Effects of Mg Content on Electric and Mechanical Properties of Al-Zn-Cu Based Alloys.

Microstructure and properties of Al-2 wt.%Zn-1 wt.%Cu-xMg (x = 0.1, 0.3, 0.5, 0.7 wt.%) alloy extrusion materials were investigated. The lattice constants for the (311) plane increased to 4.046858, 4.048483, 4.050114 and 4.051149 Å with the addition of 0.1, 0.3, 0.5, and 0.7 wt.% of elemental Mg. The average grain size of the as-extruded Al alloys was found to be 328.7, 297.7, 187.0 and 159.3 µm for the alloys with 0.1, 0.3, 0.5, and 0.7 wt.% Mg content, respectively. The changes in the electrical conductivity by the addition of elemental Mg in Al-2 wt.%Zn-1 wt.%Cu alloy was determined, and it was found that for the addition of 0.1, 0.3, 0.5, and 0.7 wt.% Mg, the conductivity decreased to 51.62, 49.74, 48.26 and 46.80 %IACS. The ultimate tensile strength of Al-2 wt.%Zn-1 wt.%Cu-0.7 wt.%Mg alloy extrusion was increased to 203.55 MPa. Thus, this study demonstrated the correlation between the electrical conductivity and strength for the Al-2 wt.%Zn-1 wt.%Cu-xMg alloys.

Analysis of Microstructure and Electric Conductivity in Al-RE Alloy by Heat-Treatment Condition.

In this study, we investigate the microstructure and mechanical properties of as-extruded Al-1.0RE alloys. The molten Aluminum alloy was maintained at 800 °C and then poured into a mould at 200 °C. Aluminum alloys were hot-extruded into a rod measuring 12 mm thick with a reduction ratio of 38:1. The microstructure and electric conductivity properties of as-extruded Al-1.0RE alloy under different annealing processes were investigated and compared. After extrusion, the intermetallic compound having a needle shape in the cast state was finely decomposed based on the direction of extrusion. Significant changes in the microstructure were detected after annealing at 500 °C with fragmentation and sphering of eutectic particles. The annealing temperature of Al-1.0RE alloy increased proportionally to the electrical conductivity. The formation of Al-RE intermetallic compounds increases the electrical conductivity and improves the mechanical properties of the alloy through precipitation hardening.

Microstructure and Mechanical Properties of the Al-RE Alloy with Ca Addition.

Aluminum and its alloys are used in a wide range of industrial applications from low density, high strength and a variety of structural materials. In this study, the effects of Ca addition on the microstructure and mechanical properties of Al-1wt.%RE alloys were investigated. The melt was held at 800 °C for 20 minutes and poured into a mold. The cast Al alloy was hot extruded with a rod having a diameter of 12 mm and a reduction ratio of 38:1. Al-1wt.%RE alloy consists of Al, Al11RE3 phase. The Al2Ca phase is increased by increasing the Ca content to 0.2 to 0.4 wt.%. As the Ca content increased from 0 to 0.4 wt.%, the average grain size of the extruded Al alloy decreased by 739.8, 400.8 and 155.0 µm. The tensile strengths were increased to 74.25, 76.53, and 79.52 MPa. The electrical conductivity of Al-RE alloy with Ca addition decreased to 60.32, 58.15 and 57.89% IACS.

New insights into the origin of the lumbrical muscles of the foot: tendinous slip of the flexor hallucis longus muscle.

PURPOSE: The aim of this study was to clarify the origins of the lumbricals of the foot toward a better understanding of its precise action in the gait. METHODS: The lumbricals in the foot were investigated in 66 specimens of embalmed Korean adult cadavers. RESULTS: The first lumbrical arose as two muscle bellies from both the tendon of the FDL and the tendinous slip of the FHL in 83.3 %, and as one muscle belly from the tendon of the FDL or the tendinous slip of the FHL in 16.7 %. These two muscle bellies subsequently merged to form the muscle belly of the first lumbrical. The second lumbrical arose from the tendinous slips of the FHL for the second and third toes as well as the tendon of the FDL in all specimens. The third lumbrical arose from the tendinous slips of the FHL for the third and fourth toes in 69.7 %, and the fourth lumbrical arose from the tendinous slip of the FHL for the fourth toe in 18.2 %. Some deep muscle fibers of the fourth lumbrical arose from the tendinous slip of the FHL for the second toe in 4.5 %, for the third toe in 28.8 %, and for the fourth toe in 15.2 %. CONCLUSIONS: The results of this study constitute new anatomical knowledge regarding the origin of the lumbricals, and provide insight into their specific role in production of gait. These findings will be useful for various types of surgery, biomechanics research, and rehabilitation programs.

