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We describe a patient who underwent arthroscopic pullout fixation for a posterior cruciate ligament (PCL) avulsion fracture. A 46-year-old female, injured in a fall while riding a motorcycle, was diagnosed with a right knee PCL tibial attachment avulsion fracture and underwent arthroscopic osteosynthesis. A Kirschner wire was drilled to a point just medial to the medial border of the anterior tibial bony bed. A suture wire was folded into a loop and introduced into the posteromedial compartment via the bone tunnel. A fixation thread was inserted from the posteromedial portal, through the medial and lateral loop wires, and into the posteromedial compartment. The lateral and medial loop wires attached to the thread were pulled to the outside, and the thread was fixed onto the tibia. Three months post-surgery, she returned to her job. This procedure represents a minimally invasive method of treating avulsion fractures of the tibial attachment of the PCL.

Background The lateral loop formed by the maxillary nerve (V2) and the mandibular nerve (V3) consists of a part of the far lateral triangle of the cavernous sinus. Because this triangle becomes a surgical corridor of the preauricular infratemporal fossa approach and a landmark of the extradural approach for the ganglion-type trigeminal schwannomas, identification of the lateral loop has important implications at the early stage of middle cranial base surgery. We realized that a bony ridge usually existed just lateral to the lateral loop. Objective To nominate midsubtemporal ridge (MSR) as the name for this anatomically unnamed bony ridge and to clarify its features. Methods Using 35 cadaver heads, we measured the shape of the MSR on both sides and the distance between the MSR and the adjacent structures. Results The MSR was recognized in 60 of 70 specimens (85.7%). The bony protrusion was 2.9 ± 1.1 mm in height, 6.0 ± 2.1 mm in width, and 9.1 ± 3.2 mm in length. A single peak with anteroposterior length was common in 47 of 60 specimens (78.3%). The MSR was located at the midpoint of the V2 and V3 in 28 specimens (46.7%) and existed 10.7 ± 3.6 mm lateral from the line that bound the foramen rotundum and the foramen ovale. Conclusion We demonstrate morphological characteristics of the MSR. These data on the MSR will assist the surgeon in identifying the lateral loop as a surgical landmark during middle cranial base surgery.

The posterior inferior cerebellar artery (PICA) is the largest branch of the vertebral artery. It usually arises at the anterolateral margin of the medulla oblongata close to the lower cranial nerves. The PICA had the most complex relationship to the cranial nerves of any artery and it is frequently exposed in approaches directed to the fourth ventricle. The aim of this article is to describe the anatomical relationship of the PICA to the lower cranial nerves. In this study, 12.5% of PICAs passed between the glossopharyngeal and vagus nerves, 20% between the vagus and accessory nerves, and 65% through the rootlets of the accessory nerve. The lateral medullary segment of the PICA showed a lateral loop which in 20% specimens pressed against the inferior surfaces of the facial and vestibulocochlear nerves. The lateral medullary segment of the PICA in 20% specimens passed superior to the hypoglossal nerve, in 47.5% through the rootlets of the hypoglossal nerve, and in 30% inferior to the hypoglossal nerve. The findings on the relationship of the PICA to the lower cranial nerves could be helpful in microsurgery of this region.

OBJECTIVE: The purpose of this study is to call attention to an anomaly in which a segment of the anteroinferior cerebellar artery (AICA) is embedded in the dura or bone surrounding the subarcuate fossa, a small depression in the bone posterior to the internal acoustic meatus (IAM), through which the subarcuate artery enters the bone. This anomaly places the artery at risk in removing the posterior wall of the IAM. METHODS: An anomalous AICA having a segment that was embedded in the dura covering on the bone surrounding the subarcuate fossa was found during a microsurgical dissection course. The senior author (ALR) has observed this anomaly in four patients during surgery for acoustic neuromas and in three specimens in microsurgery dissection courses. To define the microsurgical anatomy of the anomalous artery further, the latex-injected specimen was dissected in a stepwise manner using ×3 to ×40 magnification. RESULTS: The anomalous AICA described in this report bifurcated into a rostral trunk and a caudal trunk near the facial-vestibulocochlear nerve complex. The caudal trunk formed a sharp lateral loop that was embedded in the dura covering the subarcuate fossa. The involved trunk continued to supply the suboccipital area normally supplied by the posteroinferior cerebellar artery, which was hypoplastic. The dura surrounding the anomalous loop was opened, and the adjacent bone was removed to free the anomalous loop from the subarcuate fossa so that the artery could be displaced medially to remove the posterior wall of the IAM. Although it has been reported that the AICA may occasionally be adherent to the dura over the subarcuate fossa, this study is the first to demonstrate an AICA that is embedded in the dura and bone of the subarcuate fossa. CONCLUSION: Mobilizing the AICA loop that is embedded in the subarcuate fossa posterior to the IAM places the involved AICA at significant risk in exposing the contents of the IAM.

