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PubMed1997

Radiographic standing cervical segmental alignment in adult volunteers without neck symptoms.

STUDY DESIGN: A radiographic evaluation of standing cervical and global sagittal alignment in 100 adult volunteers with no neck or radicular arm symptoms was undertaken. OBJECTIVES: To document and define cervical standing lateral alignment and balance in a volunteer population without cervical problems. SUMMARY OF BACKGROUND DATA: Minimal data exist on cervical segmental sagittal alignment distributions in stance. METHODS: Radiographic measures of spinal alignment were collected and statistically analyzed. RESULTS: Data were categorized into two age- and sex-matched groups. Group 1 had no cervical or lumbar symptoms. Group 2 had no cervical symptoms, but had lumbar symptoms. Mean total and segmental cervical alignment distributions were not statistically different between groups. Mean total cervical lordosis in stance for the entire group was -40.0 +/- 9.7 degrees. Thoracic and lumbar alignment were within previously reported measures and not statistically different between groups. Plumb line markers at C7 and sacral reference points were not statistically different between groups. Pearson correlations revealed that cervical sagittal plane alignment vaired inversely with thoracic alignment. Independent orthopedists noted cervical osteoarthritis was present in 17% of each group of volunteers with substantial kappa agreement (0.73) between observers. Intraobserver and interobserver reliability of sagittal alignment measures of 30 randomly remeasured radiographs revealed strong correlation between observations. CONCLUSIONS: No differences in total cervical lordosis were noted between cervical asymptomatic volunteers with or without low back pain. Most cervical lordosis occurred at the C1-C2 level in stance, whereas only 6 degrees (15%) occurred at the lowest three cervical levels (C4-C7). Changes in cervical lordosis correlated inversely with changes in thoracic alignment.

Adult↗
PubMed2001

Lumbar sagittal contour after posterior interbody fusion: threaded devices alone versus vertical cages plus posterior instrumentation.

STUDY DESIGN: An observational radiographic study examining lumbar sagittal contour of patients undergoing posterior interbody arthrodesis. OBJECTIVES: To compare operative alterations of lumbar sagittal contour after posterior interbody fusion using threaded interbody devices alone versus vertical cages combined with posterior compression instrumentation. SUMMARY OF BACKGROUND DATA: Technique-related alterations of lumbar sagittal contour during interbody arthrodesis have received little attention in the spinal literature. METHODS: Standing lumbar radiographs were measured for preoperative and postoperative segmental lordosis at levels undergoing posterior interbody arthrodesis using either stand-alone side-by-side threaded devices or vertical cages combined with posterior transpedicular compression instrumentation. Sagittal plane segmental correction (or loss of correction) was calculated and statistically compared. RESULTS: The radiographs of 30 patients (34 spinal segments) undergoing lumbar or lumbosacral arthrodesis were compared. Seventeen patients (18 segments) had undergone interbody fusion using threaded cages,whereas 13 patients (16 segments) underwent fusion using vertically oriented mesh cages combined with posterior compression instrumentation. Preoperative segmental lordosis averaged 8 degrees for both groups. For patients undergoing fusion with threaded cages, there was a mean lordotic loss of 3 degrees/segment. For patients undergoing fusion with vertically oriented mesh cages combined with posterior compression instrumentation,there was a mean lordotic gain of 5 degrees/segment. This difference in segmental sagittal plane contour was highly significant (P = 0.00). CONCLUSION: Threaded fusion devices placed under interbody distraction with the endplates parallel fail to preserve or reestablish segmental lordosis. Vertical cages, however, when combined with posterior compression instrumentation, not only maintain segmental lordosis, but also can correct sagittal plane deformity.

Humans↗
PubMed2003

The relation of thoracic and lumbar fracture configuration to the development of late deformity in childhood spinal cord injury.

