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Expérience GANIL; International audience; A high-purity co-axial germanium detector has been calibrated in efficiency to a precision of about 0.15% over a wide energy range. High-precision scans of the detector crystal and gamma-ray source measurements have been compared to Monte-Carlo simulations to adjust the dimensions of a detector model. For this purpose, standard calibration sources and short-lived on-line sources have been used. The resulting efficiency calibration reaches the precision needed e.g. for branching ratio measurements of super-allowed beta decays for tests of the weak-interaction standard model.

Anterior lumbar spine approaches may be indicated for fusion in degenerative lumbar spine disorders or to fill discal and bone gaps after fracture reduction. We present an anterior extraperitoneal approach applicable to any discal and vertebral levels from T12 to S1. The anatomic study, based on 25 cadavers, highlights retroperitoneal dissection principles for easy kidney and duodenopancreatic mobilisation and direct left anterior access to the entire lumbar spine. We established a precise description of the lumbar veins and the anastomoses between the left renal vein and hemiazygos system, in order to define different topographic and anatomic factors related to safe and easily reproducible approaches for cage or graft implementation. Independent of the level and previous intraperitoneal surgery, lumbar spine access with this approach safeguards the kidney, ureter, spleen, hypogastric plexus and duodenopancreatic system. Regarding operating time, blood-loss and possibilities for freshening and grafting, this technique seems an effective counterbalance to the difficulties and complex technology of endoscopic approaches. The clinical study includes our first 42 cases in traumatic and degenerative lesions. Avoiding the neurologic or hemorrhagic risk inherent in classical posterior lumbar interbody fusion (PLIF) techniques, it can be considered as a reasonable and valid alternative. This technique could be used in the near future for mini invasive discal prosthesis insertion.

Pelvic osteotomies were developed to increase or restructure the acetabular surface. Periacetabular osteotomies are considered the most difficult from the technical point of view and necessitate sufficient residual cartilaginous surface. Juxta-acetabular osteotomies avoid major disorganization of the pelvic framework and allow easier reorientation of the acetabulum. The authors present a technical variant that preserves the entire posterior column, as in the Ganz osteotomy. The effects on the vascularisation of the periacetabular region are strictly the same and there is no necrosis of the subchondral bone. This osteotomy is easier to perform, because of a single positioning associating two simultaneous approaches. The osteotomies are rectilinear and easy to check peroperatively by fluoroscopy thanks to this positioning. Another valuable aspect of this double approach consists of very easy correction of “automatic” unwanted retroversion due to the lowering of the acetabular roof. This unintended displacement is rarely reported in the literature, despite its anatomic evidence in 3-dimensional CT-scan reconstructions for pre- and peroperative evaluation.

The deformations and stresses acting on the acetabular rim have not been very precisely documented. The authors present a study based on an experimental simulation of hip loading with anatomic correlations. 122 dissections were performed in order to define the anatomic aspect of the roof (and especially of Byers's “area 17”) and the intermediate area between the anterior and posterior acetabular cornua. Ten fresh cadavers were tested on the lines of previous studies on monopodal or bipodal loading. An extensometric study was performed with special attention to the transverse acetabular ligament, supra-acetabular area and obturator foramen. The area 17 of Byers is a transitional zone and the mobility of the posterior cornu is 3 times that of the anterior cornu. Resection of the acetabular ligament modifies the displacement of the posterior cornu under loading but has no influence on deformation of the oburator foramen. The biomechanical behavior of the acetabular roof in the standing position is influenced by the conditions of monopodal or bipodal loading and by femoral rotation, but a tendency to extrusion was constantly noted.

The authors report a series of 41 dissections of the forearm intended to study the orientation of the fibers of the flexor carpi radialis (FCR). This shows that there is a constant torsion of the fibers of the FCR by an average of 180 degrees. Half of this torsion occurs in the forearm and half in the sheath of the FCR at wrist level. Awareness of this torsion is particularly useful surgically when the tendon is employed in ligamentoplasty, particularly after trapeziectomy. Our study of the orientation of the fibers was aimed at the ability to perform subcutaneous splitting of the fibers for use of part of the tendon.

The need to perform triple osteotomies of the pelvis passing very close to the articular surface leads to the isolation of bony fragments whose vascularisation may be precarious. To assess the risks of such surgery, we undertook an anatomic study of the vascularisation of the acetabulum in the fetus. 53 specimens were injected to study the vessels to the acetabulum and their distribution within the osteocartilaginous specimen. The acetabular a., a branch of the obturator a., gives a central pedicle distributed to the acetabular fossa, the triradiate cartilage and ending in the three primary bony components. The superior gluteal, inferior gluteal, internal pudendal and obturator aa. form a periacetabular vascular circle. The abundant vascularity of the acetabulum makes massive necrosis improbable in the child. However, there is a zone of precarious anastomosis at the anterior portion of the acetabulum.

