Jorge Murillo-González

Arthroscopic Study of the Knee Joint in Fetuses

PURPOSE The purpose of this study was to macroscopically examine the fetal knee joint via arthroscopy. We have attempted to identify and describe the specific characteristics of the fetal knee joint, how it evolves during the last few weeks of intrauterine development, and any possible variations with regard to the adult knee. TYPE OF STUDY Observational anatomic case series. METHODS We used 20 frozen fetuses with a gestational age of 24 to 40 +/- 2 weeks, obtained from spontaneous abortions. Examination was performed with standard arthroscopic surgical equipment, using a 2.7-mm optical lens. Whenever possible, we tried to use standard arthroscopic portals. Images were obtained for comparison with the adult knee. RESULTS Suprapatellar and infrapatellar septa were an almost consistent finding. The suprapatellar septum always opened laterally and was intact in the developmentally younger specimens. We found 2 mediopatellar septa. The femoral attachment of the anterior cruciate ligament (ACL) differed in appearance from that of the adult in that it was more ribbon-like. The lateral meniscus had a more spread-out appearance than its adult counterpart, especially in the specimens of a younger gestational age. We were surprised at the easy accessibility of the popliteal hiatus and the clear arthroscopic vision we were able to obtain of the involved structures. CONCLUSIONS To our knowledge, this is the first arthroscopic study to target the fetal knee. The results indicate minimal differences when compared with the adult knee, and for some structures, such as the popliteal hiatus, the anatomy seen was easier to discern than in adult knee arthroscopy.

Immunocytochemical study on the triple origin of the sphincter iris in the chick embryo.

Abstract The ontogenic development of the sphincter iris has been studied by immunocytochemistry and standard staining on chick embryos from stage 25 HH to the time of hatching. We have used the monoclonal antibody 13F4, a highly specific marker of muscular cells. We have observed three different regions in the iris. In the pupillary region, immunoreactive cells are in continuous contact with the inner epithelium of the pupillary margin. In the intermediate region, the outer epithelium forms buds of pigmented cells that emigrate toward the stroma. In this epithelium cells that are totally or partially unpigmented exist, and they are 13F4 positive. In the sphincter we have observed 13F4 positive cells with melanin granules. In the ciliary region, the immunoreactivity appears in dispersed mesenchymal cells. The present findings are consistent with a triple origin of the sphincter iris in the chick embryo. This muscle is derived from the inner epithelium of the pupillary margin, the intermediate region of the outer epithelium, and from the mesenchymal cells. The cells of the inner epithelium of the pupillary margin are differentiated into smooth muscle cells, and the remaining cells form striated muscle cells.

Ciliary muscle in avian is derived from mesenchymal and epithelial cells

It has long been maintained that the ciliary muscle derives from mesenchymal cells. The embryonic development of the avian ciliary muscle was studied in chick embryos from stage 25 HH to the time of hatching. Serial sections of the eye were stained routinely or immunocytochemically using the monoclonal antibody 13F4, which recognizes a cytoplasmic antigen specific for all types of muscle cells. We found that the mesenchymal immunoreactive cells, at stage 37 HH, are arranged in two distinct orientations forming the anterior and posterior portions of the ciliary muscle. At stages 38 and 39 HH the pigmented epithelium contained 13F4 positive cells, which detach from the epithelium and apparently migrate into stroma. These epithelial cells may differentiate into muscle cells. Within this same time period a progressive accumulation of myoblasts was detected between the pigmented epithelium and the ciliary muscle. Some myoblasts containing melanin were also observed. At stage 40 HH the internal portion of the ciliary muscle was visible. These findings indicate that the immunopositive epithelial cells participate in the formation of the internal portion of the muscle. We conclude that the ciliary muscle derives not only from the mesenchymal cells but also from the pigmented epithelium.

