Topographical Anatomy of the Adductor Muscle Group in the Albino Rat (Rattus norvegicus).

In comparative anatomy, the adductor muscles are said to be quite variable and to often cause difficulty in separation. The arrangement of these muscles and the possible occurrence of the adductor minimus and obturator intermedius muscles in the albino rat has not been investigated. The aim of this study was to accurately describe the adductor muscles in the albino rat (Rattus norvegicus). We hypothesized that all adductor muscles are constantly present and can be separated in a constant manner, and that the adductor minimus and obturator intermedius muscles are constant structures. Both pelvic limbs of 30 formalin-embalmed male albino rats were carefully dissected. The identification of the individual muscles was made based on their position in relation to the two branches of the obturator nerve and by comparing our results with previous findings in other species including humans. All examined rats had two gracilis muscles. The adductor longus muscle was the most superficial and smallest individual. The adductor brevis split into two parts of insertion-the femoral and genicular parts. The adductor magnus and minimus muscles could be separated constantly. The obturator intermedius muscle was a constant structure next to the obturator externus muscle. The adductor muscles of the albino rat were constantly separable and could be clearly assigned to their names. Further research is needed to investigate these muscles, especially the obturator intermedius muscle, in other species including humans.

Phrenic Nerve Transfer to Musculocutaneous Nerve: An Anatomical and Histological Study.

BACKGROUND: To restore elbow flexor muscle function in case of traumatic brachial plexus avulsion, the phrenic nerve transfer to the musculocutaneous nerve has become part of clinical practice. The nerve transfer can be done by means of video-assisted thoracic surgery without nerve graft or via supraclavicular approach in combination with an autograft. This study focuses on a detailed microscopic and macroscopic examination of the phrenic nerve. It will allow a better interpretation of existing clinical results and, thus, serve as a basis for future clinical studies. MATERIAL AND METHODS: An anatomical study was conducted on 28 body donors of Caucasian origin (female n = 14, male n = 14). A sliding caliper and measuring tape were used to measure the diameter and length of the nerves. Sudan black staining was performed on 15 µm thick cryostat sections mounted on glass slides and the number of axons was determined by the ImageJ counting tool. In 23 individuals, the phrenic nerve could be examined on both sides. In 5 individuals, however, only one side was examined. Thus, a total of 51 nerves were examined. RESULTS: The mean length of the left phrenic nerves (33 cm (29-38 cm)) was significantly longer compared to the mean length of the right phrenic nerves (30 cm (24-33 cm)) (p < 0.001). Accessory phrenic nerves were present in 9 of 51 (18%) phrenic nerves. The mean number of phrenic nerves axons at the level of the first intercostal space in body donors with a right accessory phrenic nerve was significantly greater compared to the mean number of phrenic nerves axons at the same level in body donors without a right accessory phrenic nerve (3145 (range, 2688-3877) vs. 2278 (range, 1558-3276)), p = 0.034. A negative correlation was registered between age and the nerve number of axons in left (0.742, p < 0.001) and right (-0.273, p = 0.197) phrenic nerves. The mean distance from the upper edge of the ventral ramus of the fourth cervical spinal nerve to the point of entrance of the musculocutaneous nerve between the two parts of the coracobrachialis muscle was 19 cm (range, 15-24 cm) for the right and 20 cm (range, 15-25 cm) for the left arm. CONCLUSIONS: If an accessory phrenic nerve is available, it presumably should be spared. Thus, in that case, a supraclavicular approach in combination with a nerve graft would probably be of advantage.

The Corona mortis is similar in size to the regular obturator artery, but is highly variable at the level of origin: an anatomical study.

