Safe extracapsular placement of proximal tibia transfixation pins

OBJECTIVE

To identify the anatomic detail of the knee joint capsular insertion site on the proximal tibia, specifically as it relates to transfixation pins.

DESIGN

Identification of capsular anatomy by anatomical dissection of cadaveric specimens, with radiography and arthroscopy of patients.

SETTING

Cadaveric dissection.

OUTCOME MEASURES

Anatomic observation of the capsular attachment site in relation to the tibial articular surface.

RESULTS

The capsule inserts four to fourteen millimeters below the articular surface in a regular pattern. The anterior half of the circumference is close to the joint line (less than six millimeters). Posteromedially and posterolaterally, there are extensions distally to fourteen millimeters, occasionally communicating with the tibiofibular joint.

CONCLUSION

Transfixing wires and half-pins can be placed in the proximal tibia without capsular penetration if kept more than fourteen millimeters from the subchondral line. If wire placement closer to the joint is required, wires should be placed in Zone 1 (the anterior half) and at least six millimeters from subchondral bone to avoid capsular penetration.

Hoffa's recess in the infrapatellar fat pad of the knee on MR imaging

The infrapatellar fat pad of Hoffa is a structure that is located in the space between the back side of the patellar ligament and the real capsule. It is routinely visualized on magnetic resonance (MR) images of the knee. The purpose of this study was to determine the prevalence and shape of a fluid-like indentation at the inferior posterior margin of the infrapatellar fat pad of the knee (recess) and to look for a relation between the liquid image in the fat pad and joint effusion. Three hundred and fifty consecutive MR imaging examinations of the knee were evaluated for the presence, location, size and shape of a recess in the infrapatellar fat pad and existence of joint effusion. The study population consisted of 145 females and 205 males aged between 5 and 80 years old (mean age 37.5 years). The recess in the infrapatellar fat pad was revealed on MR imaging in 54 of 350 knees (15.43%) and had a variable shape, consisting of 35 linear or ovoid (64.81%), five pipe-shaped (9.26%) and 14 globular (25.92%). Additionally, one ganglion cyst was observed in the infrapatellar fat pad. Globular and pipe-shaped recesses may be confused with cystic infrapatellar fat pad pathologies such as ganglion cyst, meniscal cyst, loose body or nodular synovitis. The existence of an infrapatellar fat pad may not be related to the presence of joint effusion.

Bi-directional mechanical properties of the axillary pouch of the glenohumeral capsule: implications for modeling and surgical repair

The objective of this study was to determine the mechanical properties of the axillary pouch of the inferior glenohumeral ligament in the directions perpendicular (transverse) and parallel (longitudinal) to the longitudinal axis of the anterior band of the inferior glenohumeral ligament. A punch was used to excise one transverse and one longitudinal tissue sample from the axillary pouch of each cadaveric shoulder (n = 10). Each tissue sample was preconditioned and then a load-to-failure test was performed. All tissue samples exhibited the typical nonlinear behavior reported for ligaments and tendons. Significant differences (p < 0.05) were detected between the transverse and longitudinal tissue samples for ultimate stress (0.8 +/- 0.4 MPa and 2.0 +/- 1.0 MPa, respectively) and tangent modulus (5.4 +/- 2.9 MPa and 14.8 +/- 13.1 MPa, respectively). No significant differences (p > 0.05) were observed between the ultimate strain (transverse: 23.5 +/- 11.5%, longitudinal: 33.3 +/- 23.6%) and strain energy density (transverse: 10.8 +/- 8.5 MPa, longitudinal: 21.1 +/- 15.4 MPa) of the transverse and longitudinal tissue samples. The ultimate stress determined for the longitudinal axillary pouch tissue samples was comparable to a previous study that reported it to be 5.5 +/- 2.0 MPa. The ratio of the longitudinal to transverse moduli (3.3 +/- 2.8) is considerably less than that of the medial collateral ligament of the knee (30) and interosseous ligament of the forearm (385), suggesting that the axillary pouch functions to stabilize the joint in more than just one direction. Future models of the glenohumeral joint and surgical repair procedures should consider the properties of the axillary pouch in its transverse and longitudinal directions to fully describe the behavior of the inferior glenohumeral ligament.

Etiology of the anterior ankle impingement syndrome: a descriptive anatomical study

BACKGROUND

In the anterior ankle impingement syndrome, recurrent traction to the anterior joint capsule is stated to be the cause of formation of talotibial osteophytes. This hypothesis involves the assumption that the osteophytes originate at the site where a capsular attachment is located. A soft tissue component that can get squeezed between the distal tibia and talus is thought to be responsible for impingement complaints during dorsiflexion movements.

