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At least 1,675 records · Page 93Linked to original sources
PubMed1992

Biomechanical properties of human lumbar spine ligaments.

Biomechanical properties of the six major lumbar spine ligaments were determined from 38 fresh human cadaveric subjects for direct incorporation into mathematical and finite element models. Anterior and posterior longitudinal ligaments, joint capsules, ligamentum flavum, interspinous, and supraspinous ligaments were evaluated. Using the results from in situ isolation tests, individual force-deflection responses from 132 samples were transformed with a normalization procedure into mean force-deflection properties to describe the nonlinear characteristics. Ligament responses based on the mechanical characteristics as well as anatomical considerations, were grouped into T12-L2, L2-L4, and L4-S1 levels maintaining individuality and nonlinearity. A total of 18 data curves are presented. Geometrical measurements of original length and cross-sectional area for these six major ligaments were determined using cryomicrotomy techniques. Derived parameters including failure stress and strain were computed using the strength and geometry information. These properties for the lumbar spinal ligaments which are based on identical definitions used in mechanical testing and geometrical assay will permit more realistic and consistent inputs for analytical models.

Adult↗
PubMed1986

Rupture of the intercondylar ligament in intertarsal joints of broiler fowls.

On examination of the intertarsal joints of approximately 150 lame broiler fowls, the intercondylar ligament was found to be ruptured, either partially or totally, in 22 birds. In some cases, rupture of the intercondylar ligament occurred in joints with gross angulation and usually in association with collateral ligament instability. In other birds, intercondylar ligament rupture occurred in limbs with minimal angulation but often with concomitant ligament or tendon failure in the same or contralateral limb. A fibrovascular layer was frequently identified between collateral ligaments and their distal tibiotarsal attachment. Haemorrhage in the fibrovascular tissue appears to be responsible for the establishment of the cyst-like structures which were present in some distal tibiotarsi.

Animals↗
PubMed1988

Further studies on collateral ligaments of knee and intertarsal joints in domestic fowl.

Collateral ligament attachments in distal femora and distal tibiotarsi were examined in broilers on ad libitum and restricted feeding and in laying strain fowls fed ad libitum. Histopathological studies revealed morphological changes in ligaments of ad libitum-fed broilers which were less apparent or absent in other birds examined. One such change was loss of crimp pattern in collagen bundles of ligaments, which suggested that structural derangement had occurred. Chondroid metaplasia and foci of hyaline cartilage were observed in ligaments of ad libitum-fed broilers and may result from tissue ischaemia. Similarities were noted between ligament attachments in broilers and Osgood-Schlatter disease in man; lesions in broilers may well have a similar aetiology. It is concluded that although feed restriction restores some semblance of normality in broiler ligaments, the propensity for abnormality remains and becomes apparent in heavier birds. Such reasoning casts doubt on the wisdom of modern broiler breeding practice where feed restriction can mask genotypic predisposition to clinical disease.

Animal Husbandry↗
PubMed1991

Ossification of posterior longitudinal ligament of the cervical spine in non-Japanese Asians.

"The Japanese disease," ossification of the posterior longitudinal ligament, is not confined to the Japanese only. A similar incidence of 0.8% was found in this study among non-Japanese Asians. Of 5167 patients who attended the Mount Elizabeth Hospital in Singapore for cervical spine complaints, 43 patients were found to have ossification of the posterior longitudinal ligament, forming the largest non-Japanese series. All but one patient were of Mongolian origin, and males were affected four times more commonly than females. Diabetes mellitus was present in 16%. There was a significant association between ossification of the posterior longitudinal ligament and calcification of other cervical paraspinal ligaments. It is suggested that a generalized tendency to calcification may be an important etiological factor in ossification of the posterior longitudinal ligament. Four of the patients required surgery, and in our experience, anterior spinal fusion with removal of the ossified ligament or multilevel laminoplasty gives satisfactory results.

Adult↗
PubMedDate not supplied

Use of pelvic tilt exercise for ligament pain relief.

The purpose of this study was to test the effectiveness of a pelvic (hip) tilt exercise in relieving ligament pain during pregnancy. A multiple pain measurement approach was used. The intensity of ligament pain was decreased as indicated by scores on three of four pain intensity measures. The duration of ligament pain also was reduced, although not significantly. Mean scores on all measures of ligament pain intensity, duration, and frequency were lower after the exercises were initiated. Verbal reports from subjects indicated that they had received effective pain relief from the exercise. Thus, pelvic (hip) tilt exercise appears to be effective in reducing ligament pain intensity and, to a lesser extent, pain duration. As a nurse-midwifery strategy, this exercise promotes patient/client comfort and facilitates self-care in the relief of ligament pain during pregnancy.

