Biomedical subjects

Kun Hwang

Publications and source records attributed to Kun Hwang.

At least 37 records · Page 2Linked to original sources

PubMed2005

Anatomy of superficial thoracic artery related to subpectoral augmentation mammoplasty.

The aim of this study is to elucidate the anatomic details of superficial thoracic artery related to transaxillary subpectoral augmentation mammoplasty.Thirty-three breasts of Korean cadavers (11 males, 6 females) were dissected. The superficial thoracic artery was found at the lateral part of the pectoralis (P.) major muscle in all cases. It originated mostly from the lateral thoracic artery (42%), thoracoacromial artery (38%), and partly from axillary artery (19%). Most of (82%) the muscle entering point was included in the circle of 2.5-cm radius. The center was located 2.5 cm superior from the intersection of the lateral border of the P. major and inferior border of the fourth rib. It was distant from 12 cm lateral to the midline and 6 cm below the sternal notch. We think that the superficial thoracic artery might be the culprit of bleeding and severe hematoma in transaxillary subpectoral mammoplasty.

Adult↗

PubMed2005

Cutaneous sensory branch of the mylohyoid nerve.

The study is aimed at the anatomical detail of the cutaneous sensory branch of the mylohyoid nerve (MHN), which is distributed to the chin, as it relates to submental surgery. Dissection was done on the both sides (16) of eight cadavers fixed in formaldehyde solution. A distance from gonion of the branch innervating the anterior digastric and mylohyoid muscle and the cutaneous sensory branch was measured. The cutaneous sensory nerve was 27.0+/-8.6 mm long and numbered 2.3 (14.4%) of 16 specimens. The area distributed by most branches (78%) was a rhombus, having all four sides equal (15 mm), extending to the mental prominence and submentum. The divergent angle of the two facing sides of the bilateral rhombi was 60 degrees. Informed surgical manipulation of the mental area may avoid unnecessary damage to the sensory nerve.

Chin↗

PubMed2005

Interrelated buccal fat pad with facial buccal branches and parotid duct.

The facial nerve branches are vulnerable during manipulation of the buccal fat pad. The aim of this study is to describe the precise anatomical interrelation among the buccal fat pad, buccal branches of the facial nerve, and parotid duct. Nineteen hemifaces of Korean cadavers (11 male and 8 female) fixed in 10% formaldehyde solution were dissected. An average 3.6 buccal branches of the facial nerve were found. The facial buccal branches and parotid duct crossed each other within a semicircle with a 30-mm radius. The base (diameter) is parallel to a horizontal line passing the corner of the mouth and 12 mm above. Its center is located 53 mm lateral to it. The buccal branches of the facial nerve have two locations at the buccal fat pad: Type I, branches crossing superficial to the buccal fat pad in 14 of 19 (73.7%) specimens; and Type II, two twigs passing through buccal extension of the buccal fat pad in 5 of 19 (26.3%). An interrelation of parotid duct and buccal fat pad is as follows: parotid duct crossing superficial to the buccal extension of buccal fat pad in 8 of 19 (42.1%) specimens, crossing deep to the buccal extension of buccal fat pad in 5 of 19 (26.3%) specimens and crossing along the superior border of the buccal extension of buccal fat pad in 6 of 19 (31.6%) specimens. There is a 26.3% chance of injury to the buccal branch during total removal of buccal fat pad. The parotid duct runs deep to the buccal extension of buccal fat pad in 26.3% of cases.

Adipose Tissue↗

PubMed2005

Neurilemmoma of the tongue.

The authors report a case of uncommon neurilemmoma on the tip of the tongue. A 23-year-old Korean man presented with a mass on the tip of the tongue, which was noted first 3 years before, when it was a small nodule. The mass had been growing slowly. Physical examination revealed a firm, not-tender, oval, elevated, protruded, red mass on the right side tip of the tongue. It measured 2 x 2 cm. The lesion was well capsulated and separated easily. A complete excision was done, and the wound was closed primarily. Histopathologic examination revealed an encapsulated spindle cell tumor, of which two types of the tissue were clear. A small and slow-growing mass in the tongue with positive history of tongue bite is first suggestive of neurilemmoma, as well as neurofibroma, lingual cyst, and minor salivary gland tumor.

Adult↗

PubMed2005

Zygomaticomandibularis muscle.