METHODS

In eight ankle specimens, the width of the nonweightbearing tibial cartilage rim and the distance of the tibial and talar cartilage to the capsular attachment were measured. The relationship of the soft tissue components to the anterior joint was studied. The average tibial cartilage rim width was 2.4 mm (1.5-3.0 mm). Tibial and talar cartilage-capsule distances were 4.3 mm (0.5-9.0 mm) and 2.4 mm (1.8-3.3 mm), respectively. In all specimens, the anterior joint space contained a triangular soft tissue component, overlying the joint capsule. The component consisted of a synovial membrane and subsynovial located fat and collagen tissue. It was observed that in 15 degrees dorsiflexion the soft tissue component was squeezed between the tibia and talus.

CONCLUSIONS

The anterior ankle joint capsule attaches proximal to the site where the anterior talotibial spurs originate. The hypothesis of formation of talotibial spurs due to repetitive capsule traction therefore does not seem plausible. The anatomic findings do support the hypothesis that an anteriorly located soft tissue component is present that can give impingement symptoms.

The anatomy of the posterolateral aspect of the rabbit knee

The purpose of this study was to determine the anatomy of the posterolateral aspect of the rabbit knee to serve as a basis for future in vitro and in vivo posterolateral knee biomechanical and injury studies. Twelve nonpaired fresh-frozen New Zealand white rabbit knees were dissected to determine the anatomy of the posterolateral corner. The following main structures were consistently identified in the rabbit posterolateral knee: the gastrocnemius muscles, biceps femoris muscle, popliteus muscle and tendon, fibular collateral ligament, posterior capsule, ligament of Wrisberg, and posterior meniscotibial ligament. The fibular collateral ligament was within the joint capsule and attached to the femur at the lateral epicondyle and to the fibula at the midportion of the fibular head. The popliteus muscle attached to the medial edge of the posterior tibia and ascended proximally to give rise to the popliteus tendon, which inserted on the proximal aspect of the popliteal sulcus just anterior to the fibular collateral ligament. The biceps femoris had no attachment to the fibula and attached to the anterior compartment fascia of the leg. This study increased our understanding of these structures and their relationships to comparative anatomy in the human knee. This knowledge of the rabbit's posterolateral knee anatomy is important to understand for biomechanical and surgical studies which utilize the rabbit knee as a model for human posterolateral knee injuries.

Anatomy and biomechanics of the acromioclavicular and sternoclavicular joints

The acromioclavicular and sternoclavicular joints have important soft-tissue static constraints that, based on biomechanical studies, imply a great deal of stability. The infrequency of significant symptoms following dislocations of these joints certainly highlights the fact that the dynamic muscle support is also very important. In performing resections of these joints for degenerative disease, our goal should be to preserve these important ligamentous supports by minimizing the amount of bone excised, as this seems to optimize results [84]. Precise isometric reconstruction of these complex, three-dimensional ligamentous structures merits further investigation in the laboratory and clinical settings.

Spatial distribution of hip capsule structural and material properties

Contemporary computational models potentially allow the practical incorporation of the effects of a joint capsule on both motion and the loads transmitted to the other parts of the joint. However, the required material properties have not been available for this purpose. To determine these properties we took both hip joints from five fresh-frozen, nondiseased cadavers. Following dissection and potting of the hemi-pelvis, distraction of the intact joint was conducted to measure the structural tangent stiffness of the joint capsule. Anatomical insertion points of the hip capsule were then recorded, and a complete capsulectomy was performed. Once excised, the capsule was sectioned into eight, approximately even sectors, and initial geometrical measurements were recorded for material property calculations. Material properties (i.e., structural tangent stiffness, failure load, ultimate strength, tangent modulus) were calculated using the load-displacement and geometric data collected for each of the sectors. This specimen-to-specimen thickness variability reveals significantly lower (p<0.01) average tangent structural stiffness values in the posterior-inferior portion of the capsule. Explorations of hip stability using numerical models can now be enhanced by incorporation of these experimental capsule data.

Disk position and the bilaminar zone of the temporomandibular joint in asymptomatic young individuals by magnetic resonance imaging

OBJECTIVE

The purpose was to study the disk position of the temporomandibular joint (TMJ) in young individuals without any clinical signs or symptoms or history of internal derangement or degenerative joint disease and to study the features of the bilaminar zone of the TMJ in sagittal magnetic resonance (MR) images and the behavior of the bilaminar zone during jaw opening.

