Mi-Sun Hur

Microanatomy of the incisive canal using three-dimensional reconstruction of microCT images: An ex vivo study

OBJECTIVES The purpose of this study was to investigate the general structure of the incisive canal (IC) using 3-dimensional reconstruction and to classify into various types according to several criteria. STUDY DESIGN The materials used in the study were 56 anterior maxillae harvested from human cadavers. The specimens were scanned with microscopic computerized tomography (microCT), and the resulting microCT images were reconstructed in 3 dimensions. RESULTS Many ICs had 1 foramen inferiorly and 2 foramina superiorly, and the separating level was just beneath the nasal floor. The middle part of the IC was not always a single hollow canal. Single-channel, 2-channel, 3-channel, and even 4-channel ICs were observed. The ICs were classified into 4 types according to the lateral shape of the canal: vertical-straight, vertical-curved, slanted-straight, and slanted-curved. CONCLUSIONS This study disclosed the detailed morphologic features of the IC, which will be helpful in the placement of local anesthesia or implants.

Clinical implications of the topography and distribution of the posterior superior alveolar artery.

The aim of this study was to clarify the arrangement of the anatomic courses and distribution of the intraosseous branch (IObr) of posterior superior alveolar artery. The anatomic variations in the topographic relationships were described to provide beneficial data to minimize injury to the IObr during surgical procedure of the buccal wall of the maxillary sinus. The IObrs in 42 hemifaces of embalmed Korean cadavers were examined. The courses of the IObr of the posterior superior alveolar artery were classified into 2 categories: the straight (type 1) and the U-shaped (type 2). The type 1 was the most common (78.1%), and the type 2 was observed in 21.9% of the specimens. The minimum mean height from the cervix to the IObr was 21.1 mm in the first molar region. The IObr ran at the lowest level from the maxillary sinus floor at the first premolar region. These anatomic findings in the current study could represent useful information for the various surgical procedures of the maxilla.

An anatomic assessment on perforators of the lateral circumflex femoral artery for anterolateral thigh flap

The anterolateral thigh flap was originally described in 1984 as a septocutaneous flap based on the descending branch of the lateral femoral circumflex artery (LCFA). This flap has many advantages for head and neck reconstruction. However, it is not widely used as a result of the broad range of anatomic variation of the cutaneous perforators and because dissection of these perforators is tedious when they are small. The purposes of this study are to classify the vascular anatomy of the LCFA and to assess the suitability of the anterolateral thigh flap for head and neck reconstruction in Koreans. From 38 thigh dissections of Korean cadavers, the LCFA commonly arose from the deep femoral artery and divided into ascending, transverse, and descending branches. In five cases, the LCFA arose directly from the femoral artery. The cutaneous perforators were present in 37 cases except one and the septocutaneous perforators were found in 17 of the 38 cases. Of the 160 perforators, 28 (17.5%) were the septocutaneous perforators and 132 (82.5%) were the musculocutaneous perforators. The average number of cutaneous perforators for the anterolateral thigh flap was 4.2 (range, 0-8), and these perforators were concentrated in the middle third of the anterolateral thigh. The septocutaneous perforators were located more proximally than the musculocutaneous perforators. The average length of the vascular pedicle derived from the descending branch or the transverse branch was 83.3 mm (range, 53.4-124.3 mm). The results of this study suggest that the vascular anatomy of the anterolateral thigh flap was reliable and well suited for head and neck reconstruction in Koreans.

Anatomic Variations and MRI of the Intermalleolar Ligament

OBJECTIVE The purpose of this study was to identify the intermalleolar ligament morphologically and to correlate its shape with MR images. MATERIALS AND METHODS Seventy-seven ankles were used in this study. After the intermalleolar ligament had been located in the posterior ankle space, its medial and lateral attaching sites were identified, and its length, width, and thickness were measured. MRI was performed on 26 ankles before they were dissected (20 specimens) or serially sectioned (six specimens). The serial sections were taken at a thickness of 2 mm in the sagittal and horizontal directions. RESULTS The intermalleolar ligament was observed in 81.8% of the specimens and was composed of more than two bundles of fibers in all cases. The medial arising sites of the ligament were diverse (e.g., from the medial malleolus to the floor of the fibrous tunnel of the flexor hallucis longus). The ligament narrowed laterally and attached with the posterior talofibular ligament to the medial fossa of the lateral malleolus. Their morphologic shapes were also diverse, depending on their medial arising sites, the number of the composing fiber bundles, and the degree of bundle compactness. The intermalleolar ligament appeared as a thick string or as more than two fine parallel stripes on coronal MR images and as a linear structure on axial images. On sagittal images, the ligament appeared as scattered dots in the medial part and as a thin flat or nodular structure in the lateral part. CONCLUSION The intermalleolar ligament seemed to be an almost invariably present anatomic entity with diverse morphologic features on MR images.

