gross anatomical study to the blood supply of the sciatic nerve in human

Identifying the blood supply to the peripheral nerves is important in understanding the pathology of different types of neuropathy, and in selecting the suitable nerves for vascularized nerve grafts. This work was undertaken to study the sources and distribution of the blood supply to the sciatic nerve. Twelve cadavers [10 fresh that included 8 adults and 2 stillborns, and 2 preserved cadavers] were used in the present study. The blood vessels supplying the sciatic nerves were traced to identify their sources and also, the outer sheaths of the dissected sciatic nerves were reflected to study the arrangement and distribution of the feeding blood vessels. The results showed that the inferior gluteal artery gave a branch that divided into an ascending and descending branches to the sciatic nerve. The sciatic nerve also received nutrient branches from the perforators of the profunda femoris artery and from the surrounding muscles. The popliteal artery gave a nutrient artery that ran through the sciatic nerve proximally. All the feeding vessels gave side branches in the outer sheath of the sciatic nerve forming one or two layers of arterial arcades in the epineurium. The outer sheath of the nerve with the arterial arcades inside it formed a mesentery-like structure. The ascending and descending branches of the feeding blood vessels formed a continuous tortuous central artery inside the sciatic nerve. In conclusion, the sciatic nerve received nutrient branches from the inferior gluteal, the perforators of the profunda femoris, the popliteal arteries and from the surrounding muscles. These branches ran in a mesentery-like structure and formed a central tortuous artery

blood and nerve supply of the long head of biceps femoris muscle compared to the gracilis muscle

The material used in this study was 16 cadavers [5 fresh and 8 preserved adult cadavers and 3 stillborns]. The common iliac arteries of both sides in each cadaver were injected with lead oxide solution mixed with red latex in equal proportions. The gracilis and long head of biceps femoris muscles were exposed and dissected to identify their neurovascular bundles. The long head of biceps femoris got a major arterial pedicle from the inferior gluteal artery in all the cadavers dissected. It got also three major arterial pedicles in 75% of the cadavers and in 25% of the cadavers; it got only two major arterial pedicIes from the perforators of the profunda femoris artery. Each arterial pedicle was accompanied by two venae comitants that drained into the inferior gluteal or the profunda femoris veins. The long head of biceps muscle got also several minor arterial pedicles that entered the muscle at different and inconstant locations. The most distal major arterial pedicle lied at a mean distance of 25.3cm from the insertion of the muscle. The nerve supply to the long head of biceps femoris entered its middle third in 62.5% and the proximal third in 12.5% of the specimens. In 25% of the cases a single neural trunk originated from the sciatic nerve. It divided into two branches that entered the proximal and middle thirds of the muscle. The length of the long head of biceps femoris muscle ranged from 38 to 46cm with an average of 42cm. It was possible in all the dissected cadavers to rotate the long head of biceps femoris to wrap the anal canal. Regarding the gracilis muscle, the major arterial pedicles to it were at an average of 3 pedicles. Each pedicle entered the lateral surface of the muscle. In 87.5% of the dissected cadavers, the gracilis got 4 arterial pedicles from the medial circumflex femoral and the femoral arteries. In 12.5% of the studied cases there were two arterial pedicles that came from the medial circumflex femoral and the profunda femoris arteries. The arterial pedicles were accompanied by two venae comitants that drained into the profunda femoris or femoral veins. The nerve supply to gracilis muscle entered the middle third of the muscle with the proximal vascular pedicle or near it. The whole length of the gracilis muscle was averaging 41.7cm [38.4 to 42.3cm]. Consequent to the present study, both the long head of biceps and gracilis muscles are segmentally supplied and should be classified as type IV according the standard classification of Mathes and Nahai who classified them as type II. The nerve supplying the long head of biceps is easily detected and the muscle has a suitable length to wrap the anal canal. The long head of biceps femoris can be superior to the gracilis muscle in replacing a damaged anal sphincter as it can be transposed without sacrificing much of its major arterial pedicles