The authors describe the distribution of the medial branches of the upper thoracic dorsal rami (T1 to T5 levels). At each level, after travelling through the erector spinae, they become superficial, and reach the apex of the spinous process of the corresponding vertebra. They then spread out laterally, innervating the skin. They can occasionally be compressed by paravertebral tendons, and this possibly contributes to certain forms of dorsal pain. Anastomosis of the dorsal cutaneous branch of the second thoracic nerve (T2) with the descending lateral branch of the accessory nerve has been observed. Its presence could explain the occasional clinical situations where there is no resultant paralysis from accidental surgical section of the latter nerve.

We have examined 203 lumbar and sacral skeletal specimens and have noted the frequent occurrence of a mamillo-accessory foramen, formed by the ossification of the mamillo-accessory ligament. The dorsal ramus of the lumbar nerve passes through this foramen. At the L5 level, this foramen is found frequently: in 26% of the cases on the left side and in 13.5% on the right. In some cases it is seen as a simple, deep notch. It is found much less frequently at L4 and almost never seen above. It is equally rare at the sacral level where it is formed by a narrowing and closure of the groove between the zygapophyseal joint and the sacral lateral mass. The authors propose that these bony foramina are a manifestation of osteoarthritic changes and that they could, in certain cases, irritate or compress the dorsal ramus along its passage.

A Penning-trap isobar separator is currently under construction at CENBG (Bordeaux, France) and MPIK (Heidelberg, Germany) for a future installation at the SPIRAL2/DESIR facility. This device aims at purifying the radioactive ion beams from undesired species, in order to deliver highly pure samples of exotic nuclei to the different set-ups which will be installed in the DESIR hall. The present manuscript describes the context and the motivations to build such a system, the targeted characteristics, and the studies to find an efficient purification method for large samples of isobaric species.

To assess the usefulness of magnetic resonance (MR) imaging in the diagnosis and clarification of the physiopathology of digital mucoid cysts.Twenty-three patients (14 women, nine men; aged 52-75 years) with mucoid cysts underwent MR imaging at 1.5 T with a local surface gradient coil. The pixel size was 117 microns in one direction. T2 relaxation times were measured. Contrast material was intravenously administered in 15 patients.All mucoid cysts had high signal intensity and sharp borders on T2-weighted images. Intracystic septa were present in nine patients (39%). Most cysts were solitary (n = 13) and/or in the proximal nail fold (n = 16). Satellite cysts were present in five patients. Nineteen patients (83%) had cysts with pedicles that extended to the joint. Osteoarthritis of the distal interphalangeal joint was present in 16 patients (70%). Five patients (22%) had multiple flattened cysts that were usually independent of the joint. In seven patients (30%), MR images showed cysts beneath the nail plate.Digital mucoid cysts may be polymorphic. MR imaging is helpful when cysts are in the nail bed.

To determine the magnetic resonance (MR) imaging features of subungual glomus tumors.Thirty-one patients with a clinical suspicion of glomus tumor and 10 control subjects underwent MR imaging at 1.5 T. MR images of normal glomus bodies of a cadaver finger were correlated with histologic slices. With a local surface gradient coil, the pixel size reached 117 microns in one direction. Relaxation times were measured. Gadoterate meglumine was injected in 19 patients.Normal glomus bodies were visualized in the reticular dermis of the nail bed. Twenty-seven of 28 pathologically confirmed glomus tumors were detected with MR imaging. A peripheral capsule was present in most tumors. The nail matrix was compressed in 13 cases. The authors were able to differentiate three subtypes of glomus tumors (vascular, solid, and myxoid) on the basis of relaxation times and enhancement characteristics. Four patients had mucoid cysts or angioma in the nail bed.MR imaging can help accurately define the location and limits of glomus tumors before excision.

The ligaments of the ankle are superficial and easily accessible at ultrasonography. Surprisingly, the reliability of this technique has never been proven. With this goal in mind, ten ankles were subjected to a ultrasono-anatomic comparison. The five principle ligamentous fascicles (three on the lateral side and two on the medial side) measured at ultrasonography and the values verified after dissection. This study shows that the ligaments of the ankle are analyzed with ultrasonography and that the measures done are valid and have a precision of 2 mm for the anterior fascicle and the lateral fascicle of the lateral ligamentous plane Due to its simplicity and its low price, ultrasonography appears to be an important method in evaluating the ligaments and the degree of seriousness of ankle sprains.