Topography of the masseter muscle in relation to treatment with botulinum toxin type A.

OBJECTIVE The objective of this study was to provide the safest and most efficient site for injection of botulinum toxin type A into the masseter muscle. STUDY DESIGN This study was performed on 40 hemifaces from cadavers. The surface of the masseter was compartmentalized into areas I to VIII. Areas I, III, V, and VII were assigned to represent the upper 4 compartments from the posterior aspect of each muscle, and areas II, IV, VI, and VIII were assigned to represent the lower 4 compartments. RESULTS The parotid gland usually covered compartments I and II, and the marginal mandibular branch of the facial nerve was located a mean of 7.4 mm above the inferior mandibular margin. The parotid duct was usually located above the reference line connecting the tragus and the cheilion. CONCLUSION The center of compartment VI is the safest and most efficient injection site for botulinum toxin type A into the masseter muscle.

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.

New anatomical insight of the levator labii superioris alaeque nasi and the transverse part of the nasalis.

PurposeThe aim of this study was to clarify the morphology and topography of the deep layer of levator labii superioris alaeque nasi muscle (LLSAN) and the transverse part of the nasalis. Anatomical variations in the topographic relationships were also described to understand the function of the LLSAN and the transverse part of the nasalis.MethodsAnatomical dissections were performed on 40 specimens of embalmed Korean adult cadavers.ResultsThe LLSAN was divided into two layers, which were superficial and deep in the levator labii superioris muscle (LLS), respectively. The superficial layer of LLSAN descended on the LLS, and the deep layer was located deep in the LLS. The deep layer of LLSAN originated from the superficial layer of LLSAN and the frontal process of the maxilla. It inserted between the levator anguli oris and the orbicularis oris muscles. This transverse part of the nasalis received some muscle fibers from the superficial layer of LLSAN in 90% (36/40) of specimens. The transverse part of the nasalis originated from the maxilla and ascended, passing posterior to the superficial layer of LLSAN in 65% (26/40) of specimens. However, it originated as two muscle bellies from the maxilla and the upper half of the alar facial crease, respectively, in 35% (14/40) of specimens.ConclusionsThese findings will be crucial data to understand the structure and function of the LLSAN and the transverse part of the nasalis.

Extra- and intramuscular nerves distributions of the triceps surae muscle as a basis for muscle resection and botulinum toxin injections

PurposeTo compare the distribution of extramuscular nerve branches with their intramuscular ramifications in the triceps surae muscle, thus providing anatomical substantiation for the topography of muscle resection and botulinum toxin injections.MethodsDissection and modified Sihler’s staining of 18 whole-mount human cadaveric specimens.ResultsThe distance between the areas with the highest extramuscular branch density and the area of densest intramuscular arborization in gastrocnemius and soleus muscles is approximately 10% of the calf length. This finding should be taken into consideration during nerve blocking and botulinum toxin injections for the treatment of spasticity. Intramuscular nerve arborization patterns make it possible to outline neuromuscular segments in the gastrocnemius and soleus muscles.ConclusionsSurgical or therapeutic interventions in areas of high extramuscular and intramuscular nerve density can increase the efficacy and safety of botulinum toxin injections and neurotomy. Intramuscular nerve branching patterns should be taken into consideration during triceps surae resection.

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.

Topography and Spatial Fascicular Arrangement of the Human Inferior Alveolar Nerve

BACKGROUND Topography and fascicular arrangement of the inferior alveolar nerve (IAN) can provide critical information for the estimation of damage to IAN based on patient symptoms, or conversely to evaluate the symptoms resulting from injury to the IAN. PURPOSE The fascicular composition and organization of the IAN were determined to confirm the microarchitecture of the IAN bundles into each of the mandibular teeth, including the composition of the mental nerve. MATERIALS AND METHODS The IAN within the mandibular canal (MC) was examined in 30 hemifaces of embalmed Korean cadavers. RESULTS The most common patterns of nerve fascicle innervation to the mandibular teeth could be grossly classified into three: (1) the superior buccal portion of the IAN innervating the molars, (2) the superior portion innervating the premolars, and (3) the superior lingual or the superior lingual and inferior lingual portions in the posterior MC and the lingual portions in the anterior MC, innervating the incisors and canine. The buccal two-thirds portion of the IAN was composed of the mental nerve. CONCLUSION The IAN had distinctive fascicular organizations, which make it possible to forecast the degree, location, and extent of nerve damage according to presenting symptoms.