blood supply of the muscles of the leg: Its surgical importance

Seventeen cadavers [two stillborns, five fresh cadavers and ten preserved cadavers] were used in the present study. The femoral arteries of both sides in each cadaver were cannulated and injected with red latex. All the muscles of the leg were dissected and examined except gastrocnemius, plantaris, soleus and popliteus. The present study showed that tibialis anterior muscle had an average reach of 13.3% of the lower third of the leg and an average surface area of 10.7 cm[2]. However, it is not suitable for transposition because of its importance in walking. The extensor digitorum longus and peroneus tertius muscles had an average reach of 33% of the lower third of the leg and a total surface area of 15.6 cm[2]. Their muscle flap could be easily elevated and provided a thin non bulky coverage. The extensor hallucis longus muscle had an average reach of 40% of the proximal part of the lower third of the leg. It had a surface area of an average of 18.4 cm[2] and its flap elevation was much easier than the extensor digitorum longus muscle flap. The transposed peroneus longus muscle did not reach the lower third of the leg. On the other hand the peroneus brevis muscle had an average reach of 27.4% of the lower third of the leg. It had a surface area of an average of 15.6 cm[2] and could be rotated easily to cover both tibial and fibular surfaces. The flexor digitorum longus muscle had an average reach of 24.4% of the lower third of the leg. It had an average surface area of 11.6 cm[2] and could be easily elevated. The flexor hallucis longus muscle had an average reach of 50.3% of the lower third of the leg and an average surface area of 21 cm[2]. However, its dissection and elevation was difficult and could be risky. The tibialis posterior muscle had an average reach of 0.2% of the lower third of the leg and an average surface area of 12.5 cm[2]. The dissection and freeing of the muscle was difficult. According to the anatomic findings of the present study, the following muscles could be recommended for use in the lower third of the leg when a local muscle flap is feasible and desired: extensor digitorum longus, peroneus tertius, extensor hallucis longus, flexor digitorum longus and peroneus brevis

relationship between Schwann cells and endoneurial macrophages after sciatic nerve crush injury

Twenty eight male albino rats aged 6-8 weeks [weighed 300g to 350g] were used in this study: Twenty animals were used for the ultrastuctural study while eight animals were used for the ferritin intravenous injection study. The animals of the ultrastuctural study were divided into two groups; the experimental group [16 rats] and the control group [4 rats]. The left sciatic nerves of the experimental rats were subjected to crush injury while the right and left sciatic nerves of the other 4 rats were used as a control.The animals of the ferritin intravenous injection study were divided into the experimental group [4 rats] and the control group [4 rats]. The left sciatic nerves of the experimental rats were subjected to crush injury. After one week, ferritin was injected intravenously through the vein of the rat tail. The control 4 rats were intravenously injected with ferritin without crush injury and used as a control group.The ultrastractural study of the crushed sciatic nerves showed that nerve fibres could be classified into three main categories. These are the regenerating, recovering and degenerating nerve fibres. The regenerating myelinated and recovering nerve fibres were surrounded by endoneurial macrophages, fibroblasts and collagen fibrils. The cytoplasm of the Schwann cells of the recovering nerve fibres contained large fat globules. They also showed increased pinocytotic vesicles in their cytoplasmic membranes and basal laminae. Macrophages sent their processes to be in close contact to the basal laminae of Schwann cells of the regenerating nerve fibres. Most of the regenerating unmyelinated nerve fibres were not surrounded by the endoneurial macrophages. Active mitosis of the Schwann cells was recorded during the first four weeks after the crush injury.Ferritin intravenous injection study showed that after crush injury, ferritin particles did not cross the cytoplasmic membrane of the Schwann cells indicating that fat cells inside them were of endogenous origin.It could be concluded that there are three types of nerve fibres after peripheral nerve crush injury. They are the regenerating, the recovering and degenerating nerve fibres. The presence of macrophages, fibroblasts and collagen bundles around the nerve fibres could be an indication to its viability. Macrophages might play a role in promoting the Schwann cells for myelin formation and possibly for active mitosis. The myelin carried by the endoneurial macrophages is probably the wasted myelin

Blood supply of the skin of the long posterior flap in blow knee amputation-surgical importance

The objective of this work was to study the blood supply of the posterior aspect of the leg and the soleus muscle. Material and methods: The present study was done on twelve cadavers [five preserved, five fresh and two stillborn]. Both femoral arteries of each cadaver were injected with a mixture of lead oxide and red latex in equal proportions The skin of the posterior calf was reflected to visualize the blood vessels supplying it. The soleus muscle was dissected to identify the arterial pedicles supplying it. The blood supply of the skin of the posterior calf was found to arise from three sources: the axial, the septal perforating arleries and the midposterior perforators. A constant axial artery was the saphenous ariery while the sural artery was a more variable artery. The septal perforating arteries were arranged in four approximale vertical lines or rows The midposterior perforaiors were arising from the vesseis within the gastrocnemius muscle. The soleus muscle got seven arierial pedicles, four pedicles from the peroneal artery and three arterial pedicles were arising from the posterior tibial artery. In all studied cases, the skin of the posterior calf was not supplied by vessels arising from or passing through the soleus muscle. There are logical reasons for advising excision of the soieus muscle from the long posterior flap during below-knee amputation. The use of the myoplastic flap that contains the soleus muscle should be avoided