An enlarged anastomosis connecting the vascular territory of the external iliac and the obturator artery may replace most or all of the latter. This relatively common vascular variation, known as Corona mortis, can lead to death in the worst-case scenario if injured. Despite being well-known, exact anthropometric data are lacking. The purpose of this study was to determine diameters of the regular obturator artery, the Corona mortis and the inferior epigastric artery. In addition, the level of origin of the Corona mortis was quantified. The obturator artery and its norm variants were dissected bilaterally in 75 specimens (37 females, 38 males) and measured using two different methods. The Corona mortis was present in 36 of the 150 hemipelves (24%), presenting in one third of all cases bilaterally. Its level of origin measured from the commencement of the inferior epigastric artery was subject to high variability (4.4-28.3 mm). The mean diameters of the Corona mortis (mean 2.5 and 2.1 mm, respectively) and the regular obturator artery (mean 2.4 and 2.0 mm, respectively) were similar for both methods. There were no significant sex nor side differences. The diameter of the inferior epigastric artery was significantly smaller distal to the origin of the Corona mortis. The high incidence, non-predictable level of origin of the Corona mortis and its size similar to the regular obturator artery support its clinical relevance even to date. Clinicians should always be aware of an additional arterial vessel close to the pelvic brim.

Topographical anatomy of the albino rat's ischiotrochanteric muscle group.

The obturator internus, gemelli, and quadratus femoris muscles are thought to be postural muscles. Thus, they are in the focus of research. Although these muscles are described in other species, detailed descriptions are still lacking for the albino rat. We hypothesized that the rat's ischiotrochanteric muscle group is comparable to that of humans. We aimed to provide a detailed description, and to compare the rat's condition with other species including humans. Both hind limbs of 30 adult male formalin-fixed albino rats were carefully dissected and photo documented. Our results were then compared with data for other species and descriptions of human anatomy. The gemellus muscle was one single muscle mass, originating from the lesser sciatic notch and an unnamed groove on the dorsal aspect of the ischium. The obturator internus muscle arose from the inner aspect of the tabula of ischium. Both muscles formed a continuum and inserted as one complex on the medial aspect of the greater trochanter. The quadratus femoris muscle originated from the outer aspect of the tabula of ischium and inserted on the distal portion of the intertrochanteric crest, and the dorsal aspect of the lesser trochanter. Despite minor differences, the topographical conditions of these muscles are comparable between rats and other mammals including humans.

Is There a Nerve-free Zone in Which a Subscapularis Split Can Safely be Performed? An Anatomical Study Using Embalmed Specimens.

BACKGROUND: The subscapularis muscle, which is part of the rotator cuff, is located anterior to the shoulder. In anterior approaches to the shoulder, its supplying nerves are at risk of iatrogenic injury, which may cause postoperative complications. It is unclear whether there is any nerve-free zone in which a subscapularis split can be performed without risking nerve damage. QUESTIONS/PURPOSES: In an anatomical study, we asked: (1) With the arm abducted 60° and externally rotated, what are the median and shortest distances between the entrance point of the subscapular nerves into subscapularis muscle and the myotendinous junction of this muscle? (2) What are those distances in other positions of the shoulder? (3) Did those measurements differ between specimen sexes or sides? METHODS: In 84 shoulders of 66 embalmed anatomic specimens, the distance from the myotendinous junction of the subscapularis muscle to the entrance points of the subscapular nerves into the subscapularis muscle was measured using an inelastic thread and a millimeter gauge with the arm abducted 60° and rotated externally. In 16 of 84 shoulders, which were selected randomly, after taking the measurements with the arm abducted 60° and rotated externally, arm positions were changed and further measurements were taken with the arm abducted 60° and rotated neutrally, abducted 60° and rotated internally, and abducted 90° and rotated externally. The positions of the entrance points were described with statistical parameters and compared between different sides, sexes, and joint positions. Measurements were verified using eight fresh-frozen shoulders, showing no difference in distances compared with embalmed specimens and confirming reproducibility of measurements. Absolute distances were used to minimize possible distortion when using correlations and for straightforwardness and clinical applicability. RESULTS: The median (range) distance was 43 mm (24 to 64) for the upper subscapular nerve and 38 mm (23 to 59) for the lower subscapular nerve with the arm rotated externally and abducted 60°. In the 16 subsamples, internal rotation decreased the distance to 34 mm (24 to 49) and 31 mm (15 to 43), respectively, and maximal external rotation and 90° of abduction increased it up to 49 mm (30 to 64) and 41 mm (27 to 56). Comparison of left and right sides yielded no difference. Comparison of sexes showed distances for the lower subscapular nerve of 36 mm (23 to 54) in females versus 39 mm (24 to 60) in males. CONCLUSION: In no specimen did the nerve come closer than 23 mm medial to the myotendinous junction with the arm rotated externally and abducted. Therefore, not exceeding a distance of 20 mm medial to the myotendinous junction with the arm rotated externally seems to provide sufficient protection from nerve injury during surgery. CLINICAL RELEVANCE: Based on the described zone of 20 mm medial to the myotendinous junction, the risk of nerve injury in a subscapularis split approach can be minimized.