STUDY DESIGN

MR imaging examinations of 80 TMJs of 40 symptom-free healthy subjects (20 women and 20 men) with a mean age of 26.9 years formed the basis of this study.

RESULTS

In 33 of the 40 symptom-free subjects (82.5%), there was a normal relationship between disk and condyle at occlusion, whereas 5 individuals had unilateral disk displacement and 2 had bilateral disk displacement. The superior part of the bilaminar zone could be identified in all of the 40 symptom-free subjects. The inferior band of the bilaminar zone was identified bilaterally in 57.5% of individuals and unilaterally in 20%. In 9 subjects, the inferior band of the bilaminar zone could not be identified in any of the TMJs.

CONCLUSIONS

Disk displacement of the TMJ occurred in approximately 20% of the young individuals in this sample. The use of both sagittal and oblique coronal MR images is of importance for classification of the position of the disk in that the oblique coronal imaging plane rendered significant complementary information to that of the sagittal images. The identification of both the superior and the posterior band of the bilaminar zone must be considered new information. The superior band remained consistently in contact with the fossa at the open-mouth position.

The immature athlete

The skeletally immature athlete poses unique problems in diagnosis and treatment of injuries to the extensor mechanism of the knee. An accurate and detailed history and physical examination of the knee are essential for making a specific diagnosis and formulating an appropriate treatment plan. This article presents an overview of acute and chronic injuries of the extensor mechanism of the knee that are unique to skeletally immature athletes. The subjects of femoral trochlear dysplasia and medial subluxation of the patella are briefly discussed. The etiopathology, clinical evaluation, and management (non-operative and operative) of sleeve fractures of the patella and avulsion fractures of the tibial tubercle in children and adolescents are discussed. The pathoanatomy, clinical features, and management of synovial plica syndrome, Hoffa's syndrome, Osgood-Schlatter disease, and Sinding-Larsen-Johansson disease are presented.

Clinical anatomy of the fibrous capsule of human lumbar facet joint

OBJECTIVE

To describe the anatomical and histological characteristics of the fibrous capsule of human lumbar facet joints.

METHODS

Specimens of the facet joint capsules were obtained from 5 embalmed cadavers for macroscopic investigation, and microscopic observation of L5 facet joint capsules obtained from 2 fresh cadavers was performed after the specimens were stained by way of resorzinoroseine-van Gieson method.

RESULTS

The outer layer of the fibrous capsule was constituted by dense regular connective tissue that was in turn composed of parallel bundles of collagenous fibers. In the superior part of the joint capsules, the fibers were arranged in the direction different from that taken by the fibers in the inferior part. In the middle layer of the joint capsules, large quantities of elastic fibers were identified in the roots of the capsule.

CONCLUSIONS

The anatomical and histological complexities adapt the lumbar facet joint to better withstand loads from various directions. Immoderate rotatory manipulations may result in capsule injuries, which may aggravate low back pain in some cases.

Morphometrical study of the joint surface and capsule of the lumbar zygapophysial joint with special reference to their laterality

Using 26 osteoligamentous lumbar vertebral columns (260 facets), we morphometrically investigated the cartilagenous joint surface, inner capsular surface and capsular thickness. We also examined whether the subcapsular pocket was present and, if present, how far it extended along the joint margin. The proportion of the inner capsular area in the total joint surface area in a facet (the capsular-joint surface ratio) was hypothesized to correspond to the potential looseness (or tightness) of the facet. The absolute data themselves seemed to be useful for better understanding of the joint morphology. However, further evaluations of the differences between segments, left/right differences, individual segmental fluctuation patterns and correlations between parameters provided a novel classification of specimens according to the hypothetical progress of joint degeneration. Criteria for the classification existed in 1) the laterality in parameters defined as more than 100% larger or smaller than the contralateral facet and 2) the drastic segmental difference in parameters over 50% larger or smaller than the adjacent segment. Consequently, three types were identified: 1) outside of the criteria in both area and thickness (-/- type, 9 of 26); 2) the criteria did not fit the area parameters but did fit the thickness parameters (-/+ type, 8); the criteria were filled in both categories of parameters (+/+ type, 9). Notably, in the +/+ types, the capsular thickness and capsular-joint surface ratio correlated significantly (p < 0.01), i.e., the hypothetical loose joint had a thick capsule. We speculated that early joint degeneration starts from the -/- type and advances via the -/+ type to the +/+ type. Considerating these results, we recommended using MR imaging for detailed identification of laterality in the capsular thickness for low-back pain patients to discriminate candidates for future severe degenerative changes of the articular cartilage in the lumbar spine.

