Blockade of the biceps femoris. General rules for conduction anesthesia

2. Nerve block lower limb

Innervation of the lower limb. From the branches of the lumbar plexus, the femoral nerve (L2-L4), the obturator nerve (L2-L4) and the external cutaneous nerve of the thigh (L1-L3) are formed. The femoral nerve enters the thigh under the inguinal ligament and is located lateral to the femoral artery. Dividing into two branches below the inguinal ligament, the femoral nerve innervates the skin of the anterior surface of the thigh, the quadriceps femoris, the anterior and medial sides knee joint, and also forms the saphenous nerve, which innervates the medial surface of the lower leg, including the medial malleolus. The obturator nerve exits the pelvic cavity in front of the vascular bundle through the canal of the same name, where, dividing into two branches, it innervates the deep group of adductors, the upper part of the inner surface of the knee joint and the hip joint. The external cutaneous nerve of the thigh perforates abdominal wall at the anterior spine ilium and passes under the fascia of the external oblique muscle of the abdomen. It enters the thigh under the lateral part of the inguinal ligament and through the wide fascia of the thigh penetrates into the subcutaneous fat, where it innervates the skin of the lateral part of the thigh. The sciatic nerve (L4-S3) is a branch of the sacral plexus that exits the pelvic cavity through the large sciatic foramen in the gap under the piriformis muscle and, bending around the sciatic spine, goes under the gluteus maximus muscle. Then it goes to the square muscle and is located approximately at an equal distance from the ischial tuberosity and the greater trochanter femur. At the level of the upper edge of the popliteal fossa, the sciatic nerve divides into two branches - the common peroneal nerve and the tibial nerve, which completely innervate the limb below the knee joint. The upper part of the popliteal fossa is laterally limited by the tendon of the biceps femoris muscle, and medially by the tendons of the semitendinosus and semimembranosus muscles. In the proximal parts of the popliteal fossa, the artery is located lateral to the tendon of the semimembranosus muscle, the popliteal vein is lateral to the artery, and the tibial and common peroneal nerves(inside the fascial case) pass lateral to the vein and medial to the biceps tendon at a depth of 4-6 cm from the skin surface. Distally, the tibial nerve runs deep between both heads of the gastrocnemius muscle, while the common peroneal nerve leaves the popliteal fossa around the head of the fibula.

The blockade of the femoral nerve is performed during operations on the lower limb below the middle third of the thigh, as well as to provide analgesia in the postoperative and post-traumatic period. The analgesic effect of the femoral nerve blockade is usually sufficient to transport victims with a fracture of the femur, in the absence of direct trauma to the sciatic nerve, which occurs when it is fractured in lower third.

Blockade technique. The position of the patient is lying on his back. 1-2 cm below the inguinal ligament determine the pulsation of the femoral artery. The injection site of the needle is 1 cm lateral to the artery. After a well-perceptible puncture of the superficial fascia, the needle is advanced deep into the passage of the fascia of the iliopectineal muscle (3-4 cm), where paresthesias or an induced motor reaction occur (contraction of the quadriceps femoris muscle). The fluctuations of the pavilion, synchronous to the pulse of the artery, indicate the correct insertion of the needle. The closed fingers of the hand, fixing the needle in the desired position, pinch the femoral canal distal to the needle. With a periodic aspiration test, 20 ml of anesthetic is injected. If necessary, simultaneous blockade of the femoral, obturator and external cutaneous nerves of the thigh, the dose of anesthetic is doubled. The main danger is associated with intravascular injection of anesthetic. Endoneural injection, due to the friable type of nerve structure, occurs much less frequently than with other blocks.

The obturator nerve is blocked in combination with the blockade of other nerves during operations on the knee joint, especially in its medial part and operations on the inner thigh. Isolated blockade of the obturator nerve is performed for arthropathies hip joint with severe pain syndrome.

