Large-caliber persistent sciatic artery with aneurysm

Herein is reported a rare case of right persistent sciatic artery (PSA) in the cadaver of a 96-year-old woman who did not have any clinical manifestations related to this anomaly when alive. The anomalous PSA originated from the internal iliac artery, directed toward the infrapiriform foramen, and descended the dorsal side of the thigh. Approximately 20 mm inferior to the infrapiriform foramen, the PSA formed a relatively large aneurysm elongating for approximately 30 mm in length. It then passed under the long head of the femoral biceps muscles, and reached the popliteal fossa, maintaining a constant caliber (approx. 13 mm) as it went down distally. In contrast, the femoral artery was very narrow, and tapered at the level of the knee joint. In addition, the popliteal vein gave rise to two branches, one ran along with the sciatic artery and the other pierced the adductor muscles, and appeared on the ventral side of the thigh. It then drained into the deep femoral vein, which reached the pelvis via the femoral vein. The present case is an interesting example for clinicians who work in pelvic surgery.     

A case of the persistent sciatic artery

During the dissecting practice of students at Gifu University School of Medicine in 1989, a rare developmental anomaly showing the sciatic artery was found in the left lower limb of a cadaver of 88-year-old Japanese female. The left sciatic artery (5 mm in diameter) arose from the internal iliac artery and appeared at the buttock between the piriformis and superior gemellus muscles through foramen infrapiriforme. The femoral artery (6 mm in diameter) of the left lower limb was normal in distribution and belonged to the type III by Adachi's classification (1928). The terminal vessel of the femoral artery was joined to the sciatic artery at the popliteal fossa.     

Arterial supply to the sciatic nerve in the gluteal region

The arterial supply to the sciatic nerve was investigated in 20 human lower limbs (10 right, 10 left) from 20 cadavers (14 females, aged 84 +/- 9.6 years, range 66-95 years: 6 males, aged 80 +/- 8.2 years, range 70-90 years). In all limbs examined at least 1 sciatic artery could be identified supplying the sciatic nerve in the gluteal region. In total 28 sciatic arteries were identified, of which 14 arose from the medial circumflex femoral artery, 11 from the inferior gluteal artery, 2 from the first perforating artery, and 1 from the internal pudendal artery. In 5 limbs, 2 sciatic arteries were observed, being independent branches from the medial circumflex femoral and inferior gluteal arteries in 4 limbs and separate branches of the medial circumflex femoral artery in 1 limb. In 1 limb, 4 sciatic arteries were observed: 1 from the inferior gluteal artery, 2 from the medial circumflex femoral artery, and 1 from the first perforating artery. In the remaining 14 limbs a single sciatic artery was observed, which in one case arose from the internal pudendal artery, a previously unreported observation.     

Similarities and dissimilarities of the blood supplies of the human sciatic,tibial, and common peroneal nerves

The aim was to investigate the arterial supply of the sciatic, tibial, and common peroneal nerves. Thirty‐six lower limbs of 18 human fetuses were studied. The fetuses had been fixed in buffered formalin and the blood vessels injected with barium sulfate. Fetal age ranged from 12 to 28 weeks of gestation. Microdissection of the fetal lower extremities was done under ×5 magnifying lenses. The sciatic nerves of 10 lower extremities were dissected and excised and radiographs taken. The extraneural arterial chain of the sciatic nerve was composed of 2–6 arterial branches of the inferior gluteal artery, the medial circumflex femoral artery, the perforating arteries, and the popliteal artery. The extraneural arterial chain of tibial nerve was composed of 2–5 arteries, which were branches of the popliteal, the peroneal, and the posterior tibial arteries. Radiographs showed the presence of complete intraneural arterial chains in the sciatic and tibial nerves, formed from anastomosing vessels. Dissection showed that, in 97.2% of the specimens, the common peroneal nerve was supplied only by one popliteal artery branch, the presence of which was confirmed radiologically. The sciatic and tibial nerves are supplied by numerous arterial branches of different origins, which provide for collateral circulation. In contrast, the common peroneal nerve is most frequently supplied only by one elongated longitudinal blood vessel, a branch of the popliteal artery. Such a vascular arrangement may make the common peroneal nerve less resistant to stretching and compression. Clin. Anat. 26:875–882, 2013. © 2012 Wiley Periodicals, Inc.     