Blending of the lateral deep slip of the platysma muscle into the buccinator muscle.

PURPOSE: The aim of this study was to clarify the prevalence of blending of the lateral deep slip of the platysma into the buccinator, and the morphologic and spatial relationships thereof. METHODS: The lateral deep slip of the platysma was investigated in 42 specimens of embalmed adult Korean cadavers. RESULTS: The lateral deep slip of the platysma was observed in 17 of the 42 specimens (40.5 %). When present, it divided from the deep portion (16 specimens, 38.1 %) or the lateral portion (1 specimen, 2.4 %) of the platysma pars modiolaris. The lateral deep slip passed deep to the facial artery, where it blended into the inferior part of the buccinator. The blending site was located inferolateral to the modiolus. After blending into the buccinator, the fibers of the lateral deep slip coursed longitudinally with the inferior fibers of the buccinator. CONCLUSION: The present description of the topography of the lateral deep slip of the platysma and its relationship with surrounding structures could improve the understanding of the detailed movements of the lower face and the related EMG activities, with the data also being useful when performing facial surgery.

Termination of the ligamentum venosum and the topographic relationship between the left portal vein, left hepatic artery, and ligamentum venosum in the fissures for the ligamentum teres and ligamentum venosum.

PURPOSE: The aim of this study was to clarify the location of termination of the ligamentum venosum (LV) and topographic relationships between the left portal vein (LPV), left hepatic artery (LHA), and LV in the fissures for ligamentum teres and LV. METHODS: Anatomical examination was performed on 50 livers from embalmed Korean adult cadavers. RESULTS: The LV originated from a point between the transverse and umbilical portions of LPV (Tr-Um point) in all specimens, and terminated in the common trunk of the middle hepatic vein and left hepatic vein (LHV) (61%) or in the LHV (39%). In the fissures for ligamentum teres and LV, the courses of the LHA relative to the LV and the LPV varied, such that four main patterns could be discerned. In type I (48%), the LHA crossed the inferior surface of Tr-Um point and passed just left of the origin of LV. In type II (20%), the LHA crossed the inferior surface of umbilical portion of LPV. In type III (10%), the LHA crossed the inferior surface of Tr-Um point to pass just left of origin of LV, with one branch of the right hepatic artery crossing the inferior surface of umbilical portion of LPV. In type IV (12%), no arterial branches ran on the inferior surfaces of transverse and umbilical portions of LPV. CONCLUSION: These details may play a role as external landmarks for facilitating preestimation of intrahepatic structures during various surgical procedures involving the liver.

Spinal nerve composition and innervation of the axillary nerve.

INTRODUCTION: The purpose of this study was to evaluate the spinal nerve composition of the axillary nerve and the contribution of each spinal nerve. METHODS: Thirty brachial plexi extracted from Korean adults (15 men, 14 women, 1 unknown; left side, 13; right side, 17) were examined in this study. RESULTS: The frequency of the contribution of C4 was 13.3%, and it was mainly innervated the deltoid and teres minor muscles. The frequency of inclusion of C7 was 20.0%. C7 fibers were mainly involved in the deltoid and cutaneous branches. The axillary nerve was primarily composed of fibers from C5 and C6 in 66.6%; C4, C5, and C6 in 13.3%; and C5, C6, and C7 in 20.0%. CONCLUSIONS: These findings may be helpful to diagnose damage to axillary nerve structures that occur in such injuries as humerus fractures.

An anatomic study of the medial fibers of depressor anguli oris muscle passing deep to the depressor labii inferioris muscle.