Developmental morphological and histological studies on structures of the human fetal shoulder joint

In the present work, morphological changes in the interior structures of the developing human shoulder joint were studied at different prenatal ages (9, 12, 16, 23 and 40 weeks) and were compared with the same structures in the adult joint. It was found that the shoulder joint had gone through important developmental changes during the 12th week of the prenatal life and it is assumed that genetic factors operative during this stage of development were more important than mechanical factors. A subsequent development of the intracapsular glenohumeral ligaments was present at the 16th week. The glenoid labrum, the biceps tendon and the three glenohumeral ligaments formed a complete ring around the glenoid fossa which constituted a functional unit, which seemed to have a role in stabilizing the joint. In the present work, histological prenatal studies were done on sagittal and radial sections from the glenoid fossa and its associated structures and the results were compared with the same structures in adults. At a crown-rump length of 30 mm (9 weeks), intermingling of the collagen fibres of the superior labrum and the biceps tendon was observed and the superior labrum could be considered as an extension of the biceps tendon. While the superior and inferior parts of the labrum appeared fibrous, the posterior labrum appeared as a primitive cellular condensation. At the 12th week, it became a fibrocellular structure and changed to a fibrocartilaginous structure at the 16th week. But until full term, no definitive fibrocartilage was found due to its hypercellularity compared to the adult. It was found that at all ages, the capsule was formed of cellular and fibrous elements, its collagenous content was progressively increased with age and at full term, it became generally fibrous but was still different compared to adults. In all stages of development, the synovial tissue of different regions of the same joint exhibited marked variations in thickness, vascularity, cellular density and collagenous content. It lined the capsule, surrounded the biceps tendon and reflected on the labrum. Its cell density as well as their vascular and collagenous contents were progressively increased with age. At full term, the synovial tissue was thickest at its inferior reflection and forming large folds. The synovial tissue lining the capsule was thinner than the synovial tissue at its reflection from the labrum, many villi and processes arising from it and projecting into the joint cavity.

Contribution of acetabular labrum to articulating surface area and femoral head coverage in adult hip joints: an anatomic study in cadavera

The purpose of our study was to describe the gross anatomy of the adult acetabular labrum and to determine its contribution to the depth, surface area, and volume of the acetabulum. Fifty-five embalmed hips were studied. Each hip was disarticulated, and standardized measurements were taken. Calculations of the acetabular articulating surface area and volume, with and without the labrum, were performed based on these measurements. Average width of the acetabular labrum was 5.3 mm (SD, 2.6 mm). The labrum was wider anteriorly and superiorly than posteriorly. The surface area of the acetabulum without the labrum was 28.8 cm2; with the labrum, it was 36.8 cm2 (P < .0001). The volume of the acetabulum without the labrum was 31.5 cm3; with the labrum, it was 41.1 cm3 (P < .0001). There was no side-to-side difference in contribution of the labrum to either surface area or volume between right and left hips. Comparison of these indices for males and females showed statistically significant differences in absolute but not relative increases.

Capsular attachment to the distal radius for extracapsular placement of pins

The aim of this study was to evaluate the anatomy of the wrist joint capsule on the distal radius. As such the extent of the joint capsule and the limits of attachment in relation to the articular surface were determined. Furthermore, the study also determined whether there was any reflection of the capsule onto the distal radius. Fifty cadaveric specimens, preserved according to Thiel's method, were assessed. After careful dissection the distance between the chondral line of the carpal articular surface and three defined points on each of the palmar and dorsal aspects of the radius were measured. In none of the specimens was there any variation in the course and extent of the joint capsule. Using external fixators for managing fractures of the distal radius, pins and wires can be placed subchondrally close to the articular capsule. The risk of intraarticular infection, due to pin tract infection in intraarticularly positioned pins, is very low.

An immunohistochemical study of the dorsal capsule of the lumbar and thoracic facet joints

STUDY DESIGN

The molecular composition of the extracellular matrix in the dorsal capsules of lumbar and thoracic facet joints was analyzed immunohistochemically.

OBJECTIVES

To determine whether the immunohistochemical profile of the lumbar joint capsule suggests a role of the capsule in limiting axial rotation of the lumbar motion segment.