STUDY DESIGN: A retrospective clinical observational study was conducted. OBJECTIVE: To assess the relation of spinal fracture type and its magnitude of distortion to subsequent long-term development of late spinal deformity in childhood onset spinal cord injury. SUMMARY OF BACKGROUND DATA: In this study, 76 adults who sustained spinal cord injury during childhood were examined clinically and radiographically alongside a retrospective review of case notes and radiographs. METHODS: The nature of the spinal injury and the progression of its displacement were defined from radiographs taken immediately after injury, then at 4 months and at 1 year. Eventual adult spinal deformity was defined from standardized erect long-plate radiographs. Scoliosis, kyphosis, and lordosis were measured using Cobb's method. RESULTS: There was no statistically significant difference in the severity of scoliosis, kyphosis, or lordosis between traumatic and nontraumatic injuries, nor between patients with and those without radiologically visible bony injury. Of the 14 patients with traumatic thoracic and lumbar injuries who had undergone no surgical intervention, 10 (71%) showed development of major scoliotic curves that did not include the fracture site. The patients with no angular displacement at the fracture site after 1 year went on to experience the development of more severe scoliosis (mean, 66 degrees) than those who had displaced fractures (mean, 38 degrees). In five, a low kyphotic curve and a compensatory lordosis above it developed. CONCLUSIONS: There is no evidence that the bony injury to the vertebral column itself in the child with spinal cord injury influences the development of late scoliosis or lordosis, but it may influence any eventual kyphosis.

Adolescent↗
PubMed2002

Correlative analysis of lateral vertebral radiographic variables and medical outcomes study short-form health survey: a comparative study in asymptomatic volunteers versus patients with low back pain.

This prospective comparative study was designed to investigate the possible link between SF-36 functional status and lateral roentgenographic variables of the standing lumbar spine in patients with low back pain (LBP) versus asymptomatic volunteers. To the authors' knowledge, no previous studies have correlated SF-36 scores and sagittal roentgenographic variables in patients with LBP versus asymptomatic individuals. A total of 100 male volunteers, used as controls, and an equal number of age-, height-, and weight-comparable patients of the same ethnicity with chronic LBP were compared on the basis of roentgenographic and SF-36 data. The roentgenographic variables that were measured included the following: lumbar lordosis, sacral inclination, L1-S1 vertebral inclination, L4-S1 distal lordosis, disc index, and L1-L5 vertebral index. These variables were correlated with the eight SF-36 scales both in patients and controls. As the patients with LBP get older, they show lower functional scores in Role-Emotional (p < 0.01) and Physical Functioning (p < 0.01). Body height was not found to be a predisposition favoring LBP, but tall patients with LBP showed less Bodily Pain than patients of short stature (p < 0.001). This study showed that patients with LBP had significantly lower scores than their asymptomatic counterparts in the following SF-36 scales: Role-Physical (p < 0.01), Bodily Pain (p < 0.01), Role-Emotional (p = 0.058), and Mental Health (p < 0.001). In the controls General Health, Physical Functioning, Social Functioning, and Role-Emotional, Bodily Pain, Mental Health, and Vitality correlated statistically significantly with individuals' age, height, weight, lumbar lordosis, sacral inclination, inclination of L1, L3, and L5 vertebra, L1-L5 vertebral index, and L1-L2, L2-L3, L3-L4, L4-L5, and L5-S1 disc index. For the patients with LBP this study showed that General health, Physical Functioning, Role-Emotional, Social Functioning, and Bodily Pain were significantly correlated with age, height, L1-L2 inclination, distal lordosis, L2-L5 index, and L4-L5 and L5-S1 disc index. This comparative study showed that the functional status of hard-working patients with chronic LBP is associated with degenerative changes on the lateral radiographs of the lumbosacral spine. Spine surgeons should take into consideration the results of this study in reconstruction of painful degenerative lumbosacral spine.

Adult↗
PubMed2005

Comparison of sagittal contour and posterior disc height following interbody fusion: threaded cylindrical cages versus structural allograft versus vertical cages.

