PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Prone Position”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources
PubMed2005

Cataract surgery for residual angle closure after peripheral laser iridotomy.

PURPOSE: To investigate the frequency of residual angle closure after resolution of pupillary blocking by laser peripheral iridotomy and the effects of subsequent cataract surgery to resolve angle closure completely. DESIGN: Retrospective, consecutive, interventional study. PARTICIPANTS: Among 70 eyes treated with laser iridotomy, 13 with residual angle closure were treated with cataract surgery. METHODS: The provocative test of angle closure by prone position in a dark room for 1 hour was performed; increases in tension of > or =8 mmHg, 6 or 7 mmHg, and < or =5 mmHg were considered to be positive, suspected positive, and negative, respectively. Configuration of the anterior chamber was examined using ultrasound biomicroscopy (UBM). MAIN OUTCOME MEASURES: Intraocular pressure (IOP), response to the dark room prone position test, and morphologic analysis by UBM were evaluated before and 3 months after cataract surgery. RESULTS: Residual angle closure after iridotomy was seen in 27 (38.6%) of 70 eyes; this was confirmed functionally by the dark room prone position test and morphologically by UBM. Eyes with IOP of > or =20 mmHg or with a glaucomatous visual field defect before iridotomy had a significantly higher incidence of residual angle closure after iridotomy than eyes without these findings (P<0.05). In all the eyes with residual angle closure after iridotomy, the response to the prone position test became negative after cataract surgery, with significant lowering of IOP (P<0.01). CONCLUSIONS: Residual angle closure after iridotomy was common, especially in eyes with primary angle closure and poorly controlled IOP or glaucomatous optic neuropathy. Cataract surgery was effective to resolve completely the residual angle closure after iridotomy and lower IOP.

Adult↗
PubMed1999

Prevalence and determinants of prone sleeping position in infants: results from two cross-sectional studies on risk factors for SIDS in Germany.

The authors investigated whether there was a decline in infants sleeping prone and other modifiable risk factors for sudden infant death syndrome (SIDS) in Germany, where, as in some other countries, no nationwide intervention campaign against the prone sleeping position had been initiated. Data were obtained from parents by mailed questionnaires in two cross-sectional studies in 1991 (n = 3,330) and 1995 (n = 3,124). Prevalence of prone sleeping decreased from 37.6% to 8.7% (p < 0.05) in the German population and from 44.1% to 32.0% (p < 0.05) in the Turkish immigrant population. Parents who laid their infants prone in 1995 were less likely to follow advice from physicians, public media, and other parents (relative risks < 0.5, p < 0.05) and were more likely to have a low educational level, to be <20 years old, to be single parents, to have two or more children, to be raised in West Germany, or to be of Turkish ethnicity. Although the information on prone sleeping being a risk factor for SIDS became known among the population, these data suggest that subgroup-specific public intervention campaigns may be needed to reduce the prevalence of prone sleeping even further in those countries where no nationwide campaign has been initiated.

Adult↗
PubMed1996

Infant room-sharing and prone sleep position in sudden infant death syndrome. New Zealand Cot Death Study Group.

BACKGROUND: There is evidence that the risk of sudden infant death syndrome is lower among ethnic groups in which parents generally share a room with the infant for sleeping. We investigated whether the presence of other family members in the infant's sleeping room affects the risk of the sudden infant death syndrome. METHODS: The case-control study covered a region with 78% of all births in New Zealand during 1987-90. Home interviews were completed with parents of 393 (81.0% of total) babies who died from the sudden infant death syndrome aged 28 days to 1 year and 1592 (88.4% of total) controls, selected from all hospital births in the study region. FINDINGS: The relative risk of sudden infant death for sharing the room with one or more adults compared with not sharing was 0.19 (95% CI 0.08-0.45) for sharing at night during the last 2 weeks and 0.27 (0.17-0.41) for sharing in the last sleep, after control for other confounders. Sharing the room with one or more children did not affect the relative risk (1.25 [0.86-1.82] for sharing during last 2 weeks; 1.29 [0.85-1.94] for sharing in last sleep). There was a significant interaction (p = 0.033) between not sharing the room with an adult and prone sleep position in the last sleep. Compared with infants sharing the room with an adult and not prone, the multivariate relative risk was 16.99 (10.43-27.69) for infants not sharing with an adult and prone, 3.28 (2.06-5.23) for infants sharing the room and prone, and 2.60 (1.58-4.30) for infants not sharing the room and not prone. The interaction between adult room-sharing and prone sleep position suggests that both exposures may affect the risk of sudden infant death syndrome through a common mechanism. INTERPRETATION: We recommend that infants sleep in the same bedroom as their parents at night to reduce the risk of sudden infant death syndrome.