SUMMARY OF BACKGROUND DATA

During axial rotation of the lumbar vertebrae, the axis of rotation shifts toward the facet joints in the direction of rotation. Thus, the capsule of the opposing joint should become tensed and wrap around the inferior articular process. Previous studies suggest that wrap-around ligaments are fibrocartilaginous. However, thoracic joint capsules are largely shielded from such loading and should be purely fibrous.

METHODS

Dorsal capsules were removed from lumbar and thoracic facet joints of six adult cadavers. Specimens were immunolabeled with monoclonal antibodies for collagens, chondroitin, dermatan and keratan sulfates, versican, tenascin, aggrecan and link protein. Antibody binding was detected using the Vectastain ABC 'Elite' peroxidase kit (Vector Laboratories, Inc., Burlingame, CA).

RESULTS

Both lumbar and thoracic joint capsules immunolabelled for most glycosaminoglycans and for Type I, III and VI collagens. However, labeling for Type II collagen, chondroitin-6-sulfate, aggrecan, and link protein was restricted to lumbar capsules. Such labeling was constantly seen at entheses and occasionally in the midsubstance.

CONCLUSIONS

The molecular composition of the lumbar joint capsule suggests that it acts as a fibrocartilaginous, 'wrap-around' ligament that withstands compression in addition to tension during torsional movements of the lumbar spine. It wraps around the inferior articular process as rotation occurs and limits further movement.

Variation of heads of lateral pterygoid muscle and morphology of articular disc of human temporomandibular joint--anatomical and histological analysis

To grasp the documented evidences available regarding the cause of the anteriorly displaced human temporomandibular joint (TMJ) disc. With 20 specimens of human TMJ from cadavers, at first the number of heads of lateral pterygoid muscle (LPM) bundles were analysed with macroanatomical method. Secondary histological procedure with haematoxyline and eosine staining and orceine staining were carried out for the same specimens. Macroscopically, in 13 specimens an upper and a lower head of the LPM were present. In the other seven specimens, not only an upper and a lower head, but also a third inner head of the LPM covered with a separate fascia was observed. Histochemically, the specific localization of certain bundles of thick elastic fibres in the antero-medial parts of the anteriorly displaced deformed TMJ disc were observed.

Topography of corpuscular mechanoreceptors in the shoulder joint region of monodelphis domestica

The topography and structure of corpuscular mechanoreceptors in the shoulder joint capsule and periarticular connective tissue of a small laboratory marsupial (monodelphis domestica) were studied using light and electron microscopy. This animal is known to use its upper extremities for a wide range of activities like climbing and manipulating food. Thus, the shoulder joint of this animal species has a similar wide range of movement as the human shoulder joint, but is small enough for serial sectioning in its entirety. Silver stained serial paraffin sections were examined under the light microscope and the distribution of the different types of mechanoreceptors was reconstructed using three-dimensional image processing. In addition, selected mechanoreceptors were studied electron microscopically. Approximately 100 small lamellated corpuscles were found in the dense connective tissue of the joint capsule close to the insertion on the scapula and in the thickening of the joint capsule close to the glenoid labrum. Ruffini corpuscles were found in much smaller numbers in the moderately dense connective tissue of the axillary region. Only very few Vater-Pacinian corpuscles were seen in the soft periarticular connective tissue. The large number and localization of mechanoreceptor corpuscles in the shoulder joint capsule especially close to the glenoid labrum suggests, that these specialized nerve endings are likely to play an important role in control of joint movement. They can induce protective reflexes during extreme movements in the shoulder joint preventing shoulder luxation by increasing the tone of muscles pressing the humerus head into the glenoid cavity.

In vitro loading of human synovial membrane with 5-hydroxydopamine: evidence for dense core secretory granules in type B cells

Ultrastructural studies of the synovial membrane were performed on tissue samples obtained from the human lumbar facet joint. Ultrastructural changes in synoviocytes were studied after loading synovial samples with 5-hydroxydopamine (5-OHDA) in an oxygenated Krebs' solution, prior to fixation. Synoviocytes were set loosely in the intimal matrix and classified into type A (phagocytic) and type B (secretory) cells. In general, type A cells populated the surface of the synovial lining, whereas type B cells were located deeper in the tissue, extending a process into the synovial fluid. Type B cells in control samples contained sparse secretory granules. Free nerve endings were not found in the synovial intima. In response to incubation in 5-OHDA, a precursor of biogenic monoamines, synoviocytes clustered and established contact. The ultrastructure of type B cells in the loaded group clearly differed from controls. They possessed typical membrane-bound vesicles, containing an electron dense interior surrounded by a lucent space. The size of these dense core vesicles ranged from 100 to 260 nm (on average 180 nm). They were in relation to microtubules and located preferentially in the marginal area of the cytoplasm, close to the Golgi complex. The ultrastructure of type A cells was not significantly altered. The present observations provide morphological evidence for the amine-handling properties of type B cells, indicating that they might be added to the list of 'APUD' cells of the diffuse neuroendocrine system. A recepto-secretory function for type B cells is discussed.