Development of the Human Biceps Brachii Tendon and Coracoglenoid Ligament (7th-12th Week of Development)

The goal of this study is to clarify the development of the long head of the biceps brachii tendon (LHBT) and to verify the existence and development of the coracoglenoid ligament. Histological preparations of 22 human embryos (7-8 weeks of development) and 43 human fetuses (9-12 weeks of development) were studied bilaterally using a conventional optical microscope. The articular interzone gives rise to the LHBT, glenoid labrum, and articular capsule. During the fetal period, it was observed that in 50 cases (58%), the LHBT originated from both the glenoid labrum and the scapula, while in 36 cases (42%), it originated only from the glenoid labrum. The coracoglenoid ligament, first described by Sappey in 1867, is a constant structure that originates at the base of the coracoid process and projects toward the glenoid labrum zone, which is related to the origin of the LHBT. The coracoglenoid ligament was more easily identifiable in the 36 cases in which the LHBT originated only from the glenoid labrum. We suggest that the coracoglenoid ligament is a constant anatomical structure, is not derived from the articular interzone unlike the LHBT, and contributes to the fixation of the glenoid labrum in the scapula in cases in which the LHBT originated only from the glenoid labrum. We postulate that, when the LHBT is fixed only at the glenoid labrum, alterations in the coracoglenoid ligament could lead to a less sufficient attachment of the glenoid labrum to the scapula which could predispose to a superior labral lesion.

Evolution of embryology: A synthesis of classical, experimental, and molecular perspectives

Embryology as a modern science began at the beginning of the 19th century and continued as the classic period until the 1940s. During this period, a body of basic knowledge was established which, generally, described the events of development. From 1940 to 1970 experimental or causal embryology predominated; explanations of secondary causes were demonstrated for development. The decade of the 1970s was a decade of transition that led to the current revolution in molecular biology that began in the 1980s. Molecular biology and its new branch, molecular genetics, shook up the heretofore serene, but already limited, field of embryology. Today the discipline of embryology is being built on the analysis of the results of genetic expression. Embryology is now concerned with understanding development from the viewpoint of the activation and transcription of DNA sequences, which will allow us to approach the first causes or underlying genetic and epigenetic mechanisms of development. As a result, embryology and genetics have fused into a wider biological subdiscipline, developmental biology. Will this be enough to define the full scope of our knowledge of embryonic development? What is certainly evident is that the molecular period of embryology will help achieve a better understanding of the schemata constructed by classic and experimental embryologists. Furthermore, to the degree that the molecular analysis of whatever phenomenon of development requires additional foundational knowledge, classic and experimental embryology will not have exhausted all their possibilities. Clin. Anat. 14:158–163, 2001.

The Fetal Origin of the Human Chin

The chin prominence is a hallmark of the modern human face and bears on its labial surface an inverted-T bony relief. Evolutionarily, whether the human chin is an adaptation for mastication or speech is debated but there is little compelling data supporting either claim. Furthermore, some suggest that the inverted-T relief is more important for phylogenetic inference than the chin prominence. However, there is no evidence for the developmental independence of the inverted-T relief and chin prominence. This debate requires empirical data on fetal development of the human chin. Using 3D imaging of the musculo-cervico-craniofacial skeleton of human fetuses and geometric morphometric methods, we discovered a developmental sequence leading to a chin prominence during early fetal development that is very similar to that which we previously observed in postnatal modern humans and in chimpanzee fetuses. Furthermore, we provide the evidence that the inverted-T relief is developmentally integrated with the chin prominence. The evolution of the human chin is constrained by cervico-craniofacial developmental that maintain an unobstructed fetal airway. Finally, the inverted T-relief should be neither treated independently from the chin prominence in phylogenetic analysis, nor is it a relevant taxonomic trait that defines the symphysis of modern humans.