Exercise Therapy↗
PubMed1986

Temperature dependence of the tensile properties of interspinous ligaments of sheep.

The dependence on temperature of the tensile properties of interspinous ligaments was examined to establish whether in vitro studies at room temperature reflect behaviour in vivo at higher temperatures. Specimens consisting of sheep interspinous ligaments attached to their adjacent spinous processes were mounted in specially designed holding devices in an Instron material testing machine; the specimens were immersed in saline and tests were conducted at four temperatures between 19 degrees C and 46 degrees C. Control tests demonstrated the repeated testing to a load up to half the fail load did not affect the response of the ligaments. No difference was found in the mechanical characteristics of the ligaments at the different temperatures but the ligaments expanded at the higher temperatures, resulting in an increase in extension over which they demonstrated an initial low stiffness characteristic. Thus although temperature did not directly affect the response of the ligaments to load, the thermal expansion of the soft tissue elements may have implications for the function and mobility of spinal joints if measured at room rather than body temperature.

Animals↗
PubMed1989

Structure and mechanical properties of the longitudinal ligaments and ligamentum flavum of the spine.

Stress-strain curves were recorded from anterior and posterior longitudinal ligaments and ligamenta flava dissected from pig lumbar spines. Ligaments were examined during extension by light microscopy, to observe crimp structure, and by X-ray diffraction, to determine collagen fibril orientations. Scanning electron microscopy (SEM) was used to examine ligaments fixed at high and low strains. Initial stages of ligament extension involved alignment of collagen fibrils. Collagen fibrils in unstrained ligamentum flavum were much more disoriented than in the longitudinal ligaments. Thus, fibril alignment, and consequent stiffening, occurred at much higher strains than for longitudinal ligaments, allowing ligamentum flavum to exploit the extensibility of its elastin.

Animals↗
PubMed1990

Mechanical function of the human lumbar interspinous and supraspinous ligaments.

The mechanical function of the interspinous and supraspinous ligaments has been examined by simulating, on excised specimens, the deformation caused during forward flexion of the spine in real life. The load extension curves showed that during the first half of flexion the ligaments carried very little load but towards the end of the range of flexion they resisted up to 134N. When the supraspinous ligament was sectioned the interspinous ligament alone resisted 75% of this load. Testing at high strain rates showed an increase in load-carrying capacity of up to 30%. The maximum extension moment that can be produced by these ligaments was calculated to be approximately 7 Nm, or 5% of the moment the back muscles can produce across any intervertebral joint. Hence, during active lifting, these ligaments in isolation provide little mechanical assistance.

Aged↗
PubMed1987

Inferior pulmonary ligament lymphadenopathy: demonstration by computed tomography.

Inferior pulmonary ligament lymphadenopathy is common in bronchogenic carcinoma and may also occur in lymphoma and potentially in any condition which may cause intrathoracic lymphadenopathy. Despite the apparent frequency with which inferior pulmonary ligament lymphadenopathy occurs, we have been unable to find a description of the computed tomographic findings of this condition. In a patient with lymphoma, we found inferior pulmonary ligament lymphadenopathy by computed tomography as an oval, elongated soft-tissue density arising within the inferior pulmonary ligament and still attached to the mediastinum by a piece of the normal ligament. We believe that this appearance should be sufficient for the correct computed tomographic diagnosis of inferior pulmonary ligament lymphadenopathy.

Aged↗
PubMed1989

The dorsal carpal ligaments: their anatomy and function.

The dorsal carpal ligaments were studied in 50 embalmed wrists. The radial collateral ligament was thin and oblique. The distribution of the dorsal radio-carpal ligament varied and it was classified into four subtypes. Neither ulnar collateral ligament nor dorsal radio-ulnar ligament was isolated as a discrete structure: instead, there were confluent soft tissues on the dorso-ulnar aspect of the wrist. The dorsal radio-carpal ligament and the dorso-ulnar component of the triangular fibro-cartilage complex, as well as the fibrous septa and the extensor tendons, were found to be the most important stabilizers of the wrist dorsally.

Humans↗
PubMed1991

Scaphoid non-union with D.I.S.I. deformity. A survey of clinical cases with special reference to ligamentous injury.