Extramuscular and Intramuscular Course of the Nerve Innervating the Abdominal Part of the Pectoralis Major Muscle: An Anatomical Study with Regard to Transaxillary Endoscopic Subpectoral Breast Augmentation.

BACKGROUND: During transaxillary endoscopic subpectoral breast augmentation, the innervation of the abdominal part of the pectoralis major muscle can be injured. The question has been raised whether this could even be of value, as for a better result, the caudal fibers of the pectoralis major muscle have to be detached from their origin. The authors' aim was to identify the exact position and the intramuscular course and target of these nerve branches. METHODS: Fifty pectoralis major muscles and their supplying nerve branches from 27 formalin-fixed anatomical specimens were studied using macroscopic dissection and anthropometry. Furthermore, eight muscles underwent the modified Sihler procedure to determine the intramuscular course and target of the supplying nerve branches. RESULTS: The branches for the abdominal part of the pectoralis major muscle pierced the pectoralis minor muscle or coursed around its lower border 3.2 to 8.4 cm from the tip of the coracoid process. Within the muscle, at least one small nerve branch, innervating the abdominal part, ascended into the lowermost portion of the sternocostal head, and anastomosed with the lowest small branch of its supplying nerve branches. CONCLUSIONS: Because of the variable position of the nerve branches, they may often cross the operative field during transaxillary endoscopic breast augmentation. However, their interruption can be of value, because weakening of the lower part of the pectoralis major muscle is desired to keep the implant in place, and to avoid animation deformity.

[An innovative concept for microsurgical training: a feedback analysis]. / Mikrochirurgisches Training ­ ein innovatives, modulares Ausbildungskonzept: eine Feedbackanalyse.

BACKGROUND: There has been a shift in microsurgical education towards simulation training. Hence a number of training programs are being proposed to educate aspiring microsurgeons. However, it is challenging to master the skill of microsurgery and no program has proposed a fully satisfactory training model to date. Therefore, we present an innovative course concept and assess the participants' feedback. METHODS: Being offered a four-step modular curriculum, participants can tailor their program to their individual needs and reinforce specific aspects of their training. The program is characterised by exercises ranging from basic techniques performed on avital biologic models to specific surgical techniques performed on human anatomic specimens. In our feedback questionnaire we ask participants to evaluate the parameters "course design", "expectations" and "overall satisfaction" based on a Likert scale with 5 items (100 %, 75 %, 50 %, 25 % and 0 %). RESULTS: From 2015 to 2017, 274 students completed and evaluated individual courses. The average values exceeded 90 % for all three parameters. DISCUSSION: In conclusion, we have developed and evaluated an innovative training program with a constantly high satisfaction rate and a rising number of participants, thus contributing to the advancement of microsurgical skills in Central Europe.

A ratio to approximate the proximodistal extent of the flexor retinaculum in relation to the hand length.

