Hyun-Ho Kwak

Branching Patterns of the Infraorbital Nerve and Topography within the Infraorbital Space

The infraorbital nerve (ION) is the terminal branch of the maxillary nerve; it supplies the skin and mucous membranes of the middle portion of the face. This nerve is vulnerable to injury during surgical procedures of the middle face. Severe pain and loss of sense are noted in patients whose infraorbital nerve is damaged. In the study presented here, we investigated the branching pattern and topography of the ION, about which little is currently known, by dissecting 43 hemifaces of Korean cadavers. In most cases, the infraorbital artery was located in the middle (73.8%) and superficial to the ION bundle (73.8%) at its exit from the infraorbital canal. The ION produced four main branches, the inferior palpebral, internal nasal, external nasal, and superior labial branches. The superior labial branch was the largest branch of the ION produced the most sub-branches. These sub-branches were divided into the medial and lateral branches depending upon the area that they supplied. We were able to classify four types of branching pattern of the external and internal nasal branch and the medial and lateral sub-branches of the superior labial branch of the ION at the site of their emergence through the infraorbital foramen (types I-IV). Type I, where all four branches are separated occurred the most frequently (42.1%). These findings will help to preserve the ION while performing certain types of maxillofacial surgery, such as removal of a tumor from the upper jaw and fracture of the upper jaw.

The discomallear ligament and the anterior ligament of malleus: An anatomic study in human adults and fetuses

According to some reports, movement of the malleus, resulting from anterior hypertension on the discomallear ligament (DML), could produce aural symptoms related with damage to middle ear structures. The aim of this study was to examine the topographic relationship of the DML and the anterior ligament of malleus (ALM). Four fetuses and 16 adult hemi-sectioned heads were used to determine the anatomic-clinical relevance of DML and ALM in temporomandibular disorder. In fetal specimens, the DML was distinctly interposed between the malleus and the disc of the temporomandibular joint (TMJ), and the ALM had a structure apparently composed of the superior and inferior lamellae, running anteriorly in continuation with the sphenomandibular ligament (SML) through the future petrotympanic fissure (PTF). In all adult specimens, the DML was inserted into the malleus, and it expanded broadly toward the disc and capsular region of the TMJ in a triangular shape and inserted into the disc and capsule of the TMJ. The two-lamellae structure of the ALM was not distinguishable in adult specimens. The overstretched ALM resulted in movement of the malleus in five cases, but similar tension applied to the DML did not cause any movement of the malleus. This result provides an indication of the clinical significance of the ALM, a ligamentous structure continuous with the SML. It is apparent that the ALM has the potential to cause aural symptoms as a result of damage to the middle ear structure.

An anatomical study of the insertion of the zygomaticus major muscle in humans focused on the muscle arrangement at the corner of the mouth.

Background: The aim of this study was to clarify the arrangement of the zygomaticus major muscle by means of topographic examination, and to evaluate the anatomical variations in the insertion of the zygomaticus major at the perioral region. Methods: After a detailed dissection in the modiolar region, the insertion area of the zygomaticus major was observed in 70 embalmed cadavers. Results: At the perioral region of the dissected specimens, the anatomical aspects of the muscular arrangement and attachment of the zygomaticus major muscle were classified into four categories. In type I, the superficial muscle band of the zygomaticus major is blended and interlaced with the levator anguli oris, whereas the fibers of the deep muscle band blend into the buccinator, passing deeper to the levator anguli oris; this was the situation most commonly encountered (54.3 percent). It was found that the insertion of the zygomaticus major was divided into superficial and deep bands (types I and IV) [42 cases (60 percent)] and into three layers of superficial, middle, and deep fibers (type II) [17 cases (24.3 percent)]. The others were cases where the zygomaticus major was inserted deep into the levator anguli oris as a single muscle band (type III) [11 cases (15.7 percent)]. Conclusion: The arrangement and insertion patterns of the zygomaticus major in this study are expected to provide critical information for surgical planning for the procedure of facial reanimation surgery.

