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At least 721 records · Page 40Linked to original sources
PubMed1995

Development of fibroblast-seeded ligament analogs for ACL reconstruction.

We fabricated "ligament analogs" in vitro by seeding high-strength resorbable collagen fiber scaffolds with intraarticular (anterior cruciate ligament, ACL) or extraarticular (patellar tendon, PT) rabbit fibroblasts. Fibroblasts attached, proliferated, and secreted new collagen on the ligament analogs in vitro. Fibroblast function depended on the tissue culture substrate (ligament analog vs. tissue culture plate) and the origin of the fibroblasts (ACL vs. PT) PT fibroblasts proliferated more rapidly than ACL fibroblasts when cultured on ligament analogs. Collagen synthesis by ACL and PT fibroblasts was approximately tenfold greater on ligament analogs than on tissue culture plates. The composition, structure, and geometry of the collagen fiber scaffolds may promote collagen synthesis within ligament analogs in vitro. Ligament analogs roughly approximate the structure and strength of native ligament tissue. Ongoing in vivo studies suggest that autogenous fibroblast-seeded ligament analogs remain viable after implantation into the knee joint. With further development, ligament analogs may be useful as implants for ACL reconstruction surgery.

Animals↗
PubMed1996

Signal pathways and ligament cell adhesiveness.

The influence of signal pathways involved in the adhesion of fibroblasts from the anterior cruciate and medial collateral ligaments to fibronectin was investigated. Specific emphasis was paid to the cyclic adenosine monophosphate and Ca2+/phospholipid pathways to determine the signaling mediated by integrin receptors during cell binding and spreading on a fibronectin-coated glass surface and to compare the roles of these two pathways in integrin-mediated adhesion in fibroblasts from the two ligaments. Individual cell adhesion strengths were determined using a micropipette-micromanipulation system after the cells were treated with signal pathway inhibiting agents. Adhesion in fibroblasts from the medial collateral ligament was significantly reduced by inhibiting agents for Gi protein, protein kinase A, protein kinase C, protein kinase G, phospholipase C, and calmodulin, which suggests a crucial role for cyclic adenosine monophosphate and Ca2+/phospholipid signaling in integrin-mediated adhesion of these fibroblasts. Adhesion in fibroblasts from the anterior cruciate ligament, however, was reduced only by a protein kinase C inhibiting agent and was increased by inhibiting agents for protein kinase A, protein kinase G, and calmodulin, which suggests only a partial role of Ca2+/phospholipid signaling in integrin-mediated adhesion of these fibroblasts. On the basis of additional parallel studies on the role of intracellular calcium in integrin-mediated adhesion, medial collateral ligament and anterior cruciate ligament fibroblast adhesion was calcium dependent throughout the 60 minute time course of adhesion experiments. Fibroblasts from the medial collateral ligament demonstrated a 2.2-fold increase in cytosolic free calcium upon binding to fibronectin, whereas fibroblasts from the anterior cruciate ligament demonstrated no significant increase in calcium. Overall, the study of the intrinsic differences between anterior cruciate ligament and medial collateral ligament fibroblasts in their signal pathways upon binding to fibronectin may reveal information important for further explaining the lack of functional healing response in the anterior cruciate ligament after injury.

Adult↗
PubMed1994

Biochemical properties of collagen from ligaments and periarticular tendons of the human knee.