Various surgical approaches to the infratemporal fossa (ITF) have been reported. Among them, the preauricular transzygomatic anterior ITF approach (anterior ITF approach) has been used for exposure of the antero-superior part of the ITF. The purpose of this article is to show anatomical dissections using the anterior ITF approach and to evaluate our surgical experience using this approach. An anatomical study of the anterior ITF approach was performed using six sides of three cadaveric heads. Clinical course was retrospectively reviewed for 34 patients who underwent microsurgical resection of tumor in or around the ITF using this approach. Medical, surgical, and neuroimaging records of these patients were evaluated. The key point of this approach was mobilization of the second and third divisions of the trigeminal nerve after drilling of the lateral loop between the foramina rotundum and ovale. After mobilization of the trigeminal nerve, the auditory tube, tensor veli palatini muscle, and pharyngobasilar membrane could be seen. Removal of the pterygoid muscles and plates allowed surgical access to the ITF, orbit, maxillary sinus, pterygopalatine fossa, and parapharyngeal space. We used this approach in 31 patients with skull base tumors between 1994 and 2007. Gross total removal was achieved in 27 of the 31 patients. No mortality or severe morbidity was encountered. Therefore, the anterior ITF approach provides easy access to the ITF and adjacent regions without destruction of important organs.

Twelve patients with catatonic schizophrenia and 12 matched healthy controls were examined with functional MRI while performing a motor task. The aim of our study was to identify the intracerebral pathophysiological correlates of motor symptoms in catatonic patients. The motor task included three conditions: a self-initiated (SI), an externally triggered (ET) and a rest condition. Statistical analysis was performed with SPM5. During the self-initiated movements patients showed significantly less activation than healthy controls in the supplementary motor area (SMA), the prefrontal and parietal cortex. Our results suggest a dysfunction of the "medial motor system" in catatonic patients. Self-initiated and externally triggered movements are mediated by different motor loops. The "medial loop" includes the SMA, thalamus and basal ganglia, and is necessary for self-initiated movements. The "lateral loop" includes parts of the cerebellum, lateral premotor cortex, thalamus and parietal association areas. It is involved in the execution of externally triggered movements. Our findings are in agreement with earlier behavioral data, which show deficits in self-initiated movements in catatonic patients but no impairment of externally triggered movements.

Arthroscopic-assisted simultaneous reconstruction of the posterior cruciate ligament (PCL) and the lateral collateral ligament (LCL) using hamstring tendon grafts is described. The femoral tunnel is drilled through an incision over the medial femoral condyle and the tibial tunnel through the same skin incision used for harvesting the tendon graft. PCL reconstruction is performed using a 4-strand hamstring tendon graft and absorbable screw fixation. The tendon of the semitendinosus muscle of the uninvolved knee is used as a lateral loop for LCL reconstruction. After pulling the transplant through the fibular head, femoral fixation of the loop is made with an absorbable screw.

Approximately 70% of the dry weight of myelin is lipid, with the galactolipid galactocerebroside (GalC) and its sulfated derivative sulfatide encompassing about one-third of the lipid mass (reviewed by Norton and Cammer, 1984). This abundance, along with the results of a number of antibody perturbation studies, led to the hypothesis that the galactolipids play an important role in the formation and maintenance of the myelin sheath (reviewed by Dyer, 1993; Coetzee et al., 1998; Dupree et al., 1998b; Stoffel and Bosio, 1997). The isolation of the gene that encodes UDP-galactosexeramide galactosyltransferase (CGT) (Schulte and Stoffel, 1993; Stahl et al., 1994; Schaeren-Wiemers et al., 1995), the enzyme which catalyzes the final step in the synthesis of GalC (Morell and Radin, 1969), enabled the genetic analysis of galactolipid function. In particular, Coetzee et al. (1996b) and Bosio et al. (1996) used the gene targeting approach in embryonic stem cells to generate mice with a null mutation in the CGT gene. In this chapter we will review the results of the detailed biochemical and ultrastructural analyses of these mutant animals and provide a summary of the current hypothesis concerning the function of galactolipids in the myelination process.

