Width Of Scapula Research Articles

Comparison of the Scapula in Human and Laboratory Rat Species from the Perspective of Translational Medicine

Aim: The aim of the study is to provide anatomical differences between rat and human scapula and definitive information to the literature about which strain is most appropriate for rat modeling, particularly in orthopedics. Methods: In current study, a total of 40 scapulas belonging to Wistar Albino, Brown Norway, Sprague Dawley and Lewis strains were examined morphologically and morphometrically with each other and with the human scapula. Digital calipers were used to measure parameters for rat scapula. Literature searches were conducted for the measurements of the human scapula, and the obtained literature data was evaluated. A statistical analysis of the observed parameters was conducted using mean values, standard deviations, and One Way Anova Analysis in the IBM SPSS program. The Tukey post hoc test was used to determine the differences between groups that have a statistical difference. A fold ratio was calculated for each parameter based on the average values of all rat and human scapulae. Results: According to One-Way Anova analysis, there is not any difference between groups for; width of collum scapula, length of cavitas glenoidalis-1, length of cavitas glenoidalis -2, width of cavitas glenoidalis, external width of cavitas glenoidalis, length of processus hamatus, width of processus hamatus, distance between processus coracoideus and incisura scapula, distance between cavitas glenoidalis to acromion at p<0.05 level. There is a statistical difference groups for; length of scapula (p<0.001), width of scapula (p<0.001), length of margo cranialis (p=0.001), length of margo caudalis (p<0.001), length of spina scapula (p<0.001), length of acromion (p=0.007), width of acromion (p=0.001), coracoacromial distance (p=0.003), distance between cavitas glenoidalis and incisura scapula (p<0.001), angle of angulus cranialis (p=0.001) levels. Conclusions: Wistar Albino, Brown Norway, Sprague Dawley and Lewis rat strains are suitable for orthopedical animal models for especially models including cavitas glenoidalis. Any strain can be used in modeling indiscriminately. However, in modeling where the acromion, spina scapula, and edges of the scapula are important, the most appropriate strain specified in the current study should be selected.

AN INTERPOPULATION COMPARISON AND CORRELATION OF 3D MORPHOMETRIC MEASUREMENTS OF THE SCAPULA

In patients with shoulder arthritis, the ability to accurately determine glenoid morphological alterations affects the outcomes of shoulder arthroplasty surgery significantly. This study was conducted to determine whether there is a correlation between scapular and glenoid morphometric components. Existence of such a correlation may help surgeons accurately estimate glenoid bone loss during pre-operative planning.The dimensions and geometric relationships of the scapula, scapula apophysis and glenoid were assessed using CT scan images of 37 South African and 40 Chinese cadavers. Various anatomical landmarks were marked on the 77 scapulae and a custom script was developed to perform the measurements. Intra-cohort correlation and inter-cohort differences were statistically analysed using IBM SPSS v28. The condition for statistical significance was p<0.05.The glenoid width and height were found to be significantly (p<0.05) correlated with superior glenoid to acromion tip distance, scapula height, acromion tip to acromion angle distance, acromion width, scapula width, and coracoid width, in both the cohorts. While anterior glenoid to coracoid tip distance was found to be significantly correlated to glenoid height and width in the South African cohort, it was only significantly correlated to glenoid height in the Chinese cohort. Significant (p<0.05) inter-cohort differences were observed for coracoid height, coracoid width, glenoid width, scapula width, superior glenoid to acromion tip distance, and anterior glenoid to coracoid tip distance.This study found correlations between the scapula apophyseal and glenoid measurements in the population groups studied. These morphometric correlations can be used to estimate the quantity of bone loss in shoulder arthroplasty patients.