Extraneural arterial blood vessels of human fetal sciatic nerve

Nerves get segmental blood supply either from the neighboring muscular and cutaneous branches or from the regional main arterial trunks. The aim of our research was to detect, in the gluteal and posterior femoral region, the blood vessels which are involved in the blood supply of the human fetal sciatic nerve, as well as to establish their origin. Micro-dissection was performed on 48 fetal lower extremities which were previously fixed in 10% formalin. Micropaque solution (barium sulfate) was injected into their blood vessels. The fetal gestational age was established by measuring the crump-crown length and it ranged from the third to the ninth lunar month. The observed nutritional arteries of the human sciatic nerve originated from the inferior gluteal artery, medial circumflex femoral artery, perforating branches, and popliteal artery. The anastomotic arterial chain of the human sciatic nerve was observed in all cases. In 75% of the cases it was composed of the branches of the inferior gluteal artery, the medial circumflex femoral artery and the first two perforating arteries. The nutrient branch of the third perforating branch was less frequently (in 14.5% of the cases) part of this anastomotic arterial chain.     

Anatomical bases of superior gluteal nerve entrapment syndrome in the suprapiriformis foramen

Observation of a 60 year-old-man with superior gluteal nerve (SGN) entrapment neuropathy in the suprapiriformis foramen encouraged us to explore, through anatomical dissection, the possible morphological etiologies of this condition. Ten SGNs in five embalmed cadavers were dissected via gluteal and pelvic access. The origin, course and distribution of the nervous trunk and its relations were studied. In most cases, the nerve fibers of the SGN arose from ventral branches of L4, L5 and S1 to constitute the nervous trunk in the pelvis, then reached the gluteal area and divided into two branches, cranial and caudal. By running through the suprapiriformis foramen with the cranial gluteal vascular pedicle, the nervous trunk was always up between the superior edge of the piriformis muscle and the greater sciatic notch; rarely some of the nerve fibers went through the muscle. Bone, muscular and vascular morphological factors liable to cause SGN entrapment syndrome, and the circumstances of discovery, were analyzed. The role of hypertrophy of the piriformis muscle, resulting in a narrow suprapiriformis foramen, was confirmed through surgery.     

收肌管下口处隐神经阻滞的应用解剖

目的　探讨收肌管下口处隐神经的精细解剖和体表定位。 方法　采用12具尸体标本20侧下肢对收肌管及其下口部位进行精细解剖和测量。 结果　收肌管下份隐神经在前内侧、股动脉居中、股静脉在后。在收肌管下口和稍上位置,膝降动、静脉和隐神经分别穿大收肌腱板出收肌管并伴行下行,隐神经在膝内侧缝匠肌腱和股薄肌腱之间穿深筋膜,伴大隐静脉下降至小腿和足内侧。收肌管下口分别距髌骨上缘（5.85±0.15）cm、髌骨底内侧缘（2.72±0.60）cm、股内侧皮肤表面（4.08±0.66）cm。 结论　髌骨上缘上5.85 cm、髌骨底内侧缘内2.72 cm、股内侧皮肤表面4.08 cm深处为收肌管下口隐神经阻滞的体表定位;股动脉是收肌管下口上隐神经阻滞的定位标志;膝降动脉的隐支是收肌管下口下隐神经阻滞的识别标志。     

收肌管下口处隐神经阻滞的应用解剖

目的探讨收肌管下口处隐神经的精细解剖和体表定位。方法采用12具尸体标本20侧下肢对收肌管及其下口部位进行精细解剖和测量。结果收肌管下份隐神经在前内侧、股动脉居中、股静脉在后。在收肌管下口和稍上位置,膝降动、静脉和隐神经分别穿大收肌腱板出收肌管并伴行下行,隐神经在膝内侧缝匠肌腱和股薄肌腱之间穿深筋膜,伴大隐静脉下降至小腿和足内侧。收肌管下口分别距髌骨上缘(5.85±0.15)cm、髌骨底内侧缘(2.72±0.60)cm、股内侧皮肤表面(4.08±0.66)cm。结论髌骨上缘上5.85 cm、髌骨底内侧缘内2.72 cm、股内侧皮肤表面4.08 cm深处为收肌管下口隐神经阻滞的体表定位;股动脉是收肌管下口上隐神经阻滞的定位标志;膝降动脉的隐支是收肌管下口下隐神经阻滞的识别标志。     

Bilateral persistent sciatic vein: report of a case with developmental,histological and clinical aspects

Objective

Bilateral large variant veins were encountered in the lower extremity. It was aimed to identify the structural characteristics of this rare case and then, regarding the structural features, to overview its formation process and denomination.