Adult↗
PubMed1992

Venous air embolism in prone dogs positioned with the abdomen hanging freely: percentage of gas retrieved and success rate of resuscitation.

Based on reports of fatal venous air embolism (VAE) occurring during lumbar laminectomy and spinal fusion in prone patients positioned with the abdomen hanging freely, it has been recommended that monitoring for VAE should be used for such cases and that a multiorificed central venous catheter should be inserted for aspiration of VAE. The present study was designed to examine aspiration of VAE when prone dogs positioned with the abdomen hanging freely were given a fatal VAE via a femoral vein. Twenty-one dogs were anesthetized with halothane and nitrous oxide in oxygen and positioned with the abdomen ventral and hanging freely, the head fixed in a stereotaxic frame, the upper extremities resting on a surface approximately 10 cm below the level of the stereotaxic frame, and the lower extremities on a surface below the level of the upper extremities (to ensure that VAE entering the inferior vena cava would ascend toward the heart). In the control group (n = 7), a central catheter was placed but was not used to aspirate VAE. In a second group (n = 7), a Cook Bunegin-Albin multiorificed catheter was inserted; and in a third group (n = 7), an American Edwards 7F Swan-Ganz catheter was inserted. Dogs were then given a predetermined lethal dose of air (5 mL/kg) over 30 s via the femoral vein. In groups 2 and 3, attempts to aspirate VAE were begun with the first decrease in expired CO2. The amounts of gas retrieved (expressed as a percent of the injected air) and the incidence of successful resuscitation were compared.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Effect of modified labor posture on oxygenation of the fetus--a pulse oximetry study].

BACKGROUND: The evaluation of the birth position and its effects on maternal and fetal wellbeing has been a topic of perinatal research over the last decades. The aim of our observational study was to determine the effects of a modified and vertical maternal position on fetal oxygen saturation measured by pulse oximetry. METHODS: Fetal oxygen saturation was measured by pulse oximetry in 56 labouring women randomly and successively adopting the supine position in 96.4%, the sitting position in 25.0%, the standing position in 14.3% and the prone position in 12.5%. The statistical analysis addressed the integrated 10 minutes period of SpO2 registrations before versus after adopting the modified position. Furthermore the mean values and the standard deviation (SD) for the total registration periods of different birth position was calculated. RESULTS: While the supine position induced a reduction in oxygen saturation, sitting and prone position were favorable for fetal oxygenation as compared to horizontal position. DISCUSSION: These findings implicate a clinical benefit of the modified birth position.

Adult↗
PubMed2001

Optimizing intrapulmonary perfluorocarbon distribution: fluoroscopic comparison of mode of ventilation and body position.

OBJECTIVE: Partial liquid ventilation with the perfluorochemical, perflubron, has been shown to improve lung mechanics and enhance gas exchange in the treatment of severe acute lung injury. However, the most effective strategy to provide optimal intrapulmonary distribution of perflubron has not been fully accessed. The objective of this study was to examine the effect of body position (supine vs. rotational) and mode of ventilation (conventional mechanical ventilation [CMV] vs. high-frequency oscillatory ventilation [HFOV]) on perflubron distribution and oxygenation improvement. DESIGN: Prospective, randomized, animal trial. SETTING: Research laboratory at a university medical center. SUBJECTS: Twenty healthy piglets (4.5-6.6 kg). INTERVENTIONS: Subjects underwent repetitive saline lavage to achieve a uniform degree of lung injury and then were randomized to either CMV or were converted to HFOV. Within each ventilator group, animals were randomized to supine positioning (S) or rotational positioning with alternation between supine and prone position (R) during incremental dosing of three 5-mL/kg doses of perflubron. MEASUREMENTS AND MAIN RESULTS: Arterial blood gas tensions, hemodynamic variables, and the oxygenation index were recorded after each dose of 5 mL/kg. Lateral cinefluoroscopic images after each dose were digitized for computer analysis of density. A density index was calculated for a 2-cm2 window in three dorsal and three ventral lung regions. Uniformity of distribution was calculated by comparing the mean density among the six regions. Oxygenation improvements were compared between groups. There were no significant differences in hemodynamic variables or gas exchange after lung injury in the four groups. Rotational positioning produced significantly more uniform perflubron distribution during both CMV and HFOV. This effect was independent of the mode of ventilation. The mean ventral density index was affected by rotating position and HFOV mode of ventilation after 10 mL/kg of perflubron, and rotating position was affected only after 15 mL/kg of perflubron. There was a significant reduction in the oxygenation index from baseline to end lavage in both CMV groups, as well as all of the animals that were rotated. CONCLUSION: Perflubron is more uniformly dispersed when dosed in a rotational fashion with alternation between supine and prone position during incremental dosing. This effect is independent of mode of ventilation. There was no relationship between oxygenation improvements and nondependent perflubron distribution. CMV and rotating dosing both led to a significant decrease in the oxygenation index after a 15 mL/kg dose of perflubron. This information has important impact on the future development of dosing strategies and clinical trial design.