To clarify whether or not scapho-lunate ligamentous injury is common in scaphoid non-union with D.I.S.I. deformity and whether ligamentous repair is required to treat scaphoid non-union with D.I.S.I. deformity, roentgenographic, arthrographic and arthroscopic findings were analysed and compared to those of scaphoid non-union without D.I.S.I. deformity. The carpal alignment of scaphoid non-union with D.I.S.I. deformity treated by reduction and anterior wedge grafting without ligamentous repair was also studied. No significant difference in the scapho-lunate gap was present between 26 patients with D.I.S.I. deformity and 20 without. No statistically significant difference was detected in the incidence of arthrographically-proved scapho-lunate ligamentous tears between the two groups. Arthroscopic examination carried out in 22 patients did not detect massive ligamentous injury, and carpal alignment was satisfactory in most patients who underwent anterior wedge grafting. These results show that ligamentous injury rarely causes D.I.S.I. deformity in scaphoid non-union, and anterior wedge grafting alone is sufficient to correct D.I.S.I. deformity in most cases.

Adolescent↗
PubMed1994

Predicting palmar radio-carpal ligament disruption in fractures of the distal articular surface of the radius involving the palmar cortex.

12 adult cadaver wrists were dissected to identify the regions of origin of the four palmar radio-carpal ligaments. A non-dimensionalized value, called the radio-carpal ligament ratio (RLR), was defined as the width of ligament origin from the radius divided by the length of the capitate. Both values were measured directly from radiographs of the cadaver specimens. The RLRs for the four palmar radio-carpal ligaments were found to be statistically consistent. We applied the RLR concept retrospectively to 20 wrists with intraarticular distal radius fractures requiring open reduction. It was found that those fracture patterns in which the fracture fragment ratios (FFR: widths of the fracture fragments divided by the length of the capitate) were outside the limits of corresponding RLRs had clear intra-operative evidence of palmar radio-carpal ligament disruption, while those with FFRs within the limits of corresponding RLRs were noted to have no ligament disruption.

Adult↗
PubMedDate not supplied

Evidence for slowly conducting afferent fibres innervating both tooth pulp and periodontal ligament in the cat.

The presence of afferent nerve fibres branching to innervate both the dental pulp and periodontal ligament was studied in pentobarbitone-anaesthetised cats. Extracellular single nerve-fibre recordings were made from fine filaments split from the proximally cut end of the inferior alveolar nerve. Nerve fibres were identified by bipolar constant-current stimulus pulses applied to the periodontal space via platinum wire electrodes. In each case activation of the nerve fibres was also attempted by monopolar electrical stimulation of the dental pulp via a platinum wire electrode inserted into the dentine. Eleven of 142 C fibres and 4 of 97 A delta fibres identified by electrical stimulation of the periodontal ligament also could be activated by electrical stimulation of the dental pulp. Fourteen of the 142 C fibres identified by electrical stimulation of the periodontal ligament exhibited discrete latency jumps at different suprathreshold stimulus strengths. Eight of them also could be activated by electrical stimulation of the dental pulp. Eight of the 15 fine branching afferent fibres were tested with non-electrical stimuli of both periodontal ligament and dental pulp by application of heat, cold and potassium chloride. Three of the 4 C fibres could be activated with at least one of these stimuli applied to both tissues. In one case receptive fields were located in both periodontal ligament and dental pulp. The remaining 5 slowly conducting fibres were activated only from one type of tissue. The results suggest that a small percentage (6%) of the slowly conducting nerve fibres in the inferior alveolar nerve innervate both the periodontal ligament and the dental pulp. According to their response behaviour they might be involved in nociception.

Action Potentials↗
PubMed1990

Microvascular anatomy of the radioscapholunate ligament of the wrist.

The microvascular circulation and basic structural features of the radioscapholunate ligament of the wrist were studied in six fresh cadaver specimens by injection and clearing techniques. A rich vascular supply was found to originate from vessels that perforate the palmar capsule and enter the synovium that surrounds the ligament. By way of branches from the synovium, the radioscapholunate ligament and most of the scapholunate interosseous ligament receive an abundant blood supply. No contributions are derived from the bony attachments. Observation under light microscopy revealed a delicate, well-vascularized ligament consisting of regular collagen bundles. No elastic fibers were observed. This study indicates that the radioscapholunate ligament has a vascular supply that may be sufficient for healing by known methods.

Humans↗
PubMed1994

Magnetic resonance imaging of the anterior radiocarpal ligaments.

Magnetic resonance imaging was applied to eight cadaver wrists to evaluate the efficacy of imaging the anterior radiocarpal ligaments. In order to verify a correlation between the magnetic resonance images and anatomic structures, ancillary studies using gadolinium-DTPA ligamentography and gross sectioning of the specimens were performed. The ligaments targeted for evaluation were the radioscaphocapitate, long radiolunate, and short radiolunate ligaments. The highest resolution images were obtained using a 1.5 Tesla magnetic resonance imaging scanner and a surface coil applied to the wrist region, and producing T1-weighted images, with 3 mm thick sections with an 8 cm field of view. The radioscaphocapitate, long radiolunate, and short radiolunate ligaments were most consistently identified in sagittal planes, however they were also identified in coronal planes. The radioscapholunate ligament and the interosseous ligaments between the scaphoid, lunate, and triquetrum were most consistently identified in coronal planes. Transaxial planes provided consistently inferior views, and should be reserved for imaging of the flexor and extensor retinaculae.