The biochemical properties of collagens from the periarticular connective tissues of the human knee (ligaments, semitendinosus and gracilis tendons, and the iliotibial band) were investigated in subjects ranging from 20 to 70 years of age. Although the total collagen content of most tissues was more than 90% of the dry weight, the anterior cruciate ligament and the iliotibial band had relatively low collagen contents. There were no significant changes in the tissue collagen content with aging. However, the anterior cruciate ligament and the patellar tendon of the 20-year-old subject had a higher content of soluble collagen than the other ligaments and tendons. The iliotibial band of the 20-year-old subject contained more collagen that was soluble by a combination of salt, sodium citrate extractions and pepsin digestion. Dihydroxylysinonorleucine was the major reducible cross-link of collagen from all the ligaments. The amount of dihydroxylysinonorleucine in the anterior cruciate ligament of the 20-year-old subject was much higher than that in the other ligaments. In contrast, the tendons and the iliotibial band contained a large amount of histidino-hydroxymerodesmosine and hydroxylysinonorleucine, while the patellar tendon was the only tendon with a significant content of dihydroxylysinonorleucine. Hydroxypyridinium non-reducible cross-links were more abundant in collagens from ligaments than in collagens from the other tissues. The cross-link study and the analysis of collagen solubility showed that patellar tendon collagen more closely resembled the collagen from the anterior cruciate ligament than that from periarticular tendons. It was also shown that the anterior cruciate ligament contains relatively immature collagen compared with the other ligaments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2002

Coordination of the anterior and posterior cruciate ligaments in constraining the varus-valgus and internal-external rotatory instability of the knee.

Tension along both cruciate ligaments was measured simultaneously under various loading conditions, and the interaction of these ligaments as constraints on knee instability was analyzed. Six fresh cadaveric knees were used. The attachments for both cruciate ligaments were detached from the femur and reattached to their original positions using metal plates equipped with 12 strain gauges. Each knee was moved under various loading conditions, and changes in tension along the cruciate ligaments were recorded simultaneously using the output of the strain gauges. Under varus torque, tension along the anterior cruciate ligament increased near full extension whereas that along the posterior cruciate ligament increased near 90 degrees of flexion. Similar results were obtained under valgus torque. Under internal rotatory torque, a pattern similar to that under varus torque was also observed. Under external rotatory torque, no remarkable changes in tension were observed along either cruciate ligament. Thus, we conclude that both the anterior cruciate ligament and the posterior cruciate ligament cooperate to control varus-valgus and internal rotatory instabilities of the knee, and that the constraining function is transferred from the anterior cruciate ligament to the posterior cruciate ligament as the knee joint is flexed.

Adult↗
PubMed2006

Influence of functional bracing on the kinetics of anterior cruciate ligament-injured knees during level walking.

BACKGROUND: Use of functional knee braces has been suggested to provide protection and to improve kinetic performance of the knee in anterior cruciate ligament-injured patients. However, the efficacy of knee bracing in achieving these goals is still controversial. The purpose of this study was to examine the immediate effects of functional bracing on the three-dimensional kinetics of the knee in individuals with anterior cruciate ligament injuries during level walking. METHODS: Fifteen anterior cruciate ligament-deficient and 15 anterior cruciate ligament-reconstructed subjects were each fitted with a DonJoy Goldpoint brace and walked at a self-selected pace, first without and then with the brace. Kinematic and kinetic data were measured and three-dimensional joint moments and angular impulses at the knee were calculated and compared between bracing conditions and between limbs. FINDINGS: Functional knee bracing did not significantly affect the kinetics of the unaffected knees for either group. Bracing significantly increased the peak abductor moments in anterior cruciate ligament-deficient knees and reduced the bilateral kinetic asymmetry in the coronal plane. For the anterior cruciate ligament-reconstructed group, bracing increased peak moments and impulses of the abductors and extensors. It also reduced bilateral kinetic asymmetry in the sagittal and coronal planes. INTERPRETATION: Effects of the knee brace were apparent in the coronal plane for both anterior cruciate ligament-deficient and anterior cruciate ligament-reconstructed patients, and in the sagittal plane for anterior cruciate ligament-reconstructed patients. Functional bracing can be recommended for anterior cruciate ligament-reconstructed patients to assist in achieving better bilateral kinetic symmetry during gait. For anterior cruciate ligament-deficient patients, apart from bracing, additional emphasis on the rehabilitative training for better kinetic knee performance in the sagittal plane is needed.

Adult↗
PubMed2006

Erratum to "The change in length of the medial and lateral collateral ligaments during in vivo knee flexion".

