Palmar grasp behavior in full-term newborns in the first 72 hours of life.

BACKGROUND: The palmar grasp behavior is one of the items of an infant's routine neurological tests. Its exacerbated presence after the fifth month of age or absence in the first day after birth is an important sign of neuro-sensorimotor disorders. This study aimed to describe the palmar grasp behavior of full-term newborns in the first 72 h of life. METHODS: This nonrandomized cross-sectional developmental study included 219 typical newborns aged 12-2 4h, 25-48 h and 49-72 h. Three measurements were performed with newborns in the supine position, recording the palmar grasp time and strength. Statistical analysis was applied with significant level of p<0.05. RESULTS: Higher palmar grasp strength was observed in newborns aged 49-72 h compared to newborns aged 12-24 h and 25-48 h (F=7.42, p=0.01). There was significant difference in palmar grasp strength between hands (F=6.55, p=0.01), only in 12-24h, with greater strength in the left hand (t=-2.43, p=0.01), and difference in palmar grasp between strength (F=18.7, p=0.01) with greater strength in females (t=-5.40, p=0.01) only at the age 48-72 h. CONCLUSIONS: It was concluded that the palmar grasp behavior modifies in the first 72 h of life.

Proximo-distal gain of asymmetry in lamb metacarpals.

The ability of an organism to produce an ideal phenotype, despite the disturbances encountered during its development, is the causal mechanism of developmental stability. This ability is used to evaluate a variety of stress types and the genotypic ability to correct them. Geometric morphometric techniques were used to study the matched symmetry in form (size and shape) of right and left metacarpal bones in a sample of 48 lambs collected from abattoir facilities, on which 10 landmarks were located. Left and right metacarpal form showed statistically significant directional asymmetry, i.e. left and right body sides differed consistently from each other. The main shape differences were on the condylar reliefs of the distal part of the bone. These findings provide a reliable reference data set for future investigation on whether the morphology of the metacarpals is influenced by age and other factors such as the productive use of the animal (e.g. for meat, milk or wool).

The prevalence of pseudoepiphyses in the metacarpals of the growing hand.

Normally the metacarpals have an epiphysis at one end--distally for the second to fifth and proximally for the first. Pseudoepiphyses are notches or clefts that occur at the non-epiphyseal ends of bones where an epiphyseal plate would be expected and are common incidental findings in the metacarpals of the growing hand. We aimed to identify the prevalence of pseudoepiphyses on serial radiographs of 610 healthy asymptomatic children. Pseudoepiphyses in the form of notches or clefts were common, identified most often in the second metacarpal (15.25%), fifth metacarpal (7.21%), and third metacarpal (0.49%). Complete pseudoepiphyses, in which the cleft extended across the full width of the metacarpal, were seen in the first metacarpal (1.97%) and the second metacarpal (1.31%). Pseudoepiphyses are a normal variant of metacarpal ossification and should not be confused with fractures in skeletally immature patients.

Functional adaptation through changes in regional biochemical characteristics during maturation of equine superficial digital flexor tendons.

OBJECTIVE: To quantify and compare biochemical characteristics of the extracellular matrix (ECM) of specimens harvested from tensional and compressive regions of the superficial digital flexor tendon (SDFT) of horses in age classes that include neonates to mature horses. SAMPLE POPULATION: Tendon specimens were collected on postmortem examination from 40 juvenile horses (0, 5, 12, and 36 months old) without macroscopically visible signs of tendonitis. PROCEDURE: Central core specimens of the SDFT were obtained with a 4-mm-diameter biopsy punch from 2 loaded sites, the central part of the mid-metacarpal region and the central part of the mid-sesamoid region. Biochemical characteristics of the collagenous ECM content (ie, collagen, hydroxylysylpyridinoline crosslink, and pentosidine crosslink concentrations and percentage of degraded collagen) and noncollagenous ECM content (percentage of water and glycosaminoglycans, DNA, and hyaluronic acid concentrations) were measured. RESULTS: The biochemical composition of equine SDFT was not homogeneous at birth with respect to DNA, glycosaminoglycans, and pentosidine concentrations. For most biochemical variables, the amounts present at birth were dissimilar to those found in mature horses. Fast and substantial changes in all components of the matrix occurred in the period of growth and development after birth. CONCLUSIONS AND CLINICAL RELEVANCE: Unlike cartilage, tendon tissue is not biochemically blank (ie, homogeneous) at birth. However, a process of functional adaptation occurs during maturation that changes the composition of equine SDFT from birth to maturity. Understanding of the maturation process of the juvenile equine SDFT may be useful in developing exercise programs that minimize tendon injuries later in life that result from overuse.