The flexor retinaculum of the hand is a fibrous structure forming the carpal tunnel in conjunction with the carpal bones. To prevent incomplete release of the carpal tunnel it is of benefit to know about the expected longitudinal expansion of the flexor retinaculum. The objective of the present study was to identify a possible correlation between the proximodistal expansion of the flexor retinaculum and the length of the hand. We conducted an anatomical study on 124 hands of 62 body donors. The hand length and the length of the flexor retinaculum were measured in millimeters. By dividing the length of the flexor retinaculum by the hand length an individual ratio was calculated. The mean length of the observed hands was 187.8 mm. The mean proximodistal length of the flexor retinaculum was 27.2 mm (range, 14-39 mm). A positive correlation was noted between the proximodistal length of the flexor retinaculum and length of the hand (p = 0.01). On average, the length of the flexor retinaculum corresponded to 14% (range, 8-20%) of the hand length in right hands versus 15% (range, 11-20%) in left hands. A greater proximodistal length of the flexor retinaculum in longer hands compared to shorter hands can be expected. The length of the flexor retinaculum corresponds to 14-15% of the length of the hand. However, one should be aware that the length of the flexor retinaculum extends as far as 20 % of the length of the hand.

Innervation of the distal part of the vastus medialis muscle is endangered by splitting its muscle fibers during total knee replacement: an anatomical study using modified Sihler's technique.

Background and purpose - The distal part of the vastus medialis muscle is an important stabilizer for the patella. Thus, knowledge of the intramuscular nerve course and branching pattern is important to estimate whether the muscle's innervation is at risk if splitting the muscle. We determined the intramuscular course of the nerve branches supplying the distal part of the vastus medialis muscle to identify the surgical approach that best preserves its innervation.Material and methods - 8 vastus medialis muscles from embalmed anatomic specimens underwent Sihler's procedure to make soft tissue translucent while staining the nerves to study their intramuscular course. After dissection under transillumination using magnification glasses all nerve branches were evaluated.Results - The terminal nerve branches were located in different layers of the muscle and ran mostly parallel but also transverse to the muscle fibers. In half of the cases, the latter formed 1 to 3 anastomoses and coursed close to the myotendinous junction. Additionally, most of the branches extended into the ventromedial part of the knee joint capsule.Interpretation - To preserve the innervation of the distal part of the vastus medialis muscle, any split of the muscle during surgical approaches to the knee joint should be avoided.

A Phylogenetic and Ontogenetic Perspective of the Unique Accumulation of Arterial Variations in One Human Anatomic Specimen.

Background and objectives: Anatomical dissection is an indispensable means of acquiring knowledge about the variability of the human body. We detected the co-existence of several arterial variations within one female anatomic specimen during routine anatomical dissection. The aim of this study was to evaluate if this status is a regular pattern in any of other vertebrates. Materials and Methods: Besides of a meticulous anatomic dissection, we performed a literature review concerning the frequency, the phylogenesis, and ontogenesis of all of these variations. Results: Exceptionally, the middle colic artery arose from an extraordinarily divided celiac trunk. The kidneys received three polar arteries. On the left side, a corona mortis replaced the obturator artery. The aortic arch gave rise to a bicarotid trunk, and the right subclavian artery originated and coursed as a typical lusorial artery leading to a non-recurrent laryngeal nerve on the right side. Furthermore, variations of the branches of the thyrocervical trunk were found to be present. Extraordinarily, in their cervical portion both internal carotid arteries gave rise to two arteries each. All of these variations developed within two to three weeks, around the sixth week of gestation. It was not possible to ascribe all or even one of the variations to a singular species of vertebrates. Conclusion: Apparently, arterial variations are frequently a result of random development. Medical professionals must always be aware of anatomical variations; the absence of such awareness would create major difficulties during surgery. The present case confirms the relevance of anatomical dissection, particularly for medical students.

There are no safe areas for avoiding the perforating arteries along the proximal part of the femur: A word of caution.