Animals↗
PubMed2000

[Effect of bronchial drainage on the improvement in gas exchange observed in ventral decubitus in ARDS].

OBJECTIVES: A bronchial secretion draining effect is frequently suggested as a mechanism for oxygenation improvement during prone positioning (PP) in patients with acute respiratory distress syndrome (ARDS). Nevertheless, it has never really been evaluated. The aim of this study was to search for an interrelationship between the volume of the bronchial secretion and the improvement of the PaO2/FIO2 ratio during prone positioning, with NO inhalation or not. STUDY DESIGN: Open prospective clinical study. PATIENTS: The study included 15 consecutive patients with severe ARDS (PaO2/FIO2 < 200 after alveolar recruitment, Murray score > 2.5). METHODS: They were returned to the prone position for 4 hours (h0-h4) combined with an inhalation of 5 ppm NO during 1 hour (h2-h3). Tracheal suction were performed hourly between h-2 and h6 and weighed on a precision scale from h-1 to h6. Haemodynamic, blood gas and respiratory compliance were recorded at h0, h2, h3, h4 and h6. RESULTS: No significant haemodynamic changes were observed in the various phases. Compared with the baseline condition at h0, PP and PP + NO respectively improved PaO2/FIO2 by 102 +/- 62% at h2 (P < 0.005) and 156 +/- 79% at h3 (P < 0.005/h0 and < 0.01/h2). 14/15 patients responded to PP and 15/15 to PP + NO (gain in PaO2/FIO2 > 10%). Concerning secretions, we collected 3.0 +/- 7.5 g, 4.4 +/- 6.1 g, 1.7 +/- 1.4 g and 1.7 +/- 1.6 between h-2 and h0, h0 and h2, h2 and h4, h4 and h6. Individual assessments showed no relationship between the PaO2/FIO2 evolution at any time and the quantity of secretions obtained during the first 2 hours in the prone position. Six patients presented secretions of less than 1 g between h0 and h2, and for whom the improvement in oxygenation was higher than average (115 +/- 53% at h2). CONCLUSION: In patients with little or moderate secretions, the improvement observed in oxygenation, with or without NO, does not depend on their volume.

Aged↗
PubMed1996

Hip joint congruence: experimental studies.

Three-dimensional imaging of hip joint preparations was carried out by means of computed tomography (CT). On the assumption that the head of the femur and acetabulum are incongruent, a special experimental design was used to quantify the extent and direction of the gliding movement of the head and socket. A series of CT images in the supine and prone positions was made from hip preparations, and the cartilage was visualized by injecting a contrast medium. In all the preparations dorsal movement was noted in the supine position, and ventral movement in the prone position. Cryomicrotome slices of the hip preparations were used to verify the results of our CT scans and the measurements correlated with the anatomical examinations. Thus, there is a certain amount of play in the hip joint-it is not an ideal ball-and-socket joint. This knowledge is important for the planing and success of hip adjustment surgery.

Acetabulum↗
PubMed2006

Thoracoscopic and laparoscopic oesophagectomy improves the quality of extended lymphadenectomy.

