Delineation and histological examination of the intramuscular innervation of the platysma: Application to botulinum neurotoxin injection.

This study aimed to identify the whole innervation pattern of the platysma using the Sihler's staining, and the axonal composition profile of the sensory-motor anastomosis identified by immunofluorescence assays. The findings provide a comprehensive understanding of the neural anatomy of the platysma and facilitate efficient and safe manipulation for neurotoxin injection. Ten fixed and two fresh hemifaces were included in this study. Sihler's staining was used to the study 10 fixed hemifaces and two fresh hemifaces were used for immunofluorescence assays. In all cases, the cervical branch of facial nerve (Cbr) broadly innervated the platysma, and the marginal mandibular branch of facial nerve (MMbr) provided supplementary innervation to the uppermost part of the platysma. The transverse cervical nerve (TCN), great auricular nerve (GAN), and supraclavicular nerve (SCN) were observed in the lower half of the platysma. In 30% of all cases, there was a communicating loop between the Cbr and TCN. In 20% of all the cases, a communicating branch joined between the Cbr and GAN. For successful esthetic rejuvenation procedures, a clinician should consider the Cbr distribution to the overall platysma and additionally innervation by individual nerves (MMbr, GAN, TCN, and SCN) to the middle and lower portions of the platysma muscle.

Intramuscular innervation of the tensor fasciae latae: Application to total hip arthroplasty.

The aims of this study were to clarify the extra- and intramuscular branching patterns of the tensor fasciae latae (TFL) with reference to surface landmarks on the thigh and to thus suggest a safe approach for total hip arthroplasty. Sixteen fixed and four fresh cadavers were dissected and subjected to the modified Sihler's staining method to reveal the extra- and intramuscular innervation patterns, and the findings were matched with surface landmarks. The landmarks were measured from the anterior superior iliac spine (ASIS) to the patella and divided into 20 parts along the total length. The average vertical length of the TFL was 15.92 ± 1.61 cm, which was 38.79 ± 2.73% when converted to a percentage. The entry point of the superior gluteal nerve (SGN) was an average of 6.87 ± 1.26 cm (16.71 ± 2.55%) from the ASIS. In all cases, the SGN entered parts 3-5 (10.1%-25%). As the intramuscular nerve branches traveled distally, they had a tendency to innervate more deeply and inferiorly. In all cases, the main SGN branches were intramuscularly distributed in parts 4 and 5 (15.1%-25%). Most tiny SGN branches were found inferiorly in parts 6 and 7 (25.1%-35%). In three of 10 cases, very tiny SGN branches were observed in part 8 (35.1%-38.79%). We did not observe SGN branches in parts 1-3 (0%-15%). When information on the extra- and intramuscular nerve distributions was combined, we found that the nerves were concentrated in parts 3-5 (10.1%-25%). We propose that damage to the SGN can be prevented if parts 3-5 (10.1%-25%) are avoided during surgical treatment, particularly during the approach and incision.

Analysis of the positional relationship of the long thoracic nerve considering clinical treatment.

INTRODUCTION: The long thoracic nerve (LTN) has a risk of being damaged during chest surgery and should be considered when performing anesthesia such as a serratus anterior plane block (SAPB). We analyzed the relationship between landmarks-the fourth to ninth intercostal space (ICS) at the midaxillary line (MAL), through which the distal part of the LTN passes-and the LTN. MATERIALS AND METHODS: We used 25 specimens from 17 embalmed Korean cadavers. The MAL, level of rib and ICS, and regions 5 cm anteroposterior to the MAL (aMAL/pMAL) were established to measure the position of the LTN crossing the MAL, pathway of the LTN, and entering points of the LTN to the SA. RESULTS: The LTN crossed the MAL in 76% of the specimens. The LTN crossed the MAL within the fifth to sixth rib level in 70.8%. Seventy-six percent of the branches entered the SA within the fourth to sixth ICS. The fifth rib and ICS were the most frequent regions aMAL; however, several branches were found pMAL. The LTN entered the SA in 92.6% of the specimens within 3 cm anterior and 1 cm posterior to the MAL. CONCLUSIONS: We set the danger zone as 4 cm near the MAL at the fourth to sixth ICS for thoracotomy. In addition, we proposed the fifth ICS in aMAL at the superficial plane as the alternative injection point for SAPB when blocking the LTN, and the fifth ICS in pMAL at the deep plane to prevent blocking the LTN.