Knowledge about the variable course of the perforating arteries near the body of the femur is essential during surgical procedures (e.g., percutaneous cerclage wiring, plate osteosynthesis, Ilizarov technique). Our aims were to determine the number of perforating arteries, and to identify safe zones along the body of the femur within which perforating arteries are unlikely to pass toward the back of the thigh. The number of perforating arteries was determined in both legs of 100 formalin-fixed anatomic specimens of both sexes. The level of passage of perforating arteries near the body of the femur was measured in reference to a line from the anterior superior iliac spine to the medial femoral condyle. In each leg, two to seven perforating arteries were present. In 64% of legs, at least one artery divided into two to four branches before entering the back of the thigh. Thus, the total number of branches passing near the body of the femur varied between two to nine. Perforating arteries passed to the back of the thigh at every level between 14.0 and 36.5 cm from the anterior superior iliac spine (16-39% of the leg length). Within this distance, no safe zones along the body of the femur could be identified. The present study shows the high variability regarding number and course of the perforating arteries. Surgeons can be faced with an artery at every level on the posteromedial aspect of the body of the femur between 14.0 and 36.5 cm distally to the anterior superior iliac spine. Clin. Anat. 33:507-515, 2020. © 2019 Wiley Periodicals, Inc.

When and why was the phrenicoabdominal branch of the left phrenic nerve placed into the esophageal hiatus in German textbooks of anatomy? An anatomical study on 400 specimens reevaluating its course through the diaphragm.

BACKGROUND: The phrenicoabdominal branch of the left phrenic nerve passes between muscle fiber bundles within the costal part of the diaphragm near the pericardium. In most German textbooks of anatomy, however, its passage is described to be found in the esophageal hiatus. The aim of this study was to reevaluate its topography relative to the diaphragm in a multicentric study and to identify the initiation of this description. METHODS: In this multicentric study, the most dorsomedial branch of the left phrenic nerve was identified as the phrenicoabdominal branch in 400 embalmed anatomic specimens of Caucasian origin. The distance between its passage and the apex of the pericardium, the left border of the esophageal hiatus, and the inner aspect of the left sixth rib was measured on the cranial aspect of the diaphragm. Textbooks on human anatomy published in German language between 1700 and 2018 were reviewed for their description of the passage of the left phrenicoabdominal branch through the diaphragm. RESULTS: The first statement on the passage of the left phrenicoabdominal branch through the esophageal hiatus was given in 1791 by Sömmering. Since then, in German textbooks of anatomy, a duality in the description of the passage of the left phrenicoabdominal branch persists. In none of the individuals examined in this study, the left phrenicoabdominal branch passed through the esophageal hiatus. In 99.5% of all cases, it pierced the costal part of the diaphragm dorsal to or at the same level as the apex of the pericardium. The mean distances (standard deviations) were 3.4 (±1.5) cm to the apex of the pericardium, 5.8 (±2.2) cm to the esophageal hiatus, and 5.5 (±1.6) cm to the inner aspect of the left sixth rib. CONCLUSION: The findings on the position of the left phrenicoabdominal branch relative to the diaphragm help to improve topographical knowledge and prevent inadvertent nerve injury during surgical interventions on or near the diaphragm. Further to this, these results may form a substantial basis to adopt the correct description of the passage of the left phrenicoabdominal branch to anatomical textbook knowledge.

The anterolateral ligament of the knee and the lateral meniscotibial ligament - Anatomical phantom versus constant structure within the anterolateral complex.