Evaluation of Anthropometric Scapula Indices in CT Scan Images for Gender Distinction in the Besat NAHAJA Hospital

Background: In forensic medicine, several bones are used to determine gender. The most important and widely used are the skull and pelvis. But in some cases, the mentioned bones may not be available, and other bones, such as the scapula bone, should be used. Objectives: This study aimed to investigate and locate the anthropometric indices of scapula bone in the Iranian population to determine gender. Methods: In this project, a study was performed on a chest scan of 259 Iranians referred to Besat NAHAJA Hospital in 2016. Pack software was used to measure the scapula's indices. The obtained data, including age, gender, and different scapula sizes of max width of glenoid (MWG), max length of glenoid (MLG), max width of scapula (MWS), and max length of scapula (MLS), were analyzed using appropriate statistical tests. Assessment of differential ability, sensitivity, and specificity of scapula anthropometric indices was used in determining gender. Results: Of 259 participants in this study, 133 (51.4%) were female, and 126 (48.6%) were male. Generally, the mean index of MWG, MLG, MWS, and MLS was higher in men than women in the studied population. The results of this study showed there is a significant difference among scapula features in men and women (P < 0.05). The highest accuracy in determining gender was assigned to MLS, with 88.9%, and the lowest was assigned to MLG, with 66.3%. Conclusions: Our study showed that measured anthropometric indices, including length and width of scapula bone and glenoid cavity, will help to predict gender and also can be used as an accurate and practical tool in gender determination.

Clinical Significance of the Morphometric Structures of the Scapula with the Emphasis on the Glenoid Cavity

Aim: The aim of this study is to determine the average of the morphometric parameters of the scapula to accurate and successful analyzes in the clinic. Material and Methods: A total of 24 dry bone scapula were included in the study. Parameters determined on the scapula; superio-inferior glenoid diameter (SIGD), anterio-posterior glenoid diameter 1 (APG1), anterio-posterior glenoid diameter 2 (APG2), anterio-posterior glenoid diameter 3 (APG3), scapula width (SW), scapula length (SL), basis-spina distance (BS), spina scapula width (SSW), acromiocoracoid width (AW), scapula margo lateralis length (SML), scapula margo medialis length 1 (SML 1), scapula margo medialis length 2 (SML 2), cavitas glenoidalis antero-posterior width (CGAPW), cavitas glenoidalis superio-inferior width (CGSIW), incisura scapula width (ISW), incisura scapula depth (ISD), the maximum length of proccessus coracoideus (MLPC), maximum proccessus coracoideus thickness (MPCK), the shortest distance between the lateral edge of the proccessus coracoideus tip and the anterior upper edge of the cavitas glenoidalis (PCL-CGK). Results: Among the determined parameters, SSW, MSW, ISW, ISD, MPCU, MPCK, PCL-CGK were found to be in parallel with the analyzed literatures. Conclusion: It is thought that the results of the analysis of the parameters determined in the study will add clinical depth to many surgical approaches such as glenohumeral arthrodesis, internal fixation, fracture stabilization, and rotator cuff tendinitis, in more accurate analysis of shoulder anomalies and fractures.

A Morphometric and Morphological Analysis of Superior Border of Dry Scapulae

Aim: The recognition of the scapula anatomy and visible variations is important in surgical treatments and arthroscopic procedures in case of any diseases of the shoulder. The morphological and morphometric characteristics of the scapular notch on the superior margin are very important. Because compression of the suprascapular nerve extending inside the scapular notch causes entrapment neuropathy. Therefore, the present study was planned in order to contribute to us as well as practitioners about morphometric and morphological characteristics of the superior margin of the scapula.Materials and Methods: Morphometric measurements (SL: scapula length; SW: scapula width; SI: scapula index; STD: superior transverse diameter of the scapular notch; MTD: medial transverse diameter of the scapular notch; VD: vertical diameter) were performed on 90 (50 left; 40 right) scapulae of Turkish population without unknown age and gender. Furthermore, the superior scapular margin and the scapular notch were categorized through observational classification as well as measurement. Results: The mean scapular width was detected 98.87±7.71 mm on the right and 94.38±13.01 mm on the left. The scapula index was measured 67.51±4.40 mm on the right and 63.80±8.29 mm on the left. The SL, STD, and VT was larger on the left; the SW, SI, and MTD were larger on the right. The difference between right and left for the SW and SI measurements was statistically significant (p<0.005). The most common scapular notch appearance, the U shape (64.4%) was the most common scapular notch shape as VD>MTD (%48.9). The most common superior margin type was moderately oblique (41.1%). Conclusion: We believe that the data obtained would be helpful for orthopedic surgeons in intramedullary nailing and radiologists in the differential diagnosis of some osteolytic lesions in that region. Furthermore, scapula measurements would help to identify the gender and race in forensic medicine and anthropology.