The aim of this study was to elucidate the precise anatomy of the zygomaticomandibularis muscle through cadaveric dissection and magnetic resonance imaging (MRI). Five fresh human cadavers and 10 fixed cadavers were dissected. Nine preserved human cadavers were used for the MRI study. Four volunteers took MRIs of their head as well. Zygomaticomandibularis muscle was found in all the cadaveric specimens. It is a fan shaped muscle. The length of the muscle is 25.1 +/- 4.6 mm, and the width at the zygomatic arch is 16.6 +/- 4.2 mm. The thickness is approximately 4.8 +/- 1.9 mm. It originates from the deep layer of the deep temporal fascia approximately 1 cm above the zygomatic arch and is inserted into the superior border and outer surface of the mandible between the coronoid process and mandibular notch. The deepest layer of the masseter muscle covers the lateral surface of zygomaticomandibularis. We believe that this muscle functions as coordinator of the temporalis and masseter in mammals with strong masticatory power but is a degraded or rudimentary muscle in humans.

Cadaver↗

PubMed2005

Laser welding of rat's facial nerve.

The aim of this study is to compare regeneration of the severed nerves that were repaired by laser welding with those repaired by microsurgical suturing and evaluate the value in use of laser nerve welding in the head and neck area. In 12 rats the buccal branches of the facial nerves on the both sides were transected, and CO2 laser welding of the epineurium was performed on the right side and microsurgical suture technique was applied on the left side. In six rats Cholera Toxin B Subunit (CTb) was injected in the epineurium distal to the nerve anastomosis site at postoperative week 4. Another six rats were treated exactly in the same way in postoperative week 8. Six normal rats were used as controls. Intact facial nerve was observed after injection of CTb as well. Neurons of facial nuclei labeled positively by CTb were detected immunohistochemically, and the numbers were counted. CTb-positive neurons in the control group were 1311 +/- 258 (n = 6). CTb-positive neurons in the group (n = 6) with laser nerve welding were 1174 +/- 122 in postoperative week 4 and 1562 +/- 565 in postoperative week 8. CTb-positive neurons in the group (n = 6) with microsurgical suture were 1066 +/- 89 in postoperative week 4 and 1443 +/- 531 in postoperative week 8. CTb-positive neurons were seen significantly more in the group with laser welding than in the group with microsurgical suture in postoperative week (P = 0.028), but there was not much difference in postoperative week 8 (P = 0.463). None of 12 rats showed dehiscence at the nerve anastomosis done by laser welding. This study shows that nerve regeneration is more apparent in the nerve repaired by laser welding than in that repaired by microsurgical suture.

Animals↗

PubMed2005

Anthropometric comparison of portraits of Korean and Japanese beauty in the late 18th and early 19th centuries.

The aim of this study is to elaborate comparative portraits of Korean and Japanese beauty in the late 18th and early 19th centuries. Six portraits of beauty in the Korean Joseon Dynasty (early 19th century) and 5 in Japanese Edo Dynasty (late 18th century) were analyzed. Twenty anthropometric items were applied to the measure of the features on each portrait and 18 proportional indices of the face were calculated. Among the 18 indices, Korean and Japanese beauty did not show any significant differences in 13, but in 5: 1) the ratio of eye fissure to intercanthal distance was greater in Japanese beauty; 2) eye inclination was greater in Japanese beauty; 3) the ratio of nasal width to intercanthal distance was greater in Japanese beauty; 4) the ratio of nasal and facial width was greater in Korean beauty; and 5) the ratio of vermilion size to mouth width was greater in Japanese beauty. It is assumed that Korean had narrower eye fissure, lower eye inclination, wider nasal ala, and thinner lip than what Japanese craved during that era.

Anatomy, Comparative↗

PubMed2005

Anatomy of lower lacrimal canaliculus relative to epicanthoplasty.

The aim of this study is to elucidate detailed anatomy of the lower lacrimal canaliculus relative to epicanthoplasty. Nine lower eyelids of Korean adult cadavers were studied. Serial sagittal sections of the medial side of the lower eyelids including canaliculi were made, and the specimens were observed under a light microscope. The depth and width (diameter) of the vertical portion were 2.58 +/- 0.24 mm and 0.44 +/- 0.07 mm, respectively. A vertical portion of the canaliculus was about 1 mm (1.11 +/- 0.16 mm) deep, and the horizontal portion was about 2 to 3 mm (2.08 +/- 2.74 mm) long 2 mm below the mucocutaneous junction, where an incision may be given in epicanthoplasty. The lower lacrimal canaliculus is vulnerable to injury during epicanthoplasty.

Adult↗

PubMed2005

Insertion of frontalis muscle relating to blepharoptosis repair.