Glenohumeral mechanics: a study of articular geometry, contact, and kinematics

Stereophotogrammetry was used to investigate the functional relations between the articular surface geometry, contact patterns, and kinematics of the glenohumeral joint. Nine normal shoulder specimens were elevated in the scapular plane by using simulated muscle forces in neutral rotation (NR) and starting rotation (SR). Motion was quantified by analyzing the translations of the geometric centers of the humeral head cartilage and bone surfaces relative to the glenoid surface. In both NR and SR, the ranges of translations of the center of the humeral head cartilage surface were greatest in the inferior-superior direction (NR 2.0 +/- 0.7 mm, SR 2.9 +/- 1.2 mm). Results of this study also show that joints with less congruence of the articular surfaces exhibit larger translations, and elevation in SR yields greater translations than in NR. Kinematic analyses with the humeral head bone surface data yielded larger values of translation than analyses that used the cartilage surface data, suggesting that similar overestimations may occur in radiographic motion studies. Results of this study demonstrate that small translations of the humeral head center occurred in both SR and NR. The proximity of the origin of the helical axes to the geometric center of the humeral head articular surface confirmed that glenohumeral elevation is mainly rotation about this geometric center with small translations.

The microanatomy of the rhesus monkey temporomandibular joint

PURPOSE

The objective of this study was to describe and compare the histology of the rhesus monkey temporomandibular joint (TMJ) with that of the human joint.

MATERIALS AND METHODS

Seventeen rhesus monkeys (Macaca mulatta) with an age range from 4 to 11 years were used. Both TMJs of the first animal and the left TMJs of the remaining 16 animals were used for this study. The joint specimens were sectioned sagittally and processed for light and electron microscopic studies.

RESULTS

The rhesus monkey TMJ consists of the condylar, glenoid fossa, and articular disc components. The histology of these components is described at the light and electron microscopic level.

CONCLUSIONS

The monkey TMJ was found to be anatomically similar to the human joint. It was concluded that the rhesus monkey is one of the most suitable animal models for studies involving the TMJ.

Geometric and mechanical properties of human cervical spine ligaments

This study characterized the geometry and mechanical properties of the cervical ligaments from C2-T1 levels. The lengths and cross-sectional areas of the anterior longitudinal ligament, posterior longitudinal ligament, joint capsules, ligamentum flavum, and interspinous ligament were determined from eight human cadavers using cryomicrotomy images. The geometry was defined based on spinal anatomy and its potential use in complex mathematical models. The biomechanical force-deflection, stiffness, energy, stress, and strain data were obtained from 25 cadavers using in situ axial tensile tests. Data were grouped into middle (C2-C5) and lower (C5-T1) cervical levels. Both the geometric length and area of cross section, and the biomechanical properties including the stiffness, stress, strain, energy, and Young's modulus, were presented for each of the five ligaments. In both groups, joint capsules and ligamentum flavum exhibited the highest cross-sectional area (p < 0.005), while the longitudinal ligaments had the highest length measurements. Although not reaching statistical significance, for all ligaments, cross-sectional areas were higher in the C5-T1 than in the C2-C5 group; and lengths were higher in the C2-C5 than in the C5-T1 group with the exception of the flavum (Table 1 in the main text). Force-deflection characteristics (plots) are provided for all ligaments in both groups. Failure strains were higher for the ligaments of the posterior (interspinous ligament, joint capsules, and ligamentum flavum) than the anterior complex (anterior and posterior longitudinal ligaments) in both groups. In contrast, the failure stress and Young's modulus were higher for the anterior and posterior longitudinal ligaments compared to the ligaments of the posterior complex in the two groups. However, similar tendencies in the structural responses (stiffness, energy) were not found in both groups. Researchers attempting to incorporate these data into stress-analysis models can choose the specific parameter(s) based on the complexity of the model used to study the biomechanical behavior of the human cervical spine.