OBJECTIVE: Segmental restoration of sagittal contour is recognized as critical for improved long-term success following instrumented lumbar fusions. As such, the use of wedged implants has become more popular. Few studies exist to assess the postoperative lordotic and disc height changes following these varied techniques in spinal fusion. An observational radiographic study examining lumbar sagittal contour and posterior intervertebral disc space height following posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) was conducted using vertical cages (VCs), wedged structural allograft (WSA), and threaded cylindrical cages (TCCs). METHODS: Forty-nine consecutive patients (59 spinal segments) were evaluated following single- or two-level interbody fusion with either stand-alone TCCs (n = 18 levels), WSA with posterior transpedicular compression instrumentation (n = 25 levels), or VCs with posterior transpedicular compression instrumentation (n = 16 levels). Standing lumbar radiographs were measured by two independent observers preoperatively, immediately postoperatively (within 1 week), at 6-week follow-up (range 4-8 weeks), and postoperatively (at 1-year follow-up) for segmental lordosis at each level undergoing posterior interbody arthrodesis and posterior intervertebral disc space height to assess indirect nerve root decompression. RESULTS: At the 1-year follow-up, postoperative lordosis was improved in the VC group (+5.3 degrees ; P < 0.005), whereas it decreased in the WSA group (-0.9 degrees ; P = 0.407) and TCC group (-3.5 degrees ; P < 0.005). The posterior disc space height decreased in the VC group (-0.5 mm; P = 0.109), whereas it increased for both the WSA group (+1.2 mm; P = 0.05) and the TCC group (+0.8 mm; P = 0.219). CONCLUSIONS: PLIF with stand-alone TCC and PLIF (or TLIF) with WSA and posterior transpedicular instrumentation results in an increased posterior disc height and thus improved indirect nerve root decompression. PLIF (or TLIF) with VC and posterior transpedicular instrumentation results in an overall decrease in posterior disc height. However, TCC and WSA resulted in a loss of lumbar lordosis, whereas VC resulted in an increase in lumbar lordosis.

Adult↗
PubMed1995

Spinal posture during pubertal growth.

A cohort of children was followed-up annually from a mean age of 10.8-13.8 years to determine the development of their posture. Of the sample of 1060 children, 847 (79.9%) participated in the final examination. Thoracic kyphosis and lumbar lordosis were measured annually with a spinal pantograph. Those children whose thoracic kyphosis in pantography was more than 35 degrees at entry and 45 degrees or more at the final examination underwent a lateral standing radiograph. The 3-year incidence of Scheurermann's disease was 0.4%. The mean thoracic kyphosis increased and the mean lumbar lordosis decreased with age in both sexes, but these changes were not constant. Thoracic kyphosis was most pronounced at a mean age of 12.8 years and lumbar lordosis was least pronounced at a mean age of 13.8 years. In accordance with the literature, the wide individual variation found in this study for both thoracic kyphosis and lumbar lordosis during the pubertal growth period was mainly physiologic.

Adolescent↗
PubMed1993

Decreased availability of metabolic fuels suppresses estrous behavior in Syrian hamsters.

The availability of oxidizable metabolic fuels affects reproductive physiology and behaviors in female mammals. In Syrian hamsters, 48 h of food deprivation is sufficient to suppress secretion of gonadotropins and ovarian steroids and to prevent the occurrence of ovulation and estrous behavior. These experiments attempted to determine whether the deprivation-induced suppression of lordosis is entirely due to the disruption of ovarian steroid secretion or whether there are also changes in behavioral responsiveness to estradiol and/or progesterone (P). Estrous behavior was induced in ovariectomized hamsters with sequential injections of 5 micrograms of estradiol benzoate (EB) and 200 micrograms P. Food deprivation for 48 h, either before or just after EB treatment, significantly suppressed the amount of time females spent in lordosis during a 5-min test with a sexually experienced male. Treatment with an inhibitor of glycolysis (2-deoxy-D-glucose) in combination with an inhibitor of fatty acid oxidation (methyl palmoxirate) for 48 h mimicked the effects of food deprivation and suppressed the amount of time spent in lordosis after treatment with EB+P. Given alone, neither metabolic inhibitor had an effect on lordosis. These findings indicate that suppression of hamster estrous behavior by metabolic fuel deprivation is at least in part due to a reduced responsiveness to estradiol and/or progesterone. Furthermore, estrous behavior is responsive to metabolic fuels in general. This is unlike hamster ovulatory cycles, which are primarily responsive to glucose availability.

Animals↗
PubMed1994

Change in spinal curvature following release of tethered spinal cord associated with spina bifida.

Changes in spinal curvature, scoliosis, kyphosis and lordosis are associated with the growth of patients with myelomeningocele. Previous investigators have stated that progressive developmental scoliosis is related to tethered spinal cord. In order to investigate the relationship of tethered spinal cord release to progression of spinal curvature, we surveyed the medical records of 262 patients with a history of one or more tethered spinal cord release. For 216 of these patients, a total of 2,369 serial spine x-rays, obtained over a 20-year period, were reviewed by the standard Cobb method for progression of scoliosis, thoracic kyphosis and lordosis. In addition, the serial spine x-rays of 74 patients without clinical findings of tethered spinal cord were collected and reviewed for comparison of progressive scoliosis and kyphosis. One hundred and sixty normal lumbar x-rays were evaluated to compare the progression of the lordotic curve in patients with tethered cord release with a normal population. Progression of scoliosis plateaued or declined following release of tethered cord in patients with lumbar and sacral level lesions, however, tether release did not halt the progression of scoliosis in the thoracic level group. Tethered cord release altered the course of lordosis in L1 through L3 level lesions, but had little affect on the normal progression of lordosis in patients with L4, L5 or sacral level lesions. Finally, tethered spinal cord release appears to be associated with a decrease in the incidence and magnitude of kyphosis.