BACKGROUND: Oesophagectomy with extended lymphadenectomy carries considerable morbidity due to parietal trauma. It is also technically extremely demanding because the difficult access even through a large thoracotomy requires the use of long instruments to reach the deepest recess in the chest cavity. Since the first thoracoscopic oesophagectomy reported by Cuschieri et al. [1] in 1992, different minimally invasive approaches have been proposed [2-12]. The aim of this video is to show the accurate and relative ease of an entirely thoracoscopic and laparoscopic oesophagectomy with an extended lymph node dissection of mediastinum in prone position (thoracoscopically) and celiac trunk (laparoscopically). METHODS: Oesophagectomy by thoracoscopy, laparoscopy and cervicotomy was proposed in a 63-year-old man with a lower third oesophageal cancer. General anaesthesia was performed with a double-lumen endotracheal tube and the patient was placed in prone position. Surgeons were positioned at the right side of the patient. Only three trocars were needed. A 10 mm 30-degree angled scope was inserted in the 7th intercostal space on the posterior axillary line and the remaining two 5 mm trocars were inserted in the 5th and 9th intercostal spaces on the posterior axillary line. Prone position allows an excellent visibility of the operative field even in an only partially deflated lung. In order to achieve a good exposure, transitory pneumothorax with CO2 (14 mmHg) was performed. The mediastinal pleura overlying the oesophagus was incised and the arch of azygos vein was isolated, ligated and divided. The oesophagus was circumferentially mobilized from the thoracic inlet down to oesophageal hiatus. Para oesophageal and subcarinal lymph nodes were dissected so as to remain in block with the surgical specimen. A 28 F chest tube was inserted in the 8th intercostal space on the anterior axillary line. In the second stage the patient was placed in supine position and pneumoperitoneum was established. Five trocars were placed along an ideal semicircular line, with the concavity facing the subcostal margin and a 30-degree angled laparoscope was used. The lesser omentum was widely opened up the right pillar of the hiatus. Mobilization of the greater curvature of the stomach was performed preserving the right gastroepiploic artery. A wide Kocher maneuver was performed. Celiac lymphadenectomy started with skeletonization of the hepatic artery until the root of left gastric artery was reached. This artery and the left gastric vein were dissected, clipped and sectioned. All fatty tissue and lymph nodes along hepatic artery, left gastric artery and celiac trunk were resected in block with the surgical specimen. Multiple applications of a linear endoscopic stapler were used to create the gastric tube. Finally the distal oesophagus was dissected, until the thoracoscopic dissection field was joined. In the third stage a left lateral cervicotomy was performed and the cervical oesophagus was dissected down to the thoracoscopic dissection plane. Oesophagus and stomach were delivered through the cervical incision and an oesophagogastric anastomosis was created by a linear stapler technique. Cervical and abdominal drainages were installed. RESULTS: The total operative time was 271 minutes (thoracoscopy: 106 minutes, laparoscopy 120 minutes and cervicotomy 45 minutes) and blood loss was about 100 ml. Histological examination demonstrated a squamous cell carcinoma. Both margins of resection were free of tumour and 29 lymph nodes were retrieved. The final stage was IIA (pT3N0Mx). CONCLUSIONS: Thoracoscopic and laparoscopic oesophagectomy with extended lymphadenectomy is technically feasible and safe. Thoracoscopic oesophagectomy in prone position improves the quality of dissection because: The oesophagus and aorto-pulmonary window are reached under excellent visibility, despite a partially deflated lung, which because of gravity will always remain out of harm's way. For the same reason small to moderate bleeding will not obscure the operative field. Dissection with the long endoscopic instruments is more accurate due to the support provided by the entrance site at the parietal level and the ergonomic position of surgeon. This article contains a supplementary video.

Blood Loss, Surgical↗
PubMed1981

Colonic gas distribution in toxic megacolon.

To determine whether dilation of the transverse colon is a specific pathophysiologic feature in toxic megacolon, plain films of the abdomen in different positions were obtained of 6 patients with ulcerative colitis complicated by toxic megacolon. All patients were examined initially in the supine position and subsequently in the prone position. Redistribution of gas in the colon occurred in all patients when the prone position was assumed. The shift of gas was largely from the transverse colon to the descending colon. Pathological examination of the colon in 5 patients revealed the transverse colon to be no more severely involved than the remainder of the colon. The findings suggest that distribution of colonic gas in toxic megacolon is largely governed by the influence of gravity and the anatomic position of the colon in the peritoneal cavity.

Adult↗
PubMed1994

Influence of positioning on ventilation-perfusion relationships in severe adult respiratory distress syndrome.