Blockade technique. The position of the patient is lying on his back. After infiltration anesthesia of the skin 2 cm below and lateral to the pubic tubercle, a 9-10 cm long needle is passed in the dorsomedial direction until it contacts the inferior ramus of the pubis, prescribing a small amount of anesthetic. Then it is somewhat pulled up and directed deeper at a more obtuse angle to the frontal plane, as if sliding off the bone into the obturator foramen. The subsequent advancement of the needle 2-4 cm deep is sometimes accompanied by the occurrence of paresthesia, the achievement of which is not an end in itself for the anesthesiologist. After a mandatory aspiration test, an anesthetic solution is injected in a volume of 10-15 ml. Complications of blockade of the obturator nerve are rare and most often manifest themselves in the form of a failed blockade and patient discomfort during the manipulation.

The blockade of the external cutaneous nerve of the thigh complements the blockade of other nerves during operations on the lateral part of the thigh and knee joint. Selective blockade of this nerve is sufficient to obtain a split skin graft or biopsy of the lateral thigh muscles.

Blockade technique. In the supine position, 2 cm below and medially to the anterior superior iliac spine in the direction under the inguinal ligament infiltrate the skin and subcutaneous tissue. By advancing the needle, they overcome the fascia. A fascia puncture is felt as a click and is accompanied by a loss of resistance. Fan-shaped injected 10 ml of anesthetic both medially and in the direction of the spine. The introduction may be accompanied by the occurrence of paresthesia. Complications are rare and usually associated with nerve injury.

The blockade of the sciatic nerve is a constant component of conduction anesthesia in all operations on the lower limb. The most widely used blockades are carried out at the level of the hip joint from various accesses.

Blockade technique from the posterior access. The position of the patient lying on a healthy side. The leg on the blockade side is bent at the hip and knee joints at an angle of 45-60°. From the middle of the line connecting the most protruding part of the greater trochanter and the posterior superior iliac spine in the caudal direction, a perpendicular 4-5 cm long is lowered. This point coincides with the mark of the distance from the coccyx to the posterior superior iliac spine to the line connecting the coccyx with the upper part of the greater trochanter and projected onto the sciatic nerve in the sciatic notch, proximal to the origin of the branches. After infiltration anesthesia of the skin in the area of the found point, a 10 cm long needle is inserted perpendicular to the body surface. At a depth of 4-6 cm, depending on the body weight and muscle mass of the patient, the nerve is determined. It is necessary to induce paresthesias or an induced muscular reaction (dorsal or plantar flexion of the foot). After secure fixation of the needle, 20 ml of anesthetic is slowly injected. The appearance of burning pain during injection indicates an endoneural injection and requires pulling the needle 1-3 mm and continuing the injection.

Blockade of the sciatic nerve from the anterior approach has no alternative when the patient is in a forced supine position. An imaginary line is drawn (or drawn) from the most protruding part of the greater trochanter to the anterior superior iliac spine. Then, from the first point on the anterior surface of the thigh relative to the drawn line, a perpendicular is restored, the length of which is equal to the distance between the greater trochanter and the anterior upper spine. The end of this perpendicular is the projection point of the sciatic nerve on the anterior surface of the thigh. With the limb in physiological position after skin infiltration, a 12.5 cm (4.5 in) spinal anesthesia needle is inserted vertically down until it contacts the periosteum of the femur. After the needle slips off the bone, without changing its main direction, it is advanced even deeper by 4-5 cm until paresthesia or an induced muscle reaction (dorsal or plantar flexion of the foot) occurs. If paresthesia cannot be achieved, the needle is returned to the bone. Having rotated the limb by 7-10 ° inward, the needle is advanced again until paresthesia is obtained or electrical stimulation is used to facilitate finding the nerve. Enter 25-30 ml of anesthetic.

Nerve blockade in the popliteal fossa is performed during interventions on the foot and in the ankle joint, when it is impossible to block the sciatic nerve in its proximal sections. In combination with the blockade of the saphenous nerve of the lower leg, it provides complete anesthesia in the distal segment of the lower limb.