The paranodes of cerebral white matter of lanthanum-treated rats were studied in thin sections. The transverse bands were found to be oriented both parallel, and at an angle to the spaces between lateral loops.

Several tornariae were obtained from the plankton collected during the Cruise of the "Baependi" and the "Vega" to Trindade Is. and vicinities on 18th June 195D, also from plankton collected at Fernando de Noronha Is. These larvae were fixed in a solution of formalin at 4%. Those of Trindade Is. were in a very bad state of conservation (Fig. 1) . They proved to be probably Tornari a weldoni Stiasny in a young Krohn stage of progressive development (no coeloma were noticed). The secondary loops and lobes which were 4 to 6 in number, the high oral arch, the very large oral field, the elevated and narrow ventral loop are characteristic of the above mentioned species and were observed in our best preserved specimen. It is only 1,01mm long, therefore smaller than the T.weldoni described by Stiasny & Stiasny-Wijnhoff (1996). Distribution:- Bahamas Is. and New-England. The beautiful large tornariae from Fernando de Noronha Is. (4mm in height)(Figs. 2-6) are all T.chierchiai I Stiasny in the Krohn stage of development. This is a Ptychodera type larva, according to Stiasny and Stiasny-Wijnhoff (1926), with lobate tentacles, no anal ring, not apically pointed, with a narrow oral field and very deep superior lobes with an inferior bifurcation (Fig. 2). The oral arch is very narrow and low (Fig. 5). The inferior dorsal lobes are narrow, long and without lobate tentacles (Fig. 4). The lateral lobe is short, oblique (as in T. morgani) , narrow, with more or less 8-10 lobate tentacles and provided with a lateral loop as in T.morgani (Fig. 4 and 2), the connective belt between the median and the lateral loops of the post-oral and the pre-oral fields is provided with 6-10 lobate tentacles (Fig. 2). There are about 26 lobate tentacles on the loops. There are no lobate tentacles on the apical region, where the eyes are situated (Fig. 3). Hydrocoel has large "spurs". There is a strong pigmentation on the ciliated ring. The trunk and collar coeloma are periferically situated. The larva is in an advanced Krohn stage of development. T. chierchiai I has only been found in the Pacific up to now. It is generally considered to be the larva of Ptychodera flava widely distributed in that Ocean. A species very closely related to P.flav a occurs in the Atlantic - Ptychodera bahamensis - whose larva T.morgani, differs from T.chierchia i I chiefly by the absence of the inferior dorsal lobes. The larva found at Fernando de Noronha Is. is T. chierchiai I or a morphologically intermediate type between T. chierchiai I and T. morgani. Its occurrence in the Atlantic near to the West Indies strongly supports Trewawas' (1931) and Van der Horst's (1939) suggestions that P. flava and P. bahamensis are probably varieties of the same species. Probably their larvae are also very variable. Or else, T.morgani and T. chierchiai I are not the larvae of the mentioned species of Ptychodera , which is not probable. T. morgani has been reared up to a young Ptychodera sp. stage. Dr. K. P. Rao in India is now trying to rear the larva of P. flava and thus to settle all this controversy. Several tornariae were also sent to me from Algiers (Mediterranean Sea) by Prof. A.Hollande. They are beautifully coloured and mounted in Canada balsam by Dr. J. Cachon, who collected them on the 28th March 1949. One of them had been reared to a stage of metamorphosis. These tornariae belong to two different species: T.krohn i Stiasny and T.dubi a Spengel, both already known from the Mediterranean Sea. T. krohni is very similar to T.mielcki (Stiasny & Stiasny-Wijnhoff 1926, p. 160-161) and my specimens in the Krohn stage of development were intermediate in shape and characteristics between the two above mentioned species, thus proving that the two are varieties of the same species. The height of the tornariae were from 1,1mm to 1,3mm (smaller than the first T. krohni described, probably in part due to fixation and mounting). They belong to the Balanoglossus and Glossobalanus type of tornaria, with the anal field in the shape of an inverted cone, the anterior part of the larva bell shaped, a median apical plate, a narrow ventral loop, which is not very elevated (Fig. 7). The lateral lobe with its corresponding lateral loops is like T.krohni's from Messina (Fig. 10). The stomach is balloon shaped. The primary and the secondary dorsal lobes are very large (Fig. 8). The secondary loops are narrow and protruding (Fig. 7). The oral arch is elevated (Fig. 7). The hydroporus is situated slightly to the right of the median line (Fig. 8). Strongly developed primary inferior dorsal lobes. There are 4 to 5 secondary loops ventrally (Fig. 7). Dorsally there are 3 to 4 (Fig. 8) of the same. The hydrocoel has no "spurs" and the pericardium is already developed. Both collar and trunk coeloma are present. The tornaria is therefore an advanced Krohn stage of development. Fig. 11 shows a tornaria of this species in the Spengel stage of development (with greatly developed coeloma and hydrocoel). Fig. 12 shows the same species at a very late Metschnikoff stage of development (with only very poorly developed trunk coeloma and the beginning of the secondary loop formation, the hydrocoel with thin walls). T. krohni i Spengel is here considered a different species of tornaria probably belonging to Balanoglossus clavigerus, as stated in Stiasny & Stiasny-Wijnhoff (1926, p. 66). Tornaria dubia Spengel collected in the same region, in the vicinities of Algiers, (Figs. 13, 14, 15 and 16) belongs to the Glandiceps type of Stiasny and Stiasny-Wijnhoff. The tornaria is double-cone shaped, with pre-oral field in the form of an upside down Y, and with protruding not separate lqops which give it also the shape of a butterfly. Oral arch with not parallel limbs. The ventral loop has two inferior ventral lobes and two corresponding loops (Fig. 13). It is not long, but large and flat. No lateral lobe, nor lateral loop (Fig. 15). Dorsal primary loops partly in the ventral region with one or two secondary lobes (resulting in an S shaped band) with a long narrow horizontal connection to the median field (Fig. 15). The hydrocoel is very large with pericardium and coeloma well developed. This and the great height of the tornaria (1, 23-1,34mm) show that the larvae of Figs. 13, 14 and 15 are in an advanced Krohn stage of progressive development. They are more developed than the larvae figured by Stiasny & Stiasny-Wijnhoff (1926, fig. 36a and 36b) and by Spengel (1893, pi . 22, fig. 17, 18, 19). Fig. 16 shows this larva in the Spengel stage of development with smaller number of loops and lobes and coeloma far more developed as well as larger hydrocoel. Two metamorphosis stages are also figured (Figs. 17 and 18) but have not been described because they were already mounted in Canada balsam. They belong to T. dubia or to T. krohni and were also obtained in Algiers. It would be interesting to rear both larvae and to settle the question as to which adult species they belong.