In 12 patients with severe adult respiratory distress syndrome (ARDS), pulmonary gas exchange and hemodynamics were evaluated before, during, and after a 2-h period of pressure-controlled mechanical ventilation with the patient in the prone position. Ventilation-perfusion relationships (VA/Q) were assessed by a multiple inert gas elimination technique. Pressure-controlled mechanical ventilation in the prone position resulted in an overall increase (p < or = 0.05) of arterial oxygenation after 120 min (98.4 +/- 50.3 to 146.2 +/- 94.9 mm Hg). Whereas eight patients revealed an improvement of PaO2 of more than 10 mm Hg after 30 min in the prone position (responders), four patients reacted to positional changes with a deterioration of arterial oxygenation (nonresponders). Data about the continuous distribution of ventilation-perfusion ratios revealed that in the responder group positioning caused a decrease of shunt perfusion of 11 +/- 5% and a concomitant increase of normal VA/Q by 12 +/- 4% after 30 min. There was no change demonstrable within low VA/Q areas. Returning the patient to the supine position reversed the improvement in gas exchange. The nonresponder group did not show any significant alteration in the distribution of VA/Q during the study. We concluded that improvement of oxygenation during pressure-controlled mechanical ventilation in the prone position is due to a shift of blood flow away from shunt regions, thus increasing areas with normal VA/Q. This redistribution of blood flow is most likely caused by a recruitment of previously ateletatic but nondiseased areas induced by altered gravitational forces.

Adolescent↗
PubMed1997

Prone postioning and low-volume pressure-limited ventilation improve survival in patients with severe ARDS.

STUDY OBJECTIVES: Investigating the effect of low-volume pressure-limited ventilation and repeated prone positioning on the short-term course and outcome in patients with severe ARDS. SETTING: Level 1 trauma center of a university hospital. PATIENTS: Twenty-five patients suffering from ARDS with a lung injury score (LIS) > or = 2.5 admitted consecutively to our ICU from January 1992 to December 1994. METHODS: Mechanical ventilation with peak inspiratory pressure limitation to 35 mbar, irrespective of hypercapnia and prone positioning to achieve adequate oxygenation. SCORING AND MEASUREMENTS: Patient assessment with LIS, APACHE (acute physiology and chronic health evaluation) II score, injury severity score, and multiple organ failure score. Blood gas analyses and estimation of static compliance were repeated at least every 4 h during the treatment period. PaO2/FIO2 (fraction of inspired oxygen) ratio, alveolo-arterial oxygen difference, and intrapulmonary shunt were calculated according to standard equations. The best values taken from each 4-h period during the investigation were used to evaluate the best possible performance of the lung within this interval and to investigate the entire course. RESULTS: Mean predicted mortality based on the APACHE II score was 35.4+/-15.2%. Three of the 25 patients (12%) died. However, none was related to respiratory failure. No pneumothorax occurred. Sixteen patients, lacking any contraindication for prone positioning, responded positively to this change in position, each to a different individual degree. CONCLUSION: We assume that our low mortality in patients with severe ARDS might be due mainly to low-volume pressure-limited ventilation and prone positioning. This simple strategy seems to allow successful treatment for patients with severe ARDS.

APACHE↗
PubMed1997

Dosimetry studies with TLDs for stereotactic radiation techniques for intraocular tumours.

Between March 1993 and January 1997, stereotactic radiation techniques were used to irradiate 66 intraocular tumour patients with the Gamma Knife (Leksell Gamma Knife, model B unit) at the University of Vienna, Austria. This study investigates the dosimetry for stereotactic irradiation of ocular structures. For the dosimetry program KULA 4.4, Gamma Knife stereotactic irradiation of the eye represents an extreme frontal skull position. In addition, irradiation of the eye may be performed in the usual supine position in exceptional cases only. With the patient in the prone position, the dose planning program has to calculate with a significantly large number of single-beam extrapolations. In our first experiment we measured the isocentre dose for eight different gamma-angle positions, both in prone and supine positions, using TLD measurements in an Alderson head phantom. We found a maximum deviation of +/- 1.6% using these individually calibrated TLDs. In the second experiment we examined the dose cross profiles for the two most frequently used treatment positions (supine position, gamma = 65 degrees, and prone position, gamma = 140 degrees). For this purpose we implanted a specially designed TLD array into the orbit of a human cadaver head. We found excellent agreement of the dose values measured for the isocentre as well as the posterior part of the eye with orbit with deviations of less than -2.7%. However, for the anterior part of the eye, deviations between computer-generated calculations and the TLD measurements were found to range up to -30%. These differences were noticed both for supine and prone positions. For the Gamma Knife stereotactic irradiation of ocular tumours or pathologies, precautions should be taken to avoid significant underdosage in the anterior part of the radiation field.