The trajectory of the medial fibers of depressor anguli oris muscle that pass deep to the depressor labii inferioris muscle (dDAO) and the anatomic relationship have not yet been examined. The aim of this study was to clarify the arrangement of the dDAO and its relationships with the surrounding structures. The dDAOs were investigated in 40 hemifaces from Korean cadavers. The dDAOs were observed in 18 of the 40 specimens (45%). The anatomic relationships of the dDAO were classified into the following 4 categories according to their connection with the incisivus labii inferioris muscle (ILI): (1) connected to the ILI and attached to the inferior border of the mandible lateral to the mentalis muscle (14 specimens, 35%), (2) connected to the ILI and intermingled with the lateral lower fibers of the mentalis muscle (2 specimens, 5%), (3) connected to the ILI but neither attached to the mandible nor intermingled with the mentalis muscle (1 specimen, 2.5%), and (4) not connected to the ILI but intermingled with the mentalis muscle (1 specimen, 2.5%). Therefore, in 17 specimens, the dDAOs were connected to the ILI (42.5%), in 14 specimens, they were attached to the inferior border of the mandible (35%), and, in 3 specimens, they were intermingled with the mentalis muscle (7.5%). The new anatomic data regarding the dDAO will contribute toward the understanding of movements of the mouth and lower face, which will be helpful when designing effective botulinum toxin type A therapies and performing various types of facial surgery.

Expression of transient receptor potential channels in the ependymal cells of the developing rat brain.

Cerebrospinal fluid (CSF) plays an important role in providing brain tissue with a stable internal environment as well as in absorbing mechanical and thermal stresses. From its initial composition, derived from the amniotic fluid trapped by the closure of neuropores, CSF is modified by developing and differentiating ependymal cells lining the ventricular surface or forming the choroid plexus. Its osmolarity and ionic composition brings about a change through the action of many channels expressed on the ependymal cells. Some newly discovered transient receptor potential (TRP) channels are known to be expressed in the choroid plexus ependyma. To detect additional TRP channel expression, immunohistochemical screening was performed at the choroid plexus of 13-, 15-, 17-, and 19-day embryos, using antibodies against TRPV1, TRPV3, and TRPA1, and the expression was compared with those in the adult TRP channels. The level of TRP channel expression was higher in the choroid plexus which suggests more active functioning of TRP channels in the developing choroid plexus than the ventricular lining ependyma in the 15- and 17-day embryos. All the expression of TRP channels decreased at the 19th day of gestation. TRPA1 was expressed at a higher level than TRPV1 and TRPV3 in almost all stages in both the choroid plexus and ventricular lining epithelium. The highest level of TRPV1 and TRPV3 expression was observed in association with the glycogen deposits in the cytoplasm of the choroid plexus ependymal cells of the 15- and 17-day embryos.

Morphology of the mentalis muscle and its relationship with the orbicularis oris and incisivus labii inferioris muscles.

The mentalis muscle (MT) is the only elevator of the lower lip and the chin, and it provides the major vertical support for the lower lip. However, there are few reports on the relationship between the MT and its surrounding muscles. The aim of this study was to clarify the morphology of the MT, especially in relation to the orbicularis oris muscle and the incisivus labii inferioris muscle (ILI), thereby providing data to understand the function of the MT in relation to the surrounding muscles. The MT was examined in 40 specimens of embalmed adult Korean cadavers. The medial fibers of both MTs descended anteromedially and crossed together, forming a dome-shaped chin prominence in all specimens. The lateral fibers of the MT descended inferomedially in 38 specimens (95%) and inferolaterally in 2 specimens (5%). The upper fibers of the MT were short and ran horizontally, whereas the lower fibers were long and descended inferomedially or vertically. The upper fibers of the MT were intermingled with the inferior margin of the orbicularis oris muscle in all specimens. The originating muscle fibers of the ILI were intermingled with the upper lateral MT in all specimens. Some of the ILI fibers extended inferomedially to the middle or lower portion of the MT in 22 specimens (55%). The results of this study constitute new anatomical knowledge regarding the MT and will be useful to surgeons performing various surgical procedures of the chin area.

Masticator space abscess in a 47-day-old infant.

A 47-day-old male infant presented with fever, poor oral intake, irritability, and right-sided bluish buccal swelling. Contrast-enhanced computed tomography of the neck showed a round mass lesion of about 2.0×1.5 cm that suggested abscess formation in the right masticator space. Ultrasound-guided extraoral aspiration of the abscess at the right masseter muscle was successful. Staphylococcus aureus was identified in the culture from the aspirated pus and blood. Appropriate antibiotics were given and the patient recovered. The patient underwent follow-up ultrasonography that showed an improved state of the previously observed right masseter muscle swelling at about 1 month after hospital discharge. A masticator space abscess usually originates from an odontogenic infection in adults. We report a case of masticator space abscess in a 47-day-old infant in whom septicemia without odontogenic infection was suspected.

An anatomic study of the quadratus plantae in relation to tendinous slips of the flexor hallucis longus for gait analysis.

