Intercondylar Fossa Research Articles

Anatomy and function of the anterior cruciate ligament

The anterior cruciate ligament originates at the medial wall of the lateral femoral condyle and inserts into the middle of the intercondylar area. It contributes significantly to the stabilization and kinematics of the knee joint. The femoral origin is oval and is located in the posterior aspect of the lateral femoral condyle. Therefore, it is difficult to visualize the femoral origin arthroscopically. This might be one reason for anterior malpositioning of the femoral bone tunnel during anterior cruciate ligament reconstruction. The position of the femoral origin is behind the center of rotation of the knee joint; therefore, it becomes tense when the knee is extended. The tibial insertion is oval and its center is nearly in the middle of the tibial plateau. Definite landmarks for tibial tunnel placement in anterior cruciate ligament reconstruction are the distance between the central insertion point at the intercondylar floor and the posterior cruciate ligament (7-8 mm) and the anterior horn of the lateral meniscus. The anterior cruciate ligament consists of multiple small fiber bundles. From a functional point of view, one can differentiate the anteromedial and posterolateral fiber bundles. The anteromedial fibers are tense during a greater range of motion than the posterolateral fibers. The main part of the anterior cruciate ligament consists of type I collagen-positive dense connective tissue. The longitudinal fibrils of type I collagen are divided into small bundles by thin type III collagen-positive fibrils. In the distal third, the structure of the tissue varies from the typical structure of a ligament. In this region, the structure of the tissue resembles fibrocartilage. Oval-shaped cells surrounded by a metachromatic extracellular matrix lie between the longitudinal collagen fibrils. The femoral origin and the tibial insertion have the structure of a chondral apophyseal enthesis. Near the anchoring region at the femur and tibia, there should be various mechanoreceptors, which might have an important function for the kinematics of the knee joint. The blood supply of the anterior cruciate ligament arises from the middle geniculate artery. The ligament is covered by a synovial fold where the terminal branches of the middle and the inferior geniculate artery form a periligamentous network. From the synovial sheath, the blood vessels penetrate the ligament in a horizontal direction and anastomose with a longitudinally orientated intraligamentous network. The distribution of blood vessels within the anterior cruciate ligament is not homogeneous. We detected three avascular areas within the ligament: Both fibrocartilaginous entheses of the anterior cruciate ligament are devoid of blood vessels. A third avascular zone is located in the distal zone of fibrocartilage adjacent to the roof of the intercondylar fossa.

Arthroscopically assisted treatment of avulsion fractures of the posterior cruciate ligament from the tibia.

The attachment of the posterior cruciate ligament to the posterior intercondylar fossa of the tibia is in a location that is difficult to access for arthroscopic surgical procedures. This report presents a variety of arthroscopically assisted reduction and fixation methods for managing avulsion fractures of the posterior cruciate ligament from the tibia. Thirteen patients (fourteen knees) who had an avulsion fracture of the posterior cruciate ligament were treated with an arthroscopic procedure. Eleven patients underwent the operation in the acute phase (four to ten days after the injury), and two patients had delayed surgery (at nineteen and twenty months after the injury) because of nonunion. The choice of fixation method was based on the size of the avulsed fragment. Six knees that had a small bone fragment (<10 mm) with comminution were fixed with use of multiple sutures. Two knees that had a small bone fragment without comminution were fixed with 23-gauge wires. Two knees that had a medium-sized fragment (10 to 20 mm) were fixed with Kirschner wires. Four knees that had a large single fragment of bone (>20 mm) that involved the condyles were fixed with one or two cannulated screws. All patients had osseous union as determined on radiographs. Three injured knees in two patients showed limitation of motion after the operation. These patients had been immobilized for two or three months after the surgery because of concomitant fractures. The eleven patients who had undergone the operation in the acute phase, including two in whom postoperative arthrofibrosis had developed, showed no or trace posterior instability following the procedure. However, the two patients in whom the surgery had been delayed had residual grade-I posterior instability. The postoperative side-to-side differences, when measured with use of the KT-2000 arthrometer and posterior stress radiographs, showed better results in the patients in whom the surgery had been performed in the acute phase than in the patients in whom the operation had been delayed. Arthroscopic procedures can be used to treat tibial avulsion fractures of the posterior cruciate ligament.