Clinical and anatomical approach using Sihler's staining technique (whole mount nerve stain)

Sihlers staining allows visualization of the nerve distribution within soft tissues without extensive dissection and does not require slide preparation, unlike traditional approaches. This technique can be applied to the mucosa, muscle, and organs that contain myelinated nerve fibers. In particular, Sihlers technique may be considered the best tool for observing nerve distribution within skeletal muscles. The intramuscular distribution pattern of nerves is difficult to observe through manual manipulation due to the gradual tapering of nerves toward the terminal end of muscles, so it should be accompanied by histological studies to establish the finer branches therein. This method provides useful information not only for anatomists but also for physiologists and clinicians. Advanced knowledge of the nerve distribution patterns will be useful for developing guidelines for clinicians who perform operations such as muscle resection, tendon transplantation, and botulinum toxin injection. Furthermore, it is a useful technique to develop neurosurgical techniques and perform electrophysiological experiments. In this review, Sihlers staining technique is described in detail, covering its history, staining protocol, advantages, disadvantages, and possible applications. The application of this technique for determining the arterial distribution pattern is also described additionally in this study.

Topography of the third portion of the maxillary artery via the transantral approach in Asians.

The maxillary artery (MA) passes over the lateral pterygoid muscle in the infratemporal fossa and enters the pterygopalatine fossa through the pterygomaxillary fissure. Refractory epistaxis is managed by ligation of the sphenopalatine artery via a transmaxillary-transantral approach; there is considerable risk of complications associated with such invasive surgical approaches. The aim of this study was to describe the gross anatomy and variations therein of the MA and its branches at the pterygopalatine fossa. One hundred hemifaces of embalmed Korean adult cadavers were dissected to establish the precise course of the MA and its branching patterns. The average thickness of the posterior wall of the maxillary sinus was 0.8 mm, but varied over a wide range from 0.2 to 3.6 mm. We classified the third part of the MA into 3 morphological categories: looped (61%), bifurcated (19%), and straight (18%). Two cases could not be classified into any of these 3 categories. The pattern of the bifurcation between the sphenopalatine and descending palatine arteries was classified into 4 types: Y (19%), intermediate (36%), M (17%), and T (28%). The posterior wall of the maxillary sinus was divided into 9 sections. The branching areas of the sphenopalatine and descending palatine arteries were most frequently (62% of cases) located at the top of the medial partition and at the middle of the medial partition (30% of cases).

An Anatomic Study of the Bifid Zygomaticus Major Muscle

The dramatic changes in facial expression are most remarkable in the perioral region. Among the perioral musculatures, the zygomaticus major (ZMj) muscle plays an important role in the facial expression. The aim of this study was to determine the anatomic patterns of the bifid ZMj through a topographic examination at the perioral region. Through 70 dissections of the hemifaces, the insertion area of the ZMj was observed in 70 embalmed cadavers. The bifid ZMj was observed in 28 cases (40%). In most cases of the bifid ZMj, the superior muscle fibers were larger and wider than the inferior fibers. Bilateral bifid ZMj was found in 71.4% of the bifid ZMj specimens. The arrangement and insertion patterns of the ZMj in this study are expected to provide critical information for the surgical planning and procedure for facial reanimation surgery.

An anatomical study of the buccinator muscle fibres that extend to the terminal portion of the parotid duct, and their functional roles in salivary secretion

Until now there has been no definitive anatomical study describing the area where the parotid duct enters the buccinator muscle. In this study, we performed anatomical and histological examinations to investigate the relationship between the parotid duct and the buccinator muscle. Thirty specimens (including the buccinator and the terminal portion of the parotid duct) were obtained from embalmed Korean cadavers. Dissection was performed on 22 of these specimens, and the remaining eight specimens were prepared for histological examination and stained with haematoxylin–eosin or Gomori trichrome. In all specimens, small, distinct muscle fibres originating from the buccinator muscle extended to and inserted into the terminal portion of the parotid duct. The topography of these fibres varied, and we classified them into three categories according to where they originated. Type I buccinator muscle fibres, which inserted into the terminal portion of the parotid duct, originated simultaneously from the anterior and posterior aspects of the duct (ten cases, 45.5%). Type II fibres originated from the anterior aspect of the duct and inserted into the anterior side of the duct (seven cases, 31.8%). Type III fibres originated from the posterior aspect of the parotid duct and ran anteriorly toward the duct (five cases, 22.7%). These results were confirmed in the histological examination of all eight specimens. Based on these findings, we have proposed a tentative description of the physiological role of the buccinator muscle fibres in salivary secretion and in the formation of the sialoliths.