Correlation between Morphological Variations and Morphometry of Scapula and Suprascapular Notch with Its Clinical Significance in South Indian Population

Introduction: The biological profile is one of the most important things that forensic anthropologists accomplish in their work, which includes determination of age, sex, race and stature. These components aid in identification of an individual in forensic context. Since the beginning of the field of physical anthropology, anthropologists and anatomists have studied human remains in order to provide new and more accurate ways of building the biological profile. Aim: To compare the metric difference between right and left scapula, calculate scapular index, and to correlate the morphometry between the scapula and the suprascapular notch. Materials and Method: This study was carried out in 200 dry ossified adult human scapula bones collected from the Department of Anatomy and from the students of 1st year MBBS of Yenepoya Medical College. Study done using vernier calliper and measuring tape. Scapula having gross deformity or any pathological alterations were excluded from the study. Results and Discussion: Out of 100 right and left scapulae, maximal width and projection length of scapular spine and maximal length of coracoid process were more on the right sided scapula. The superior- transverse diameter of suprascapular notch, maximal depth of suprascapular notch, morphological length and width of scapula and scapular index were more on the left sided scapulae. The mean scapular index of right side scapula was 70.11 and left side was 70.26, which shows that the left scapula is slightly shorter than right. Also there were more scapulae with longer superior transverse diameter of suprascapular notch (STD>MD) with 52% than the scapulae with longer maximal depth of suprascapular notch (MD>STD) 24% and STD=MD was 9%. Absent notches were seen in 15% of scapulae. The superior transverse scapular ligament was completely ossified in 12% of cases. Both right and left scapula shows more of ‘U-shaped’ suprascapular notch. There was no statistically significant difference between anthropometric measurements of the group with higher maximal depth and the group with higher superior transverse diameter of the suprascapular notch. Conclusion: The scapular index was more in left scapula, which shows that left scapula is slightly shorter than the right scapula compared to other populations. This may be due to the difference in general built and stature of South Indians compared to other populations. Completely ossified superior transverse scapular ligament can result in entrapment of suprascapular nerve. Keywords: Scapula, Suprascapular notch, Spine of scapula, Coracoid process.

Determination of dimensions of Glenoid cavity from other scapular parameters in North Indian Population

Background: The Glenoid cavity dimensions can help to predict the incidence of glenohumeral dislocations in a population. Purpose of study: The present study involved the measurements of the body of the scapula and the glenoid cavity and to draw the relationship of them to predict the chances of glenohumeral dislocations in North Indian Population. Methods: A total number of 130 adult scapulae of unknown sex showing complete ossification and without any damage were included in the study. The various shapes of glenoid cavities both on right and left sides were noted and analysed. A digital Vernier calliper was used to measure all the dimensions of scapula as well as glenoid cavity. The data was analysed and regression formulae to estimate the glenoid cavity dimensions were drawn. Results: Most common shape of the glenoid cavity in the present study was pear shaped (52.30%) followed by inverted comma shaped (33.07%) and least common was oval shaped (14.63%). Mean maximum height of scapula (MSH) was 142.45± 2.32 mm, mean maximum width of scapula (MSW) was 102.65± 0.21mm. Mean maximum glenoid height (MGH) was 38.77± 3.15mm, mean maximum glenoid width I (MGW I) was 23.82± 2.11 mm, mean maximum glenoid width II ( MGW II) was 14.78± 9.11mm. Mean scapular index (SI) was 71.32± 0.61(60-<73) % and mean glenoid index (GI) was 60.43± 5.43%( 60-69%). Bilateral differences in these parameters were statistically insignificant. Mean maximum scapular height was significantly correlated with both mean maximum glenoid height and mean maximum glenoid width. There was also found highly significant interglenoid dimension correlation. Conclusion: Glenohumeral dislocations are expected if indices are <50% or > 89%. A deviation from the normal relation between maximum glenoid width and maximum glenoid length also indicates glenohumeral instability. KEY WORDS: Glenoid cavity, Gleno humeral, Scapula.

