Sex differences in the sciatic notch of great apes and modern humans

The sciatic notch has been widely used as a sexing criterion in modern humans. In order to better understand the sex differences of this feature in modern humans and great apes, four measurements of the sciatic notch were taken on samples of modern humans and great apes of known sex. Univariate (ANOVA) analysis and discriminant function analysis were performed on the extant taxa to determine: (1) the discriminating power of each variable in these samples of known group membership; and (2) which of these extant taxa shows the best discrimination between the sexes for the sciatic notch. Of the four extant taxa, the sciatic notch of Homo sapiens is the most sexually dimorphic, followed by Gorilla gorilla, and more weakly by Pongo pygmaeus, while Pan troglodytes is the least dimorphic of these taxa. Since the presence of a well defined sciatic notch is a hominid trait resulting from the dorsal extension of the posterior ilium, the close approximation of the sacrum to the acetabulum, the shortened ischium, and the accentuation of the ischial spine as part of the bipedal adaptation, it seems likely that the configuration of the sciatic notch in hominids was initially related to bipedalism, not reproduction. The development of sex differences in the sciatic notch of modern humans is more likely to have occurred after the transition to bipedality.     

Associated malformations in infants and fetuses with upper or lower neural tube defects

A number of studies on sexual differences in the ilium have been reported. However, most of these studies have focused on the adult ilium. With regard to sexual differences in the fetal ilium, few studies have been carried out. Especially, there have few studies regarding sexual differences in the fetal ilium using dry bones. In the present study, sexual differences in the morphological characteristics of the greater sciatic notch were investigated using dry fetal iliac bones. We examined 212 fetuses (106 males and 106 females) measuring 20.0 cm or more in fetal length with free of gross malformations or deformities which were collected at Saga Medical School. The iliac bones were excised from these fetuses and dried as materials for study. Fetal length was measured in the fully extended position and was classified into six groups each for males and females in 5-cm increments, giving a total of twelve groups. The inner lateral surface of the greater sciatic notch was magnified 25x using projector, traced, and the tracings were inputted to a computer (7600/120: Apple Co. Ltd) using a flatbed scanner. The width and height of the greater sciatic notch were measured, as well as the area of the greater sciatic notch. No sexual differences were noted regarding the increase in the width of the greater sciatic notch in fetuses up to 39.9 cm in fetal length. In fetuses measuring between 40.0 anf 44.9 cm, a significant sexual difference was observed, with the increase in greater sciatic notch width markedly greater in females. With respect to the increase in the height of the greater sciatic notch, no significant differences were noted. No significant differences were observed in the total area of the greater sciatic notch in fetuses up to 39.9 cm in fetal length. On the other hand, a significant sexual difference was observed in fetuses measuring 40.0 cm or more, with the total area markedly increased in females. In addition, no significant differences were found in the area between the two sides of the greater sciatic notch in fetuses up to 39.9 cm in fetal length, although significant differences were observed in fetuses measuring 40.0 cm or more. In female fetuses 40.0 cm or more in fetal length, the greater sciatic notch was found to be wider than in males, and the peak of the greater sciatic notch was displaced in the anteroinferior direction, farther from the auricular surface of the ilium and nearer the pubic bone. Thus these female fetuses show morphological characteristics of the adult female pelvic bone. Based on the results obtained, it is concluded that sexual differences can be identified in fetuses from the 8th month of pregnancy (fetal length 40.0 cm or more).     

Effects of sciatic nerve crush on the L7 spinal roots and dorsal root ganglia in kittens

The number and size distribution of axons and neurons were examined in the L7 spinal roots and ganglia of kittens 14 to 220 days after early postnatal sciatic nerve crush. The results show that motoraxons in the ventral root as well as axons and perikarya of sensory neurons in the dorsal root remained growth-retarded throughout the examined period. This was most evident in the dorsal root. Both ventral and dorsal roots showed some loss of myelinated axons, but this was only half that previously observed after sciatic nerve resection. Whereas in the dorsal roots and dorsal root ganglia the loss seemed to be nonselective with respect to size, axons in the gamma range were primarily affected in the ventral roots. In the dorsal roots the proportion of unmyelinated axons was comparable with controls but in the ventral roots it was somewhat elevated. In most cases the loss of dorsal root ganglion neurons was relatively greater than the decrease of dorsal root axons.     

