• Archives of Plastic Surgery
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• v.49 no.6
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• pp.750-754
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• 2022

Trigger wrist, characterized by a clicking or snapping sensation around the wrist joint during finger or wrist motion, and bifid or trifid median nerve, which occurs in carpal tunnel syndrome along with anatomical variation of median nerve, are rare conditions. We report the case of a patient with a thickened tendon caused by severe tenosynovitis and flexor tendon subluxation to the hamate hook due to bowing of the flexor retinaculum, thereby resulting in trigger wrist as well as an anatomical median nerve variation (bifid median nerve in the right wrist and trifid median nerve in the left wrist). A 59-year-old housewife visited our hospital with bilateral fingertip numbness, tingling sensation, and aggravated severe night cramping that began 2 months ago. She also complained about trigger wrist during small finger flexion. Based on magnetic resonance imaging, ultrasonography, and nerve conduction study, trifid median nerve and bilateral severe median nerve neuropathy of the wrist were diagnosed; therefore, transverse carpal tunnel release and exploration under wide-awake anesthesia were planned. Intraoperative findings showed trifid and bifid median nerves in left and right wrists, respectively. Additionally, bowing of flexor retinaculum and severe flexor tendon tenosynovitis were observed. Tenosynovitis with thickened flexor sheath resulted in subluxation of the small finger flexor tendon above the hamate hook. After transverse carpal ligament release with antebrachial fascia release and tenosynovectomy, subluxation of the flexor tendon was resolved. At 6 months postoperatively, the tingling and dullness in fingertips also resolved, and no trigger wrist or any other complications were noted.

• Journal of Korean Foot and Ankle Society
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• v.8 no.1
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• pp.114-115
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• 2004

A 18-year-old male soccer player had painful triggering and occasional locking of the great toe caused by entrapment of the flexor hallucis longus tendon within the flexor sheath posterior to the right medial malleolus. After other treatment modalities failed, the condition was relieved by a surgical procedure that removed the nodule on the flexor hallucis longus tendon and the ganglion under flexor retinaculum. Tendon rupture was not found, although there was tendinitis.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.3-10
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• 1999

There is an increasing demand for using rock anchors as foundations in many geotechnical engineering structures such as transmission towers, dams, etc. For investigate the behavior and strength of rock anchors, in-situ pull-out tests were carried out. From the tests, various forms of failure of rock anchors were observed. Ultimate capacity of each failure modes of 1) Tendon failure, 2) Interface failure(tendon-grout interface, sheath-grout interface and grout-rock interface), 3) Combined interface failure, was obtained by varying the parameters such as diameter and length of tendon, grout strength, and quality of rock.

• The Journal of Korea Robotics Society
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• v.12 no.1
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• pp.26-32
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• 2017

Previous shape sensors including bend sensors and optic fiber based sensors are widely used in various applications including goniometer and surgical robots. But theses sensors have large nonlinearity, limited in the range of sensing curvature, and sometimes are expensive. This study suggests a new concept of bend sensor using cable-conduit which consists of the outer sheath and the inner wire. The outer sheath is made of helical coil whose length of the central line changes as the sheath bends. This length change of the central line can be measured with the length change of the inner cable. The modeling and the experimental results show that the output signal of the proposed sensor is linearly related with the bend angle of the sheath with root mean square error of 5.3% of $450^{\circ}$ sensing range. Also the polynomial calibration of the sensor can decrease the root mean square error to 2.1% of the full sensing range.

• Journal of the Korean Geotechnical Society
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• v.25 no.10
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• pp.5-15
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• 2009

This paper presents the results of full-scale uplift load tests performed on 24 passive anchors grouted to various lengths at Okchun and Changnyong site. Rock anchors were installed over a wide range of rock types and qualities with a fixed anchored depth of 1~6 m. The majority of installations used D51 mm high grade steel rebar to induce rock failure prior to rod failure. However, a few installations included the use of D32 mm rebar at relatively deeper anchored depth so as to induce rod failure. In many tests, rock failure was reached and the ultimate loads were recorded along with observations of the shape and extent of the failure surface. In addition to field tests, laboratory pullout tests were conducted to determine bond strength and bond stress-shear slip relation at the tendon/grout interface when a corrosion protection sheath is installed in the cement-based grout. The test results show that the ultimate tendon-grout bond strength is measured from 18~25% of unconfined compressive strength of grout. One of the important results from these tests is that the measured strains along the corrosion protection sheath were so small that practically the reduction of bond strength by the presence of sheath would be negligible.