The aim of this study was to demonstrate the morphology of the quadratus plantae (QP) in relation to the tendinous slips of the flexor hallucis longus (FHL) and their surrounding structures, thereby providing data to understand function of the QP during gait, and for analyzing the movements of the foot and designing postoperative rehabilitation programs. The QP was investigated in 50 specimens of embalmed adult cadavers. The QP inserted into the tendon of the flexor digitorum longus (FDL) and the tendinous slips of the FHL in 96%, and only to the tendon of the FDL in 4%. The tendinous slip of the FHL targeted the tendon for the second toe in 4 of the 50 specimens (8%). The tendinous slip divided into two separate slips to the tendons for the second and third toes in 32 specimens (64%), and for the second, third, and fourth toes in 14 specimens (28%). Thus, the tendon and tendinous slips of the FHL may distribute the load of the great toe to the second toe to the third or fourth toe in the forefoot, especially during toe-off. In addition, the main attachment of the QP to the tendinous slips of the FHL may provide more efficient control of the long flexor tendons in comparison with that of the QP to the tendon of the FDL.

Destination of the C4 component of the prefixed brachial plexus.

This study was carried out to elucidate the destination of the C4 ventral ramus that forms the prefixed brachial plexus. A total of 43 sides of Korean adults (male, 22; female, 18; unknown: 3 and right, 23; left, 20) were investigated. The various C4 destinations and their frequencies were as follows: suprascapular nerve, 97.7% (42/43); musculocutaneous nerve, 79.1% (34/43); the axillary nerve, 48.8% (21/43); and the nerve to subclavius, 16.2% (7/43). The mean quantity of nerve fibers destined to the suprascapular, musculocutaneous, and axillary nerves and the nerve to subclavius was 441.8 ± 316.5 (Mean ± S.D.), 298.2 ± 209.8, 245.8 ± 239.0, and 66.4 ± 17.2, respectively. The mean nerve fibers number of C4 contributing to the brachial plexus was 983.6 ± 618.0 (range: 100-1729). The main component that contributes to the terminal nerves (suprascapular, musculocutaneous, axillary nerves, and nerve to subclavius) is C5. These results may be useful to surgeons and clinicians dealing with terminal nerves of the brachial plexus, especially the suprascapular, musculocutaneous, and axillary nerves.

Inferior bundle (fourth band) of the buccinator and the incisivus labii inferioris muscle.

The aim of this study was to clarify the morphologic and spatial relationships of the inferior bundle of the buccinator and the incisivus labii inferioris muscle (ILI) and their surrounding structures. The inferior bundle of the buccinator and the ILI were investigated in 40 hemifaces from Korean cadavers. The inferior bundle (or fourth band) of the buccinator muscle was observed in 14 (35%) of the 40 specimen sides. The ILI was found in 39 (97.5%) of the 40 specimen sides. The spatial relationships of the ILI with the buccinator muscle and the orbicularis oris muscle were classified into 4 categories based on the existence of the inferior bundle of the buccinator. These observations indicate that the lower portion of the buccinator including the third and fourth inferior bundles and the ILI could affect the alveolar bone of the mandible or occlusion during these muscular movements.

Variation of the infrahyoid muscle: duplicated omohyoid and appearance of the levator glandulae thyroideae muscles.

The embryologic origin of the omohyoid muscle is different from that of the other neck muscles. A number of variations such as the absence of muscle, variable sites of origin and insertion, and multiple bellies have been reported. However, variations in the inferior belly of the omohyoid muscle are rare. There have been no reports of the combined occurrence of the omohyoid muscle variation with the appearance of the levator glandulase thyroideae muscle. Routine dissection of a 51- year-old female cadaver revealed a duplicated omohyoid muscle and the appearance of the levator glandulae thyroideae muscle. In this case, the two inferior bellies of the omohyoid muscle were found to originate inferiorly from the superior border of the scapula. One of the inferior bellies generally continued to the superior belly with the tendinous intersection. The other inferior belly continued into the sternohyoid muscle without the tendinous intersection. In this case, the levator glandulae thyroideae muscle appeared on the left side, which attached from the upper border of the thyroid gland to the inferior border of the thyroid cartilage. These variations are significant for clinicians during endoscopic diagnosis and surgery because of the arterial and nervous damage due to iatrogenic injuries. The embryologic origins of the omohyoid and levator glandulae thyroideae muscles may be similar based on the descriptions in the relevant literature.

Spinal origins of the nerve branches innervating the coracobrachialis muscle: clinical implications.