Arterial supply of the femoral condyles

The most frequent site for aseptic bone necrosis and osteochondrosis dissecans in the human knee joint is the medial femoral condyle. The aim of this study is to analyze the three-dimensional vascularization of the human knee joint and to find out if there are any differences in the blood supply of the medial and lateral femoral condyles which may explain the preponderance of aseptic bone necrosis in the medial side. The femoral arteries of 14 unfixed lower extremities have been injected with epoxy resin. After documentation of the extraosseous course of the blood vessels the bone was macerated with 10% formic acid. The insertions of tendons and ligaments were investigated by light microscopy and immunohistochemistry. The arterial supply of the lateral femoral condyle originates from the upper lateral geniculate artery, the terminal ends of which penetrate the bone from lateral. Branches of the middle geniculate artery reach the bone from the medial wall of the intertubercular notch. The subchondral bone of the medial femoral condyle draws its blood supply mainly from the descending geniculate artery. Branches of the middle geniculate artery penetrate the medial femoral condyle only in the posterior part of the intercondylar fossa. These posterior vessels do not contribute to the supply of the subchondral bone. In the anterior part of the medial wall of the intercondylar fossa there is the wide femoral insertion of the posterior cruciate ligament. Injection techniques and immunohistochemical investigations show that the fibrocartilage of the chondral apophyseal insertion of the posterior cruciate ligament is avascular and acts as banier which impedes blood vessels to penetrate the bony surface in this region. The subchondral bone adjacent to the femoral insertion of the posterior cruciate ligament receives its blood supply from vessels that penetrate the bone at the medial wall of the medial femoral condyle. The blood vessels which supply the lateral parts of the medial condyle have the longest intraosseous course. The density of vessels within this region is largely reduced. The region adjacent to the femoral insertion of the posterior cruciate ligament is the most frequent site for osteochondrosis dissecans in the knee joint. Our results show that the arterial supply of the subchondral bone may be considered as a cofactor for the etiology of osteochondrosis dissecans.

Importance of elliptic Fourier methods for morphometry of complex outlines: application to the distal human femur.

The purpose of this technical note is to present an automatic procedure of shape characterisation using new developments in elliptical Fourier methods combined with image analysis techniques. It was applied, as an example, to the outline of the distal extremity of the distal human femur in inferior axial view. This outline was automatically extracted and characterised by an ordered series of harmonics, each harmonic being described by four new parameters called elliptical descriptors. Step by step reconstructions of outlines using an increasing number of harmonics were than performed. The simultaneous study of the elliptic descriptors and of the step by step reconstructions allowed a considerably easier geometric and morphologic interpretation of the harmonic contributions than classically. The main morphologic features of the distal femur (lateral and medial condyles, intercondylar fossa, lateral and medial borders of the articular surface, and patellar groove) were mainly described by the first seven harmonics. These new developments in elliptic Fourier methods open interesting perspectives for the study of complex outlines, providing an accurate individual morphologic characterisation, and thus the possibility of polymorphic analysis.