Biophysical Phenomena↗
PubMed2004

Optimized radiation of pelvic volumes in the clinical setting by using a novel bellyboard with integrated gonadal shielding.

The purpose of this study was to determine the feasibility of a custom-made, modified bellyboard to reduce radiotherapy side effects on small bowel, bladder, skin, and male gonads. Two groups of 10 consecutive patients each were treated from January 2003 through April 2003 with neoadjuvant (45 Gy) or adjuvant (54 Gy) radio(chemo)therapy in single fractions of 5 days a week 1.8 Gy for rectal carcinoma, using a photon energy of 15 MV. One group was positioned in a prone position without an immobilization device, the other group was positioned on our bellyboard. Treatment planning was calculated by using a 4- and a 3-field box technique. Differences in the dose of organs of risk were calculated. For 1 male patient, a gonadal shielding was developed and integrated. All patients examined with the bellyboard demonstrated an anterior and cranial dislocation of the small bowel. Using a 4-field box, the mean dose to the small bowel of patients treated on our bellyboard was 56.5% as compared to 63.1% when treated without the bellyboard. When a 3-field box was used, the mean dose to the small bowel was 52.4% when the bellyboard was used, as compared to a mean dose of 63.1% without the bellyboard. Regarding the dose volume effects to the bladder, the mean dose for patients treated with a 4-field box was about 14.5% higher as compared to patients treated with a 3-field box. The mean dose to the hip joints and skin also depended on the radiation technique. The patient who received gonadal shielding received a maximal total gonadal dose of about 75.0 cGy in single fractions of maximal 3.0 cGy (TL-dosimeters). Daily setup variations evaluated by a beam's-eye view were similar in both groups and ranged from 0.5 cm 1.0 cm. For daily use, our bellyboard appears to be an ideal compromise due to effectiveness, its easy handling, and reproductive positioning; moreover, it can also be used in combination with gonadal shielding.

Aged↗
PubMed1997

[The effect of position and mattress on the development of pressure sores].

The aim of this investigation was to determine which positions were associated with the lowest pressures to the skin in persons lying in bed. The pressure was recorded in ten different lying positions on two mattresses in 26 healthy volunteers. The semi Fowler position and the prone position were associated with a very low pressure. The 30 degrees laterally inclined position had significantly lower pressure than the classical 90 degrees side lying position. The highest pressure was measured in the 90 degrees side lying position and thus it should be avoided. A polyethylene-urethane mattress reduced pressure by 20 to 30% in comparison to a standard hospital mattress.

Adult↗
PubMed1989

[Analysis of "rising up mechanism" in months-old infants--determination of contact area and center of gravity by pedoscope].

The author studied how the rising up mechanism changed with the development of motor function in healthy infants. 1. The rising up mechanism can be evaluated from the body support pattern characteristic to each stage of posture development in supine and prone positions, the body support (contact) area and shift in the center of gravity. 2. The support patterns in supine position were classified into 4 types; S-I ("squid type", 2-4 mo), S-II ("platform type", 4-6 mo), S-III ("bell type", 7-10 mo), S-IV ("separate type"), and their characteristics were described. 3. The contact area in supine position gradually decreased as the support pattern changed from S-I (area ratio, approx. 2/3) to S-III (area ratio, 2/5). 4. The center of gravity in supine position was located at 10th thoracic vertebra at 2-4 mo, then rose with age until it was stabilized at 7th thoracic vertebra at 10 mo. 5. The support patterns in prone position were classified into 7 types; P-I ("protector type", 2-3 mo), P-II ("joint square and round type", 3-4 mo), P-III ("elongated oval type", 4 mo-first half of 5 mo), P-IV ("spindle type", 4 mo-latter half of 5 mo), P-V ("ginseng type", 5-6 mo), P-VI ("tetrapod type", 7-10 mo), P-VII ("oval type", 9 mo onward), and their characteristics were described. 6. The contact area in prone position gradually increased as the support pattern changed from P-I (area ratio, 3/5) to P-V (area ratio, 9/slightly over 10), and gradually decreased as it changed thereafter to P-VII (area ratio, 7/slightly under 10). 7. The center of gravity in prone position swung over a wide range. It was located at 12th thoracic vertebra at 2-3 mo, then ascended as far as 9th thoracic vertebra at 4 mo-first half of 5 mo, and descended thereafter to be stabilized at 2nd lumbar vertebra (level of navel) at around 10 mo. 8. Particular attention was paid to the development of rising up mechanism in the upper extremities in observation of changes in the support pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