ABSTRACT
Objective To develop a shear force-induced intervertebral disc degeneration (IDD) in vivo animal model, and investigate the relationship between shear stress and IDD. Methods A total of 20 Japanese white rabbits were randomly divided into two groups. In loading group (n=10), shear force of 50 N was applied on the disc of L4/5 for 4 weeks by a custom-made external shear force loading device. In control group (n=10), the animals underwent a sham operation with the external loading device situated, but their discs remained unloaded. After 4 weeks, all the intervertebral discs of L4/5 were executed for the pathologic examination. Results The postoperative radiographic examination showed a perfect position of the loading device, and the operation process and implanted loading device had no effect on daily activities and diet of the experiment animals. The pathological examination showed an irregular arrangement of annulus fibrosus and a significant decrease of normal nucleus pulposus cells in loading group. Conclusions The new custom made device greatly reduced the wounds on animal vertebra and provided a reliable shear force. The development of in vivo animal model indicates that IDD can be induced by shear force, which is of significance to further study the relationship between loading and IDD.
ABSTRACT
<p><b>OBJECTIVE</b>To provide appropriate needling angle and depth for the acupuncture and acupoint injection at Neiguan (PC 6), and to avoid damaging nerves and vessels so as to produce its maximum effect.</p><p><b>METHODS</b>Thirty adults' upper-limb samples were used to dissect and observe the referred hierarchical structure and adjoining crucially nerves and vessels in needling Neiguan (PC 6) according to the national standard Acupoint Location (GB 12346-90).</p><p><b>RESULTS</b>In this punctuation region, there are three parts rich in connective tissues containing the nerves and blood vessels. The surface part is between the skin and the musculus flexor digitorum superficialis and it is the tissue which contains medial and lateral antebrachial cutaneous nerve and its nutrient artery. The middle part is between the musculus flexor digitorum superficialis and the flexor digitorum profundus muscle and contains the median nerve, its palmar branch of and artery. The deep part is between the pronator quadratus muscle and the interosseous membrane and contains the anterior interosseous nerve. When perpendicular needling, the depth of needling the body from skin to the superficial surface of the musculus flexor digitorum superficialis and to the superficial surface of the flexor digitorum profundus muscle is (6.68 +/- 0.64) mm and (12.37 +/- 0.87) mm respectively. The depth of needling the body from skin to the superficial surface of the pronator quadratus muscle and to the superficial surface of the anterior interosseous terminal branch of the nerves is (17.83 +/- 1.00) mm and (30.87 +/- 1.85) mm respectively, and the proportional cun is (2.20 +/- 0.14) cm. The ulnaris cord of median nerves are located at the radial of the needle. The deep layers could touch the anterior interosseous nerve ending.</p><p><b>CONCLUSION</b>Perpendicularly needling Neiguan (PC 6) for 3 fen (6.68 mm), 5 fen (12.37 mm) and 1.4 cun (30.87 mm) will stimulate the nervus vascularis of the rich part of surface, middle and deep connective tissues respectively and produce the acupuncture effect. During the acupoint injection, perforating the needle perpendicularly at the middle point of the two tendons or deviating slightly to the direction of tendon of palmaris longus can avoid the damage of the median nerve cord.</p>