Adolescent↗
PubMed2000

[Results of lumbar and lumbosacral fusion: clinical and radiological correlations in 113 cases reviewed at 3.8 years].

PURPOSE OF THE STUDY: Spinal fusion requires the use of hardware for reduction and stabilization. We present the clinical and radiological behavior of a population of patients with lumbar and lumbosacral spinal fusion. MATERIALS AND METHODS: Between 1990 and 1992, 113 patients were operated for lumbar and lumbosacral fusion. Mean age of the population was 43 years and mean follow-up was 3.8 years. Most of the fusions were L4-S1 fusions. 56% of the patients had a previous surgery. Thirteen patients in the series were reoperated and analyzed separately. In the majority of the cases, the indication for surgery was back pain with or without leg pain. Diagnoses were: spondylolisthesis, discopathy, scoliosis, and pseudoarthrosis. The spine was fused and reduced using two lordotic rods. Peroperative and postoperative lordosis were calculated on X-rays. Clinical results were analyzed with the Beaujon-Lassale score. RESULTS: Mean improvement was significantly better for spondylolisthesis than for other pathologies (85.6% versus 77.1%). Returning to work was possible for 85.5% of those with improvement and was not possible for 69.8%. The gain achieved in lordosis at surgery was lost at last follow-up. The lordosis of the construct appeared to protect against the development of discopathies above and below the construct. Discopathis led to a poor score. The rate of non-union was 7.9%, the rate of repeated surgery 6.1% and the rate of hardware removal 23.8%. At last follow-up, improvement was achieved in 45.6% of the 13 patients of the series who had repeat surgery. DISCUSSION: The results in our series are similar to those reported by others. Lumbar lordosis is an important factor: if lost, more interbody fusions may be subsequently required. Diagnosis of non-union is difficult and reoperation is the only sure manner to prove it by applying distraction-compression manoeuvres on the screws. All non-unions presented were symptomatic; incidence in the series was thus probably higher. Non-union and reoperation with a longer fusion are perhaps correlated with insufficient elasticity in the osteosynthesis. Optimal rod elasticity is a factor which remains to be defined. CONCLUSION: Clinical results of lumbar and lumbosacral fusions are not unsatisfactory, but in our series almost one patient out of three had to be reoperated. One of the reasons for so many reoperations is certainly hardware rigidity. Hardware was not removed without testing the fusion as this is the only means of sure diagnosis of non-union. Reoperation should not be considered a failure in this difficult surgery of back pain which requires long-term surgical follow-up.

Adolescent↗
PubMed2002

The significance of correlation of radiographic variables and MOS short-form health survey for clinical decision in symptomatic low back pain patients.