Material and method

During the routine dissection of a 93-year-old male cadaver, bilateral large variant veins were found at the thigh. Valves of the veins were examined and evaluated together with the vascular wall histology.

Results

The variant vein was loosely attached to the sciatic nerve by fibrous tissue and had anastomoses with the popliteal vein in the popliteal fossa on each side. The popliteal veins were hypoplastic on both sides. The right variant vein was passing through the fibers of the adductor magnus muscle 56.2 mm above the adductor hiatus, which corresponds to the third perforating branch of deep femoral vein. The left one was turning to the front over the adductor magnus muscle, at the lower border of quadratus femoris muscle. The left variant vein was corresponding to the descending branch of the medial circumflex femoral vein. Both variant veins had one incomplete and three well-developed valves.

Conclusion

In accordance with the findings, the variant vein was concluded to be an embryonic remnant, rather than an acquired one subsequent to any obstruction of the femoral vein. Regarding their connection with the popliteal vein but not with the internal iliac vein, both variant veins were denominated as “lower type persistent sciatic vein”. Such a variation would be important with respect to the risk of complication during popliteal sciatic nerve blockade.     

The popliteal region an anatomical study and a new approach to the tibial attachment of the posterior cruciate ligament

Surgical treatment of posterior cruciate ligament injuries is gaining more and more importance. The central posterior approach according to Abbott (1945) has been considered a standard, with various complications involved owing to the local anatomic conditions. This study is intended to present a modified dorsomedial approach to the posterior capsule of the knee joint that is better adapted to the anatomic conditions. As a basis, the popliteal region was dissected in 150 knee joints, and the course of the popliteal artery with its branches as well as the bifurcation of the sciatic nerve were identified. The medial joint line served as a reference point. It has been shown that the knee joint arteries and the two sural arteries arose at relatively constant levels. At least one of the meniscofemoral ligaments was found in all of the knee joints examined the anterior ligament was present in a slightly higher percentage than the posterior ligament. The modified dorsomedial approach to the posterior joint capsule was evaluated in 50 knee joints. Dissection was achieved by blunt division of the medial head of the gastrocnemius muscle, with careful preservation of the proximal vascular supply of that muscle. It was necessary to expose neither the popliteal artery and vein nor the tibial nerve. The tibial attachment of the posterior cruciate ligament could be exposed in every knee. The advantage of the new approach to the posterior cruciate ligament described in this study consists in the preservation of the central neurovascular bundle and the excellent exposure of the tibial attachment.     

Non satellite veins in the pelvic limb of the llama (Lama glama)

The objective of this study was to determine the major differences in the venous system of the pelvic limb of the llama (Lama glama) and that of other mammals, including humans. Eight adult llamas, preserved by means of 6% formalin solution at 0°C, were dissected. The venous system was perfused with a solution of 17% coloured industrial gelatin. Two venous systems are recognised, superficial and deep. The veins of the deep system follow the same course as the arteries, except for two important veins located in the femoral, popliteal and crural regions. A more voluminous vein than the femoral originates in a venous tripod in the proximal part of the femoral canal and forms an anastomosis with the femoral vein distally. The popliteal vein gives off an expansion located along the popliteal region. In the leg, it continues with a vein that accompanies the tibial nerve and forms an anastomosis distally with the medial saphenous vein. The described venous distribution represents an interesting complement to the medial saphenous, popliteal and femoral veins, being more important than the last one for its volume. In the thigh it would correspond to the deep femoral vein as in humans and dogs; the homology in the popliteal and leg regions is too difficult because it probably corresponds to the caudal tibial vein of the human, the caudal branch of the medial saphenous vein, and the satellite vein of the tibial nerve in the horse. Anat Rec 256:99–103, 1999. © 1999 Wiley‐Liss, Inc.     