The collateral ligaments of the knee are important in maintaining knee stability. However, little data has been reported on the in vivo function of the collateral ligaments. The objective of this study was to investigate the change in length of different fiber bundles of the medial collateral ligament (MCL), deep fibers of the MCL (DMCL) and the lateral collateral ligament (LCL) during in vivo knee flexion. The knees of five healthy subjects were scanned using magnetic resonance imaging. These images were used to create three-dimensional models of the tibia and femur, including the insertions of the collateral ligaments. The MCL, DMCL, and LCL were each divided into three equal portions: an anterior bundle, a middle bundle and a posterior bundle. Next, the subjects were imaged from two orthogonal directions using fluoroscopy while performing a quasi-static lunge from 0 degrees to 90 degrees of flexion. The models and fluoroscopic images were then used to reproduce the in vivo motion of the knee. From these models, the length of each bundle of each ligament was measured as a function of flexion. The length of the anterior bundle of the MCL did not change significantly with flexion. The length of the posterior bundle of the MCL consistently decreased with flexion (p < 0.05). The change in length of the DMCL with flexion was similar to the trend observed for the MCL. The length of the anterior bundle of the LCL increased with flexion and the length of the posterior bundle decreased with flexion. These data indicate that the collateral ligaments do not elongate uniformly as the knee is flexed, with different bundles becoming taut and slack. These data may help to provide a better understanding of the in vivo function of the collateral ligaments and be used to improve surgical reconstructions of the collateral ligaments. Furthermore, the data suggest that the different roles of various portions of the collateral ligaments along the flexion path should be considered before releasing the collateral ligaments during knee arthroplasty.

Adult↗
PubMed2001

Involvement of bone morphogenic protein-2 (BMP-2) in the pathological ossification process of the spinal ligament.

OBJECTIVE: To investigate the function of bone morphogenic protein-2 (BMP-2) in the ossification of the spinal ligament (OSL). METHODS: Total RNA was prepared from the cultured spinal ligament cells from patients with OSL and analysed by reverse transcription-polymerase chain reaction using specific primers for BMP-2. BMP-2 mRNA expression in ligament tissues was examined by in situ hybridization. Spinal ligament cells from patients without OSL were treated with BMP-2 and examined for alkaline phosphatase activity. RESULTS: Expression of the BMP-2 gene was detected in cultured spinal ligament cells. In ligament tissues, BMP-2 mRNA was present in the chondrocyte-like cells in the fibrocartilage zone. Exogenous BMP-2 increased alkaline phosphatase activity in spinal ligament cells from patients without OSL. CONCLUSION: The BMP-2 gene is expressed in the spinal ligaments of OSL patients, and exogenous BMP-2 stimulates osteogenic differentiation of spinal ligament cells. The expression of BMP-2 in the spinal ligaments could be a clue in elucidating how heterotrophic osteogenesis develops in ligament tissue.

Aged↗
PubMed2002

In vitro characteristics of cultured posterior longitudinal ligament tissue.

STUDY DESIGN: To determine the osteogenicity of posterior longitudinal ligament ossification, the posterior longitudinal ligament obtained during anterior cervical surgery from patients with the disorder was analyzed with in vitro cultures. OBJECTIVES: To determine the osteogenicity of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: The osteogenicity of posterior longitudinal ligament ossification in North America requires better documentation. METHODS: The posterior longitudinal ligament obtained during anterior cervical corpectomy with fusion from seven patients, three with ossification of the posterior longitudinal ligament documented by magnetic resonance imaging and computed tomography and four with spondylosis, was blindly submitted for in vitro culture. Explants of the posterior longitudinal ligament were placed in Dulbecco modified Eagle medium with 10% fetal calf serum, antibiotics, 4 mmol/L x L-proline, and 50 mg/L ascorbic acid. After reaching confluency, cells were trypsinized, and first-passage cells were used for all osteocalcin measurements to establish their osteoblastic phenotype. Periosteal cells, previously shown to synthesize osteocalcin, were used as a positive control. The cells were incubated with 1,25(OH)2 vitamin D3 at 10E-8 M for 72 hours in serum-free medium. The supernatants were collected and frozen, after which the quantity of osteocalcin induced by exposure to 1,25(OH)2 vitamin D3 was determined using enzyme-linked immunoassay. Control replicate cultures were measured without incubation using vitamin D3. RESULTS: Ossification of the posterior longitudinal ligament cell lines responded positively with osteocalcin synthesis in the 0.1 to 0.4 ng/M range. The cell line of the patient with spondylosis alone did not respond to vitamin D3 priming. CONCLUSIONS: Posterior longitudinal ligament cells from the three North American white patients with ossification of the posterior longitudinal ligament, when cultured in vitro, synthesized osteocalcin on vitamin D3 priming, confirming their osteoblastic phenotype, whereas posterior longitudinal ligament cells from four white patients with isolated spondylosis did not.