OBJECTIVES: To assess any correlation between SF-36 scores and several lateral roentgenographic variables of the lumbar spine, both in low back pain patients and asymptomatic volunteers. The clinical relevance of the method proposed in this study to make a surgical strategy on the basis of distinct lateral roentgenographic parameters and conversely was assessed by independent radiologists and physicians. METHODS: One hundred asymptomatic male volunteers, used as controls and an equal number of age-, height- and weight- comparable consecutive patients with chronic low back pain were examined both roentgenographically and with the SF-36 questionnaire. The roentgenographic variables measured were: lumbar lordosis, sacral inclination, L1 to S1 vertebral inclination, L4-S1 distal lordosis, disc index, and L1 to L5 vertebral index. These variables were correlated with the eight SF-36 items both in patients and controls. Both sensitivity and specificity of the method were calculated to assess the impact of subjectivity on the clinical decision. RESULTS: Low back patients showed significantly lower scores than their asymptomatic counterparts, in physical role limitations (P<0.01), severity of bodily pain (P<0.01), interference of bodily pain (P<0.01) and mental health (P<0.001). In the controls, general health, physical functioning, social functioning, and role limitations displayed a statistically significant correlation with age, height, weight, lumbar lordosis, sacral inclination, inclination of L1,L3 & L5-vertebra, L1 to L5-vertebral index and L1-L2, L3-L4, L4-L5 and L5-S1 disc index. In LBP-patients previous general health, physical functioning, role limitations, social functioning, bodily pain were significantly correlated with age, height, L1-and L2-inclination, distal lordosis, L5-index, and disc index L4-L5, and L5-S1. Although the consensus between either radiologists suggesting a strategy on the basis of roentgenographic data only or between physicians based on only SF-36 data was significant (P<0.001), there was no consensus in clinical decision between physicians and radiologists. Clinical decision based on matched SF-36 and roentgenographic data made either by radiologists or surgeons showed significant correlations (P<0.001). However, both sensitivity and specificity of our method to make a clinical decision on the basis of radiology were low: 0.48 and 0.36 respectively. CONCLUSIONS: SF-36 scores were correlated with distinct lateral roentgenographic variables of the lowermost lumbar spine (L4-S1) in low back patients, and of the whole lumbar spine in asymptomatic individuals. Clinical decision should not be taken on the basis of radiological evidence of pathology because clinical decision seems to be more accurate when is taken on the basis of combined SF-36 and roentgenographic data. However, clinical examination is mandatory to SF-36 questionnaire and radiographic analysis.

Activities of Daily Living↗
PubMed2005

The evolution of sagittal segmental alignment of the spine during childhood.

STUDY DESIGN: Cross-sectional. OBJECTIVES: The purpose of this study is to describe the normative data of the sagittal plane on pediatric age population, and to document the evolution of sagittal alignment with growth. SUMMARY OF BACKGROUND DATA: Having normative data about the sagittal plane is an integral part in the planning of the three-dimensional reconstruction of the spine. Segmental sagittal plane analysis on adults has been studied thoroughly; however, there are inadequate data on children. METHODS: A total of 151 children (72 girls, 79 boys) without musculoskeletal abnormality between the ages of 3 to 15 years were studied with the 36-inch standing lateral radiograph with the arms flexed at 30 degrees . There were a minimum of 10 children, at least 4 of them from one sex, in each age group. Variables measured on the radiograms were as follows: segmental angulations from T1-T2 to L5-S1, angles of global kyphosis (T1-T12) and lordosis (L1-S1), segmental angulations of T2-T5, T10-T12, T10-L2, and L4-S1 levels, T1 and L1 offsets in millimeters, location of thoracic and lumbar apexes, and spinopelvic alignment measurements (angles of alpha and beta, sagittal vertebral axis, and sacropelvic translation). For statistical analysis, the children were grouped in terms of ages: Group I (3-6 years of age), Group II (7-9 years of age), Group III (10-12 years of age), and Group IV (13-15 years of age). RESULTS: One-way analysis of variance showed significant differences between the following parameters among groups: segmental angulations of T1-T2 (P = 0.015), T10-L2 (P = 0.014), L4-S1 (P = 0.001), global kyphosis angle (P = 0.005), global lordosis angle (P = 0.000), thoracic apex (P = 0.007), T1 offset (P = 0.000), sagittal vertebral axis (P = 0.004), and beta angle (P = 0.000). As sagittal vertebral axis increases, there is found to be a higher L1 offset and lower thoracic apex, both of which result in leaning forward. With growing, total thoracic kyphosis and total lumbar lordosis particularly due to lower 2 motion segments were found to be increased, while thoracic apex moved upwards, T1 offset increased, and L1 offset decreased. Older children stood with a more negative SVA, and sacral inclination increased. CONCLUSION: Sagittal spinal alignment is found to be changing as a child grows. There is a statistically significant difference among different age groups, especially at cervicothoracic, thoracolumbar, and lumbosacral junctions. The position of the sacrum (inclination and translation), and spatial orientation, as well as the global magnitude of thoracic kyphosis, and lumbar lordosis changes with growth. These findings should be taken into consideration for the young patients who require spinal instrumentation. The question "whether sagittal alignment should be restored according to the normative data for the child's age or to the normative data for the adulthood" remains to be answered.

Adolescent↗
PubMed1997

Evaluation of the assumptions used to derive an ideal normal cervical spine model.

