The spinal column is separated into the 7 cervical vertebra, the 12 thoracic vertebra, the 5 lumbar vertebra, the 5 sacral vertebra and the 4 coccygeal vertebra. The cervical, thoracic and lumbar vertebra are named as the movable vertebra and the sacral and coccygeal vertebra are named as the fixed vertebra. The lumbar spine includes five large vertebra situated between the rela-tively immobile rib cage and the pelvis. A typical lumbar vertebra has 2 main structures which are vertebral body and vertebral arch. The vertebral body is the anterior portion of a vertebra and the vertebral arch is the posterior portion of it and surrounds the vertebral foramen. In contrast to thoracic vertebra, lumbar vertebra has a wide disc space, sagittally oriented facets, and suf-ficient space between its lamina to permit a considerable range of motion. This report will explains some important normal anatomic features of the lumbar spine and sacrum including with their musclatures and neurovascular structures.
Pelvis ; Physiology* ; Range of Motion, Articular ; Ribs ; Sacrum ; Spine*

OBJECTIVETo explore the six degrees of freedom of jaw opening and closing movement with motion capture and analysis system to establish a quantitative method for studying mandibular movement and a digital basis for virtual reality study of mandibular movement.

METHODSIn a male adult with normal dentition without temporomandibular joint disorders, 3 fluorescent markers were pasted in the upper dentition and 4 in the lower dentition. Six cameras of the motion capture system were arranged in a semi-circular fashion. The subject sat in front of the camera at an 80-cm distance with the Frankfort plane kept parallel to the horizontal plane. The degree-of-freedom (3 linear displacement and 3 angular displacement) of jaw opening and closing movement was obtained by collecting the marker motion.

RESULTSSix degrees of freedom of jaw opening and closing were obtained using the motion capture system. The maximum linear displacements of X, Y and Z axes were 5.888 089 cm, 0.782 269 cm, and 0.138 931 cm, and the minimum linear displacements were -3.649 83 cm, -35.961 2 cm, -5.818 63 cm, respectively. The maximum angular displacements of X, Y and Z axes were 0.760 088°, 2.803 753°, and 0.786 493°, with the minimum angular displacements of -2.526 18°, -0.625 94°, and -25.429 8°, respectively. Variations of linear displacements during jaw opening and closing occurred mainly in the Y axis, and those of angular displacement occurred mainly in the Z axis.

CONCLUSIONThe six degree-of-freedom of mandibular movement can be accurately obtained with the motion capture system to allow quantitative examination of the mandibular movement.

Adult ; Humans ; Male ; Mandible ; physiology ; Movement ; physiology ; Range of Motion, Articular ; Temporomandibular Joint ; physiology ; Video Recording

BACKGROUNDWe investigated the impact of eliminating the impingement between extensor mechanism and tibial insert on patellar tracking and patellar ligament tension in high knee flexion.

METHODSSix cadaveric specimens were tested on an Oxford-type testing rig. The Genesis II knee system was implanted into each specimen knee with the traditional tibial insert and high-flex insert successively. Compared to traditional insert, the high-flex insert was characterized with a chambered anterior post and a chambered anterior lip which eliminates patella-post and patellar ligament-anterior lip impingements. The patella was tracked with an NDI Optotrak Certus system. The patellar ligament tension was measured using a NKB S-type tension transducer.

RESULTSThere was a decrease of resultant patellar translation relative to the femur with statistically significant (P<0.05) at 90 degrees to 150 degrees of knee flexion and a decrease of patellar ligament tension with statistical significance (P<0.05) at 100 degrees, 120 degrees, 130 degrees, and 140 degrees of flexion using high-flex insert compared to traditional insert.

CONCLUSIONSEliminating the impingement between extensor mechanism and implant in high knee flexion altered patellar tracking and reduced patellar ligament tension, which would facilitate high knee flexion.

Biomechanical Phenomena ; Humans ; In Vitro Techniques ; Knee Joint ; physiology ; Ligaments, Articular ; physiology ; Patellar Ligament ; physiology ; Range of Motion, Articular ; physiology

The mechanical model of knee is a system of constructional elements with specific restrains and material properties, which are deduced from the components of knee based on their functions and junctions. Kinematics and kinetics of knee can be calculated from the mechanical model. A review of some mechanical models of knee are shown in this paper.
Biomechanical Phenomena ; Computer Simulation ; Humans ; Knee Joint ; physiology ; Models, Biological ; Range of Motion, Articular ; physiology ; Stress, Mechanical

OBJECTIVETo observe the tested results of the segmental range of motion (ROM) of lumbar spine by charge couple device (CCD)-based system for 3-dimensional real-time positioning (CCD system), and to analyze its clinical significance.

METHODSSeven patients with lumbar joint dysfunction and 8 healthy subjects were tested twice by the CCD-based system with an interval of 10 min.

RESULTSThe ROM of the patients was obviously lesser than that of the healthy subjects. The measuring data of segmental ROM of lumbar spine by CCD system is correlated significantly to the same data checked later on the same subjects in every direction of the movements. The differences between two checks are usually less than 1 degree.

CONCLUSIONSpecially designed CCD based system for 3-dimensional real-time positioning could objectively reflect the segmental ROM of lumbar spine. The system would be of great clinical significance in the assessment of the biomechanical dysfunction of lumbar spine and the effect of the treatment applied.