Age and sex changes in the mass, length and width of the scapula of Romanov sheep during ontogenesis

The article presents results of morphometric studies of the scapula in the ontogenesis of Romanov sheep. The material was scapula of two-month feta, animals aged up to 12 months and 5-6-year-old sheep. The interval between the ages at the uterine stage was 1 month, and after birth – 3 months. The scapula of two male and two female animals were studied in each age group. In each scapula without scapular cartilage, the mass, length and width were studied. The average data for each indicator and each sex were compared. The results showed that absolute indices of the scapula, i.e., the mass, length and width in male animals significantly exceed those in the female ones. A growth in the scapula mass, length and width is subject to the general biological laws of reducing intensity with aging, i.e., at the uterine stage, it is more intensive for male than for female animals. In contrast to the width, the scapula length significantly increases at the uterine stage. By the one-year-old age, no scapula does not reach its definitive state. One can assume that in females the scapula width will reach its final size earlier, while in males, the scapula mass and length will reach their final values earlier.

An anatomical study on various types of suprascapular notch, its relation with glenoid cavity and morphometry of scapula in south Indian population

Introduction: Superior border of scapula presents a suprascapular notch. Suprascapular nerve entrapment syndrome may be caused due to compression of the nerve at the notch. Previous studies have shown that there are various types of suprascapular notch and clinicians must be aware of these types and their prevalence. Aim: This study was conducted with the following objectives, a: To know the morphometry and morphological variations of suprascapular notch; b: To measure the safe zone distance necessary to avoid iatrogenic injuries to nerve; c: To correlate the major scapular dimensions with that of suprascapular notch. Materials and Methods: We collected 100 dried human scapulae from department of Anatomy and medical students of AIMS&RC, Devanahalli, Karnataka and Sri Narayana Institute of Medical Sciences, Ernakulam, Kerala. The Suprascapular notch was classified according to Rengachary’s classification. Dimensions of all different class of suprascapular notches, that of scapulae and safe zone distance was measured using digital Vernier calipers. Results: Majority of scapulae had type II SSN (33%) and least common variety found was type IV (4%). Least surface area in type V notch measured was 36.16mm2. Mean safe zone distance between SSN and supraglenoid tubercle (S1) in all 100 scapulae is 30.31+/-3 mm. The mean distance between spinoglenoid notch and posterior rim of glenoid (S2) is 16.82+/-2.19 mm. Mean length of all 100 scapulae is 135.12+/-1 mm. Mean width of scapula is 101.69+/-6.8 mm. Mean length and width of glenoid fossa is 33.83+/- 3.25 mm and 24.2+/-2.34 mm respectively. Conclusion: Ossified superior transverse scapular ligament can compress the nerve causing entrapment syndrome. Since suprascapular notch presents various shapes, this study is an attempt to add further data to the existing studies about suprascapular notch, its morphometry and safe zone distance to avoid injury to nerve during surgery. Keywords: Neuropathy, Scapula, Shoulder join

Exhumation of a juvenile body. Identification and marks of battered child

The body of a young child buried in an undergrowth was exhumed with the help of DVI Belgium before being taken to the autopsy room. Radioscopic examination revealed no visible traumatic lesions in the skull, thorax or lower limbs. A fracture line to the distal third of the left humerus was observed. The body was strongly altered by putrefaction process and covered entirely with soil. The victim's body was completely naked. No personal effects were found on the body; no scarring or tattooing was visible, and there was no alteration of the skin surface. Based on the thanatological observations, the post mortem interval was estimated to be several months (5 to 6 months). No wounds or other evidence of traumatic or ballistic origin were found. After examination of the trunk cavities, complete extraction of the child's skeleton was carried out for examination and anthropological measurements. Biological sex was determined during the autopsy and age estimation was carried out by examining the stages of fusion of various bone parts (CI, CII), measurements of different bones (length of the femur and radius, width of scapula, etc.) and the stages of ossification of long bones. The estimated age was 5 years. However, macroscopic examination of the child's skeleton and thorough autopsy demonstrated the presence of dummy lesions in radioscopic and radiological examinations. These specific lesions are undeniable evidences that this child has been physically abused due to the various traumatic lesions highlighted.