Bone lengthening for congenital differences of the hands and digits in children.

PURPOSE: We investigated the growth of bones after lengthening to evaluate the effectiveness and usefulness of bone lengthening in congenital hand deficiencies. METHODS: Bone lengthening was performed to treat congenital hand deficiencies including hypoplastic thumb, hypoplasia of the small finger, cleft hand, metacarpal synostosis, brachymetacarpia, symbrachydactyly, and amniotic band syndrome. A total of 15 patients (1-13 years old) underwent lengthening of 23 bones. The average of distraction was 10 mm. The mean follow-up period was 59 months. The length of the bones at follow-up evaluation was measured and then compared with the length of the bones immediately after lengthening. The bone growth after lengthening, the percentage of growth after lengthening, and the growth rate were compared among diagnostic groups. RESULTS: In the cases involving older patients the bone length changed little and the growth plates of these patients closed naturally soon after lengthening. In contrast, in the cases in which the patients were younger than 7 years old the lengthened bones grew continuously. The amount of bone growth was different for each disease in the younger patients. In patients with amniotic band syndrome the lengthened bones grew at the same rate as the bones in the hand. Other diagnoses such as symbrachydactyly had a different growth pattern in the hand. CONCLUSIONS: We conclude that bone lengthening is a reliable method for the correction of congenital differences of the hand. The indications for this procedure must be determined while considering the relationship between the specific disease and subsequent bone growth.

[The comparative study on maturation of metacarpal bone in puberty children during their growth spurt period between urban and rural areas].

OBJECTIVES: To study maturation of the metacarpal bone in puberty children during their growth spurt period and its difference between urban and rural areas. METHODS: Totally, 560 pupils/students were selected from primary and secondary schools in urban and rural areas each, with 35 children in each gender and age group, ranging 12 - 15 years of age for boys and 10 - 13 for girls. An X-ray film of left hand-wrist site was taken for each of them. Length and width of the metacarpal bone were measured and the metacarpal index was calculated. RESULTS: Increment of length of the metacarpal bone was great in puberty children both in urban and rural areas, (6.26 - 9.31) mm in boys and (5.28 - 9.12) mm in girls. Mean length of the metacarpal bone was longer in children of urban areas than that of rural ones, regardless of their age and gender. There was significant difference in mean length of the metacarpal bone between boys aged 14 - 15 years and girls aged 12. Mean width of the metacarpal bone in most children was wider in rural areas than that in urban ones. Mean metacarpal index in children was higher in urban areas than that in rural ones, with very statistical significance, except for girls of 13 year age group. The peak age of metacarpal maturation was 1 year earlier in urban areas than in rural ones. CONCLUSIONS: Maturation of the metacarpal bone was rapid during puberty growth spurt period, with relatively significant difference in urban and rural ares.

A point scale in the study of excavated osseus remains of the domestic sheep (Ovis ammon f. aries).

On the basis of the standard measurements of 1277 long appendicular bones of the domestic sheep, a universal point scale has been elaborated. The bones examined were obtained from European, Asian and African archaeological sites dating from 4500 BC to 1500 AD. A comparative analysis of the metapodial bones of the domestic sheep from Central Europe (Poland, Germany and Hungary) has been undertaken, using this scale.

Experimental forward mandibular displacement in sheep.

In order to investigate growth modifications of the temporomandibular joint (TMJ) during dentofacial orthopaedic treatment, specific functional appliances have been used experimentally to prompt the mandible into a protrusive position in various animal models. The purpose of this study was to test the effectiveness of a functional appliance specially designed for sheep and to evaluate the sheep as a model for dentofacial orthopaedic research. Eight, 4-month-old, castrated male Merino sheep were randomly assigned to experimental or control groups, with four in each group. Cast functional appliances were fabricated for the animals in the experimental group. The treatment period was 15 weeks. Dental casts, endosseous implant markers and cephalograms were used to analyse the displacement of the mandible. Undemineralised sagittal sections of TMJ were used to evaluate the tissue responses induced by the appliances. The weight of the animals was measured monthly to monitor their growth. The growth of the metacarpus was also measured. During the experimental period, the animals maintained their weight within the normal range and grew normally. The appliance displaced the mandible to a downward and forward position. The adaptive responses in the TMJ induced by the appliances included changed anteroposterior shape of the condylar process, anteriorly thickened condylar cartilage, and a thickened compact bone layer along the anterior surface of the posterior wall of the glenoid fossa. The sheep coped well with the experimental procedures and the appliance used was demonstrably effective in inducing adaptive responses in the TMJ. Consequently, it is believed that the sheep is an appropriate animal model to study growth modifications in the TMJ region.