Blockade technique. The patient lies on his stomach, he is asked to bend his leg at the knee joint, after which the boundaries of the popliteal fossa are well contoured. The pulsation of the popliteal artery serves as a valuable guide. If it is not detected, then determine the average line. The skin is infiltrated 5 cm proximal to the skin popliteal fold. Use a 10 cm (3.5 in) spinal anesthetic needle inserted 1 cm lateral to the popliteal artery pulse or (if no pulse is detected) in the midline to a depth of approximately 2–4 cm until paresthesias or an induced motor response (dorsal or plantar flexion of the foot). Enter 20-30 ml of anesthetic solution. Sometimes it becomes necessary to block the common peroneal nerve separately because it branches off the sciatic nerve in the upper popliteal fossa. The nerve is located subcutaneously just below the knee joint at the border between the head and neck of the fibula, where it can be blocked by injection of 5 ml of anesthetic solution. The saphenous nerve of the leg is blocked by injection of 5-10 ml of anesthetic under the medial condyle of the tibia.

Blockade of the intercostal nerves is usually used for the purpose of analgesia for fractures of the ribs or postoperative period if it is impossible or undesirable to use alternative methods of pain relief.

The intercostal nerves, leaving the intervertebral foramen, lie under the lower edge of the corresponding rib along with the arteries and veins, occupying a lower position in relation to the vessels.

Blockade technique. In the position of the patient on his side or sitting along the spine along the posterior axillary line at the level of the lower edge of the selected ribs, local anesthesia skin. The needle is inserted until it touches the rib, after which, after slightly pulling it, it is directed under the lower edge of the rib and advanced by 0.5 cm. After the aspiration test, 3-5 ml of anesthetic is injected under each rib. There is a risk of intravascular injection of an anesthetic, lung damage with the development of pneumothorax.

Paravertebral blockade can be used both for a single injection of an anesthetic, and using a catheterization technique, for prolonged anesthesia or analgesia. Depending on the level, it can be used for anesthesia during surgical interventions on the chest wall within soft tissues, as well as during osteosynthesis of the scapula.

Blockade technique. In the position of the patient on the side or on the stomach at the level of the central segment of the proposed area of anesthesia, the spinous process of the vertebra is palpated, lateral to which is the transverse process of the underlying vertebra. Departing from the spinous process by 4 cm, above the transverse process with a thin needle towards the latter, the skin, subcutaneous tissue and muscles are anesthetized until the needle contacts the bone. A Tuohy-type epidural needle with an attached syringe with a "search" anesthetic solution is directed slightly below the transverse process until an elastic obstruction is felt, which is the intertransverse ligament. Using the "loss of resistance" technique, the needle is advanced through the ligament into the paravertebral space. After an aspiration test in the required direction, an epidural catheter is passed through the needle to a depth of 3-5 cm. When the catheter is advanced, paresthesias may occur. Through the catheter fractionally, slowly injected 10-15 ml of anesthetic. Anesthesia develops in 25-30 minutes.

Literature

1. "Urgent health care", ed. J.E. Tintinalli, Rl. Crouma, E. Ruiz, Translated from English Dr. honey. Sciences V.I. Candrora, MD M.V. Neverova, Dr. med. Sciences A.V. Suchkova, Ph.D. A.V. Nizovy, Yu.L. Amchenkova; ed. MD V.T. Ivashkina, D.M.N. P.G. Bryusov; Moscow "Medicine" 2001

2. Intensive therapy. Resuscitation. First aid: Tutorial/ Ed. V.D. Malyshev. - M.: Medicine. - 2000. - 464 p.: ill. - Proc. lit. For students of the system of postgraduate education.- ISBN 5-225-04560-X

Blockades of the lower extremities

Ultrasound-assisted lower extremity blocks are, in essence, single nerve blocks, with the exception of the direct lumbar block, which is a modification of the paravertebral technique and is not recommended for beginners due to the higher imaging complexity.