Horseradish peroxidase was implanted into rat forebrains and the distribution with respect to the periaxonal space was examined. The peroxidase filled the extracellular spaces. Usually, however, the flow stopped at the junction of the outer loop and the outermost lamella of the myelin sheath and at the outermost lateral loop at the node of Ranvier. Therefore, in most cases, the periaxonal space was devoid of peroxidase. Occasionally, however, peroxidase in small amounts evidently penetrated the junctions and could sometimes be clearly demonstrated within the periaxonal space.

Forty-seven patients had primary repair and extraarti cular augmentation with a lateral loop of the iliotibial tract for acute rupture of the ACL. (All of these patients had anterolateral rotatory instability (ALRI) preopera tively as diagnosed by a positive jerk test.) Of these 47 patients, 36 were available for follow-up evaluation. Followup ranged from 6 to 68 months (average, 21.6 months). Twenty-three of the patients (64%) were rated as excellent or good. Ten of the patients (27.8%) were rated as fair, and three patients (8%) were rated as poor. Thirty-three of the 36 patients (91 %) were objec tively free of ALRI as tested by the jerk test and had 1 + or less result in a Lachman test, with a firm end point. Only one patient felt his knee to be unstable (he had a positive pivot jerk). More than 90% of the patients returned to sport, and 72% returned at their preinjury level.

The territory traversed by the cortical branches of the posterior cerebral artery as they fan out is located on the inferomedial aspect of the temporal and occipital lobes, extending slightly forward of the parieto-occipital sulcus onto the posterior part of the precuneus as well as outward onto the neighboring parietooccipital convexity.