Induced mandibular condylar growth in a sheep model after functional appliance treatment.

This paper reports on changes in mandibular condylar growth in sheep fitted with experimental functional appliances. The paper also addresses the similarities of mandibular condylar growth in sheep and humans. Experimental functional appliances were developed, constructed and applied to four, four-month old, male sheep. Another four sheep served as matched controls. All animals received fluorochrome bone labels during the study and their weight gain also was recorded. Fifteen weeks later, all animals were sacrificed and each temporo-mandibular joint and left metacarpus were removed. Undecalcified mid-sagittal sections of the joint and metacarpus were prepared for fluorescence microscopy. The mandibular condylar growth vector in sheep was found to be in a postero-superior direction. Condylar growth in the control sheep during the experimental period varied from 8.8 to 11.9 mm, with the mean being 10.6 mm, which is quantitatively similar to two years of condylar growth in human adolescents. In the experimental sheep, the condylar growth varied from 8.5 to 13.3 mm, with the mean being 11.4 mm. When metacarpal growth and weight gain were taken into consideration using multivariant analysis, the coefficients for growth in the postero-superior and posterior direction were found to be high, with adjusted r2 as 0.84 and 0.82 respectively. The induced condylar growth was estimated to be largest in the posterior direction (2.30 mm), which is also similar to previous reports in humans. These findings suggest the appropriateness of using sheep as a model for quantitative histological analysis when investigating the mechanisms of functional appliance treatment.

Can some physical therapy and manual techniques generate potentially osteogenic levels of strain within mammalian bone?

BACKGROUND AND PURPOSE: Although physical therapy techniques are used to alleviate pain and stiffness in joint injuries, whether these methods are capable of affecting bone is unknown. For example, can these techniques potentially influence bone formation or resorption? To begin exploring this possibility, this study investigated the ability of 4 manual techniques to generate levels of compressive strains that presumably can stimulate bone metabolism. SUBJECTS: Six 3,4 metacarpals from three 3-year-old Merino ewes were used. METHODS: A rosette strain gauge was implanted onto the dorsomedial cortex of each ovine 3,4 metacarpal. Four different manual procedures were applied on 2 occasions on each metacarpal in vivo and ex vivo. Mean peak principal compressive strains were calculated for each technique. RESULTS: Levered bending produced greater mean peak compressive strains than almost all other manual procedures tested in vivo or ex vivo. CONCLUSION AND DISCUSSION: Manual levered bending created levels of compressive strain similar in magnitude to those created by mechanical devices used in previous animal experiments to induce new bone formation (osteogenesis). This animal model appears to be suitable for investigating the effects of manually applied procedures on bone and may establish whether manual techniques can stimulate bone formation.

Effect of exercise on bone density in distal regions of the equine third metacarpal bone in 2-year-old thoroughbreds.

The present study addressed the question of whether training induces changes in bone density in the younger racehorse in regions relevant to the genesis of the common sagittal condylar fracture pattern and, if so, the nature of such alteration. Third metacarpal bones (McIII) were obtained from 12 experimental Thoroughbred, unbroken fillies, age 18.1-21.0 months at entry to the study. Six (Group E) undertook 19 weeks of progressive high intensity exercise on a high-speed treadmill at 3% incline. Six (Group C) walked 40 min each day. Clinical bone density was studied by Computed Tomography (CT) of the right McIII. 1:1 aspects of bone density were studied by digital radiography of slices and microscopic aspects by backscattered electron (BSE) imaging. There was a distinct pattern of regional variation in bone density throughout the distal condyles of McIII. Bone density was greater in specimens from Group E than those from Group C by CT, by radiographic density and by bone volume fraction as determined from backscattered electron images: the latter also showed that the most important change was in the increased amount of bone deposited within antecedent marrow space in cancellous tissue in Group E compared with Group C, with more extensive regional involvement in the highly loaded (distopalmar) aspects of the medial and lateral condyles. However, this space-filling bone fraction had a lower degree of mineralisation than the prior bone tissue, showing that CT and radiography underestimate the resultant increased bone volume fraction. Stress fractures of the distal condyles of the McIII are common in Thoroughbred racehorses. We propose that excess stiffening within the condyles due to extensive new bone formation may lead to concentration of strain at the condylar grooves and incipient cracking through calcified cartilage and into the subchondral bone.