Structure and vascularization of the cruciate ligaments of the human knee joint

The structure and vascularization of the human anterior and posterior cruciate ligament were investigated by light microscopy, transmission electron microscopy,, injection techniques and by immunohistochemistry. The major part of the anterior and posterior cruciate ligament is composed of bundles of type I collagen. Type III collagen-positive fibrils separate the bundles. The major cell type is the elongated fibroblast, lying solitarily between the parallel collagen fibrils. The histologic structure of the cruciate ligaments is not homogeneous. In both ligaments there is a zone where the tissue resembles fibrocartilage. In the anterior cruciate ligament the fibrocartilaginous zone is located 5-10 mm proximal of the tibial ligament insertion in the anterior portion of the ligament. In the posterior cruciate ligament the fibrocartilage is located in the central part of the middle third. Within those zones the cells are arranged in columns and the cell shape is round to ovoid. Transmission electron microscopy reveals typical features of chondrocytes. The chondrocytes are surrounded by a felt-like pericellular matrix, a high content of cellular organelles and short processes on the cell surface. The pericellular collagen is positive for type II collagen. The major blood supply of the cruciate ligaments arises from the middle geniculate artery. The distal part of both cruciate ligaments is vascularized by branches of the lateral and medial inferior geniculate artery. Both ligaments are surrounded by a synovial fold where the terminal branches of the middle and inferior arteries form a periligamentous network. From the synovial sheath blood vessels penetrate the ligament in a horizontal direction and anastomose with a longitudinally orientated intraligamentous vascular network. The density of blood vessels within the ligaments is not homogeneous. In the anterior cruciate ligament an avascular zone is located within the fibrocartilage of the anterior part where the ligament faces the anterior rim of the intercondylar fossa. The fibrocartilaginous zone of the middle third of the posterior cruciate ligament is also avascular. According to Pauwel's theory of the "causal histogenesis" (1960) the stimulus for the development of fibrocartilage within dense connective tissue is shearing and compressive stress. In the anterior cruciate ligament this biomechanical situation may occur when the ligament impinges on the anterior rim of the intercondylar fossa when the knee is fully extended. Compressive and shearing stress in the center of the middle third of the posterior cruciate ligament may result from twisting of the fiber bundles.

Postcranial stem tetrapod remains from the Devonian of Scat Craig, Morayshire, Scotland

The postcranial stem tetrapod remains from Scat Craig include a neural arch, humerus, tibia, femur, and incomplete pectoral girdles and ilia. These elements are all large or very large compared with the corresponding bones of other stem tetrapods. They correlate well in size with the proportions ofElginerpeton, the known stem tetrapod from Scat Craig, and probably belong to this genus. The neural arch has weak zygapophyses, and the ilia and shoulder girdles resemble those ofIchthyostega. The femur is strongly twisted, with the intercondylar fossa facing anteroventrally, so the hind limb probably functioned as a paddle. The tibia is broad, as inAcanthostegaandIchthyostega. The humerus is approximately intermediate in shape between those of osteolepiforms and later stem tetrapods, but seems to have a ventral radial facet likeIchthyostega. Overall, the postcranial bones combine apparent synapomorphies withIchthyostegaand characters which are uniquely primitive among stem-group tetrapods. This character combination is incongruent. A recently discovered postorbital bone from the site is, strictly speaking, indeterminable but may belong toElginerpeton; it broadly resembles the postorbitals ofIchthyostegaandAcanthostega, and demonstrates that the typical stem tetrapod facial morphology had evolved before the end of the Frasnian.

Postcranial stem tetrapod remains from the Devonian of Scat Craig, Morayshire, Scotland

Abstract The postcranial stem tetrapod remains from Scat Craig include a neural arch, humerus, tibia, femur, and incomplete pectoral girdles and ilia. These elements are all large or very large compared with the corresponding bones of other stem tetrapods. They correlate well in size with the proportions ofElginerpeton, the known stem tetrapod from Scat Craig, and probably belong to this genus. The neural arch has weak zygapophyses, and the ilia and shoulder girdles resemble those ofIchthyostega. The femur is strongly twisted, with the intercondylar fossa facing anteroventrally, so the hind limb probably functioned as a paddle. The tibia is broad, as inAcanthostegaandIchthyostega. The humerus is approximately intermediate in shape between those of osteolepiforms and later stem tetrapods, but seems to have a ventral radial facet likeIchthyostega. Overall, the postcranial bones combine apparent synapomorphies withIchthyostegaand characters which are uniquely primitive among stem-group tetrapods. This character combination is incongruent. A recently discovered postorbital bone from the site is, strictly speaking, indeterminable but may belong toElginerpeton; it broadly resembles the postorbitals ofIchthyostegaandAcanthostega, and demonstrates that the typical stem tetrapod facial morphology had evolved before the end of the Frasnian.

