Kyu-Seok Lee

An anatomic study of the Martin–Gruber anastomosis: Electrodiagnostic implications

This study aimed to clarify the morphologic variations of the Martin–Gruber anastomosis (MGA) by tracing the anastomotic fascicles. We used 102 upper limbs, and MGA was found in 39.2%. Among 12 instances of MGA between the branches innervating the flexor digitorum profundus muscle, eight anastomotic branches solely innervated the muscle without crossover from median to ulnar nerve. The results of the present study showed three morphologic features of MGA that could not be detected by an electrodiagnostic method. Muscle Nerve, 2004

The marginal mandibular branch of the facial nerve in Koreans.

The marginal mandibular branch (MMB) has a particular risk of injury during surgical procedures in the submandibular region, especially over the lower border of the mandible. The facial nerve has been described in many studies, but the MMB is dealt with generally as a branch of the facial nerve. The purpose of this study was to document the anatomy of the MMB by correlation with anatomical landmarks. Eighty‐five facial halves were examined for this study. The MMB was classified according to the number of branches and their connections with other branches, and by its relationship with landmarks of the gonion, facial artery, and retromandibular vein. The MMB showed one (28%), two (52%), three (18%), or four branches (2%) where it exited the parotid gland. Classification was based on connection with other branches. Type I (60%) did not communicate with other branches. Type II (40%) communicated with the buccal or cervical branches, or with another branch of the MMB. The cervicofacial division coursed along the lateral aspect of the retromandibular vein in 83% of specimens. The MMB passed the facial artery superficially (42%), passed it deeply in 4%, and ran on both sides of it in 54% of the facial halves. The distribution of the MMB formed a quadrilateral with angles +19.8 mm, −8.1 mm, +30.0 mm, and −15.3 mm measured from two sides on the inferior border of the mandible. These topographical data should help to decrease the incidence of injuries during surgery on the submandibular regions in Koreans. Clin. Anat. 22:207–214, 2009.

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

AbstractThe 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.

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.

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. Clin. Anat. 24:768–773, 2011.

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. Muscle Nerve, 2009

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.

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.

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. Clin. Anat. 22:495–499, 2009.

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.