Gross Morphometry of Pectoral Girdle of Domestic Pigeon (Columba livia)

The pectoral girdle gives strength and range of motion to the wings of birds and plays functional role in flight mechanism of birds. Pectoral girdle of adult domestic pigeon (Columba livia) (n=10) was studied with special reference to the morphological and morphometric parameters. The girdle was composed of three pairs of bones viz. the scapulae, the coracoids and fused clavicles (furcula). The scapula was sword shaped with proximal extremity and a blade. The length and maximum width of scapula were 4.23 cm and 0.56 cm, respectively. The clavicle was in the form of thick curved plate to join the bone of opposite side forming the broad 'U' shaped furculum with rudimentary hypocleideum. The width of clavicle gradually decreased from proximal to distal end. Hypocleideum was not prominent at their meeting point. The curvature length and maximum width of clavicle were 6.38 cm and 1.61 cm, respectively. Coracoid was directed downwards and backwards to articulate the sternum distally. The length was 3.53 cm and width of distal extremity (1.45 cm) was about twice that of proximal one (0.70 cm). The proximal extremity of coracoid was hook like and articulated with proximal extremity of scapula and clavicle to form foramen triosseum (0.35 cm diameter).

Genome-wide association studies identify the loci for 5 exterior traits in a Large White × Minzhu pig population.

As one of the main breeding selection criteria, external appearance has special economic importance in the hog industry. In this study, an Illumina Porcine SNP60 BeadChip was used to conduct a genome-wide association study (GWAS) in 605 pigs of the F2 generation derived from a Large White × Minzhu intercross. Traits under study were abdominal circumference (AC), body height (BH), body length (BL), cannon bone circumference (CBC), chest depth (CD), chest width (CW), rump circumference (RC), rump width (RW), scapula width (SW), and waist width (WW). A total of 138 SNPs (the most significant being MARC0033464) on chromosome 7 were found to be associated with BH, BL, CBC, and RC (P-value = 4.15E-6). One SNP on chromosome 1 was found to be associated with CD at genome-wide significance levels. The percentage phenotypic variance of these significant SNPs ranged from 0.1–25.48%. Moreover, a conditional analysis revealed that the significant SNPs were derived from a single quantitative trait locus (QTL) and indicated additional chromosome-wide significant association for 25 SNPs on SSC4 (BL, CBC) and 9 SNPs on SSC7 (RC). Linkage analysis revealed two complete linkage disequilibrium haplotype blocks that contained seven and four SNPs, respectively. In block 1, the most significant SNP, MARC0033464, was present. Annotations from pig reference genome suggested six genes (GRM4, HMGA1, NUDT3, RPS10, SPDEF and PACSIN1) in block 1 (495 kb), and one gene (SCUBE3) in block 3 (124 kb). Functional analysis indicated that HMGA1 and SCUBE3 genes are the potential genes controlling BH, BL, and RC in pigs, with an application in breeding programs. We screened several candidate intervals and genes based on SNP location and gene function, and predicted their function using bioinformatics analyses.

A morphometric study of acromion process of scapula and its clinical significance

Objective: The acromion process is associated with a variety of ailments in the shoulder. Therefore, the aim of this study was to record and study all the morphometric values of the acromion process and its morphological features. Materials and Methods: The study was carried out on 50 unpaired dried scapulae. The length, width, and thickness of the acromion process were measured, and the length and width of scapula was also measured using vernier calipers. The acromiocoracoid and acromioglenoid distances were also measured. The shape, type of acromion process, and the presence of enthesophytes were noted and whether the anterior 2/3 rd of inferior surface of acromion process is rough or smooth was also noted. Results: The mean length, width, and thickness of acromion process were 4.21, 2.42, and 0.73 cm, respectively. The mean length and width of scapula were 13.93 and 10.14 cm, respectively. The mean acromiocoracoid distance and acromioglenoid distance were 3.09 and 2.47 cm, respectively. The most common shape of the acromion process noted was quadrangular in 40% of scapulae. In 90% of scapulae, the anterior 2/3 rd of inferior surface was rough and in 80% scapulae, enthesophytes were present. Conclusions: This study will help the clinicians in understanding and curing various shoulder joint disorders.