OBJECTIVES: To evaluate the accuracy of anatomical assumptions made to derive a geometrical, ideal, normal model of the upright, static, sagittal cervical spine, to make comparisons with other spinal models and to discuss the implications of a normal cervical model. BACKGROUND: Anatomical assumptions were made based on observations to assist in the development of a computerized geometrical model of the ideal upright, static, sagittal cervical spine. These assumptions address the magnitudes of the contribution made by the vertebral bodies and intervertebral discs to the overall magnitude and geometric shape of the cervical lordosis. STUDY DESIGN: (a) Data were collected from 400 lordotic lateral cervical radiographs and compared with the predictions of a geometric normal cervical lordotic model. Angels of intersecting tangent lines, drawn at posterior vertebral body margins, were measured at each disc space and between C2 and C7. Height-to-length ratios and an anterior weight-bearing distance were measured. (b) LITERATURE REVIEWs were obtained through Medline and Chirolars. RESULTS: (a) Modeling: the 400 sample subjects varied from the geometric model by approximately 5%. Subgroup averages, from partitioning the C2-C7 angle into 5 degrees intervals, were less than 8% in error to model predictions. (b) LITERATURE REVIEW: lordosis is the normal configuration for the cervical spine and many chiropractic empirical models are similar. CONCLUSIONS: The anatomical assumptions used to derive our normal geometric model of the cervical lordosis seem to be supported by the average values and literature reviewed. Two typical geometric configurations of the cervical spine were identified as a normal circular lordotic arc of 34 degrees and an ideal normal of 42 degrees. LITERATURE REVIEWed establishes cervical lordosis as a desirable clinical outcome of care.

Cervical Vertebrae↗
PubMed2002

Food deprivation inhibits estrous behavior in hormone-treated Syrian hamsters despite elevated estradiol levels.

Estradiol and progesterone (P) induce female mammalian reproductive behaviors, which are, in turn, sensitive to food availability. When ovariectomized, steroid-primed hamsters are food deprived for 48 h, estrous behavior is suppressed. While this suppression of estrous behavior may be due to alterations in neural steroid receptor levels, it is also possible that decreased levels of circulating estradiol could be involved in mediating this suppression. Ovariectomized Syrian hamsters given varying doses of estradiol benzoate (EB) and P were tested to determine whether increasing doses of sex steroids would overcome the suppressive effects of food deprivation on estrous behavior. As expected, lordosis duration decreased in food-deprived animals. Increasing the levels of EB, but not P, increased lordosis duration in the food-deprived animals so that animals who were given 20 microg of EB had lordosis durations significantly longer than food-deprived hamsters that received 1.5 microg and 2.5 microg EB. Following an injection of 2.5 microg of EB, food-deprived hamsters actually had higher circulating levels of estradiol than ad libitum-fed animals. Therefore, increasing circulating levels of estradiol can increase lordosis durations in fasted animals; however, the suppression of estrous behavior occurs despite increased circulating estradiol levels in ovariectomized, steroid-treated animals. The most parsimonious explanation for this phenomenon is a deprivation-induced reduction in neural responsiveness to estradiol.

Animals↗
PubMed1976

Comparison of the action of lysergic acid diethylamide and apomorphine on the copulatory response in the female rat.

The effects of lysergic acid diethylamide (LSD) and apomorphine were compared using female copulatory behavior (lordosis response), in ovariectomized estrogen + progesterone-treated rats. Both serotonin and dopamine are implicated in the inhibition of this behavior. Each compound inhibited lordosis behavior dose dependently and with a similar time-course. Pimozide (0.1; 0.5 mg/kg) blocked the apomorphine (0.2 mg/kg)-induced decrease of lordosis response, while only a certain abbreviation of the LSD (0.10 mg/kg) inhibition was achieved by pimozide (0.5 mg/kg). Chlorpromazine (0.5 mg/kg) in a dose without effects on lordosis of its own had an action similar to pimozide on the LSD effect. It is concluded that the predominant action of LSD on the female copulatory response is not mediated by increased dopamine receptor activity but that the LSD effect might be modulated by decreased dopaminergic activity.

Animals↗
PubMed1976

Effects of genotype on differential behavioral responsiveness to progesterone and 5alpha-dihdroprogesterone in mice.