Intramuscular innervation patterns of the splenius capitis and splenius cervicis and their clinical implications for botulinum toxin injections.

INTRODUCTION: The purpose of this study was to clearly characterize the intramuscular nerve distributions of the splenius capitis and splenius cervicis muscles that are both responsible for the onset of a chronic tension type headache and to use this information to identify the effective botulinum toxin (BoNT) injection sites. MATERIALS AND METHODS: Ten splenius capitis and splenius cervicis specimens were subjected to Sihler's staining to reveal intramuscular nerve arborization patterns and determined the optimal location for BoNT injection. RESULTS: Nerve distribution patterns in the splenius capitis were identified as nerve pathways that travel down toward the origin point and others that travel up toward the insertion point. This neuromuscular innervation from the central (50%) point was distributed evenly in these two directions. The neural pathways of splenius cervicis traveled vertically from the insertion point to the origin point. If the length from the muscle origin point to the insertion point is normalized to 100%, motor neurons innervate the muscle from around the 30% to the 70% point. CONCLUSIONS: The safest and most-effective BoNT injection sites for the splenius capitis and splenius cervicis were found at around the 50% point and the 30% to the 70% point, respectively.

Guideline for Botulinum Toxin Injections in the Effective Treatment of Fibular Spasticity.

This study used a modified Sihler's staining method to analyze the nerve distributions of the fibularis muscle to identify the most effective sites for botulinum toxin injection for fibular spasticity treatment. Ten specimens of the fibularis longus and brevis were obtained bilaterally from five fixed cadavers. The applied method of modified Sihler's staining was designed to reveal the intramuscular nerve distribution of the fibularis muscles. We divided the fibularis muscles into four quarters, which were defined as Sections 1-4 starting from the proximal part of the leg. There were one, two, and three nerve entry points in one (10%), six (60%), and three (30%) of the fibularis longus specimens, respectively, and in four (40%), five (50%), and one (10%) of the fibularis brevis specimens, respectively. We counted the number of nerve endings in each section: 321 and 195 points were identified in the fibularis longus and brevis, respectively. The densities of nerve endings were highest in Section 2 of the fibularis longus (147 of 321, 46%) and in Section 3 of the fibularis brevis (78 of 195, 40%). The landmarks used in this study (the fibular head and lateral malleolus) are easily palpable on the skin's surface, allowing clinicians to target the effective injection site (Section 2) without requiring ultrasound guidance, especially for the fibularis longus. Clin. Anat. 33:365-369, 2020. © 2019 Wiley Periodicals, Inc.

A Detailed Analysis of the Blood Supply to the Subscapularis Muscle.

This study aimed to provide a comprehensive description of the arterial supply to the subscapularis (SSC) muscle. This will provide critical information for various surgical procedures. Ten specimens of embalmed Korean cadavers were dissected and subjected to modified Sihler's method to reveal the branching pattern of the arteries surrounding the subscapularis, and its intramuscular blood supply. The SSC muscle was generally supplied by branches from the subclavian artery (suprascapular artery, supraSA; circumflex scapular artery, CxSA; and dorsal scapular artery, dSA) and the axillary artery (subscapular artery, subSA; lateral thoracic artery, LTA; posterior circumflex humeral artery, PCxHA; and a branch of the axillary artery, AAbr). The anterior aspect of the muscle was supplied by the subSA, LTA, CxSA, supraSA, and AAbr. The posterior aspect of the muscle was supplied by the supraSA, PCxHA, and subSA. The dSA was more scarcely distributed than the other arteries. In two cases, the dSA supplied the portion of the muscle near the medial border of the scapular. The anterior side of the muscle tendon was supplied by the CxSA, and its posterior side was supplied by the PCxHA. The subSA can be considered to be the main branch supplying the SSA based on its distribution area of arteries. It was mostly situated within the lower region of the SSC. After distributing to the anterior surface of the SSC, some branches of the subSA reached the posterior surface as perforating branches. Clin. Anat. 32:642-647, 2019. © 2019 Wiley Periodicals, Inc.

Intramuscular innervation of the subscapularis muscle and its clinical implication for the BoNT injection: An anatomical study using the modified Sihler's staining.