RADIOGRAPHIC AND COMPUTED TOMOGRAPHIC EVALUATION OF THE CANINE INTERCONDYLAR FOSSA IN NORMAL STIFLES AND AFTER NOTCHPLASTY IN STABLE AND UNSTABLE STIFLES

The role of the intercondylar fossa in cranial cruciate ligament injury has gained notable attention in humans and it's role is now being questioned in animals. Controversy exists regarding the accuracy of radiographs and computed tomography (CT) in evaluating the intercondylar fossa. This study compared radiographic and CT evaluation with gross evaluation of the intercondylar fossa. Six greyhounds were evaluated before notchplasty, immediately after notchplasty and 6 months after notchplasty in stable and unstable stifles. A fossa width index was used for comparison because it negates the effects of patient size and radiographic magnification. The fossa width index is calculated by dividing the width of the intercondylar fossa by the total condylar width.The fossa width indices of dogs determined from radiographs and CT were not significantly different before notchplasty except for the cranial fossa width indices which were more inconsistent and tended to underestimate the size when compared to gross measurements. At six months, both stable and unstable stifles had refilling of the notchplasty, but the unstable stifles had significantly greater refilling resulting in no significant enlargement in intercondylar fossa size as compared to the prenotchplasty size. Osteophytes that occurred within the intercondylar fossa were less radiopaque and more easily visualized by computed tomography. Computed tomography provided several advantages, including clearer visualization of the intercondylar fossa, avoiding superimposition of the intercondylar fossa by caudal thigh muscles or tuber ischii and the ability to analyze the cranial and caudal components of the intercondylar fossa separately.

Gadolinium-DTPA-enhanced MR imaging in asymptomatic knees.

To evaluate the occurrence and extent of Gd-DTPA-enhanced synovial structures in asymptomatic knee joints of middle-aged healthy individuals. MR imaging of the knee joint was performed in 10 healthy subjects aged 40-61 years. The study included a sagittal T1-weighted SE sequence before and after i.v. injection of 0.1 mmol Gd-DTPA/kg b.w. Contrast-enhanced synovial structures were found in all knees. The extent of the synovial structures was usually not uniform within the examined joint. In the intercondylar fossa, the thickness of synovial structures was more often pronounced. In the suprapatellar recess, synovial thickness was constant and minimal. The presence and the varying extent and thickness of synovial structures in asymptomatic knees in middle-aged individuals must be considered in the evaluation of early and mild synovitis of the knee joint with Gd-enhanced MR imaging in this age group.

RADIOGRAPHIC IMAGING OF THE CANINE INTERCONDYLAR FOSSA

The intercondylar fossa is believed to play an important role in the pathology of cranial cruciate ligament rupture and therefore has received considerable attention in the last decade. Accurate radiographic imaging of the intercondylar fossa requires that the central x‐ray beam pass through the center of the intercondylar “tunnel”. The anatomy of the canine intercondylar fossa is similar to humans, however, the orientations of the intercondylar fossa's differ. Consequently, the positioning techniques described for humans are not appropriate for the dog. To pass through the center of the dog, intercondylar fossa, the central x‐ray beam should be 12° (S.D. 1.7°) caudal from the femoral diaphysis in the sagittal plane and obliqued caudolateral to craniomedial 7° (S.D. 0.60°) (caudo78°proximo7° lateralcraniodistomedial oblique). Cross table positioning was used with the hip flexed and the radiograph cassette placed on the cranial surface of the stifle. However, superimposition of the tuber ischii and soft tissues caudal to the femur made 15° to 20° the best angle obtainable. There was not a significant difference (p = 0.17) in the notch width index between a 12° versus 20° angle of the central x‐ray beam caudal to the femoral diaphysis, both with 7° of external rotation of the stifle. The notch width index of 0.252 obtained from radiographic measurements was not significantly different from measurements obtained grossly of 0.254 (n = 26; p = 0.69). Failure to oblique the central x‐ray beam caused a significant (p = 0.0008) decrease in the apparent fossa width radiographically.

The intercondylar fossa of the normal canine stifle an anatomic and radiographic study.