Anatomic characterization of the femoral nutrient artery: Application to fracture and surgery of the femur

The localization of nutrient foramina and direction of nutrient canals have been studied. However, information about the origin and extraosseous course of nutrient arteries is lacking in some types of long tubular and irregular bones. Thus, we aimed to reexamine the origin and course of the femoral nutrient artery (FNA) through cadaveric dissection to clarify its anatomic characteristics. Sixty thighs were collected from 57 cadavers. To fix the cadavers and visualize the small arterial branches, 10% formalin was injected from the femoral artery, followed by an injection of acrylic ink. The arterial tree in the posterior part of the thigh was recorded by line drawings. The femur received single or double FNAs via the femoral nutrient foramina, which were on and along the linea aspera. In cases with single FNA (41 of the 60 thighs), it typically arose from the four parts of the profunda femoris system: profunda femoris artery between the origins of the third and fourth perforating arteries; second perforating artery; third perforating artery; and terminal branch. In cases with double FNAs (remaining 19 thighs), the superior FNA typically arose from the second perforating artery, and the inferior FNA arose from the terminal branch of the profunda femoris artery and popliteal system. FNAs are described as branches of the perforating arteries in Terminologia Anatomica and anatomy textbooks. However, we found that FNAs also frequently arose from the profunda femoris artery and popliteal system, in addition to the perforating arteries. Clin. Anat. 33:479–487, 2020. © 2019 Wiley Periodicals, Inc.     

股内侧推进肌瓣的应用解剖

在40侧成人下肢标本上,观察了股内侧肌的形态、血供和神经支配。该肌血供分布呈节段性,来自股动脉,膝降动脉、股深动脉和旋股外侧动脉。肌的静脉回流通过与动脉的伴行静脉注入股静脉。肌的运动神经来自股神经的股内侧肌支。本文讨论了股内侧推进肌瓣的应用解剖学要点。     

Arterial variations of the upper extremities

During the dissection of the right and left upper limbs of a 70-year-old female cadaver, we encountered combined vascular anomalies. On the left side, we observed the presence of a lateral inferior superficial brachial artery, large anterior interosseous artery and an absence of a radial artery, which is quite a rare anomaly. The lateral inferior superficial brachial artery that arose 39 mm distal to the brachial artery descended to the wrist. The anterior interosseous artery originated from the brachial artery at the level of 12 mm distal to the head of the radius and descended on the anterior aspect of the interosseous membrane with the anterior interosseous branch of the median nerve. On the right side, a trifurcation of the brachial artery was observed. It gave off three terminal branches: the radial, ulnar and a muscular artery at the proximal one-third of the humerus. It is obvious that accurate information concerning unusual patterns of the arteries in the upper limbs is relevant clinically, especially in order to avoid accidental injury or intra-arterial injection.     

带腓浅神经及其营养血管筋膜皮瓣的应用解剖

目的：提供带腓浅神经及其营养血管筋膜皮瓣的形态学依据。方法：在３２侧成人下肢标本上,观测了腓浅神经及其营养血管、周围皮肤的血供情况。结果：腓浅神经（皮下段）近侧的血供为腓浅动脉深支的皮动脉、第１支肌间隔动脉,起始处外径分别为０．８ｍｍ、１．１ｍｍ;第１支肌间隔动脉穿出深筋膜前长为１．８ｃｍ。远侧则为腓动脉穿支之升支、降支的皮支和足背动脉皮支,起始处外径分别为０．９ｍｍ、０．７ｍｍ和０．８ｍｍ,穿出深筋膜前长分别为１．２ｃｍ、０．７ｃｍ和０．８ｃｍ。其神经支在神经干内或旁彼此吻合,构成纵向链式血管网,并借分支与皮肤、皮下及筋膜血管网沟通。结论：可设计带皮神经及其营养血管筋膜皮瓣,顺行或逆行转位修复邻近部位软组织缺损     

Anatomical relation between sciatic nerve and piriformis muscle and its bifurcation level during fetal period in human

Purpose

The aim of this study is to determine the morphometric development, location and variant formations of the sciatic nerve using anatomic dissection method during the fetal period.