Computer Systems ; Humans ; Lumbar Vertebrae ; physiology ; Orthopedic Equipment ; Range of Motion, Articular ; physiology

The motions of humeral external rotation with and without the anterior band of inferior glenohumeral ligament complex (AB-IGHL) were simulated. As a result of comparison, the contact pressure and contact force are all higher when the AB-IGHL was included in the model. Therefore, it is theoretically proved that the AB-IGHL constrains the motion of humerus during humeral external rotation. The predicted values for von Mises and the maximum tense force in the AB-IGHL were 4.433 MPa and 37.32 N respectively, occurring on the humeral side of the ligament. This approach to evaluating the function of AB-IGHL would provide greater insight into the mechanical contribution of AB-IGHL to joint function, identify the mechanism of a hurt to AB-IGHL, and provide a quantitative means for developing low-risk rehabilitation protocols.
Finite Element Analysis ; Humans ; Ligaments, Articular ; physiology ; Range of Motion, Articular ; Rotation ; Shoulder Joint ; anatomy & histology ; physiology ; Tensile Strength

In order to provide data for clinical approach to Hand-functional rehabilitation, we conducted this study on the relationships among flexor tendon load, tendon excursion and finger joint angle. Using the dynamic biomechanical test, three-dimension motion image analysis and computer analysis, we investigated eight intact normal male cadavers, hand mechanics of flexor tendon load, tendon excursion and joint angle. The results showed that, at the time when the top of finger touched the palm, the mean tendon load of flexor digitorum profundus(FDP) tendon was 7.9 N, the mean tendon excursion 43.4 mm, the mean total range of motion 237.0 degree. When the top of finger touched the palm, the mean tendon load of flexor digitorum superficial(FDS) tendon was 8.9 N, the mean tendon excursion 38.5 mm, and the mean total range of motion 206.3 degree. These findings demonstrated that there are some curvilinear relationships between flexor tendon load, tendon excursion and finger joint motion. When we flex our fists, the proximal interphalangeal(PIP) joint plays an important role in both FDP and FDS tendon.
Biomechanical Phenomena ; Cadaver ; Finger Joint ; physiology ; Fingers ; physiology ; Humans ; Male ; Muscle Contraction ; Muscle, Skeletal ; physiology ; Range of Motion, Articular ; Tendons ; physiology

In order to discuss the evaluation method of human upper limb movements, the patterns of movement coordination during healthy people prehension have been researched. Eight subjects were asked to perform different reaching-grasping and drinking water from the cup tasks with different indices of difficulty, and the arm movement trajectories and the main muscles group electromyography (EMG) data were collected. To explore the prehension control mechanism, a comparison has been made between the solution of the theoretic calculation and the experimental data. The results show that the topological invariance was observed in the trajectories of different task performance, and the linear relationships between joints covariation were exhibited. Moreover, the different muscles were controlled and combined into units of synergistic muscular group necessary to reach and grasp the goal.
Adult ; Electromyography ; Hand ; physiology ; Hand Strength ; physiology ; Humans ; Male ; Models, Biological ; Range of Motion, Articular ; physiology ; Upper Extremity ; physiology

It is the functional connectivity between motor cortex and muscle that directly relates to the rehabilitation of the dysfunction in upper limbs and neuromuscular activity status, which can be detected by electroencephalogram-electromyography (EEG-EMG) coherence analysis. In this study, based on coherence analysis method, we process the acquisition signals which consist of 9 channel EEG signal from motor cortex and 4 channel EMG signal from forearm, by using 4 groups of hand motions in the healthy subjects, including flexor digitorum, extensor digitorum, wrist flexion, and wrist extension. The results showed that in the β-band, the coherence coefficients between C3 and flexor digitorum (FD) was greater than extensor digitorum (ED) in the right hand flexor digitorum movement; the coherence coefficients between C3 and ED was greater than FD in the right hand extensor digitorum movement; the coherence coefficients between C3 and flexor carpi ulnaris (FCU) was greater than extensor carpi radialis (ECR) in the right hand wrist flexion movement; the coherence coefficients between C3 and ECR was greater than FCU in the right hand wrist extension movement. This analysis provides experimental basis to explore the information decoding of hand motion based on corticomuscular coherence (CMC).
Electroencephalography ; Electromyography ; Healthy Volunteers ; Humans ; Motor Cortex ; physiology ; Movement ; Muscle, Skeletal ; physiology ; Range of Motion, Articular ; Wrist ; physiology ; Wrist Joint ; physiology

With an un-calibrated camera a new method is proposed in this paper to measure dynamically the bending angle of knee-joint based on cross ratio invariability. Firstly, by video image processing technique, we detected 25 circular objectives distributed in the aided measurement tool and determined their geometric centers in the video frame respectively. Then we further computed the extending direction of thigh and shank by detecting position of two rectangular targets tied on them. Finally, using of the principle of cross ratio invariability in Projection Geometry, we could realize real-time dynamic measurement of the bending angle of knee-joint based on the method. Experiments have proved that the measurement precision of the introduced approach could satisfy basic requirements of clinical applications.
Algorithms ; Biomechanical Phenomena ; Humans ; Knee Joint ; anatomy & histology ; physiology ; Movement ; physiology ; Posture ; physiology ; Range of Motion, Articular ; physiology ; Video Recording