Shoulder pain is commonly associated with spasticity of the rotator cuff muscles including the subscapularis (SSC). The aim of this study was to elucidate the intramuscular innervation pattern of the SSC using the modified Sihler's staining technique to facilitate the targeting of botulinum neurotoxin (BoNT) injections to alleviate shoulder spasticity. Ten SSC specimens (mean age, 81.5 years) were used in this study. Modified Sihler's staining was used to clarify the muscle and to stain the intramuscular nerves. Their extramuscular and intramuscular innervation patterns were examined. The upper subscapular, lower subscapular, thoracodorsal, and axillary nerves (USN, LSN, TDN, and AXN) innervated the SSC in 100%, 80%, 20%, and 40% of specimens, respectively. There was an anastomosis between the USN and LSN in the central portion of the SSC in more than half of the cases. The USN innervated the overall portion of the muscle. In contrast, the additional branches from the TDN and AXN innervated the inferior SSC portion. The superficial branches of the USN were mostly distributed in the superior SSC portion while the deep branches were distributed in the inferior portion. As a major intramuscular nerve within the SSC, the USN should be targeted by a BoNT injection. Regarding the USN distribution, the aim should be to spread the BoNT injectate within the central SSC portion. For supplementary injection to the AXN, the lateral approach would be more appropriate than alternatives. A physician performing a BoNT injection should consider the intramuscular innervation of the SSC portion. Clin. Anat. 32:110-116, 2019. © 2018 Wiley Periodicals, Inc.

Interfascicular septum of the calcaneal tunnel and its relationship with the plantar nerves: A cadaveric study.

The relationship between the plantar nerves and internal fascial structure of the calcaneal tunnel is clinically important to alleviate pain of the sole. The study aimed to investigate the three-dimensional (3D) anatomy of the calcaneal tunnel and its internal fascial septal structure by using microcomputed tomography (mCT) with a phosphotungstic acid preparation, histologic examination, and ultrasound-guided simulation. Twenty-one fixed cadavers and three fresh-frozen cadavers (13 men and 11 women, mean age 82.1 years at death) were used in this study. The 3D images of the calcaneal tunnel harvested by mCT were analyzed in detail. Modified Masson trichrome staining and serial sectional dissection after ultrasound-guided injection were conducted to verify the 3D anatomy. Within the calcaneal tunnel, the interfascicular septum (IFS) commenced proximal to the malleolar-calcaneal line and distal to the bifurcation of the tibial nerve into the plantar nerves. The medial and lateral plantar nerves were separated by the IFS, which divided the calcaneal tunnel into two compartments. The plantar nerves were ramified into two or three branches within each compartment. The IFS terminated around the talocalcaneonavicular joint, and the plantar nerves traveled into the sole. Clinical manipulation of the plantar nerves should be performed in consideration of the fact that they are clearly separated by the IFS. Clin. Anat. 32:877-882, 2019. © 2019 Wiley Periodicals, Inc.

Characterizing the Lateral Border of the Frontalis for Safe and Effective Injection of Botulinum Toxin.

BACKGROUND: The forehead is a common site for injection of botulinum neurotoxin type A (BoNT-A) to treat hyperactive facial muscles. Unexpected side effects of BoNT-A injection may occur because the anatomy of the forehead musculature is not fully characterized. OBJECTIVES: The authors described the lateral border of the frontalis in terms of facial landmarks and reference lines to determine the safest and most effective forehead injection sites for BoNT-A. METHODS: The hemifaces of 49 embalmed adult Korean cadavers were dissected in a morphometric analysis of the frontalis. L2 was defined in terms of FT (the most protruding point of the frontotemporal region), L0 (the line connecting the infraorbital margin with the tragus), and L1 (the line parallel to L0 and passing through FT) such that L2 was positioned 45° from L1 and passed through FT. RESULTS: The distance from FT to the superior margin of the orbicularis oculi was 12.3 ± 3.3 mm. The frontalis extended more than 5 cm along L2 in 49 of 49 cases (100%), more than 6 cm in 47 cases (95.9%), more than 7 cm in 34 cases (69.4%), more than 8 cm in 11 cases (22.4%), and more than 9 cm in 3 cases (6.1%). The lateral border of the frontalis ran parallel to and within 1 cm of the medial side of L2. CONCLUSIONS: Surface anatomy mapping can assist with predicting the lateral border of the frontalis to minimize the side effects and maximize the efficiency of BoNT-A injections into the forehead.

Effects of asymmetric sitting on spinal balance.