BACKGROUND: Concerning the ongoing controversy about the existence and nature of the anterolateral ligament (ALL) of the knee joint, we reinvestigated the formation of the anterolateral part of its fibrous capsule in anatomic specimens. Furthermore, we wanted to clarify if the lateral meniscus has established a constant anchoring to the lateral tibial condyle via a lateral meniscotibial ligament (lmtl). METHODS: Forty paired embalmed lower extremities taken from 20 human body donors (15 men and five women) underwent exact macroscopic dissection. For the detailed evaluation of the lmtl, additionally 12 specially dissected joint specimens were used. In two of these specimens, the lmtl underwent further histological examination. RESULTS: In all specimens, the anterolateral part of the knee joint fibrous capsule was established by the iliotibial tract and the anterior arm of the aponeurosis of the biceps femoris muscle. According to their close connection and the fact that the anterolateral part of the fibrous capsule is exclusively assembled by these two aponeuroses, they do not leave any space for a distinct ALL connecting the lateral femoral epicondyle and the lateral tibial condyle. The constantly present lmtl was identified as a flat, rectangular bundle of collagen and also elastic fibers reinforcing the inner aspect of the fibrous capsule. Following an oblique direction, it connected the lateral face of the lateral meniscus with the superolateral margin of the lateral tibial condyle. The lmtl measured, on average, 17.1mm in longitudinal and 13mm in anteroposterior direction. CONCLUSION: Our results show that there is no evidence for the existence of an ALL in human knee joints. It is represented either by the iliotibial tract or - most likely - by the anterior arm of the short head of the biceps femoris muscle. On the other hand, the lmtl was found to be a constantly present structure.

Morphological characteristics and variations of the human quadratus plantae muscle.

The quadratus plantae (QP) is a highly variable structure. A number of partly inexact descriptions of this entity have been provided in textbooks of anatomy. Although several authors have examined the QP, its exact site of origin and type of insertion have hitherto not been specified. The aim of this study has been to provide detailed qualitative and quantitative data about the number of heads, points of origin, and type of insertion of the QP. The QP in both feet of 50 formalin-fixed specimens of body donors (25 men and women) were analyzed by gross anatomical dissection. It was composed of one (34%), two (57%) or three heads (9%). The latter condition was observed only in men. The lateral head was absent in 31 feet, and the medial head only in one right foot of a man. The medial head arose, amongst others, in 100% of the examined cases from the medial calcaneal surface, in 93% from the long plantar ligament and in 80% from the plantar calcaneocuboid ligament. The lateral head arose, amongst others, from the long plantar ligament in 90%, and from the lateral process of the calcaneal tuberosity in 64% of the examined feet. The type of insertion was always a mixture of at least two of three types; i.e. muscular (84%), tendinous (89%) and aponeurotic (45%). As additional findings, the flexor digitorum accessorius longus (FDAL) and the peroneocalcaneus internus (PCI) were observed in 12% of all individuals and in 20% of men. The present investigation revealed that the QP may be classified according to the number of heads, but no classification can be given for its points of origin or type of insertion. The present data are mandatory for anatomical and surgical practice and will hopefully lead to further imaging and biomechanical studies.

Accessory Spleen in the Greater Omentum: Embryology and Revisited Prevalence Rates.

PURPOSE: To investigate in a large sample the prevalence rates of accessory spleens located in the greater omentum and to explain the embryological background and the vascular supply of this rare congenital disorder. METHODS: Evaluation of the presence of accessory spleens located in the greater omentum was performed in 5 different international anatomical centers investigating a total of 1,045 body donors. Arterial and venous blood supply and the precise location of the respective vasculature within the splenic ligaments are described based on dissection of this rare condition in a male specimen. RESULTS: The reported prevalence rates from 5 different centers were: 0.5% (out of 380 body donors), 0% (out of 230 donors), 0% (out of 200 donors), 2% (out of 200 donors), and 0% (out of 35 donors). The cumulative prevalence rate obtained from 1,045 anatomical dissections was 0.6%. The identified accessory spleen measured 3 × 3 × 2.5 cm and was located in the left upper abdominal quadrant. A vascular stag 7.5 cm in length was identified within the gastro-splenic ligament, containing an artery and a vein piercing the greater omentum from posterior. CONCLUSION: An accessory spleen located in the greater omentum is a rare congenital disorder. Physicians should be aware of the fact that in patients without any representative symptom history a nodular mass located within the greater omentum could be an accessory spleen.

The high variability of the chiasma plantare and the long flexor tendons: Anatomical aspects of tendon transfer in foot surgery.