The intercondylar fossa (ICF) in dogs consists of a cranial outlet, intercondylar shelf, caudal arch, caudal outlet, a medial wall, and a lateral wall. The normal cranial outlet is bell-shape and, in mixed-breed dogs (mean body weight 19.2 kg, N = 21), measured 5.8 mm cranially, 8.1 mm centrally, and 10.3 mm caudally. The ICF is oriented 12 degrees from the dorsal plane of the femoral diaphysis and obliqued 7 degrees, proximolateral to distomedial, in the sagittal plane. To adjust for dog size, a fossa width index (FWI) was calculated by dividing the cranial outlet width by the distance between epicondyles. The normal FWI as determined in this study was 0.18 cranially, 0.25 centrally, and 0.32 caudally. The fossa height index 0.31. Contact between the ICF and the cranial cruciate ligament began at about 115 degrees of extension. The contact area moved cranially in the intercondylar fossa as the stifle was extended. Evaluation of the ICF can be performed radiographically but positioning is critical.

The effect of intercondylar notchplasty on the normal canine stifle.

This study evaluated the effect of notchplasty (enlargement of the intercondylar fossa) in stable and unstable canine stifles. Bilateral notchplasty and unilateral cranial cruciate ligament (CrCL) transection were performed in 6 dogs. Exercise, consisting of walking 1.5 miles three times a week, began 1 month after surgery and continued until euthanasia 6 months after surgery. Evaluation methods included orthopedic examination, serial radiographs, thin section radiography, histopathology, and gross pathology. Notchplasty in the stable stifle did not cause lameness beyond 3 weeks, joint instability, or degenerative joint disease. In the stable stifle, smooth resurfacing of the notchplasty site with fibrous and osseous tissue occurred. Stifles with notchplasty and CrCL transection exhibited persistent lameness, instability, and degenerative joint disease. In CrCL deficient stifles osteophytes formed within the notchplasty site, resulting in a rough surface. Our observations indicated significant refilling in notchplasties of both stable and unstable stifles (P < .05). However, the intercondylar fossa (ICF) width 6 months after notchplasty was significantly smaller in unstable stifles compared with stable stifles (P < .05) indicating that greater refilling of the notchplasties occurred in the unstable stifles. In clinical cases, notchplasty should be larger than the desired final result to accomodate the partial refilling that occurs even in stable stifles.

Tibial attachment area of the anterior cruciate ligament in the extended knee position. Anatomy and cryosections in vitro complemented by magnetic resonance arthrography in vivo.

Knowledge of the anatomy of the anterior cruciate ligament (ACL), including its course and orientation in relation to the roof of the intercondylar fossa, is a prerequisite for successful intra-articular ACL reconstruction. To attain precision placement of the tibial attachment site and to avoid graft/roof conflict in the extended knee position, we assessed the anteroposterior tibial insertion of the ACL in the midsagittal plane of the extended knee. We measured the anterior-posterior (AP) limits and the center of the tibial attachment area of the ACL from the anterior tibial margin. The inclination angle of the intercondylar fossa roof was measured with respect to the shaft axis of the femur. The tibial attachment area of the ACL was determined in ten cadaveric knees. Using the cryoplaning technique, we determined the tibial attachment of the ACL in five knees. Using contrast magnetic resonance arthrography (MRA), we measured the tibial insertion of the ACL in 35 patients (23 male and 12 female) with intact ACLs. The total AP midsagittal diameter of the tibia averaged 51.0 +/- 5.8 mm in the cadaveric knees, 49 mm on cryosections, and 53.7 mm in men and 49.0 mm in women with MRA. The average anterior limit of the ACL, measured from the anterior tibial margin, was 14 +/- 4.2 mm in the cadaveric knees, 12.1 mm at cryosectional anatomy, and 15.2 mm in men and 13.4 mm in women with MRA.(ABSTRACT TRUNCATED AT 250 WORDS)

A three-dimensional morphometrical study of the distal human femur.