Thirty female CD-1 mice, 30 female Swiss-Webster mice, 45 hybrid female mice of the strain SWCD1F1, AND 45 HYBRId female mice of the strain CD1SWF1 were ovariectomized and administered estradiol benzoate once weekly for 6 weeks. Estrogen injections were followed 2 days later by injections of progesterone, dihydroprogesterone (DHP), or oil and the animals were tested for receptivity 7 hr later. Over the six tests, there was a progressive increase in the frequency of lordosis responses in all strains following progesterone treatment. However, lordosis scores varied widely across animals within strains. Following DHP treatment, lordosis frequency was not increased in the Swiss-Webster strain. Females in the other strains did show a progressive increase in lordosis frequency over weeks. The data indicate that the hybrid strains develop the potential to respond to DHP and thus behave like the CD-1 strain, suggesting that sensitivity to DHP is a dominant trait.

20-alpha-Dihydroprogesterone↗
PubMed1994

Longus colli has a postural function on cervical curvature.

To determine the postural role of longus colli (LC) and dorsal neck muscles, we have studied the relationship between their cross-sectional areas related to their force of contraction and the lordosis and the length of the cervical spine. This study was carried out in 36 healthy subjects. Muscle cross-sectional areas were measured by computerized tomography. The index of lordosis and the length of the cervical spine were measured on an X-ray profile. The cross-sectional area of LC was correlated to the lordosis index (R = -0.432, p < 0.02) whereas all the other parameters were not correlated. The authors conclude that LC counteracts the lordosis increment related to the weight of the head and to the contraction of the dorsal neck muscles. Postural functions of LC and postcervical muscles are complementary. They form a sleeve which encloses and stabilizes the cervical spine in all positions of the head.

Adult↗
PubMed1997

MRI of car occupants with whiplash injury.

Our purpose was to document and investigate the prognostic significance of features seen on MRI of patients with whiplash injury following relatively minor road traffic crashes. MRI was obtained shortly and at 6 months after the crash using a 0.5 T imager. The images were assessed independently by two radiologists for evidence of fracture or other injury; loss of lordosis and spondylosis were also recorded. Clinical examinations were used to assess the status of patients initially and at 6 months. The results of the independent MRI and clinical investigations were then examined for association using statistical tests. Initial MRI was performed on 29 patients, of whom 19 had repeat studies at 6 months; 48 examinations were thus examined. Apart from spondylosis and loss of lordosis, only one abnormality was detected: an intramedullary lesion consistent with a small cyst or syrinx. There were no statistically significant associations between the outcome of injury and spondylosis or loss of lordosis. No significant changes were found when comparing the initial and follow-up MRI. It appears that MRI of patients with relatively less severe whiplash symptoms reveals a low frequency of abnormalities, apart from spondylosis and loss of lordosis, which have little short-term prognostic value. Routine investigation of such patients with MRI is not justified in view of the infrequency of abnormalities detected, the lack of prognostic value and the high cost of the procedure.

Accidents, Traffic↗
PubMed2000

Psoas muscle and lumbar spine stability: a concept uniting existing controversies. Critical review and hypothesis.

Psoas muscle (PM) function with regard to the lumbar spine (LS) is disputed. Electromyographic studies attribute to the PM a possible role as stabilizer. Anatomical textbooks describe the PM as an LS flexor, but not a stabilizer. According to more recent anatomical studies, the PM does not act on the LS, because it tends to pull the LS into more lordosis by simultaneously flexing the lower and extending the upper region, but due to the short moment arms of its fascicles, this would require maximal muscular effort and would expose the LS motion segments to dangerous compression and shear. The findings of the present study indicate that the described opposite action of the PM on upper and lower LS regions, performed passively and requiring minimal muscular effort, may serve to stabilize the LS in an upright stance. It was demonstrated that a vertically placed elastic metal strip, modelled into a lordotic configuration to imitate the LS, will be brought into more lordosis, with maintenance of vertical position, if a string fastened at its upper end is pulled downward in a very specific direction. Conversely, any increase of lordosis of the strip brought about by vertical downward pushing of its top, will be stabilized by tightening the pulling string in the same specific direction. As this direction corresponded with the psoas orientation, the experiments show that the PM probably functions as a stabilizer of the lordotic LS in an upright stance by adapting the state of contraction of each of its fascicles to the momentary degree of lordosis imposed by factors outside the LS, such as general posture, general muscle activity and weight bearing. The presence of multiple PM fascicles, all of about equal length, and attaching to all LS levels, facilitates this function.

Biomechanical Phenomena↗