femoral nerve block
Blockade of the femoral nerve, or in the literature often referred to as a blockade of 3 in 1, since with cranial spread of the anesthetic, it is assumed that the blockade of the obturator and lateral cutaneous nerves (N. obturatorius et. N.cutaneus femoris lateralis) will be achieved along the way - the most commonly used peripheral blockade lower limb. Due to its relative ease of implementation and high success, it has wide indications: operations on the hip and knee joints, tibia, anterior surface of the thigh and medial malleolus, but it acquires special significance in operations on the head of the tibia and plastics of the posterior cruciate ligament. Prolonged anesthesia is indicated for hip fractures, hip and knee replacements, and cruciate ligament plasty.

On sonographic imaging, the femoral nerve is usually defined as a hyperechoic structure, but it often has an irregular shape, probably due to the fact that, caudal to the inguinal ligament, it immediately begins to divide (Rami muscularis, Rami cutanei anterioris, N. saphenus) . Thus, it can be assumed that the irregularity of the shape of the section of the femoral nerve is the outgoing branches.
The control of the puncture needle is possible both in-plane (in this case in the medial direction) and out-of-plane (in the cranial direction) by techniques. The latter is more preferable when performing prolonged anesthesia, since in this case, there is the best possibility of optimal placement of the catheter (cranial and parallel to the nerve). In both cases, passing the needle under the Fascia iliaca is considered sufficient.

Practical advice
- Since it is not always possible to clearly visualize the tissue of the femoral nerve itself - the goal is to pass a needle and inject an anesthetic directly under the fascia iliaca (ileopectinea), as a rule, a simple simultaneous injection is sufficient without trying to create a uniform depot around the nerve.
- It is recommended to perform the blockade as cranially as possible, since the nerve begins to divide into branches immediately after passing the inguinal ligament. Thus, when scanning in the optimal position, you see only two vessels - femoral artery and a vein.
- If you observe the moment of branching of the deep femoral artery (A. profunda femoris) or A. femoralis superficiales, then you are too distal - rise higher to the inguinal ligament.
- When using ropivacaine in combination with epinephrine and clonidine, the analgesic effect is observed up to 24 hours.

Blockade of the lateral femoral cutaneous nerve
N. cutaneus femoris lateralis - sensory nerve, about 1.5 - 2 cm medial to Spina iliaca anterior superior, passes under the inguinal ligament through the Lacuna musculorum. The purpose of the blockade is to anesthetize the skin and subcutaneous tissues, with a typical access for operations on the hip joint. Isolated nerve block is used in pain therapy for diagnostic purposes. For the blockade, 5 ml of anesthetic is sufficient.

Due to the very small cross section, it is far from always possible to visualize the nerve during ultrasound, even with the use of modern ultrasound scanners, therefore the following technique is recommended: since the nerve lies on the sartorius muscle (m. Sartorius) for several centimeters, you should navigate namely, on this muscle (attached to the large crest at its highest and anterior point). Identify the sartorius muscle (not to be confused with M. tensor fascia lata, which attaches in the same place, but lies more lateral!) and inject the anesthetic into the region of the lateral edge of the sartorius muscle.

Some authors recommend injecting the anesthetic into the interfascial space. To do this, position the sensor so that the shadow of the Spina iliaca anterior superior and Fascia lata with the adjacent Fascia iliaca are visible, the anesthetic must be injected, just between the two fascia. In this case, the required volume of anesthetic is increased to 10 ml.