An unusual cause of sciatica. A case report

STUDY DESIGN: This case report illustrates the need to be aware of extraspinal causes of sciatica. A patient with a strangulated sciatic hernia showed the clinical features of sciatic leg pain, intestinal obstruction, and a left gluteal abscess. OBJECTIVE: To highlight the need to examine the course of the sciatic nerve for local pathology when the cause of sciatica is not obvious. SUMMARY OF BACKGROUND DATA: Sciatic herniae are rare. The coexistence of sciatica and a gluteal abscess, caused by a strangulated sciatic hernia, does not appear to have been reported previously. METHODS: A 66-year-old woman with preexisting low back pain and left leg pain was admitted to the hospital with intestinal obstruction and a left gluteal mass. Results of needle aspiration suggested the diagnosis, which was confirmed by laparotomy. The sciatic hernia was repaired via a transabdominal approach. RESULTS: The symptoms of sciatic nerve compression and intestinal obstruction resolved fully after surgery. CONCLUSION: The possibility of local pathology causing sciatic nerve compression should be considered when a patient reports sciatic leg pain, particularly if the presentation is atypical. Intestinal obstruction or the presence of a gluteal mass should suggest the possibility of a sciatic hernia.     

A primary intrapelvic hydatid cyst presenting with foot drop and a gluteal swelling: a case report

A primary hydatid cyst in the pelvis is rare, and usually presents with pressure symptoms affecting the adjacent abdominal organs. We describe such a cyst which protruded through the sciatic notch and presented as a gluteal swelling with a foot drop due to compression of the lumbosacral nerve roots. Surgical excision and postoperative treatment with albendazole for six weeks were effective in controlling the disease and preventing recurrence.     

Can Rinne''s test quantify hearing loss?

Several years after undergoing surgery for a malignant melanoma on his left lower back, a 51 year old man developed intermittently severe pain in his left posterior thigh. Plain X-rays showed no abnormality, but computerized tomography and magnetic resonance imaging scans demonstrated an abnormal soft tissue mass in the left sciatic notch. Although a metastasis from the original melanoma was suspected, exploration of the suspicious area revealed only hypertrophy of the left piriformis muscle. This was due to regular gymnasium exercises designed to selectively build up the musculature of the left lower limb, which the patient had undertaken in the firm belief that it would help to prevent a recurrence of his left-sided melanoma. Complete relief of the unilateral piriformis syndrome was achieved by division of the hypertrophied piriformis muscle, thereby relieving the pressure on the left sciatic nerve as it passed through the greater sciatic foramen.     

The pelvic osteotomy of Chiari: an anatomical study of the hazards and misleading radiographic appearances

The medial displacement osteotomy of Chiari has an established place in the management of older children and adults with severe hip dysplasia. The results claimed for the operation are, however, variable. There have also been reports of sciatic nerve lesions. In this study ten cadavers were operated upon. Chiari osteotomy was performed upon five, and five acted as controls. The hemipelvis was removed from each cadaver; each specimen was deep-frozen and sectioned transversely. The distance of the sciatic nerve from the nearest bony point was measured in each section and the results were recorded graphically. A further radiographic and photographic study was performed to determine whether apparent displacement at the osteotomy might be misleading. The conclusion was drawn that the sciatic nerve is angulated at the osteotomy and further endangered by the risk of bone splintering at the sciatic notch. The radiographic study suggested that some poor clinical results may be explained by a radiological artefact, because there is a tendency for the osteotomy to hinge posteriorly at the sciatic notch opening anteriorly like a book. Radiographs may suggest excellent medial displacement whereas in fact the femoral head is very poorly covered.     

Sciatic nerve palsy following uneventful sciatic nerve block

We describe the loss of function in the sciatic nerve after an uneventful sciatic nerve block using 25 ml of lignocaine 1% with adrenaline 1 in 200,000 in a patient receiving beta blocker drugs. Lack of pain on injection and complete regeneration of the nerve after 12 months in a patient with severe peripheral vascular disease led us to postulate ischaemic nerve damage as a mechanism of injury. Adrenaline-induced unopposed alpha-mediated vasoconstriction in a beta-blocked patient is suggested as a possible mechanism of peripheral nerve injury worthy of further investigation.     

Differential expression of galanin immunoreactivities in the primary sensory neurons following partial and complete sciatic nerve injuries