Calcitriol↗
PubMed2004

The nuchal ligament restrains cervical spine flexion.

STUDY DESIGN: A biomechanical study using a cadaver model was conducted to define the function of the nuchal ligament in the restraint of flexion of the cervical spine. OBJECTIVE: To test the hypothesis that surgical resection of the nuchal ligament significantly reduces the structural restraints to cervical flexion. SUMMARY OF BACKGROUND DATA: Although previous studies have examined the role of the posterior ligaments and capsules on cervical stability, no prior study has quantified the biomechanical significance of the nuchal ligament. The clinical significance may include progressive loss of lordosis or even kyphosis after trauma or posterior surgical procedures such as laminectomy, laminoplasty, or tumor resection. METHODS: Cervical spines from the occiput to the first thoracic vertebra were harvested from 12 human cadavers. Specimens were tested under 3 conditions: all ligaments intact, after resection of the nuchal ligament, and then after additional resection of the supraspinous, interspinous, and yellow ligaments. Flexion moments were applied; load and displacement were measured. Changes in flexion range of motion and tangent stiffness between treatment conditions were statistically compared. RESULTS: The flexion range increased 28% after removing the nuchal ligament. After subsequent resections, the flexion range increased 52% compared with intact (P <0.005). Tangent stiffness decreased 27% after nuchal ligament resection; after all resections, stiffness was 35% lower than intact (P <0.05). CONCLUSION: Resection of the nuchal ligament increased the flexion range of motion and decreased stiffness in flexion. Injury to the nuchal ligament may increase the risk of cervical spine instability and malalignment.

Aged↗
PubMedDate not supplied

Radiographic and ultrasonographic evaluation of the patellar ligament following tibial plateau leveling osteotomy.

Objective evaluation of patellar ligament changes following tibial plateau leveling osteotomy (TPLO) for cranial cruciate ligament injury has not been published to date. In this study, the patellar ligament was evaluated using radiographs and high-resolution ultrasound in 31 stifles (29 dogs) preoperatively and at 1 month (n=31), 2 months (n=18), and 6 months (n=13) postTPLO. A ratio of the thickness of the proximal to distal patellar ligament was determined for all radiographs evaluated. Ultrasound evaluation included proximal, middle, and distal mid-sagittal thickness and transverse thickness, and transverse area measurements. Subjective grading (0 being normal through a scale of 3) of the ultrasound changes was also performed at each evaluation. Significant thickening of the distal patellar ligament was noted postoperatively as evidenced by thickness and area measurements and a decreased radiographic ratio (P < 0.01). Preoperative patellar ligament thickness and area were similar at the proximal, middle and distal sites. Ultrasound-derived thickness and area measurements of the distal patellar ligament were increased at 1 and 2 months (P < 0.01). The radiographic ratio was significantly decreased at 1, 2 and 6 months (P < 0.01). Subjectively, all patellar ligaments scored a 0 preoperatively and 16/31 received a score of 2 or 3 during follow-up evaluation. Additionally, these dogs had ultrasonographic and radiographic changes consistent with distal patellar ligament thickening. Body weight (kg) and postoperative TPLO angle had a significant influence on 1-month postoperative distal patellar ligament area using a stepwise logistic model (P < 0.05). Patellar ligament desmitis is a common postoperative sequela to the TPLO procedure, however its clinical significance (i.e., correlation with a residual lameness) was not evaluated in this study.

