Mitsuhiro Aoki

Ligament strain on the iliofemoral, pubofemoral, and ischiofemoral ligaments in cadaver specimens: Biomechanical measurement and anatomical observation

The iliofemoral, pubofemoral, and ischiofemoral ligaments are major structures that stabilize the hip joint. We have sought evidence on which to base more effective hip stretching positions. The purpose of this study was to measure strains on these ligaments and to observe them. Eight fresh/frozen translumbar cadaver specimens were used. Clinically available stretching positions for these ligaments were adopted. Strain on each ligament was measured by a displacement sensor during passive torque to the hip joint. Hip motion was measured using an electromagnetic tracking device. The strained ligaments were captured on clear photographs. Significantly, high strains were imposed on the superior iliofemoral ligament by external rotation of the hip (3.48%); on the inferior iliofemoral ligament by maximal extension and 10° or 20° of external rotation with maximal extension (1.86%, 1.46%, 1.25%); on the pubofemoral ligament by maximal abduction and 10°, 20°, or 30° of external rotation with maximal abduction (3.18%, 3.28%, 3.11%, 2.99%); and on the ischiofemoral ligament by 10° or 20° of abduction with maximal internal rotation (7.11%, 7.83%). Fiber direction in each ligament was clearly identified. Significantly, high strains on hip ligaments corresponded with the anatomical direction of the ligament fibers. Positions were identified for each ligament that imposed maximal increase in strain on it. Clin. Anat. 27:1068–1075, 2014.

Effect of simultaneous stretching of the wrist and finger extensors for lateral epicondylitis: a gross anatomical study of the tendinous origins of the extensor carpi radialis brevis and extensor digitorum communis

BackgroundPulling the wrist into flexion with the elbow in extension and forearm in pronation has been used as the stretching technique of wrist extensors for lateral epicondylitis. Simultaneous stretching of the fingers in addition to the wrist flexion has also been applied. However, the mechanism of this simultaneous stretching has not been clarified. This study is designed to clarify the mechanism underlying this simultaneous stretching technique based on the anatomical features of the origins of the extensor carpi radialis brevis (ECRB) and extensor digitorum communis (EDC).MethodsThirty-nine arms from formalin-embalmed Japanese human specimens were dissected. The features of the origins of the ECRB and EDC were macroscopically observed, and the locations of each origin on the lateral epicondyle were measured.ResultsThe ECRB had a long and wide, purely tendinous origin which originated from the anterior slope of the lateral epicondyle. The tendinous origin of the index finger of the EDC (EDC-IF) arose from the posterior aspect of the ECRB tendinous origin, with a coexisting muscular portion observed at the level of the proximal forearm. The middle finger of the EDC (EDC-MF) had a short tendinous origin with an associated muscular portion and originated proximo-laterally to the origin of the ECRB on the lateral epicondyle. In addition, the muscular origin of the EDC-MF arose on the superficial and posterior aspect of the ECRB tendinous origin. In contrast, the ring and little fingers of the EDC originated from the tendinous septum of the extensor digiti minimi and extensor carpi ulnaris, and had no connection with the ECRB tendinous origin.ConclusionsOn the basis of our anatomical findings, simultaneous stretching of the wrist extensors by wrist, index and middle fingers flexion could provide stretching force to both the tendinous origins of the ECRB and EDC through the EDC-IF and EDC-MF.

Effect of wrist and finger flexion in relation to strain on the tendon origin of the extensor carpi radialis brevis: A cadaveric study simulating stretching exercises

Background: Stretching exercises based on wrist flexion‐ulnar deviation with elbow extension, forearm pronation, and additional index or middle finger flexion have been used to stretch the wrist extensors for lateral epicondylitis. The purpose of this study was to quantify the strain on the tendon origin of the extensor carpi radialis brevis in cadaver specimens during these stretching exercises. Methods: We used 8 fresh frozen/thawed cadaveric upper extremities. The strain on the extensor carpi radialis brevis tendon origin was measured by the addition of 4 types of traction (no traction, wrist flexion‐ulnar deviation, and index or middle finger flexion in combination with wrist flexion‐ulnar deviation) in 7 sequential elbow flexion angles during forearm pronation. Two types of varus stress load to the elbow (none, gravity on the forearm) were also applied. Findings: A significant increase in strain was obtained by wrist traction with 0°, 15° and 30° of elbow flexion (P < 0.05). The strain was also significantly increased by adding finger traction (P < 0.05) and varus stress load (P < 0.05). A maximum strain value of 5.30 (SD 1.73) % was obtained when traction on the middle finger in combination with traction of the wrist was added at 15° elbow flexion with varus stress load. Interpretation: The present study provides data about the amount of strain on the extensor carpi radialis brevis tendon during stretching exercises of the wrist and finger extensors. The results of this study could be applied to stretching exercises for patients with lateral epicondylitis. HIGHLIGHTSStrain on the extensor carpi radialis brevis tendon in cadaversWrist flexion‐ulnar deviation produced a large strain.The strain was also increased by adding finger flexion, and elbow varus stress.A maximum strain value of 5.30% was obtained.

Measurement of strain and tensile force of the supraspinatus tendon under conditions that simulates low angle isometric elevation of the gleno-humeral joint: Influence of adduction torque and joint positioning

Background: Recently, supraspinatus muscle exercise has been reported to treat rotator cuff disease and to recover shoulder function. However, there have been no report on the direct measurement of strain on the supraspinatus tendon during simulated isometric gleno‐humeral joint elevation. Methods: Ten fresh‐frozen shoulder specimens with the rotator cuff complex left intact were used as experimental models. Isometric gleno‐humeral joint elevation in a sitting position was reproduced with low angle of step‐by‐step elevation in the scapular plane and strain was measured on the surface layer of the supraspinatus tendon. Findings: In isometric conditions, applied tensile force of the supraspinatus tendon increased significantly with increases in adduction torque on the gleno‐humeral joint. Significant increases in the strain on the layer were observed by increase in adduction torque, which were recorded in isometric elevation at − 10° and 0°, but little increase in the strain was observed at 10° or greater gleno‐humeral elevation. Interpretation: Increased strain on the surface layer of the supraspinatus tendon was observed during isometric gleno‐humeral elevation from − 10 to 0°. These findings demonstrate a potential risk of inducing overstretching of the supraspinatus tendon during supraspinatus muscle exercise. HighlightsStrain in the supraspinatus tendon was measured directly in cadaver shoulder models.The shoulder elevation at − 10°, 0° increased strain of the supraspinatus tendon.The elevation at 10°, 20°, and 30° did not increased strain of the tendon.These strain values are inconsistent from those obtained from ultrasound or MRI.There is a potential risk during isometric exercise in low gleno‐humeral elevation.