CT Evaluation of Extra-articular Glenoid Neck Fractures

Medial translation of the glenoid is frequently described as the main mode of displacement after glenoid neck fracture. Indeed, plain radiographs typically show the glenoid medialized relative to the scapular body. However, whether this truly represents medialization of the glenoid relative to the axial skeleton or lateralization of the scapular body remains unclear. The goal of this investigation was to assess the relationship between the glenoid, the scapular body, and the axial skeleton in patients with glenoid neck fractures using computed tomographic data analysis with the contralateral shoulder serving as an internal control. Retrospective radiographic review. Two Level I trauma centers. Eighteen patients (5 women and 13 men; average age, 38.7 years; range, 17-75 years) admitted between January 2000 and March 2006 with isolated extra-articular glenoid neck fractures (OTA 14C1 fractures) and chest computed tomographic scans that included both shoulders. Glenoid to midline distance and scapular width. The injured glenoid was lateralized an average of 9.8 mm (range, 8 mm medialized to 23 mm lateralized) (P < 0.001). Relative to the uninjured side, glenoid medialization infrequently occurred (4 of 18 patients) and when present was less than 1 cm (range, 2-8 mm). Lateralization occurred more frequently (14 of 18 patients), with an average displacement of 13.7 mm (range, 1-23 mm). The injured scapula was shortened by an average of 3.3 mm (range, 18 mm shorter to 20 mm longer) (P = 0.09). In 15 of 18 patients, the scapular width was shortened by an average of 5.9 mm (range, 1-18 mm), whereas in only 3 of 18 patients was the injured scapular width longer, an average of 9 mm (range, 1-20 mm). In patients with glenoid neck fractures, pure medial translation of the glenoid relative to the axial skeleton rarely occurs. Instead, there is typically a component of shortening of the scapula width combined with lateralization of the scapular body.

Appropriate Slice Location to Assess Maximal Cross-sectional Area of Individual Rotator Cuff Muscles in Normal Adults and Athletes

We investigated appropriate slice locations for magnetic resonance (MR) imaging evaluation of the maximal cross-sectional area (CSA) of individual rotator cuff (RC) muscles in normal adults and athletes. We used a 1.5-tesla MR system with body-array and spine coils to obtain oblique sagittal T(1)-weighted shoulder images of 29 normal adults (16 men, 13 women); 6 national-level competitive swimmers (4 men, 2 women); 10 collegiate-level female badminton players; and 7 collegiate-level male rowers. We calculated the supraspinatus, infraspinatus, teres minor, and subscapularis CSAs at the 0-1 locations on the scapula (dividing scapula width into 11 locations), 0 representing the medial border of the scapula and 1, the glenoid fossa surface. We evaluated the differences in CSAs at relative locations on the scapula for each muscle in normal adults, swimmers, badminton players, and rowers using a one-way analysis of variance followed by the Tukey test (P<0.05). The supraspinatus CSAs were maximal at 0.7 for all groups. The infraspinatus CSAs were maximal at 0.5 for normal men and women and badminton players, 0.4- and 0.5 locations for swimmers, and 0.4 for rowers. The teres minor CSAs were maximal at 0.9 for all groups except the swimmers (1 location). The subscapularis CSAs were maximal at 0.7 in men, swimmers, and badminton players and 0.6 in women and rowers. The appropriate slice locations for evaluating maximal CSAs are slightly lateral to the center of the scapula for the supraspinatus and subscapularis, at approximately the center of the scapula for the infraspinatus, and near the glenoid fossa for the teres minor. These slice locations should be clinically useful for morphological and/or function-related assessments of shoulder RC muscles.