Adult↗
PubMed1994

Incidence of ligament lesions and associated degenerative changes in the elderly wrist.

The scapholunate, lunotriquetral, and triangular fibrocartilage of 62 cadaveric wrists were examined to determine the incidence of pathologic changes in asymptomatic elderly wrists. A scapholunate ligament lesion was noted in 18 wrists; the majority of defects were incomplete and involved the central portion of the ligament only. Lunotriquetral ligament defects were noted in 20 wrists; eight were partial defects, most of them were central ligament lesions. Triangular fibrocartilage defects were present in 33 wrists and consisted of two distinct patterns: a central oval pattern with actual tissue loss and a linear defect running in the dorsal anterior direction 2-3 mm ulnar to the radial attachment of the triangular fibrocartilage. X-ray film evaluation showed few significant degenerative changes with no pronounced collapse deformities. Defects involving the scapholunate, lunotriquetral, or triangular fibrocartilage were very common, with the presence of at least one of these ligament defects in wrists. These ligament defects occur as a process of aging and behave in a manner quite different from traumatic lesions of these same structures in the younger population.

Aged↗
PubMed1995

Neural anatomy of the glenohumeral ligaments, labrum, and subacromial bursa.

The neural histology of the human shoulder ligaments, glenoid labrum, and subacromial bursae were studied using a modified gold chloride stain. Two morphological types of mechanoreceptors and free nerve endings were found in the ligaments. Slow adapting Ruffini end organs and rapidly adapting Pacinian corpuscles were identified in the superior, middle, inferior, and the posterior glenohumeral ligaments. These specialized proprioceptive nerve endings were also found in the coracoclavicular, and coracoacromial ligaments. Only free nerve endings were found in the glenoid labrum and these were located in the peripheral half. Scattered free nerve endings were found throughout the subacromial bursae. This is the first histological evidence of neural receptors in the human shoulder ligaments, glenoid labrum, and the subacromial bursae. Any disruption of the labrum or these ligaments by trauma or surgery can deprive the shoulder of mechanical stability, and may cause a decrease in proprioception because of the loss of these afferent neural receptors. Removal of symptomatic, inflamed bursae may decrease pain signals from this area of the shoulder.

Adult↗
PubMed1989

Tooth extrusion effects on microvessel volumes, endothelial areas, and fenestrae in molar apical periodontal ligament.

Extrusive tooth loads, simulating short-term orthodontic movements, have not previously been used for transmission electron microscopic quantification of their effects on the periodontal ligament vessels. In this study, a continuous extrusive load of 1.0 N, applied to the rat maxillary first molar for 30 minutes, produced statistically significant changes in the microvascular bed of the tensioned apical periodontal ligament. The mean vascular volume, as a percentage of apical periodontal ligament volume, increased (p less than 0.01) in postcapillary-sized venules, venous capillaries, arterial capillaries, and terminal arterioles from 16.6% to 22.3%, 2.0% to 2.7%, 0.4% to 1.0%, and 1.0% to 2.5%, respectively. Mean endothelial surface area per cubic millimeter of apical periodontal ligament tissue increased (p less than 0.01) in postcapillary-sized venules from 16.8 to 25.7 x 10(6) microns 2/mm3, in venous capillaries from 3.0 to 4.8 x 10(6) microns 2/mm3, and in arterial capillaries from 0.7 to 1.5 x 10(6) microns 2/mm3. The number of fenestrae per square micron of endothelium in postcapillary-sized venules, venous capillaries, and arterial capillaries showed a mean increase from 0.02 to 0.07, 0.11 to 0.31, and 0.02 to 0.21 fenestrae/microns 2, respectively (p less than 0.01). Fenestrae per cubic millimeter of periodontal ligament tissue also demonstrated a statistically significant increase with extrusion (p less than 0.01) in postcapillary-sized venules from 0.37 to 1.55 x 10(6) fenestrae/mm3, in venous capillaries from 0.27 to 1.34 x 10(6) fenestrae/mm3, and in arterial capillaries from 0.02 to 0.22 x 10(6) fenestrae/mm3. Fenestrae in control vessels had a mean diameter of 54.2 +/- 0.56 nm (SE) compared with 61.1 +/- 0.7 nm in tensioned vessels (p less than 0.01). This investigation demonstrates multiple ultrastructural changes in the periodontal ligament microvascular bed after tooth extrusion.

Animals↗