Neuropeptide expression in primary sensory neurons is highly plastic in response to peripheral nerve axotomy. While neuropeptide changes following complete sciatic nerve injury have been extensively studied, much less is known about the effects of partial sciatic nerve injuries on neuropeptide plasticity. Galanin. a possible endogenous analgesic peptide, was up-regulated in primary sensory neurons following complete sciatic nerve injury. We investigated the effects of partial sciatic nerve injuries on galanin expression in primary sensory neurons, and compared this effect with that after complete sciatic nerve injury. Complete transection, partial transection and chronic constriction injury were made, respectively, on the sciatic nerves of three groups of rats at high thigh level. Animals were allowed to survive for four and 14 days before being killed. L4 and L5 dorsal root ganglia, L4 5 spinal cord and lower brainstem were processed for galanin immunocytochemical staining. After all three types of sciatic nerve injuries, galanin-immunoreactive neurons were significantly increased in the ipsilateral dorsal root ganglia, and galanin-immunoreactive axonal fibres were dramatically increased in the superficial laminae of the dorsal horn and the gracile nuclei, compared to the contralateral side. However, in partial injury models, the percentages of galanin-immunoreactive dorsal root ganglion neurons were significantly higher than in complete nerve transection. Size frequency distribution analysis detected that more medium- and large-size galanin-immunoreactive dorsal root ganglion neurons were present after partial nerve transection and constriction injury than after complete nerve transection. Using a combined approach of retrograde tracing of flurorescent dyes and galanin immunostaining, we found that a partial transection increased the proportions of galanin-immunoreactive neurons among both axotomized and non-axotomized neurons. Galanin-immunoreactive axonal fibres were not only detected in the superficial laminae, but also in the deeper laminae of the dorsal horn of partial injury animals. Furthermore, more galanin-immunoreactive axonal fibres were observed in the ipsilateral gracile nuclei of partially injured rats than in completely injured rats. We conclude that partial sciatic nerve injuries induced greater galanin up-regulation in medium- and large-size dorsal root ganglion neurons than complete sciatic nerve injury. Galanin expression in primary sensory neurons seems to be differentially regulated following partial and complete sciatic nerve injuries.     

Exclusion of a sciatic artery aneurysm and an obturator bypass

This case report describes surgical treatment in a sciatic artery aneurysm with hypoplastic external iliac and femoral arteries. An obturator bypass grafting procedure from the internal iliac artery to the distal sciatic artery was performed after aneurysmal exclusion was achieved by proximal and distal ligation. This method offers an acceptable option for surgery in some types of sciatic artery aneurysms.     

Sacral plexopathy and sciatic neuropathy after total knee arthroplasty

While peroneal and tibial neuropathies have been described as a complication of total knee arthroplasty (TKA), a computerized literature search failed to reveal any previously reported cases of associated sacral plexopathy or sciatic neuropathy. This case report describes the diagnosis and management of a patient found to have evidence of a right sacral plexopathy and a left sciatic neuropathy, following bilateral TKA. This case suggests that these may be rare complications of TKA.     

Secretion and processing of apolipoprotein A-I in the avian sciatic nerve during development

Apolipoprotein A-I (apo A-I), a major apolipoprotein synthesized by liver and intestine to facilitate transport of plasma lipids as lipoproteins, has been detected also in the avian sciatic nerve. The mRNA and protein levels of apo A-I have been shown to increase during the period of rapid myelination (LeBlanc et al.: J Cell Biol 109:1245-1256, 1989). In order to assess the synthesis of apo A-I protein and the processing of apo A-I isoforms during development, endoneurial slices of avian sciatic nerves from chicks during active myelination at 15 and 17 days embryonic and 1 day posthatch age were incubated with [35]S-methionine. The incubations were fractionated into secreted and intracellular fractions, and incorporation of the label was assessed for apo A-I protein. The pattern of labeling of Po protein, as a marker of myelination, was also determined in the intracellular and compact myelin fractions. Methionine incorporation into Po protein was highest in the intracellular compartment at the 15-day embryonic stage and decreased thereafter, with a corresponding increase in the myelin fraction. During these developmental periods, the levels of nascent apo A-I increased in both the secreted and intracellular fractions. The synthesis of apo A-I specifically increases in the secreted fraction compared with total protein synthesis. The processing of the pro-apo A-I is also developmentally regulated. In the intracellular compartment, there are approximately equal proportions of the acidic and basic isoforms. However, with increasing age, a higher proportion of the apo A-I is secreted as acidic isoforms. It is concluded that the secretion and processing of apo A-I is developmentally regulated in the chick sciatic nerve, in parallel with the process of active myelination.     

Neonatal sciatic palsy: etiology and outcome of 21 cases

INTRODUCTION: Sciatic nerve paralysis is a rare entity in the newborn. Few reference in specialized tests indicate that in the majority of cases the sciatic palsy has been observed after misplaced injections into the buttocks. The prognosis is variable and appears to be better after umbilical vessel catheterization for injection of medications than after misplaced muscular injections. In case of recovery it takes place within 3 to 12 months. OBJECTIVE: The objective of the present study is to know the evolution of neonatal sciatic palsy and to determine their injury noxe in regard to perinatal factors, and their relationship with long-time outcome, and to look for prognostic clues of clinical utility. MATERIAL AND METHODS: We evaluated perinatal factors of newborn children with sciatic nerve paralysis, followed for more than 18 months of clinical evolution, in a neuropediatric centre. RESULTS: Twenty one newborn with such criteria were evaluated. Gestational age was within 32 and 42 weeks (median 38.2). The birth weight was between 2,100 and 4,100 g (median 2,973). The majority of cases obtained total recovery (16 of 21). The time of recovery was 4 to 14 months (median 8.8). Free ambulation was obtained by all cases (at 10 to 24 months). No apparent cause was observed in the majority of cases. Cesarean delivery was more frequent specially in cases with permanent consequences. CONCLUSION: Long-time prognostic of neonatal sciatic palsy is generally good. In our series all the cases with consequences were associated to cesarean delivery. The duration of cesarean intervention and the anesthesic hypotony of the newborn could be implicated in the sciatic nerve injury of poor outcome.     