Methods

Sciatic nerves of 200 human fetuses (103 males and 97 females) aged between 9 and 40 weeks of gestation were studied bilaterally. The bifurcation level of the sciatic nerve to its terminal branches was evaluated with respect to popliteal fossa. Then the length of the sciatic nerve, starting from where it leaves the piriformis muscle till the bifurcation point of the nerve, and its width at the point where it leaves infrapiriforme foramen and its width at the bifurcation level were measured. We also measured the distance of the sciatic nerve to the ischial tuberosity, the greater trochanter and the intergluteal sulcus. Mean values and standard deviations of all parameters according to trimesters were calculated.

Results

We found that all parameters increase with age during the fetal period (P < 0.05). Parameters do not show any significant differences between sexes (P > 0.05). In our analysis, we observed that in 98 % of the cases (on the right and the left side) the sciatic nerve leaves the pelvis below the piriformis muscle. The remaining cases (2 %) are variant formations.

Conclusion

We believe that our study will be useful for better understanding of sciatic nerve development and it may contribute to future studies in obstetrics, orthopedics and fetal pathology. Knowledge of variant formations of the sciatic nerve, its bifurcation level and its relation with neighboring structures may be important for blockade of the nerve in newborn surgeries.     

Innervation of vastus lateralis muscle

The lateral surgical approach to the proximal femur potentially damages the nerve supply to the vastus lateralis (VL) muscle. This study describes the detailed anatomy of the nerve supply to the VL muscle based on dissection of ten cadaveric lower limbs. In all specimens, a single nerve trunk arose from the femoral nerve, which is most subsequently divided into two main divisions. These divisions gave two branches each. These branches coursed from anteriorly and proximally to posteriorly and distally within the muscle. When the muscle was reflected anteriorly from its attachment to the linea aspera, there was no damage to its innervation. Splitting of the VL in the midlateral line of the femur, however, resulted in denervation of the posterior half of the muscle. Precise knowledge of the nerve supply to the VL will help avoid iatrogenic denervation of the muscle in surgical procedures at the proximal femur through the lateral approach.     

A sciatic nerve with three roots and its perforation by the enlarged ischiadic artery

Knowledge about the variations of the sciatic nerve (SN) is important for many medical science disciplines. Its compression, entrapment or injury of any kind can result in loss of sensation, pain or motor disabilities in the lower limbs. We observed concurrent neurovascular variations in the gluteal region of an adult female cadaver. The SN had three roots as it emerged out of the greater sciatic foramen. The upper root passed above the piriformis; the middle and lower roots passed below the piriformis. The three roots joined to form the SN in the gluteal region. The inferior gluteal artery (IGA) was large, and it passed below the piriformis, between the middle and lower root of the SN. After a tortuous course, this artery continued down as the sciatic/ischiadic artery. The ischiadic artery (IA) was large in size and pierced the SN in the thigh. After piercing the nerve, it terminated by dividing into muscular branches. The inferior gluteal nerve emerged out from the pelvis through the greater sciatic foramen, above the level of the piriformis. The SN in this case was highly predisposed to compression by the piriformis, IGA or IA, which in turn may lead to altered cutaneous sensation or weakness of the muscles.     

经皮椎弓根螺钉技术的解剖学基础及其临床意义

目的：为经皮椎弓根螺钉技术提供解剖学基础并在此基础上分析经皮植入椎弓根螺钉较常规开放植入椎弓根螺钉临床应用的优点。方法：选用10具经防腐固定，在解剖显微镜下对胸腰段脊柱后部结构进行逐层解剖，重点观测脊神经后支及其分支、脊柱节段动静脉的后支的来源、走行以及分布规律。结果：脊神经后支的内侧支经骨纤维管下行沿途支配横突棘肌，支配下方小关节突、筋膜和韧带。外侧支向外下行走，沿途支配背部深层肌肉。节段动脉的后支在椎间孔的上外方绕向后下方，走行于脊神经的下方和下位脊椎上关节突的外方，分为内外两支穿行于腰部深层肌肉。节段静脉后支与同名动脉伴行，并与对侧、相邻节段同名静脉在棘突和横突部位构成静脉丛。结论：避免损伤脊神经后支和节段动静脉的后支并运用可视化操作系统的经皮椎弓根螺钉植入技术，是微创脊柱外科一种新的技术手段。