This anatomic study, based on six subjects, is aimed at a better description of the anterolateral thoracic fascia, not previously studied in its entirety. The literature describes a fascia of the pectoralis major m. continuous with that of the serratus anterior m., starting at the lateral border of the pectoralis major or pre-pectoral. The upper limits have never been studied and the lower limits are ill-defined, the aponeurosis of the pectoralis major or the pre-pectoral fascia being continuous with that of the rectus abdominis m. It is shown that this fascia, from a retropectoral origin, extends to the base of the axilla above and is stretched as bridge between the pectoralis major and latissimus dorsi mm. and the muscles of the anterolateral wall of the abdomen. This fascia has some surgical importance as a plane of coverage in the protection of mammary implants. The lack of concordance with classical anatomic accounts, the histology and the vascularisation of this fascia call for complementary studies.

Examination of the knee joint by magnetic resonance imaging (MRI) is a noninvasive technique of proven reliability as regards lesions of the menisci and ligaments [3, 4, 11]. It provides good definition of the different anatomic structures [10]. The meniscofemoral ligaments have been observed with varying frequency and may be responsible for false images [5, 16, 17]. However, it is important to detect them in cases of hypermobile discoid menisci of the ‘Wrisberg ligament type’ in order to guide the surgeon in their excision during total meniscectomy [2, 7]. We have attempted to assess the ability of MRI to visualise the meniscofemoral ligaments in correlation with an anatomic study and to identify certain anatomic pitfalls. This study will allow better investigation of the hypermobile menisci associated with the meniscofemoral ligaments. A clinical case is reported to illustrate its practical importance.

Ossifications in the caudal attachments of the ligamentum flavum were studied on 121 dried thoracic spines. Most of them were aged. Frequency increased in a caudal direction. At T12, frequency depended on the orientation of the zygapophyseal joints of T11-12 which determined the range of rotation. When they were of thoracic orientation, allowing large range of rotation, ossifications were present in 83% of cases. If orientation was lumbar, allowing poor range of rotation, ossifications became much less frequent:33%. The size of ossifications was also studied. The smaller were in T1 and T2. In T11 and T12, size also depended on the orientation of the zygapophyseal joints of T11-12. If it allowed important range of rotation, ossifications were large sized. In the opposite case, they were small sized. Ossifications of caudal attachments of ligamentum flavum appear to be a normal feature of the aged lower thoracic spine. Their frequency in a given motion segment seems to be influenced by rotational strains.

Thirty-seven dissections have shown that the skin of the low back is innervated by the lateral branches of the dorsal rami of T12 and L1 in 22 cases (60%) or T12 L1 and L2, in 10 cases (27%) or T12 L1 and L2 receiving an anastomosis from L3 in 5 cases (13%). The most medial nerve crossed the iliac crest through a rigid osseo-aponeurotic orifice located 7–8 cm from the midline which was seen compressing the nerve in 2 instances. This pattern of distribution may sometimes explain unilateral low back pain.

On the supposition that some "pseudocoxalgias" might be due to a neuralgia of the lateral rami leaving the subcostal and iliohypogastric nerves above the lateral edge of the iliac crest, the authors undertook an anatomic study of their pathways and pattern of distribution. These rami supplying the skin below the iliac crest, which they cross close together, the ramus arising from the subcostal nerve by perforating the internal and external oblique abdominal muscles, that arising from the iliohypogastric nerve a little lower, creating a bony groove palpable in thin subjects and transformed into an osseomembranous tunnel by the aponeurosis of these muscles. This arrangement may give rise to an entrapment syndrome. At this intersection, the course is either vertical or "bayonet-shaped", directly subcutaneous, and hence exposed to possible friction and microtraumata (tight clothes). The two rami are of unequal length. Frequently, the ramus arising from the subcostal nerve is short, not exceeding 10 cm, below the iliac crest, thus corresponding to the usual description. That arising from the iliohypogastric nerve descends further, passing 3 to 5 cm anterior to the great trochanter. It ends either at this level or 8 to 10 cm below. This accounts for the distribution of the pain felt when there is irritation of this ramus.

Manual compression of the vertebral artery is used in routine clinical practice for diagnosis of positional hemodynamic vertebro-basilar insufficiency (VBI). The supraclavicular and suboccipital areas were carefully dissected in 20 cadavers. Anatomical variations observed on dissection were compared to angiographic data from 150 patients and data from the literature. Objective results of manual compression of the vertebral artery can be obtained by sonography. In patients with VBI, such compression induces signs of reversible cerebellar or brain stem ischemia, whereas no signs are observed in patients without VBI.

Deux elements nouveaux apparaissent au terme de notre travail: les branches posterieures de T12 et L1 innervent a elles seules la region fessiere superieure dans 60% des cas alors que celle de L3 n'a de territoire cutane que dans 13 % des cas, la branche posterieure la plus interne (L1 en regle ou L2) peut etre interessee par un syndrome canalaire lorsqu'elle croise la crete iliaque, a l'origine de douleurs lombaires unilaterales.