The aim of the study is to elucidate the precise anatomy and histologic structure of frontalis muscle relating to blepharoptosis repair. Five Korean adult cadavers were used. The soft tissues of the lower forehead, including muscle and periosteum, were dissected at different sagittal planes and then observed histologically and photographed. Masson's trichrome was used for staining the section specimens. The frontalis muscle passed through and inserted into the bundles of the orbicularis oculi muscle on the superior border of the eyebrow at middle and medial side of the upper eyelid. However, at the lateral side it inserted about 0.5 cm below the superior border of eyebrow. At the medial side of the eyelid, the most distal frontalis muscle was located deep to the procerus muscle and superficial to the corrugator muscle. A knowledge of the distal insertion of the frontalis muscle is referred to the muscle transfer procedure for blepharoptosis repair.

Aged↗

PubMed2005

Effect of cog threads under rat skin.

BACKGROUND: The aging face loses the tensile strength of structural integrity. Cog threads have been used recently to tighten lax skin and soft tissue. OBJECTIVE: A comparative study of the effects of cog, monofilament, and multifilament threads under rat skin. METHODS: Each cog, monofilament, and multifilament thread was inserted under the facial skin of a cadaver and the panniculus carnosus of rat dorsal skin. The maximum holding strength (MHS) of the thread and the tearing strength of the skin around the thread were measured with a tensiometer. The thickness of the capsule around the thread and the myofibroblasts was observed histologically. RESULTS: In the cadaver, the MHS of the cog thread was 190.7 +/- 65.6 g. It was greater than that of the monofilament (22.4 +/- 7.7 g) or multifilament (40.4 +/- 19.7 g) thread. In the rat, the MHS of the cog thread was 95.1 +/- 18.8 g. It was greater than that of the monofilament (4.3 +/- 1.3 g) or multifilament (10.9 +/- 2.1 g) thread in the second week. The thickness of the capsule around the cog thread was 93.0 +/- 3.2 microm. It was thicker than the monofilament thread's capsule, 39.2 +/- 12.1 microm, in the fourth week. The number of myofibroblasts presented significantly more in the cog (96.0 +/- 72.4) than in the monofilament thread (4.3 +/- 4.4). The rumpled in-between skin suspended by each of the three different threads returned to its original state in 2 weeks. CONCLUSION: The cog thread placed under the rat skin immediately pulled the skin and subcutaneous tissue. The myofibroblasts around the thread played a role in fibrous tissue contracture 4 weeks postinsertion of the thread. These findings could be the basis for clinical application.

Animals↗

PubMed2004

Topographical anatomy of the anconeus muscle for use as a free flap.

A small triangular anconeus muscle in the depth of the elbow is a continuation of the triceps brachii muscle and takes part in extension of the forearm. It is utilized clinically by certain surgeons as a muscle pedicle flap to cover defects around the elbow. However, there has been no report of an anconeus muscle free flap. This study provides the detailed anatomy of the anconeus muscle to encourage a safer utilization of it as a free flap. Thirty-four cadaveric upper extremities were treated by injections of colored latex, lead oxide, and methylene blue into the axillary artery. The average size of the muscle was 73.11 +/- 10.32 mm x 27.39 +/- 3.29 mm and the total area was 2002.48 +/- 33.95 mm2. The muscle received its blood supply from three sources: recurrent posterior interosseous artery, medial collateral artery, and posterior branch of the radial collateral artery. The recurrent posterior interosseous artery was constantly present. Its average outer diameter was 1.11 +/- 0.32 mm and its average length was 29.05 +/- 9.29 mm. The anconeus muscle free flap is large enough to cover a defect of 25.65 cm2 in either the hand or forearm, and the recurrent posterior interosseous artery and venae comitantes are suitable for microvascular anastomosis.

Aged↗

PubMed2004

Cutaneous distribution of infraorbital nerve.

The aim of this study is to elucidate precisely the cutaneous distribution of the infraorbital nerve. Ten hemifaces of five Korean adult cadavers (2 males and 3 females) were subjected to the dissection. The cutaneous branches of the infraorbital nerve were distributed over the infraorbital area, which bounds on superiorly the lower eyelid margin, inferiorly the horizontal line crossing the mouth corners, medially 0.5 cm to midline, and laterally 2 cm lateral to the temporal canthus of the eyes. The infraorbital nerve had 19.5 branches (range, 15-24 branches). The mean area supplied by the infraorbital nerve was 25.8 cm2 (range, 24.0-28.2 cm2). The mean area of the superior labial branch was 13.1 cm2 (range, 11.2-14.3 cm2) and broader than either the 7.5 cm2 (range, 6.6-8.8 cm2) of the lower palpebral branch or the 7.6 cm2 (range, 6.7-9.3 cm2) of the external nasal branch. The external nasal branch was overlapped with the lower palpebral and superior labial branch, but the last two branches do not overlap each other. The nonoverlapped branch of the infraorbital nerve exhibits a restricted anesthesia, but the overlapped branch sustains sensory perception to some extent when being damaged.