Animals↗
PubMedDate not supplied

Anatomic and biomechanical study of the lateral collateral and popliteofibular ligaments.

The position of the fibula around the proximal tibia varies in different people; it was therefore hypothesized that this variation would affect the orientation of the lateral collateral ligament and the popliteofibular ligament complex. This hypothesis was studied in 10 cadaveric knees by measuring the orientation and length changes in these structures as the knee was flexed. The data were correlated with tibiofibular joint position. The strength of the ligaments was also tested. There were significant correlations between fibular head position and ligament orientation with the knee extended. The lateral collateral ligament slackened significantly with knee flexion, whereas the popliteofibular ligament complex did not. The structures became significantly steeper in the sagittal plane as the knee was flexed. The lateral collateral ligament passed through vertical at 70 degrees of knee flexion and was thus poorly oriented to withstand tibial external rotation. The lateral collateral and popliteofibular ligaments had tensile strengths of 309 and 186 N, respectively. The popliteofibular ligament is dominant when the knee is flexed, because of the slackening of the lateral collateral ligament, and so it should always be reconstructed. The anatomic variation causes some knees to have better ligament orientations to withstand posterolateral tibial displacements and, conversely, other knees may be inherently more difficult to stabilize by reconstruction.

Aged↗
PubMed1996

Combined injuries of the anterior cruciate and medial collateral ligaments of the knee. Effect of treatment on stability and function of the joint.

We performed a retrospective study of sixty-six patients (forty-one male and twenty-five female) who had a combined injury of the anterior cruciate and medial collateral ligaments. Our purpose was to determine the prevalence of late valgus instability of the knee. The mean age of the patients was thirty-five years (range, sixteen to sixty-three years). The mean follow-up interval was forty-five months (range, twenty-one to 108 months). Twenty patients had been injured while snow-skiing; twenty-four, during other sports activities; seven, in a motor-vehicle accident; and the remaining fifteen, during activities of daily living. Eleven patients had reconstruction of the anterior cruciate ligament and repair of the medial collateral ligament, thirty-three had reconstruction of only the anterior cruciate ligament, and twenty-two were managed non-operatively. There was no evidence of valgus instability on clinical examination at the most recent follow-up visit. However, there was evidence of instability on stress roentgenograms of the knee in eight (13 per cent) of sixty patients. With the numbers available, we could detect no relationship between the presence of valgus instability and the method of treatment of the ligamentous tears ( p > 0.4). We also compared the results for twenty-one of the thirty-three patients who had a combined ligamentous injury and reconstruction of only the anterior cruciate ligament with those for thirty-seven patients who had reconstruction of an isolated tear of the anterior cruciate ligament. After a mean follow-up interval of thirty-five months (range, twenty-one to sixty-six months), there was no difference in the anterior displacement, impairment of function, level of participation in sports activities, results of the one-leg-hop for distance test, or strength as determined by testing on a Cybex machine. On the basis of the findings in this study, we believe that, when there is mild or moderate valgus instability, an injury of the medial collateral ligament does not need to be repaired when the anterior cruciate ligament is repaired after a combined ligamentous injury.

Adolescent↗
PubMed1994

MR diagnosis of tears of anterior cruciate ligament of the knee: importance of ancillary findings.