The coracobrachialis muscle (Cb M) receives nerve branches from the musculocutaneous nerve (Mc N). Many textbooks describe that the Cb M is innervated by the C5, C6, and C7 spinal nerves. The present study was performed to identify the spinal nerve composition of the nerve branches innervating the Cb M and to evaluate the number of myelinated axons of the nerve branches. Two types of spinal nerve compositions were observed: type I, composed of both C6 and C7 nerves, comprised 88.9% (40/45) of the sides; and type II, composed of only C7 nerves, comprised 11.1% (5/45) of the sides. Of the type I branches, 245.4 +/- 26.3 (mean +/- SD, range 201-267) of the myelinated nerve fibers were derived from C6 and 520.0 +/- 41.8 (range 469-567) of the fibers were derived from C7. Of the type II branches, 836.4 +/- 125.5 (range 709-991) of the nerve fibers were derived from C7. Imbroglio Modometer version 2.0 was used to count the number of fibers innervating the Cb M. The main component of these nerve branches was the C7 spinal nerve. The C5 spinal nerve, did not contribute to innervating the Cb M in the present study. The number of branches varied from one to four, with C7 being concentrated in the first and second branches. Therefore, these two branches may be suitable for the neurotization procedure as a donor nerve at the upper trunk (C5 and C6) lesion of the brachial plexus.

Spinal root origins and innervations of the suprascapular nerve.

The suprascapular nerve branches provide efferent innervation to the supraspinatus and infraspinatus muscles as well as sensory innervation to the shoulder joint. This study was carried out to verify the spinal root origins and innervations of the suprascapular nerve. Fifty samples of the suprascapular nerve taken from 37 adult Korean cadavers were used in this study. The suprascapular nerve was found to comprise the ventral rami of the C5 and C6 in 76.0% of the fifty samples; C4, C5, and C6 nerves in 18.0%; and C5 nerve in only 6.0%. The C5 nerve was consistently shown to be the largest in mean diameter and was found to be a major contributor of nerve fibers leading to the suprascapular nerve. This study shows that the main spinal component of the suprascapular nerve is C5 nerve. In most cases, the rate of the involvement of the C4 and C6 nerves (18.0 and 94.0%, respectively) with the suprascapular nerve was less than that of C5 nerve. C4 and C5 nerves were shown to contribute nerve fibers to the supraspinatus and infraspinatus muscles and to both shoulder joints, whereas C6 nerve displayed variable patterns of innervation.

Anatomic variation of the innervation of the flexor digitorum profundus muscle and its clinical implications.

In anterior interosseous nerve syndrome and ulnar neuropathy, paralysis or weakness of the flexor digitorum profundus (FDP) muscles has been shown to vary according to the degree of involvement of the median and ulnar nerves, respectively. We traced these nerves in 50 cadaveric specimens in which each FDP was completely separated. The specimens were classified into six anatomic and another six presumptive electromyography (EMG) types according to the innervation patterns of the entire and the proximal one-third of the FDP muscles, respectively. The diverse anatomic and presumptive EMG types in this study suggest that the FDP muscles of the 2nd to the 5th digits should be examined by functional tests and EMG in lesions of the median or ulnar nerve.

Origin of the radial nerve branch innervating the brachialis muscle.

The brachialis muscle is dually innervated by the musculocutaneous nerve running via the anterior division of the brachial plexus and the radial nerve running via the posterior division of the plexus. There have been inconsistent descriptions of the pathway of the radial nerve branch at the brachial plexus. This study investigated the route of the radial nerve branch innervating the brachialis muscle at the brachial plexus. In 20 samples, the radial nerve branch innervating the brachialis muscle was separated and traced up to the cervical nerve under a surgical microscope. All the radial nerve branches innervating the muscle ran via the posterior cord, the posterior division, and the superior or middle trunk at the brachial plexus. The radial nerve branches arose from C5 in 5 cases, C6 in 11 cases, C5 and C6 in 3 cases, and C6 and C7 in 1 case.

An abnormal muscle in the superficial region of the popliteal fossa.

An abnormal muscle was observed in the superficial region of the popliteal fossa during a dissection procedure conducted for medical students. This abnormal muscle originated from the biceps femoris tendon and inserted into the medial head of the gastrocnemius muscle. The innervating nerve branched from the lateral sural cutaneous nerve. The distributing artery arose from a branch of the sural artery. This abnormal muscle mostly comprised one sheet of muscle mass (not tendon type) and ran transversely.