Endoscopic Lesser Trochanter Resection With Refixation of the Iliopsoas Tendon for Treatment of Ischiofemoral Impingement

Ischiofemoral impingement is a source of hip pain derived from impingement between the lesser trochanter and the ischium. Lesser trochanter excision has been recommended for recalcitrant ischiofemoral impingement through either an anterior or posterior approach. However, neither of these approaches involves refixation of the iliopsoas tendon. We describe an endoscopic procedure involving anterior trochanter-plasty, minimizing the risk of sciatic complications, with refixation of the partially detached iliopsoas tendinous insertion, potentially minimizing compromise to hip flexion strength and anterior hip stability.

Combined Double Bundle Anterior Cruciate Ligament Reconstruction and Anterolateral Ligament Reconstruction

A double-bundle anterior cruciate ligament (ACL) reconstruction associated with an anterolateral ligament (ALL) reconstructions is performed. The semitendinosus and gracilis are harvested. At knee maximum flexion, the anteromedial (AM) femoral tunnel is performed in the AM footprint area. Through the anterolateral portal, the tip of the outside-in femoral guide is placed in the posterolateral footprint area. The guide sleeve is pushed onto the lateral femoral cortex at the ALL attachment. At 110° knee flexion, the posterolateral-ALL tunnel is performed. The tibial ACL tunnel is performed as usual. The tibial guide is placed between the ALL tibial attachment and the tibial ACL tunnel entrance to perform the ALL tibial tunnel. The gracilis graft is introduced from caudal to cranial, achieving fixation with a 6-mm diameter screw (outside-in). The AM femoral fixation is achieved with a suspension device. ACL tibial graft fixation is achieved with a screw. Afterward, the gracilis is passed under the fascia lata to the tibial entry point. A 6-mm diameter screw is placed from the external cortex into the tibial ALL tunnel. The biomechanical advantage of the double-bundle ACL reconstruction with the biomechanical advantage of the ALL anatomic reconstruction is achieved.

Development of the long head of the biceps brachial tendon: A possible explanation of the anatomical variations

The anatomical variations of the proximal portion of the long head of the biceps brachii tendon (LHBT) are rarely observed in clinical practice. However, an increase in the rate of shoulder arthroscopic surgery has led to an increase in the observation of anatomical variations of this region. The aim of this work was to analyze the development of the LHBT in 23 human embryos ranging from the 6th to 8th weeks of development. The LHBT develops from the glenohumeral interzonal mesenchyme in the 6th week. By week 7, the myotendinous junction of the LHBT develops. The anlage of the LHBT is separated from that of the glenohumeral capsule during week 8. Our results suggest that the most important period for the LHBT development occurs between the 6th and 8th weeks of embryonic development. Alterations during this critical period may cause anatomical variations of the LHBT. An additional case report from our own experience is provided as Supplementary material.

Arthroscopic stabilisation of an acute acromioclavicular dislocation grade III in a patient with ectopic insertion of the pectoralis minor: technical considerations.

AbstractThe different approaches used in arthroscopic stabilisation of the acromioclavicular joint are well known. However, and despite a great incidence of ectopic pectoralis minor insertion, an alternative choice for the use of arthroscopic portal has not being sufficiently described. Here, we describe a case of acute acromioclavicular dislocation grade III. The arthroscopic stabilisation was achieved using the TightRope (Arthrex, Naples, USA) implant. Through this technique, the approach to the articular portion of the coracoid process can be made intra-articularly or from the subacromial space. We accessed intra-articularly, by opening the rotator interval to reach the coracoid process from the joint cavity. After opening the rotator interval, an ectopic insertion of the pectoralis minor was observed. The choice of approach of the coracoid process from the subacromial space would have complicated the intervention, making it necessary to sever the ectopic tendon to complete the technique, lengthening the surgical time and increasing the chance of complications. For this reason, the use of a standard posterior portal providing intra-articular arthroscopic access through the rotator interval is recommended since the aforementioned anatomical variation is not infrequent. Level of evidence Therapeutic studies—investigating the results of treatment, Level V.