[Purpose] To investigate the effects of two common asymmetric sitting positions on spinal balance. [Subjects and Methods] Thirty-seven healthy subjects in their twenties were enrolled and randomly divided into two groups. Asymmetric positions of resting the chin on a hand and crossing the legs were performed by each group for 1 hour. After 1 hour, the subjects lay in the supine position again and spinal imbalance was measured using a device. [Results] After 1 hour of resting with the chin on a hand, sagittal imbalance, coronal imbalance, pelvic obliquity and lordosis angle presented spinal imbalance worsening of 1 hour of crossing legs, sagittal imbalance, pelvic torsion showed in mainly learned spinal imbalance living. [Conclusion] Good posture could be an innate ability, however it through habits. So this study is meaningful from the perspective of the importance of good posture.

Intramuscular innervation patterns of the brachialis muscle.

The aim of this study was to provide accurate anatomical descriptions of the patterns of innervation of the brachialis muscle by the musculocutaneous, radial, and median nerves. Sihler's staining method was applied to 20 brachialis muscles from 10 cadavers to reveal the intramuscular distribution patterns of the musculocutaneous, radial, and median nerves. Three patterns of innervation of the brachialis muscle by the three studied nerves were found: single, double, and triple. These innervation patterns were categorized into four types: Type I--only the musculocutaneous nerve; Type II--double innervation by the musculocutaneous and radial nerves; Type III--double innervation by the musculocutaneous and median nerves; and Type IV--triple innervation by all three nerves. Single, double, and triple innervation patterns occurred 25%, 70% (Type II, 55%; Type III, 15%), and 5% of the samples, respectively. The brachialis muscle is not solely innervated by the musculocutaneous nerve but also by the radial and median nerves, thus making it a potentially triply innervated muscle. Double innervation of this muscle with either the musculocutaneous and median nerve or the musculocutaneous and radial nerves was also observed.

Neurovascular structures of the mandibular angle and condyle: a comprehensive anatomical review.

BACKGROUND: Various surgical interventions including esthetic surgery, salivary gland excision, and open reduction of fracture have been performed in the area around the mandibular angle and condyle. This study aimed to comprehensively review the anatomy of the neurovascular structures on the angle and condyle with recent anatomic and clinical research. METHODS AND RESULTS: We provide detailed information about the branching and distributing patterns of the neurovascular structures at the mandibular angle and condyle, with reported data of measurements and proportions from previous anatomical and clinical research. Our report should serve to help practitioners gain a better understanding of the area in order or reduce potential complications during local procedures. Reckless manipulation during mandibular angle reduction could mutilate arterial branches, not only from the facial artery, but also from the external carotid artery. The transverse facial artery and superficial temporal artery could be damaged during approach and incision in the condylar area. The marginal mandibular branch of the facial nerve can be easily damaged during submandibular gland excision or facial rejuvenation treatment. The main trunk of the facial nerve and its upper and lower distinct divisions have been damaged during parotidectomy, rhytidectomy, and open reductions of condylar fractures. CONCLUSION: By revisiting the information in the present study, surgeons will be able to more accurately prevent procedure-related complications, such as iatrogenic vascular accidents on the mandibular angle and condyle, complete and partial facial palsy, gustatory sweating (Frey syndrome), and traumatic neuroma after parotidectomy.

Anatomical study of medial zygomaticotemporal vein and its clinical implication regarding the injectable treatments.

BACKGROUND: The medial zygomaticotemporal vein (MZTV), clinically known as sentinel vein, has been observed in the vicinity of the temporal branch of the facial nerve during endoscopic procedures aiming to lift the upper face. The aim of the present study was to describe the topography of the MZTV with reference to the superficial landmarks for providing detailed anatomical information during injectable treatment procedures. METHODS: Eighteen hemifaces were harvested from nine embalmed Korean adult cadavers (5 males and 4 females, mean age 76 years). The piercing location, vascular diameter, drainage pattern of the MZTV, and its relationship with the orbicularis oculi muscle (OOc) were recorded photographically, and using diagrams and written notes. RESULTS: The piercing point of the MZTV was located 26.8 ± 5.9 mm from the lateral epicanthus, 18.8 ± 6.9 mm lateral to the plane (HP) through the tragus and the lateral epicanthus, and 19.0 ± 5.4 mm superior to the plane (VP) through the lateral epicanthus point and perpendicular to the HP. The diameter of the MZTV at the piercing point was 1.9 ± 0.8 mm. All of the MZTV ultimately connected with the middle temporal vein (MTV). In particular, the MZTV was connected the MTV by anastomosing with the periorbital vein. Anastomosis of the MZTV and a well-developed periorbital vein was found in 27.8 % of cases. CONCLUSION: The physician must determine the location of the MZTV and should be able to accurately estimate its connection with significant veins at the temple to reduce the risk of severe complications during injectable treatments.