Adult↗

PubMed2004

Communication of infraorbital nerve and facial nerve: anatomic and histologic study.

The maxillary nerve, second division of the trigeminal nerve, is entirely sensory. It has been reported that drooling may occur later in the event of fracture of the zygoma in which hypesthesia prevails. The aim of the study is to elucidate additional detailed anatomy of the infraorbital plexus, consisting of the superior labial branch of the infraorbital nerve and facial nerve in the cheek. The authors dissected infraorbital nerves and facial nerves in 16 cadavers. Most terminals of the zygomatic branch of the facial nerve emerged from under the levator labii superiors and zygomatic muscle and infraorbital nerve. A hazardous zone of infraorbital plexus is found in a circle 36 mm in diameter. Its center is located 22 mm below the inferior orbital foramen. This hazardous zone of infraorbital plexus should be kept in mind when performing any procedures related to zygoma, maxilla, or deep cheek injuries.

Cheek↗

PubMed2004

Zygomaticotemporal nerve passage in the orbit and temporal area.

Injury of the zygomaticotemporal nerve causes paresthesia in its distributed area, and its entrapment induces protractive pain in case of manipulation of the orbital lateral wall, a Gillies or Dingman reduction procedure for a zygomatic fracture, or an endoscopic subperiosteal facelift. The aim of this study was to elucidate the surgical anatomy of the zygomaticotemporal nerve in the orbit and temporal area. Twenty hemifaces from 10 adult Korean cadavers (10 male and 10 female) were used in the study. The zygomaticotemporal nerve ran along the lateral wall of the orbit, passed through the zygomaticotemporal foramen, and reached to the temporal fossa. The point where the zygomaticotemporal nerve appears at the margin of zygomatic bone is defined as the vulnerable point (Vp); hence, the nerve might be injured during surgical procedures. The Vp was 11.29 +/- 2.65 mm below the zygomaticofrontal suture and 21.76 +/- 2.76 mm from the superior border of zygomatic arch. The most vulnerable points were within a 10-mm diameter circle (vulnerable zone). Its center was 11 mm from the zygomaticofrontal suture at an angle of 45 degrees inferolaterally. The zygomaticotemporal nerve ran between the deep layer and the superficial layer of the deep temporal fascia. It ran just superficial to the deep layer of the deep temporal fascia toward the temporal area and innervated the temporal skin. The area innervated by terminal branches of the zygomaticotemporal nerve included a circle with 30-mm diameter, with the center located 10 mm superior to the top of the auriculocephalic sulcus and 30 mm lateral to the lateral canthus. Precautions should be taken when working in the area of the vulnerable zone during the Dingman procedure involving periorbital incision in case of zygomatic fracture.

Adult↗

PubMed2004

A split ostectomy of mandibular body and angle reduction.

Combined mandibular angle resection with angle-splitting ostectomy (ASO) is more effective than conventional simple or multistaged ostectomy. Removal of the outer cortex of the mandibular body by ASO lessens the protuberance of the masseter muscle. In this study, the anatomy of the mandibular canals in seven human cadavers was studied in detail, and a guideline for ASO and mandibular angle ostectomy was set up so as to avoid injury to the inferior alveolar nerve. The most vulnerable area of the inferior alveolar nerve is the line from the gonion (G) to the junction (O) of the intersecting vertical line along the anterior border of the ramus and the horizontal line on the alveolar crest because of the thin anterior distance (AD) between the buccal surface of the mandible and the outer wall of the mandibular canal. The resection line should not be above 17.5 mm at the GO line to ensure a safe inferior distance, the distance between the inferior border of the mandible and the floor of the mandibular canal (21.6 +/- 4.1 mm). The body of the mandible was less vulnerable to injury to the inferior alveolar nerve in ASO because of the relatively thicker AD at the second molar (8.3 mm) and first molar (6.8 mm). Pilot surgery was performed in five cadavers. The lateral cortex was safely split off, avoiding injury to the inferior alveolar nerve, and angle ostectomy was then done. This method was applied in two clinical cases without any complications. The "split ostectomy of mandibular body and angle reduction" is a new and safe method of avoiding the injury to the inferior alveolar nerve.

Adult↗

PubMed2004

Innervation of the temporalis muscle for selective electrical denervation.