Behavioral signs of acute pain produced by application of endothelin-1 to rat sciatic nerve

We examined whether endothelin-1 (ET-1), a potent vasoconstrictive peptide secreted in high concentration by metastatic prostate cancer cells, produces endothelin receptor-dependent pain behavior when applied to rat sciatic nerve. ET-1 (200-800 microM) applied to the epineurial surface of rat sciatic nerve produced reliable, robust, unilateral hindpaw flinching lasting 60 min. Pre-emptive systemic morphine completely blocked this effect in a naloxone-reversible manner, suggesting that this behavior was pain-related. Equipotent doses of epineurially applied epinephrine had no effect, suggesting that ET-1 effects are on tissue sites other than sciatic nerve microvessels. Prior and co-administration of BQ-123, an endothelin-A (ET(A)) receptor antagonist, also blocked ET-1-induced hindpaw flinching establishing that pain behavior induced by ET-1 application to rat sciatic nerve is ET(A) receptor mediated.     

Persistent primitive sciatic artery

Angiography revealed persistence of the primitive sciatic artery in two cases. In one, the artery supplied a large arteriovenous malformation, and the profunda femoris artery was absent. In the other, there were associated findings of neurofibromatosis, decreased left lower limb lymphatic vessels, a left subinguinal lymphocele, and absent external iliac and femoral arteries.     

Application of sciatic functional index in nerve functional assessment

In order to confirm the reliability of the sciatic functional index (SFI) in the rat, SFI, muscle strength, electrophysiological, and morphometric assessments were carried out from the 10th day to the sixth month after nerve injury or repair. The results showed that the SFI has a positive correlation with all tested indices of muscle strength, electrophysiology, and morphology (r = 0.925-0.996, P < 0.01 or P < 0.001). These results indicate that the SFI is a reliable index for evaluating rat sciatic nerve regeneration and can be widely used.     

Aneurysm in a persistent sciatic artery. Apropos of 2 cases

Persistent sciatic is a vascular malformation resulting in the embryo from the preferential growth of the ischiatic posterior axis remaining atrophic. We report here two cases of unilateral, complete and incompleted, persistent sciatic arteries, complicated by buttock aneurysm.     

Differential time course of neuronal and glial apoptosis in neonatal rat dorsal root ganglia after sciatic nerve axotomy

Sensory neurons in neonatal rat lumbar dorsal root ganglia die after sciatic nerve axotomy, and previous studies have estimated the total cell loss to be 40-95%. We have used the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) technique, combined with immunohistochemistry, to investigate the contribution of apoptosis to the cell loss that occurs after unilaterally transecting the sciatic nerve of new-born rats. TUNEL-positive cells were detected 1 day post-lesion, and their number peaked 3 days after the injury. Combining TUNEL labelling with immunohistochemistry, for neuron-specific neurofilament 150 kDa, or glial-specific S-100beta, enabled us to identify dying neurons and dying glia. One day after axotomy, most of the TUNEL-positive cells (58%) were neurons, whereas 3 days post-injury, only a small number of dying cells (6%) were neuronal. This lower incidence was due to a decrease in neuronal death and an increase in glial death. The glia in the dorsal root ganglia therefore die subsequent to the neurons. The apoptotic nature of the cell death was confirmed by electron microscopy, with fine structural features of apoptotic cell death, e.g. chromatin compaction and membrane blebbing, being observed in both glia and neurons. Our results confirm that extensive apoptosis occurs in the neonatal lumbar dorsal root ganglia after sciatic nerve section, and show that neurons and glial cells die with different time-courses. The results suggest a neuron-glia trophic interdependence in the dorsal root ganglia.     

Modulation of vastus medialis motoneuronal excitability by sciatic nerve afferents

We activated the sciatic nerve afferents by either the discharge of a magnetic coil or a needle inserted near the nerve. Both types of stimulation induced facilitation of the vastus medialis (VM) H reflex, and of the VM response to transcranial magnetic stimulation, at the joint time of arrival of conditioning and test volleys, while a subsequent inhibition was induced only in the H reflex. We conclude that sciatic nerve afferents induce reciprocal inhibition of VM motoneurons presynaptically on the la afferent terminals.