Analysis of abnormalities of the configuration of the anterior inferior cerebellar artery in lateral projection facilitates diagnosis of posterior fossa masses. Cerebellopontomedullary angle lesions frequently cause arcuate posterior-inferior displacements of the rostrolateral artery or reversal of curvature of the ascending segment of the meatal loop. Vermian, hemispheric, intra-fourth ventricular, and suitably situated extra-axial masses alter the plane of the lateral loop of the caudomedial artery. Tonsillar herniation may be detected in patients with hypoplastic or absent posterior inferior cerebellar arteries by analyzing the relationship of the biventral segment of the descending or caudomedial artery to the foramen magnum.

The structure and synaptic relationships of an intersegmental inter‐neurone in the mesothoracic ganglion of the locust were studied by intra‐ccllular labelling for light and electron microscopy. Before labelling, the interneurone was characterized physiologically. It is depolarized and pro‐duces spikes when either of the two forewings are elevated, and by sensory inputs from the tarsi of the middle legs. The gross morphology of the in‐terneurone is quite distinctive. Its cell body is on the ventral surface of the ganglion near the midline and its primary neurite lies in the T‐tract. Its axon performs a characteristic lateral loop around the lateral dorsal tract before entering an anterior connective and ascending at least as far as the prothoracic ganglion. Within the mesothoracic ganglion, the interneurone gives rise to a profusion of branches. Ultrastructural examination and re‐construction of three regions of the interneurone from serial sections shows that input and output synapses are present in approximately equal num‐bers, and often are close to each other. There is no evidence for separate input and output regions. Output synapses are characterized by the presence of a presynaptic bar and a population 500‐2,000 round, electron‐lucent vesicles. Most of the estimated 105‐10 6 synapses occur on the smaller di ameter processes or on spines. The spines are of uniform diameter along their lengths, and are pre‐ or postsynaptic or both, but the postsynaptic spines are of smaller diameter than the others.

Amphibian oocytes offer many advantages for studying nucleo-cytoplasmic interaction, the nature and properties of the nuclear membrane, the protein constituents of cell nuclei, the proteins involved in RNA transcription, and those that accompany RNA to the cytoplasm, some of which are concerned with RNA stockpiling and perhaps with the masking of mRNAs that are not translated until oocyte maturation has occurred. How these virtues have been exploited has recently been reviewed by Scheer and Dabauvalle (1985). For studying nuclear proteins there are two particular advantages. Potential cytoplasmic contaminants can be eliminated by manual isolation in saline, and rapidly; for “easy” species this operation takes about 30 s. Some loss of soluble protein occurs even in so short a time (Paine et al. 1983) but substantial loss is avoided (Macgregor 1962). Amphibian oocyte nuclei are exceptionally large. According to Paine et al. (1983) a single Xenopus nucleus from an oocyte approaching maturity, with a water content of about 90%, contains about 5 μg of protein. According to Maundrell (1975) a half-grown 0.8 mm diam oocyte of Triturus c. carnifex, at a stage when the lampbrush chromosomes have reached their maximum bulk, contains about 1.2 μg of nuclear protein, of which more than 1 μg represents the contribution from nuclear sap, 100 ng is nucleolar, and 30 ng is chromosomal. However despite the exceptionally large amount of protein associated with lampbrush chromosomes, analysis of the constituent polypeptides by direct means has so far merely established their complexity. This is in marked contrast to the wealth of information that has come from experimental studies where various materials have been injected into oocytes, notably those of Xenopus,the host oocytes cultured in vitro, and thereafter subjected to analysis by various sophisticated techniques. The virtues of the oocyte as an experimental system were first spectacularly exploited by J. B. Gurdon and his many colleagues, and more recently other groups of cell and developmental biologists have done likewise. The field has been extensively and repeatedly reviewed, and for the most part lies beyond the scope of this monograph. Nevertheless some general conclusions arising from this work are directly relevant, and these will be briefly discussed before turning to the main topic of this chapter.

The lampbrush chromosomes of Amphibia are obtained from the germinal vesicle nuclei of oocytes. The oocyte’s nucleus is isolated and freed from cytoplasm in an appropriate saline by means of forceps, needle, and pipette, under a dissecting binocular microscope. It is then transferred to a “bored” slide, with a coverslip sealed across the hole to make a chamber, containing an appropriate saline. The nuclear membrane is now removed by means of fine forceps and a tungsten wire needle, the chamber is sealed above with another coverslip, and the nuclear sap allowed to disperse. The chromosomes, which come to lie on the floor of the chamber, are observed using a phase-contrast microscope whose optical train is inverted, i.e., with condenser above the object, and objective lens below.