plane is seen in Figure 1, A beneath the heads of the arrows. A photograph was then made with the flexor digitorum profundus elevated and rolled off the surface of the pronator quadratus (Fig. 2, B). The pronator quadratus muscle is attached to the lower one-sixth of the radius and ulna.

The Retrorectal Soft-Tissue Space in Ulcerative Colitis

During the past few years, there has been an increasing tendency toward radical surgical intervention in severe ulcerative colitis. In cases with slight or moderate inflammatory rectal changes, when the perirectal soft tissues are not involved, colectomy with preservation of the rectum and ileorectostomy is the operation of choice (Ehrenpreis et al., 2). The preoperative knowledge of the appearance of these tissues is therefore important to the surgeon. Increase of the retrorectal soft-tissue space in ulcerative colitis was reported by Ilha and Job (3) and by Edling and Eklof (1) in adults and by Rudhe (5) in children. The relationship of this finding to the inflammatory changes in the large bowel has previously received only slight attention. In the present paper this relationship will be considered at some length, as will correlation with other features of the disease. Method and Material The retrorectal soft-tissue space is roentgenologically estimated in true lateral projections of the rectum and sacr...