α-Mangostin Induces Apoptosis and Cell Cycle Arrest in Oral Squamous Cell Carcinoma Cell

Mangosteen has long been used as a traditional medicine and is known to have antibacterial, antioxidant, and anticancer effects. Although the effects of α-mangostin, a natural compound extracted from the pericarp of mangosteen, have been investigated in many studies, there is limited data on the effects of the compound in human oral squamous cell carcinoma (OSCC). In this study, α-mangostin was assessed as a potential anticancer agent against human OSCC cells. α-Mangostin inhibited cell proliferation and induced cell death in OSCC cells in a dose- and time-dependent manner with little to no effect on normal human PDLF cells. α-Mangostin treatment clearly showed apoptotic evidences such as nuclear fragmentation and accumulation of annexin V and PI-positive cells on OSCC cells. α-Mangostin treatment also caused the collapse of mitochondrial membrane potential and the translocation of cytochrome c from the mitochondria into the cytosol. The expressions of the mitochondria-related proteins were activated by α-mangostin. Treatment with α-mangostin also induced G1 phase arrest and downregulated cell cycle-related proteins (CDK/cyclin). Hence, α-mangostin specifically induces cell death and inhibits proliferation in OSCC cells via the intrinsic apoptosis pathway and cell cycle arrest at the G1 phase, suggesting that α-mangostin may be an effective agent for the treatment of OSCC.

Topographic and histologic characteristics of the sural nerve for use in nerve grafting.

The sural nerve (SN) is a sensory nerve supplying the skin of the lateral and posterior parts of the inferior third of the calf and the lateral side of the foot and is easy to harvest because of its location posterior and superior to the tip of the lateral malleolus. Seventy-one lower limbs from 42 Korean cadavers were dissected to describe the joining type and level of perforated the fascia of the SN. The segments of sural nerve were stained and measured. The communication and joining patterns of the SN formed by the medial sural cutaneous nerve and the communicating branch of the lateral sural cutaneous nerve could be divided into five types. The region where the medial sural cutaneous nerve and the communicating branch of the lateral sural cutaneous nerve join together was observed in 52 cases with this found in the lower two fifths of the calf in 28 (53.8%) of the specimens. The mean number of fascicles was 8.1 (range, 2-12) at the lower calf and 5.8 (range, 1-11) at the middle calf before where the medial sural cutaneous nerve and the communicating branch of the lateral sural cutaneous nerve joined. The mean total areas of the fascicles were 0.55 mm2 and 0.43 mm2 in the lower and middle calf, respectively. This study demonstrates that the anatomy of the SN affects its harvesting for use in nerve grafts with the reported results providing a useful reference for SN grafting procedures.

Medial muscular band of the orbicularis oculi muscle.

Abstract Despite the importance of anatomic variations in the muscular bands around the orbicularis oculi muscle (OOc), little is known about them. The morphology and variations therein of the medial muscular band of the OOc were thus examined in the current study. Sixty-one hemifaces of Korean cadavers were dissected to enable examination of the anatomic organization of the muscles around the OOc. A medial muscular band of the OOc was observed in 40 cases (65.6%). Three patterns of attachment were found. In type A (14 cases, 23%), it attached to the frontal belly without being attached to the medial canthal tendon; in type B (14 cases, 23%), it originated from the medial canthal tendon at the lower portion of the OOc and inserted into the cheek skin, and in type C (12 cases, 19.7%), it was also observed to insert into the cheek skin and attach to the frontal belly without being attached to the medial canthal tendon. The distance between the inferior edge of the OOc and the subnasale was 16.3 (SD, 4.3) mm and 14.5 (SD, 4.4) mm in cases with and without a medial muscular band, respectively. A space was observed on the inferolateral side of the OOc in about 67.2% of cases. These findings regarding the medial muscular band of the OOc increase further the anatomic variations associated with this region. In addition, it appears that this medial muscular band of the OOc can help to prevent drooping of the OOc.