OBJECTIVE: Detection of tears of the anterior cruciate ligament with MR is usually based on the appearance of the ligament. However, other MR findings may be useful to establish the diagnosis. We assessed the utility of these ancillary MR findings for detecting tears and for differentiating partial from complete tears of the anterior cruciate ligament. MATERIALS AND METHODS: MR images of 68 patients who had arthroscopic correlation were retrospectively reviewed by two radiologists who did not know the arthroscopic findings. The reviewers noted the presence and location of bone bruises (nonlinear low signal in the bone marrow on T1-weighted images), assessed posterior displacement of the posterior horn of the lateral meniscus, and measured the posterior cruciate ligament angle. At arthroscopy, 39 patients had tears of the anterior cruciate ligament (24 complete, 15 partial) and 29 had intact anterior cruciate ligaments. RESULTS: The presence of bone bruising in the posterolateral tibial plateau had sensitivities of 50% and 46%, with corresponding specificities of 97% and 97% for the two reviewers. Posterior displacement of the posterior horn of the lateral meniscus had a sensitivity of 56% for both reviewers, with 100% and 97% specificities. An angle of the posterior cruciate ligament less than 105 degrees had sensitivities of 72% and 74%, with corresponding specificities of 79% and 86%. The prevalence of these findings was similar in patients with partial tears and those with complete tears. CONCLUSION: Ancillary MR imaging findings may be helpful for diagnosing tears of the anterior cruciate ligament when diagnosis based on the MR appearance of the ligament is equivocal. Ancillary findings cannot be used to differentiate patients with partial tears from those with complete tears. The presence of bone bruising in the posterior aspect of the tibial plateau and posterior displacement of the posterior horn of the lateral meniscus are highly specific for a torn anterior cruciate ligament; therefore, the presence of either of these findings should be considered strong evidence of a tear of the anterior cruciate ligament.

Adult↗
PubMed1991

New aspects of the morphology and function of the human hip joint ligaments.

The capsular ligaments of the human hip joint were submitted to exact morphological analysis, and they proved to be multiple and numerous. We have described various ligamentous systems and their interconnections, and have suggested new terminologies and systematics. The ligaments were subjected to functional analysis by means of measuring strips to determine the positions in which the ligaments are taut. The ligament systems were all found to serve a restrictive function, and various parts of the apparatus restricted all possible movements in the hip joint. Extension is restricted by the medial iliofemoral complex, abduction by the pubofemoral ligament, and adduction by the posterior coxal ligaments and by the superior ischiofemoral ligament. Flexion is restricted by the inferior ischiofemoral ligaments, inward rotation by the superior ischiofemoral ligament, and outward rotation by the lateral iliofemoral complex. Only the ligament of the femoral head is unable to exert a restricting function, despite reaching a state of tension in extreme adduction.

Femur Head↗
PubMed2004

The broad ligament: a review of its anatomy and development in different species and hormonal environments.

The broad ligament is a double fold of peritoneum forming a mesentery for the human female genital tract. We investigated the anatomy of the broad ligament in different species and its hormonal regulation to determine if it had a role in gonadal positioning. The medical and veterinary literature was reviewed for descriptions of broad ligament anatomy and development. In addition, four adult female rats were dissected to compare the macroscopic anatomy of the broad ligament with any homologous structures in the male (n = 2). Detailed review was made of human males with persistent Müllerian duct syndrome (PMDS) and of bovine freemartin calves to determine the effect of abnormal hormonal environments on broad ligament development. Human and veterinary texts show variable broad ligament development between species, most being consistent with the size and shape of the uterus and uterine tubes. The broad ligament in adult female rats is a simple peritoneal fold and is homologous with the mesentery of the testis and vas deferens in males. Patients with PMDS and bovine freemartins have a broad ligament with intermediate anatomy. In PMDS the broad ligament is elongated and narrow, and not attached to the pelvic wall. The broad ligament is the mesentery of the genital ducts, and its anatomy varies with the degree of Müllerian duct fusion. The absence of a human male homologue is unusual, as the genital mesentery persists in male rodents. Apparent lack of a male homologue in the human may relate to obliteration of the processus vaginalis. The variable development of the broad ligament in pathological conditions is consistent with a role for steroid hormones in its development.

Adult↗
PubMed2007

Three-dimensional analysis of the ligamentous attachments of the second through fifth carpometacarpal joints.