• Applied Microscopy
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• v.26 no.2
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• pp.157-175
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• 1996

The development of flexor digital tendon of the hand was studied by electron microscopy in human fetuses ranging from 9 mm to 260 mm crown rump length. The primordium of tendons was first identified as discrete collection of mesenchymal cells at 25 mm fetus. Synovial sheath formation had commenced by 40 mm fetus and was complete by 70 mm fetus. Cell junction or adhesion sites at all ages were noted between the tendon cells. When dilatation of the synovial cavity occurred, two types of synovial cells were observed. A-type cells had numerous vesicles and large vacuoles. In contrast, B-type cells were characterized by abundant rough endoplasmic reticulum and well-developed Golgi complex. By $150mm{\sim}260mm$ fetuses, a mojority of the synovial cells were type B. The most remarkable difference between the synovial cells of full-term fetus and adult was the larger amount of collagen fibers in the latter. The vascular buds were first observed between the individual fibril bundles in the interfascicular space at 150 mm fetus. At 25 mm fetus, collagen fibrils were first noted within narrow cytoplasmic recesses which were continued with the extracellular space. Collagen fibrils were filled in almost entire extracellular space at 150 mm fetus. Besides collagen fibrils in the extracellular space small elastic fibers were also identified and followed in their development.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.498-500
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• 2011

Purpose: Neurilemoma is benign tumor of the nerve sheath which arises from Schwann cells. It is usually formed along the path of a peripheral nerve but is rarely separate from normal nerve fascicles. We experienced a patient with an isolated neurilemoma localized in the palmaris longus tendon with no connection to the major nerve trunk, which was in an unusual location and has never been reported. We report our case with the review of the literature. Methods: A 23-year-old female visited our clinic with mild pain on the mass at the flexor area of the right wrist which had been present for about one year. The physical examination revealed a $1{\times}1cm$ sized subcutaneous mass at the flexor area of the right wrist. Sonography and computed tomography showed an ovoid, superficial solid mass on the palmaris longus tendon. Upon surgical excision, a $1{\times}0.5cm$ sized mass attached to the palmaris longus tendon was found. The tumor had no connection with the median nerve and was detached easily from the palmaris longus tendon. Results: Histological examination demonstrated the mass to be a neurilemoma, which consists of spindle shaped cells with oval elongated nuclei arranged fascicles. No sensory dysfunction or evidence of recurrence was found during the 12 months of postoperative follow-up. Conclusion: We experienced a rare case of neurilemoma attached to the palmaris longus tendon with no connection to the major nerve trunk. We wish to emphasize its unusual location through our case and hope to expand our spectrum in exploring the upper extremity mass.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.6
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• pp.691-697
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• 2015

In this paper, an embedded EM sensor was researched to estimate prestressing force of PS tendon in PSC girder. Recent methodologies for managing prestressing force loss were staying on verifying a applying prestressing force under construction, namely the loss management can not be controlled after construction. To estimate the tensile force of PS tendon during lifetime of PSC girder, this research proposed a bobbin-type embedded EM sensor that can be embedded in PSC girder is designed and fabricated considering the shape properties of anchorage zone and sheath. To verify the proposed sensor, a small PSC girder test was performed. The embedded EM sensor was connected to a sheath and anchor block, and the concrete was poured. After curing, the change of the permeability of PS tendon under tensile forces of 200, 710, 1070, 1300kN was measured using embedded EM sensor. The permeability of PS tendon had decreased according to the increment of applied tensile force. Also it is confirmed that the change of permeability due to applied tensile force could resolve the applied tensile force values. As a result, proposed embedded EM sensor could be embed into the PSC girder and it could be used to estimate the tensile force variation during lifetime of PSC girder.

• Journal of Korean Foot and Ankle Society
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• v.6 no.1
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• pp.111-116
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• 2002

Synovial chondromatosis is an uncommon benign lesion characterized by metaplastic cartilage formation within the synovial connective tissue, usually intraarticular, commonly affects the knee, hip and elbow. An extraarticular lesion is rare, most often seen in a synovial sheath and bursa of the hand or foot. We present a case of extraarticular synovial chondromatosis in the left ankle, originated from the FHL tendon sheath of a 31 year-old-female diagnosed by a radiography, MRI confirmed histopathologically.

• The Journal of Korea Robotics Society
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• v.14 no.3
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• pp.221-227
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• 2019

This paper studies an effect of vibration on twisted string actuation inside conduit at high curvature angles. In our previous work. we have mentioned that twisted string actuators can be used to transmit power even at significant curvature angles of the conduit. However, several undesirable effects, namely pull-back, hysteresis, and chattering, were present during actuation due to friction between strings and the internal sheath of the conduit. This paper reports the results of experimental study on effects of vibration on twisted string actuation inside curved conduits. We have demonstrated that applying vibration generated near natural frequency of the system during the stages of twisting and untwisting cycles helped reduce pull-back and hysteresis and increase string contraction. In case when sheath was deflected by $180^{\circ}$ under a constant load of 3 kg, we were able to achieve over 40% decrease in pull-back and 30% decrease in hysteresis, compared with no vibration case.