The objective of this paper is to present a method to describe the three-dimensional variations of the geometry of the three portions forming the distal part of the human femur: the medial and lateral femoral condyles and the intercondylar fossa. The contours of equally spaced sagittal slices were digitized on the distal femur to determine its surface topography. Data collection was performed using a digitizer system which utilizes low-frequency, magnetic field technology to determine the position and orientation of a magnetic field sensor in relation to a specified reference frame. The generalized reduced gradient optimization method was used to reconstruct the profile of each slice utilizing two primitives: straight-line segments and circular arcs. The profile of each slice within the medial femoral condyle was reconstructed using two circular arcs: posterior and distal. The profile of each slice within the lateral femoral condyle was reconstructed using three circular arcs: posterior, distal and anterior. Finally, the profile of each slice within the intercondylar fossa was reconstructed using two circular arcs: proximal-posterior and anterior, and a distal-posterior straight-line segment tangent to the proximal-posterior circular arc. Combining the data describing the profiles of the different slices forming the distal femur, the posterior portions of each of the medial and lateral femoral condyles were modelled using parts of spheres having an average radius of 20 mm. The anterior portion of the lateral condyle was approximated to a right cylinder having its circular base parallel to the sagittal plane with an average radius of 26 mm. The anterior portion of the intercondylar fossa was modelled using an oblique cylinder having its circular base parallel to the sagittal plane with an average radius of 22 mm. Furthermore, it is suggested that the distal portion of the lateral femoral condyle could be modelled using parts of two oblique cones while the distal portion of the medial femoral condyle could be modelled using a part of a single oblique cone, all cones having their circular bases parallel to the sagittal plane. It is also suggested that the posterior portion of the intercondylar fossa could be modelled using two oblique cones: a proximal cone having its base parallel to the sagittal plane and a distal cone having its base parallel to the frontal plane.

An aid to remembering cruciate ligament position.

Many of us have learned the mnemonic ‘ ‘ LAMP: Lateral = Anterior, Medial = Posterior’ ‘ for remembering the femoral attachments of the cruciate ligaments. But sometimes one cannot remember whether the mnemonic refers to the femoral or the tibial attachments. A simple method is to use crossed fingers; the long finger of one hand is crossed over the index finger. Superimposing this hand over the ipsilateral knee reminds us of the orientation of the cruciate ligaments (fig. 1). The anterior cruciate ligament originates superiorly from the lateral femoral condyle along the posterior surface of the intercondylar notch. It courses obliquely downward and medially to attach to the medial aspect of the intercondylar area of the tibia just in front of the intercondylar eminence. The posterior cruciate ligament attaches superiorly to the medial femoral condyle along the midpart of the intercondylar notch. It passes obliquely downward, laterally, and posterior to the anterior cruciate ligament to attach to the posterior margin of the intercondylar fossa of the tibia on the lateral side [1 , 2]. The ligaments are thus named for their anteroposterior relation on the tibia. The cruciate ligaments are extrasynovial structures. However, they are closely invested by synovium, with the result that positive contrast material or air within the surrounding synovial space allows their demonstration. Although the preferred method for demonstrating the cruciate ligaments is in the lateral projection [3, 4], it is occasionally desirable to identify the structures on a frontal view. This is one reason why we routinely use the intercondylar notch view. The use of the crossed fingers technique is a fast, simple, and accurate method for remembering the orientation of the cruciate ligaments and closely approximates their appearance on the intercondylar notch view. All one needs to remember is which finger to put over which!

The role of the iliopsoas muscle in femoral rotation.

THE axis of femoral rotation in the anatomical position is a line joining the centre of the head of the femur to the middle of the intercondylar fossa. The relationship of the iliopsoas to this axis was studied in eleven specimens with the femur unrotated, medially and laterally rotated in the fully flexed, extended and ‘resting’ positions. The mean angle between the psoas tendon and the plane of rotation was significantly decreased by flexion and increased by extension but remained unaltered by medial and lateral rotation. In all but three instances the axis of rotation passed through the iliopsoas. These results suggest that the iliopsoas does not play a significant part in the rotation of the normal femur.

Is persisting antigen responsible for the chronicity of experimental allergic arthritis?

Animals were injected intra-articularly with antigen after prior immunization with that antigen in Freund's incomplete adjuvant in order to precipitate immune complexes in the surfaces of menisci, ligaments, and cartilage. On reimmunization with antigen in Freund's complete adjuvant 10 weeks later, generally an arthritis limited to the intercondylar fossa developed; but on intra-articular injection of antigen a second time a widespread arthritis developed in that joint. Thus immune deviation had not occurred and animals were in an immunological condition such as to be capable of developing widespread arthritis given the correct intra-articular stimulus. It is concluded that antigen, persisting as immune complexes, plays no part in maintaining widespread monarthritis, presumably owing to its inability to participate in a delayed hypersensitivity reaction as a result of sequestration.