As tendon transfer of the flexor hallucis longus (FHL) and the flexor digitorum longus (FDL) is an established procedure, exact knowledge of the formation of the chiasma plantare is of great interest. Although the quadratus plantae (QP) appears to play a major role, it has been rarely addressed in previous studies. The aim of the present study was to reinvestigate the formation of the chiasma plantare and the composition of the long flexor tendons in order to clarify the inexact and partly contradictory descriptions published from 1865 onward. The chiasma plantare and the long flexor tendons in both feet of 50 formalin-fixed specimens of body donors (25 men and women) were analyzed by gross anatomical dissection. It was composed of one (3%), two (69%) or three layers (28%) which were variably established by the tendinous and muscular fibers of the FHL, the FDL and the QP. In 61% the FHL gave one or more slips to the FDL, and in 39% there was a bidirectional interconnection between the two tendons. The slip from the FHL to the FDL largely reinforces the second (45%), or the second and third tendon (46%). Thus, the FHL is involved in the first tendon in all cases, in the second one in 97% of cases, and in the third tendon in about one half of cases (53%). In all instances, the FDL contributes to the third to fourth, in 98% the second, and in at least 39% to the first tendon. The QP reinforces the second to fourth tendon in nearly all cases, the fifth in about one half of cases, and even the first tendon in 14% of cases. In addition, the individual composition of the five long flexor tendons arising from the chiasma plantare was analyzed in detail. Special emphasis was placed on the evaluation of side and sex differences as well as individual symmetry. Furthermore, biomechanical, developmental and phylogenetic aspects were outlined. In terms of the outcome of this study, the FHL appears to be the better donor for tendon transfer to restore lost function, but harvesting the FDL seems to be more suitable to prevent long-term functional damage. The decision depends on the individual patient's needs and should be made with due care.

Distribution Pattern of the Superior and Inferior Labial Arteries: Impact for Safe Upper and Lower Lip Augmentation Procedures.

BACKGROUND: Understanding the precise position and course of the superior and inferior labial arteries within the upper lip and the lower lip is crucial for safe and complication-free applications of volumizing materials. METHODS: One hundred ninety-three anatomical head specimens (56.5 percent female cadavers) of Caucasian ethnicity were investigated in this large multicenter anatomical study. In total, six 3-cm-long vertical incisions were performed on each lip (midline and 1 cm medial to the angles of the mouth) to identify the position of the superior and inferior labial arteries in relation to the orbicularis oris muscle. RESULTS: Three different positions of the superior and inferior labial arteries were identified: submucosal (i.e., between the oral mucosa and the orbicularis oris muscle in 78.1 percent of the cases), intramuscular (i.e., between the superficial and deep layers of the orbicularis oris muscle in 17.5 percent of the cases), and subcutaneous (i.e., between the skin and the orbicularis oris muscle in 2.1 percent of the cases). The variability in changing the respective position along the labial course was 29 percent for the total upper and 32 percent for the total lower lip. The midline location was identified in both the upper and lower lips to be the most variable. CONCLUSIONS: Based on the results of this investigation, a safer location for the application of volumizing material is the subcutaneous plane in the paramedian location of both the upper lip and the lower lip. Care has to be taken when aiming to inject in the midline, as the artery can be identified more frequently in superficial positions.

Congenital Bilateral Absence of the Radial Artery: A Very Rare Variation in Humans - Phylogenetic and Ontogenetic Aspects.

In an 80-year-old Caucasian woman, both radial arteries were found to be replaced by an enlarged anterior interosseous artery. Additionally, the right forearm revealed a persistent median artery which formed the superficial palmar arch together with the ulnar artery. In both hands, the replaced radial artery was connected only to the deep but not the superficial palmar arch. In clinical practice, lack of an arterial pulse on the radial aspect of the wrist joint may indicate the presence of this anatomic variation. In this case, arterial blood sample collections, application of contrast media, invasive measurements of blood pressure, and several angiographic interventions cannot be performed via the radial artery. As this is the fourth reported case since 1830, bilateral aplasia of the radial artery appears to be an exceptional variation in humans. Thus, the phylo- and ontogenetic aspects of this anomaly are discussed.