Influence of exercise on bone mineral density of immature cortical and trabecular bone of the equine metacarpus and proximal sesamoid bone.

Bone mineral density (BMD) and cross-sectional area (CSA), measured using peripheral quantitative computed tomography, were determined in the left third metacarpal bone (MCIII) and left medial proximal sesamoid bone (psb) in 3 differently exercised groups of foals. Group(box) (n = 14) was confined to a box stall from birth to age 5 months, Group(training) (n = 14) was kept in similar box stalls but additionally given a daily exercise programme consisting of an increasing number of gallop sprints and Group(pasture) (n = 15) remained at pasture. At 5 months of age, 8 foals from each group were randomly selected and subjected to euthanasia, the remaining 19 foals were given an identical light exercise regimen for an additional 6 months and were killed at age 11 months. In MCIII CSA increased with age and was also significantly (P<0.05) larger in Group(pasture) compared to Group(box) at age 5 months. At 11 months this difference had disappeared. In the dorsal cortex, BMD was significantly (P<0.05) higher in Group(box) than in both other groups. At age 11 months all significant differences had disappeared. In the psb, CSA increased with age, but there were no differences between the exercise groups. At the apical level, trabecular BMD was higher in Group(training) than in Group(box) and Group(pasture) (P<0.001 and P<0.01, respectively). At 11 months, trabecular BMD in the foals that had belonged to Group(training) was less than in the foals that had belonged to Group(box) (P<0.05). It is concluded that box-rest during the first months of life results in a retardation of normal development which is compensated for when the restriction on exercise is lifted. Exercise during the first months of life induces an increase in CSA in the third metacarpal bone. In the psb exercise increases BMD, principally in trabecular bone. There is an indication that the specific training regimen used in this study led to an overstimulation of the bone resulting in less active mineral deposition in the longer term.

Metacarpal index in short stature before and during growth hormone treatment.

AIMS: To assess the usefulness of the metacarpal index (MCI) as a radiographic measure of the proportions of the metacarpals in the differential diagnosis of short stature. To investigate the significance of the MCI in following the longitudinal growth and proportions of individual long bones during growth hormone stimulated catch up growth in children with short stature with and without growth hormone deficiency. SUBJECTS: 124 children, including 65 children with short stature caused by growth hormone deficiency, 13 with familial short stature, 29 with idiopathic short stature, and 17 with Ullrich-Turner syndrome. METHODS: Retrospective analysis of the MCI in five posterior-anterior radiographs of the left hand of all patients, which were performed sequentially for routine bone age determinations (Greulich and Pyle) before and during the first three years of growth hormone treatment. RESULTS: The MCI was similar in all patient groups, resembled that of healthy children, and correlated significantly with chronological age, bone age, and height before and during growth hormone treatment. Despite a remarkable growth hormone stimulated catch up growth, the MCI did not change significantly during growth hormone treatment. CONCLUSIONS: The role of the MCI is insignificant in the diagnosis of short stature, but the MCI can serve as an auxological measure of osseous proportions during longitudinal growth. Growth hormone treatment accelerates longitudinal growth without affecting the proportions of the long bones, indicating that growth hormone stimulated bone growth closely resembles spontaneous bone growth.

Mechanical correlations derived from segmental histologic study of the equine superficial digital flexor tendon, from foal to adult.