A functional-morphometric analysis of forelimbs in bipedal and quadrupedal heteromyid rodents

The rodent family Heteromyidae contains bipedal hoppers and quadrupedal runners. The possibility that bipedalism is associated with forelimb specialization for nonlocomotory functions, such as burrowing and seed-gathering, motivated a static functional-morphometric and interspecific allometric analysis of 18 metric characters of the forelimb skeleton. A principal-components analysis, across 28 species in six genera, showed that lengths of proximal (scapula, humerus) and distal (ulna, radius, metacarpal) elements were negatively allometric, and widths were positively allometric. Quadrupedal and bipedal species groups showed qualitatively similar allometric patterns, except that scapula width anterior to the spine was positively allometric in quadrupeds and negatively allometric in bipeds; scapula width posterior to the spine was positively allometric in bipeds and isometric in quadrupeds; and olecranon length was isometric in bipeds and positively allometric in quadrupeds. Most morphometric characters varied significantly among species within genera, even when effects of size variation were reduced by reconstructing all species to a common general size (as indicated by their score on the first principal component). These shape differences caused species to vary in the mechanical advantage of the forelimb, of possible importance for digging and seed-harvesting performance. Relative to quadrupeds, bipedal species tended to have greater mechanical advantage for proximal forelimb elements and smaller mechanical advantage for distal forelimb elements, but only the distal pattern remained in reconstructed forms, and no functional character was significantly different when tested over variation among genera nested within locomotion type. Cluster analysis confirmed that forelimb characters related to digging or seed-harvest are not coincident with mode of locomotion. Forelimb characters were, however, associated with digging or seed-harvest performance. Mechanical advantage of the proximal forelimb was positively related to an index of the compaction of soils with which 26 desert-dwelling species are associated, and also to relative use of heavy vs. light soils by nine species in the laboratory. Across 10 species, deviations in seed-harvest rate from expected allometric values were negatively correlated with mechanical advantage of the distal forelimb.

A functional-morphometric analysis of forelimbs in bipedal and quadrupedal heteromyid rodents

The rodent family Heteromyidae contains bipedal hoppers and quadrupedal runners. The possibility that bipedalism is associated with forelimb specialization for nonlocomotory functions, such as burrowing and seed-gathering, motivated a static functional-morphometric and interspecific allometric analysis of 18 metric characters of the forelimb skeleton. A principal-components analysis, across 28 species in six genera, showed that lengths of proximal (scapula, humerus) and distal (ulna, radius, metacarpal) elements were negatively allometric, and widths were positively allometric. Quadrupedal and bipedal species groups showed qualitatively similar allometric patterns, except that scapula width anterior to the spine was positively allometric in quadrupeds and negatively allometric in bipeds; scapula width posterior to the spine was positively allometric in bipeds and isometric in quadrupeds; and olecranon length was isometric in bipeds and positively allometric in quadrupeds. Most morphometric characters varied significantly among species within genera, even when effects of size variation were reduced by reconstructing all species to a common general size (as indicated by their score on the first principal component). These shape differences caused species to vary in the mechanical advantage of the forelimb, of possible importance for digging and seed-harvesting performance. Relative to quadrupeds, bipedal species tended to have greater mechanical advantage for proximal forelimb elements and smaller mechanical advantage for distal forelimb elements, but only the distal pattern remained in reconstructed forms, and no functional character was significantly different when tested over variation among genera nested within locomotion type. Cluster analysis confirmed that forelimb characters related to digging or seed-harvest are not coincident with mode of locomotion. Forelimb characters were, however, associated with digging or seed-harvest performance. Mechanical advantage of the proximal forelimb was positively related to an index of the compaction of soils with which 26 desert-dwelling species are associated, and also to relative use of heavy vs. light soils by nine species in the laboratory. Across 10 species, deviations in seed-harvest rate from expected allometric values were negatively correlated with mechanical advantage of the distal forelimb.

The experimental errors in measuring the size of bones in mice

An experiment was conducted with 236 mice (3-9 weeks of age) to determine the bias in taking soft-X-ray photograph, and systematic and random errors of the values measured with a picture analyzer. Sites measured are length of scapula (SCAL), humerus (HUML), ulna (ULNL), coxae (COXL), femur (FEML), tibia (TIBL), thoracic vertebrae (VTL), lumbar vertebrae (VLL) and sacral vertebrae (VSL), and width of scapula (SCAW) and coxae (COXW). Systematic bias peculiar to the procedure was found in the values of bones measured. The X-ray photograph caused the downward bias to the length of sacral vertebrae alone, but did not to others. The standard errors of measurements (squared root of error variance) with picture analyzer ranged between 0.12 and 0.24 mm and had no apparent relationship to the size of bone.

A study of pre-natal growth and development in the sheep

A study of pre-natal growth and development in the sheep