Clinical implications of the middle temporal vein with regard to temporal fossa augmentation.

BACKGROUND: The middle temporal vein (MTV) traverses the temporal fossa between the superficial and deep layers of the deep temporal fascia. During filler injection into a deficient temporal fossa, filling agents may be inadvertently injected into the MTV, which results in vascular complications. OBJECTIVE: To investigate the course of the MTV to enable safe filler injection in the temple area. MATERIALS AND MATERIALS: The course and diameter of the MTV were measured in 18 hemifaces from 9 Korean cadavers. RESULTS: The MTV was located 23.5 and 18.5 mm above the zygomatic arch at the jugale and the zygion, respectively. The diameter of the MTV at its thickest point was 5.1 mm. A splitting and reuniting pattern, such that the MTV occupied more space than a single trunk, was observed in 28% of cases. CONCLUSION: We propose that the safest area for filler injection in temporal fossa augmentation is one finger width above the zygomatic arch.

The Sihler staining study of the infraorbital nerve and its clinical complication.

The infraorbital nerve (ION) is a cardinal cutaneous nerve that provides general sensation to the mid face. Its twigs are vulnerable to iatrogenic damage during medical and dental manipulations. The aims of this study were to elucidate the distribution pattern of the ION and thus help to prevent nerve damage during medical procedures and to enable accurate prognostic evaluation where complications do occur. This was achieved by treating 7 human hemifaces with the Sihler modified staining protocol, which enables clear visualization of the course and distribution of nerves without the accidental displacement of these structures that can occur during classic dissection. The twigs of the ION can be classified into the usual 5 groups: inferior palpebral, innervating the lower eyelid in a fan-shaped area; external and internal nasal, reaching the nosewing and philtrum including the septal area between the nostrils, respectively; as well as medial and lateral superior labial, supplying the superior labial area from the midline to the mouth corner. Of particular note, the superior labial twigs fully innervated the infraorbital triangle formed by the infraorbital foramen, the most lateral point of the nosewing, and the mouth corner. In the superior 3-quarter area, the ION twigs made anastomoses with the buccal branches of the facial nerve, forming an infraorbital nervous plexus. The infraorbital triangle may be considered a dangerous zone with respect to the risk for iatrogenic complications associated with the various medical interventions such as implant placement.

Description of a novel anatomic venous structure in the nasoglabellar area.

Injectable dermal fillers are frequently used to reduce the appearance of various facial creases and rhytids. However, venous complications can develop while injecting dermal filler, especially in the nasoglabellar area. The aims of this study were to determine the anatomic patterns of the veins in the nasoglabellar area and to elucidate their detailed location with reference to various facial landmarks. Forty-one heads from Korean and Thai cadavers were dissected. When the anastomosing vein between the bilateral angular veins (AVs) was located in the nasoglabellar area, it was designated the intercanthal vein (ICV). The bilateral AVs continued as the facial vein without any communicating branches in 12 cases (29.3%). At the radix of the nose, the AV communicated with the ICV, connecting them bilaterally. The ICV was found above (type IIA) and below (type IIB) the intercanthal line in 26 (63.4%) and 3 (7.3%) cases, respectively. The ICV can be regarded as a candidate causative site for the frequent complications associated with dermal filler injection in the nasoglabellar area, and utmost care should be taken when injecting in this area, such as when performing radix augmentation and softening wrinkles in the glabellar area.

Neuroanastomosis and the innervation territory of the mental nerve.

The aim of this study was to clarify the distribution pattern and innervation territory of the mental nerve (MN) in the skin and mucosa by topographic examination by Sihler's staining, thereby providing reference anatomical information for surgical procedures and to enable prediction of regions of sensory disturbance following nerve damage. Ten human specimens were subjected to Sihler's staining, which is a highly accurate method for visualizing the distribution of nerve fibers without altering their topography. Each branch of the MN overlapped adjacent branches (five cases), or else they were distributed individually at the lower lip (five cases). The MN anastomosed with some branches of the facial nerve near the mental foramen. Moreover, some branches of the MN anastomosed with the buccal nerve of the trigeminal nerve, which supplies sensation to the skin and mucosa over the lateral region of the lower lip (six cases). The details of the distribution pattern and innervations territory of the MN presented herein may enable the prediction of a region of sensory disturbance following MN damage. Moreover, knowledge of the pattern of synapses with adjacent branches of other nerves, such as the facial (marginal mandibular and cervical branches) and the buccal nerves, might help to improve our understanding around incomplete anesthesia during the surgical procedures in oral & maxillofacial region.