OBJECTIVE: To assess histologic variations of the equine superficial digital flexor tendon (SDFT) according to site and to horse age and activity, and to correlate these data with reported segmental mechanical results. SAMPLE POPULATION: Superficial digital flexor tendons isolated from 42 horses 0.5 hour to 23 years old. PROCEDURE: 7 segments of each SDFT were delimited and submitted for conventional histologic examination. Each segment was examined and graded for fiber undulation, cellularity, number and size of interfascicular connective spaces (ICS), presence or absence of focal and diffuse chondroid metaplasia, and differentiation of the dorsal (DB) and palmar (PB) borders of the tendon. RESULTS: Fiber undulation and cellularity significantly decreased with age. The proximal and middle metacarpal segment fibers were significantly less undulated and their ICS were smaller than those of the other segments, especially in old horses. Focal chondroid metaplasia developed from 5 years onward, mainly in the sesamoidean segments. Diffuse chondroid metaplasia was characteristic of the digital region in horses > 6 years old. The DB of the metacarpodigital region tended to differentiate into fibrocartilage in association with age. The PB was generally differentiated as nonfascicular dense connective tissue. Activity induced a decrease in the number and size of the ICS. CONCLUSIONS: The lesser undulation of the proximal and middle metacarpal segments fibers can be correlated to their mechanical behavior (stress-strain curve) and relative weakness within the SDFT. Focal chondroid metaplasia and fibrocartilage on the DB are normal features, related to the compression stresses undergone by the sesamoidean region of the tendon.

Desenvolvimento ósseo de crianças portadoras da síndrome de Down: estudo morfométrico radiográfico de ossos do carpo e metacarpo / The osseous development of Down's syndrome children: morphometric and radiographic study of the carpal and metacarpal bones

A criança é um ser em constante desenvolvimento, necessitando de análises criteriosas quanto ao seu padräo de crescimento e desenvolvimento, principalmente para a elaboraçäo de um adequado plano ortodôntico. No entanto, pouco se conhece a respeito do desenvolvimento de crianças portadoras da síndrome de Down. O presente estudo analisa o desenvolvimento ósseo de crianças portadoras desta síndrome, através de estudo morfométrico radiográfico de sete ossos do carpo e dos cinco ossos do metacarpo. As imagens radiográficas desses ossos foram transferidas, através de seus contornos, em folhas de papel vegetal, levadas a um scanner de mesa (HP SCANJET II CX), acoplado a um microcomputador Pentium 233 MHZ. Estas imagens foram captadas e morfometradas utilizando-se o software JANDEL SIGMASCAN IMAGE MEASUREMENT V 2.0, obtendo-se, assim, valores referentes às imagens das áreas dos ossos do carpo e comprimentos dos ossos do metacarpo. Estes valores obtidos nas análises morfométricas dos ossos das crianças com síndrome de Down, foram comparados com as imagens obtidas, desses mesmos ossos, de crianças normais, com as mesmas idades e ambos os sexos. Tabulados estes dados, foram eles submetidos à análise estatística através do teste de médias por comparaçöes múltiplas, ao nível de 5 por cento, com a utilizaçäo do sistema computacional SAS. Nas condiçöes experimentais deste trabalho e face a seus resultados, podemos concluir que as meninas portadoras da síndrome de Down, apresentaram desenvolvimento ósseo menor que o apresentado pelas meninas normais; as meninas portadoras da síndrome de Down, apresentaram desenvolvimento ósseo menor que os meninos portadores desta mesma síndrome e, os meninos portadores da síndrome de Down, apresentaram desenvolvimento ósseo semelhante aos dos meninos normais, em relaçäo aos picos de crescimento aos quatorze e quinze anos de idade

Brachymetacarpia V in familial short stature.

This study was planned to search for the presence of possible tubular bone abnormalities in familial short stature (FSS) as has been previously noted in some reports. Twenty-five (17 male, 8 female) children with FSS aged 10.0 SD 3.6 years were taken as the study group, and 23 (14 male, 9 female) children of normal stature aged 10.6 SD 2.7 years comprised the control group. FSS was defined as height of the child and mean parental height below 3rd centile line, normal growth velocity and bone age within 2 years of chronological age. Other causes of short stature were ruled out. Height, weight, sitting height and arm, forearm and upper arm length measurements were taken by standard methods. A left hand and wrist X-ray was taken to evaluate the length of the 5th metacarpal. Children with FSS had a significantly higher prevalence of brachymetacarpia V (64%) than the children with normal stature (21.7%) (p < 0.001). Other tubular bone parameters, however, were normal. Sitting height/height ratios were in normal ranges and comparable in FSS and the control group. Similarly arm to height and upper arm to forearm ratios were comparable in the two groups excluding disproportionate shortening of the limbs. The finding of increased incidence of brachymetacarpia V in FSS may suggest an underlying tubular bone abnormality, which may explain the short stature in FSS.

Ontogeny and limb bone scaling in two New World Marsupials, monodelphis domestica and Didelphis virginiana.