Bilateral hypertrophy of the temporal muscle can give the impression of an aggressive and violent facial appearance. The authors performed closed selective denervation of the deep temporal nerve using electrocauterization. Before the procedure, precise anatomical knowledge of the deep temporal nerve is mandatory. Sixteen hemifaces of Korean cadavers were dissected. To standardize the position of the anterior division of the deep temporal nerve, we recorded the distance from six anatomical landmarks to the nerve. In 19% (3 of 16) of cadavers, one deep temporal nerve was observed, and in the remainder, two deep temporal nerves were identified. In all our specimens, a mean of three (range: 1-4) temporal branches also arose from the buccal nerve. One temporal branch arising in common with the masseteric nerve was observed in 2 of 15 of our specimens. On the infratemporal crest, the distances from the anterior division of the deep temporal nerve to the posterior division of the deep temporal nerve and to the masseter nerve were 4.7 +/- 0.9 mm (range: 3-6 mm) and 8.3 +/- 1.1 mm (range: 6-10 mm), respectively. On the superior surface of the zygomatic arch, the distance from the most concave point of the zygomatic bone (point A) to the anterior division of the deep temporal nerve was 19.4 +/- 1.2 mm (range: 18-21 mm). On the inferior surface of the zygomatic arch, the distance from the prominent point of the condylar process of the mandible to the anterior division of the deep temporal nerve was 22.3 +/- 1.6 mm (range: 22-25 mm). Great consistency in the position of the anterior division of the deep temporal nerve was shown. The results of this study could provide a basis for closed selective denervation of the anterior division of the deep temporal nerve using electrocauterization. Clinical application is needed.

Adult↗

PubMed2004

Pattern of the temporal branch of the facial nerve in the upper orbicularis oculi muscle.

The purpose of this study is to clarify a pattern of the temporal branch of the facial nerve in the upper orbicularis oculi muscle (OOM) and an impact in exploiting the frontalis myofascial advancement flap. The authors investigated the pattern of the temporal branch of the facial nerve in the upper OOM in 20 cadavers. The highest and lowest level of the nerve coursing into the OOM were measured at three different sagittal/vertical planes through the lateral canthus, midpalpebral fissure, and medial canthus, respectively. The authors designate a hazard zone that delineates a circle with 1.0-cm diameter and its center located inferiorly and laterally in the direction of -15 degrees 7.5 cm from the lateral canthus. The highest level of the those twigs that entered OOM on the X-axis and Y-axis with the origin of lateral canthus is +2.51 +/- 0.23 cm, +2.70 +/- 0.35 cm, and the lowest is 0 cm, +2.68 +/- 0.32 cm, respectively. The highest level of the those twigs on the Y-axis with the origin of lateral canthus, mid-palpebral fissure, and medial canthus is +3.47 +/- 0.27 cm, +3.49 +/- 0.45 cm, and +2.97 +/- 0.35 cm, and the lowest is +1.62 +/- 0.12 cm, +1.82 +/- 0.17 cm, and +1.63 +/- 0.22 cm, respectively. Those twigs of the temporal branch of the facial nerve coursed horizontally along the fibers of OOM with interconnections but did not cross over the superior orbital rim. The authors describe details of the temporal branch of the facial nerve in the OOM and designate a hazard zone, wherein the temporal branch should be spared. They also assure that injury of the temporal branch of the facial nerve is inevitable in the procedure of the frontalis myofascial advancement flap.

Cadaver↗

PubMed2004

Selective neurectomy of the masseteric nerve in masseter hypertrophy.

Asian women prefer to have more delicate and feminine features rather than prominent squared mandibular angles. It was proposed that a selective neurectomy of the masseteric nerve might result in muscular atrophy and subsequent reduction of the hypertrophic mass of the masseter muscle. This study is aimed at an elucidation of the precise course of the masseteric nerve and the impact of a neurectomy in case of masseter hypertrophy. Eleven heads of Korean cadavers were halved and dissected. The masseteric nerve and artery in the mandibular notch were clearly located. A selective neurectomy of the masseteric nerve was performed in four cases of masseter hypertrophy. The masseteric nerve and artery behind the temporalis muscle at the mandibular notch cross over to the masseter. The masseteric nerve was found 11.3 +/- 2.6 mm horizontally from the anterior border of the ramus and 11.3 +/- 2.6 mm above the mandibular notch and the superior masseteric artery, 25.6 +/- 3.7 mm from the ramus, and 7.8 +/- 2.6 mm above the notch. A neurectomy of the masseteric nerve can be used to reduce the hypertrophied masseter and as an ancillary procedure of mandibular angle ostectomy. One procedure can accompany another in the reduction of a prominent mandibular angle.

Adult↗