Topography of the greater palatine artery and the palatal vault for various types of periodontal plastic surgery.

The purpose of the present study is to provide useful data that could be applied to various types of periodontal plastic surgery by detailing the topography of the greater palatine artery (GPA), looking in particular at its depth from the palatal masticatory mucosa (PMM) and conducting a morphometric analysis of the palatal vault. Forty-three hemisectioned hard palates from embalmed Korean adult cadavers were used in this study. The morphometry of the palatal vault was analyzed, and then the specimens were decalcified and sectioned. Six parameters were measured using an image-analysis system after performing a standard calibration. In one specimen, the PMM was separated from the hard palate and subjected to a partial Sihler's staining technique, allowing the branching pattern of the GPA to be observed in a new method. The distances between the GPA and the gingival margin, and between the GPA and the cementoenamel junction were greatest at the maxillary second premolar. The shortest vertical distance between the GPA and the PMM decreased gradually as it proceeded anteriorly. The GPA was located deeper in the high-vault group than in the low-vault group. The premolar region should be recommended as the optimal donor site for tissue grafting, and in particular the second premolar region. The maximum size and thickness of tissue that can be harvested from the region were 9.3 mm and 4.0 mm, respectively.

Sihler staining study of anastomosis between the facial and trigeminal nerves in the ocular area and its clinical implications.

INTRODUCTION: The trigeminal nerve (CN V) supplies mostly sensory innervation to the face, and the facial nerve (CN VII) conveys primarily motor fibers. The aim of this study was to elucidate their distributions and anastomoses. METHODS: Fourteen specimens of hemisectioned faces were gathered from human cadavers and stained with Sihler staining. RESULTS: The temporal (Tbr), zygomatic (Zbr), and buccal (Bbr) branches of CN VII formed trigeminofacial anastomoses in the ocular area. Communications were observed between the supraorbital nerve and the Tbr (85.7%), the infraorbital nerve and the Bbr (100%) and Zbr (28.6%), and the zygomaticofacial nerve and the Zbr (41.7%). Anastomoses were formed between the supratrochlear nerve and the Tbr (57.1%) and Bbr (50%), and the infratrochlear nerve and the Bbr (85.7%). CONCLUSIONS: Motor and sensory axons to the face contribute to trigeminofacial anastomoses, which may play key roles in subtle movements of muscles of facial expression.

Topography of the lingual foramen using micro-computed tomography for improving safety during implant placement of anterior mandibular region.

The aim of this study was to determine the location and size of the lingual foramina and the course of their canals using micro-computed tomography. Twenty Korean mandibles were scanned using a micro-computed tomography system and reconstructed three-dimensionally to enable observation of the lingual foramina and their canals. Four mandibles (20%) had a single foramen at the lingual side of the mandibular midline, 8 mandibles (40%) had 2 foramina, and 5 mandibles (25%) had 3 foramina. Three mandibles (15%) had 4 small foramina with short canals. The foramina were classified as either superior lingual foramina or inferior lingual foramina according to their vertical location relative to the mental spine. The diameters of superior lingual foramina and inferior lingual foramina were 0.75 ± 0.36 and 0.73 ± 0.38 mm (mean ± SD), respectively. The distances from the inferior border of the mandible to superior lingual foramina and inferior lingual foramina were 12.58 ± 2.49 and 6.43 ± 3.08 mm, respectively. Ten canals (21%) traveled upward to the labial side, 24 canals (51%) downward, and 13 canals (28%) parallel to it. Ten mandibles (50%) had lateral foramina.With regard to implant surgery of the anterior mandibular region, the most hazardous zones for lingual foramina are 0 to 2 mm from the midline, the upper 3 to 17 mm from the inferior border of the mandible, and the anterior 0 to 7 mm from the lingual side. Careful preoperative planning taking into account the anatomical location of these foramina might help to avoid complications due to damage to the foramina, their canals, and their contents.