This study examines the growth of two species of marsupials who share common ancestry and are born at the same neonatal size of a little less than 1 g. Despite this similarity at birth, adult size of these two species differs by about 50 times, with the smaller species believed to be the more ancestral. We quantified the growth in the limb bones (humerus, femur, ulna, tibia, metacarpal, and metatarsal) beginning around 40 days of age until adult size was reached. Results indicate that the larger species grows at a higher rate of growth as well as for a longer period of time to reach its larger adult size. Despite these differences in growth, there were few differences observed in the scaling over time of length to width in the various limb bones that were measured. The two species, although different in their adult size and the patterns of growth, maintain the same length to width proportions in each limb bone. The biggest difference between species in scaling was observed in the bones of the hands and feet, which may suggest adaptation to size and/or locomotor performance as body size increases. Despite variation in size, these heterochronic patterns do not affect the shape among adults or over evolutionary time.

Investigation of bone developmental and histopathologic changes from intraosseous infusion.

STUDY OBJECTIVE: To evaluate clinical and cellular changes of bone through the rapid growth phase of development after intraosseous infusion of hypertonic or isotonic solutions at slow or fast infusion rates in a pig model. METHODS: This was a prospective, randomized, partially blinded, comparative study using a porcine model in an urban teaching hospital laboratory with further development in a local farm environment. Sixty pigs weighing 12 to 30 kg were anesthetized and endotracheally intubated, and a no. 15 Jamshidi bone marrow needle was inserted into a front forelimb. Hypertonic (mannitol) or isotonic (saline) solutions of 8 mL/kg were infused through the intraosseous site at a rapid or slow infusion rate. Animals were observed for approximately 6 months, after which they were killed and the front forelimbs harvested for gross pathologic and histologic evaluation. RESULTS: No clinical complications were noted in any of the animal groups. No substantial histologic differences were found between the hypertonic and isotonic groups. Although gross pathologic lesions were found in 32% of the hypertonic groups and in fewer than 5% of the isotonic groups, this difference was not statistically significant. Equal bone changes were found in the slow- and rapid-infusion groups. CONCLUSION: The rate of intraosseous infusion and the osmolarity of the infused fluid did not appear to be related to any gross pathologic or histologic cellular or marrow changes or to any clinical complications in animal development in this study.

Evidence of structural and material adaptation to specific strain features in cortical bone.

BACKGROUND: Functionally induced strains provide epigenetic signaling for bone modeling and remodeling activities. Strain gauge documentation of the equine third metacarpal reveals a neutral axis passing through the craniolateral cortex, resulting in a narrow band of cortex loaded predominantly in tension, with the remainder of the cortex experiencing a wide range of compression strain magnitudes that are maximal in the caudomedial cortex. This predictable strain pattern provides a model for examining the hypothesis that strain mode, magnitude, and strain energy density are potential correlates of compact bone structural and material organization. METHODS: Structural and material variables were quantified in nine equine (standard breeds) third metacarpals for comparison with the in vivo strain milieu that was evaluated in thoroughbred horses. The variables quantified included secondary osteon population density (OPD), fractional area of secondary bone (FASB), fractional area of porous spaces, collagen fiber orientation, mineral content (% ash), and cortical thickness. Each bone was sectioned transversely at 50% of length, with subsequent quantification of eight radial sectors and three intracortical regions (periosteal, middle, endosteal). Linear regression analysis compared these variables to magnitudes of corresponding regional in vivo longitudinal strain, shear strain, and strain energy density values reported in the literature. RESULTS: The craniolateral ("tension") cortex of this bone is distinguished by its 30% lower FASB and with the lateral cortex exhibits 20% darker gray level (more longitudinal collagen) compared with the average of all other locations. Conversely, the remaining ("compression") cortices as a group have a high OPD, are more extensively remodeled, and contain more oblique-to-transverse collagen. The caudal cortices (caudomedial, caudal, caudolateral) are significantly thinner (P < 0.01) and have 4% lower mineral content (P < 0.05) than all other locations. Moderately strong correlations exist between collagen fiber orientation and normal strain (r = 0.752) and shear strain (r = 0.555). When normal and shear strains were transformed to their respective absolute values, thus eliminating the effects of strain mode (tension vs. compression), these correlation coefficients decreased markedly. CONCLUSIONS: Collagen fiber orientation is related to strain mode and may function to accentuate rather than attenuate bending. These differences may represent adaptations that function synergistically with bone geometry to promote a beneficial strain distribution and loading predictability during functional loading.