The purpose of this study is to clarify, measure, and show the anatomic locations and areas of specific ligamentous attachments and paths of the second through fifth carpometacarpal (CMC) joints on a three-dimensional (3D) surface model. Ten fresh-frozen cadaver wrists were used to dissect and identify the second through fifth CMC ligaments. Their ligamentous attachments and whole bone surfaces were digitized three-dimensionally and their areas calculated. The attachments of each ligament were represented in a model combining CT surfaces overlaid by a digitized 3D surface, and were also visually demonstrated with a specific color on 3D images of the bones. Nine dorsal and 11 palmar CMC ligaments and one CMC interosseous ligament were identified in the second through fifth CMC joints. An intra-articular ligament between the third metacarpal (MC), the fourth MC, capitate, and hamate was also identified. Five dorsal and five palmar intermetacarpal ligaments and three intermetacarpal interosseous ligaments were also identified in the second through fifth intermetacarpal joints. A previously undescribed palmar intermetacarpal ligament was located between the third, fourth, and fifth MC bases. The anatomic 3D attachment sites of the second through fifth CMC ligaments were visually depicted qualitatively, and their areas quantified. This 3D information will not only afford a better understanding of the anatomy and mechanics of the second through fifth CMC joints, but will also assist in the assessment of radiographic images and treatment of various injuries.

Aged↗
PubMed1988

Biomechanics of the craniocervical region: the alar and transverse ligaments.

In the treatment of spine fractures and fracture-dislocations, stability of the spine is one of the major objectives. In the craniocervical joint, the alar and transverse ligaments provide much of the stability of the healthy spine. Because the anatomy appears well described, the contribution of each of these structures so far has received little attention. The alar ligament restrains rotation of the upper cervical spine, whereas the transverse ligament restricts flexion as well as anterior displacement of the atlas. A lesion in one or both structures can produce damage to the neural structures and/or cause pain. To investigate the possible role of each of these ligaments, a mechanical and histologic study of the upper cervical spine was made. The bone-ligament-bone complex of the alar and transverse ligaments was subjected to uniaxial mechanical testing in seven specimens. The alar ligaments had an in vitro strength of 200 N, and the transverse ligaments had an in vitro strength of 350 N. Histologic analysis revealed a mainly collagenous nature of these ligaments. Clinical evidence (broken odontoid processes) suggests that the transverse ligament is strong enough to withstand physiologic loads. The alar ligament, on the other hand, due to its lower strength and its axial direction of loading, might be prone to injury and therefore require stabilization of the appropriate vertebra more often than normally is assumed.

Aged↗
PubMed1992

Tensile properties of the inferior glenohumeral ligament.

The tensile properties of the inferior glenohumeral ligament have been determined in 16 freshly frozen cadaver shoulders. The inferior glenohumeral ligament was divided into three anatomical regions: a superior band, an anterior axillary pouch, and a posterior axillary pouch. This yielded 48 bone-ligament-bone specimens, which were tested to failure in uniaxial tension. The superior band was consistently the thickest region, averaging 2.79 mm. The thickness of the inferior glenohumeral ligament decreased from antero-superiorly to postero-inferiorly. The resting length of all three anatomical regions was not statistically different. Total specimen strain to failure for all bone-ligament-bone specimens averaged 27%. Variations occurred between the three regions, with the anterior pouch specimens failing at a higher strain (34%) than those from the superior band (24%) or the posterior pouch (23%). Strain to failure for the ligament midsubstance (11%) was found to be significantly less than that for the entire specimen (27%). Thus, larger strain must occur near the insertion sites of the inferior glenohumeral ligament. Stress at failure was found to be nearly identical for the three regions of the ligament, averaging 5.5 MPa. These values are lower than those reported for other soft tissues, such as the anterior cruciate ligament and patellar tendon. The anterior pouch was found to be less stiff than the other two regions, perhaps suggesting that it is composed of more highly crimped collagen fibers. Three failure sites were seen for the inferior glenohumeral ligament: the glenoid insertion (40%), the ligament substance (35%), and the humeral insertion (25%). In addition, significant capsular stretching occurred before failure, regardless of the failure mode.

Aged↗