A radiographic study of hip rotation.

A radiographic study was undertaken in 15 adult volunteers to determine whether the femur rotated around the generally accepted axis, a line joining the centre of the head of the femur to the centre of the intercondylar fossa. This line proved to be the axis only when the lower end of the femur was fixed. The axis of rotation passed through other distal points on the limb when they were fixed. These findings would support the view that so-called medial and lateral rotation do not constitute true rotation at the hip joint.

The So-called Squatting Number of the Femur in Japanese

Observations on the lower ends of 378 femora from modern Japanese who were accustomed to squat both at rest and at work were made and compared with other published results.The average mean of the so-called squatting number by which the depth of the intercondylar fossa at the level of the intercondylar line was to be multiplied to give the greatest depth of the lower articular surface of the femur for Japanese was 3.23.It gave Japanese an intermediate position between Punjabis (2.90) or Indians (3.10) and modern Canadians (3.43) or Irish (3.44).It was, however, found that the Japanese femora were not distin-guishable from the modern Irish or Canadian ones by the so-called squatting number, because there was a considerable amount of overlap of the squatting number among them.The depth of the intercondylar fossa in female was relatively greater than that in male, the difference being attributed to the fact that the articular surface of the knee joint in female was absolutely smaller than that in male.It was, therefore, necessary in comparison of the so-called squatting numbers of the femora among different populations to consider first whether given bones were of male or of female.In addition, the average mean of the squatting index of SHAH for Japanese was 31.0 (male 30.3, female 32.5), being smaller than that (34.2) for Punjabis.

Bone and Joint Changes in Hemophilia

Bone and joint changes are among the most common manifestations of hemophilia. In their absence one is inclined to question the diagnosis in adult life. Roentgenologically, these changes are varied and relatively non-specific, depending to a large extent on the frequency of hemarthroses, the joints involved, and the age of the patient. During the past eight years we have had the opportunity of studying a group of hemophiliacs of various ages. In several instances x-ray examinations of involved joints were made initially prior to epiphyseal closure and periodically thereafter for several years. Thus a record of the progression of the bone and joint changes has been obtained. In addition to the serial changes, a variety of joint lesions ranging from minimal to far advanced are demonstrated in this group of patients. Clinical and Radiological Data Twelve cases are presented here, representing 6 families (Table I) . The first 5 cases have been under observation since 1945. Cases 6 through 9, from the third family, were seen in 1949. The last 3 cases, from unrelated families, were seen in 1952. In all of these cases the following laboratory criteria have been met: prolonged coagulation time of blood; positive Quick test; normal prothrombin, bleeding and clot retraction times. In 8 of the cases the prothrombin consumption was determined and found to be poor. The other 4 patients were studied prior to the development of prothrombin consumption determinations. The whole blood coagulation time in these subjects was as shown in the accompanying table. The details of the clinical course, laboratory data, and genealogical history are reported elsewhere (1). In the first family (McC.) there are 3 known hemophiliacs, the only children of their parents. Figure 1 shows the physical appearance of one of these brothers (T. McC.). Note the presence of genu valgum on the left, with posterior displacement of the tibia, associated with general atrophy of the left lower extremity. The carrying angle of the left elbow is reduced. The x-ray changes in this subject are of moderate severity. Figure 2 shows the right elbow, with enlargement and flaring of the radial head. Small rounded radiolucent defects are seen along its articular margin and along the lateral epicondyles of the humerus, indicative of cystic dissolutions. Figure 3 (HH4) shows bulging of the synovium and slight widening of the joint space due to a massive hemarthrosis in the right knee. The intercondylar fossa is slightly wider than normal, but the articular margins are smooth. Small ill-defined rarefactions are present in the subarticular portion of the tibial epiphysis, suggesting early cyst formation. During a seven-year period, x-ray studies of this knee have disclosed progressive changes. Figure 4 (1951) shows increased widening and deepening of the intercondylar fossa, decreased joint space with irregularity of articular surfaces, and slightly increased cystic changes.