Sciatic nerve

Due to its size (the largest nerve!) Nervus ischiadicus is well visualized and, as a result, sciatic nerve blocks are increasingly used, not only intraoperatively and for postoperative pain relief, but also for therapy chronic pain especially ischemic.
For blockade of the sciatic nerve, there are several traditional approaches; with blockade under ultrasound control, posterior approaches are much easier to perform, since the distance from the skin surface to the nerve is the smallest and, as a result, the relative ease of visualization. For anterior access, a low frequency (3-5 MHz) convex probe is recommended. At the same time, the quality of visualization of the nerve and the large distance of the required penetration often require the combined use of a neurostimulator.
Sono identification- in the posterior scan, the sciatic nerve is determined as the most echogenic formation, but proximally, in the muscle mass, "superechogenicity" may not be obvious, so it is recommended to start looking for the nerve distally, at the point of division into the tibial and peroneal nerves (10 cm above the popliteal fossa and below ) and then, if necessary, follow him more proximal.

Distal sciatic nerve block

The easiest way to visualize the sciatic nerve is in the region of the popliteal fossa and somewhat more proximal: firstly, the nerve is located quite superficially, secondly, the nerve retains its large caliber before separation, and finally, the very division of the sciatic nerve into the tibial nerve (N. Tibialis, medially) and laterally leaving the common peroneal nerve (N.fibularis / peroneus communis) - the main identifying sign, as well as the phenomenon of the "dancing" nerve, is especially clearly visible in the area of \u200b\u200bdividing the sciatic nerve when the patient moves the feet. Often, the nerve is covered by the biceps femoris, which often contributes to misinterpretation on ultrasound imaging, as well as the tendon mm. semitendinosus et. semimemebranosus can be mistaken for the tibial and peroneal nerves. Therefore, beginners are advised to adhere to the following rule: "Perform the blockade only after a clear visualization of the place of division of the sciatic nerve!".

Practical Tips

When searching, focus on A. Poplitea - the nerve is always nearby and is more superficial.
- When the lower limb is extended (straightened), the sonographic picture changes due to local tissue tension, so search with the leg slightly bent at the knee, regardless of the patient's position (on the back, on the stomach, etc.)
- Puncture access becomes important when installing a catheter and has its advantages and disadvantages. For example, with lateral, usually in-line, the working openings of the catheter are significantly removed from the nerve, since the manipulation is carried out perpendicular to the axis of the nerve, while the probability of dislocation of the catheter in the postoperative period is much less than with direct access (out-of-line), in which it is much easier to place the catheter in close proximity and parallel to the nerve.
- Try to create a uniform depot around the nerve, with an anesthetic volume of at least 30 ml.

Proximal sciatic nerve block

The onset (fixation) time is up to 30 minutes! (logistics!)
Anterior access is the most used, approx. 8 cm distal to the site of the femoral nerve block. In combination with a neurostimulator, the goal is to get a response from 0.5 mA.
Purpose: passing the needle to the lateral edge of the sciatic nerve
Indications: mandatory for operations on the posterior cruciate ligament

A. Indications. The obturator nerve is blocked during surgery that requires relaxation of the adductor muscles of the thigh, or during surgery in the medial region of the thigh (eg, muscle biopsy). Blockade of the obturator nerve is also indicated when a pneumatic tourniquet is applied to the thigh (this manipulation facilitates the surgeon's work).

B. Anatomy. The obturator nerve is formed from the branches L 2 -L 4 in the thickness of the psoas major muscle. It comes out from behind its medial edge and descends to the obturator canal, located retroperitoneally. Coming out of the obturator canal to the medial surface of the thigh below the inguinal ligament, it innervates the hip joint, the skin of the medial surface of the thigh, and the adductor muscles of the thigh. The most reliable anatomical landmark is the obturator foramen, located immediately dorsal lower branch pubic bone.

Rice. 17-19. femoral nerve block

B. Blockade technique(Fig. 17-20). A 9 cm long, 22 G needle is used for spinal puncture. local anesthetic infiltrate the skin 2 cm laterally and below the pubic symphysis. Through the skin nodule, the needle is advanced medially to the inferior branch of the pubic bone, while a small amount of anesthetic is injected to reduce the discomfort experienced by the patient. When the needle reaches the periosteum, it is advanced down the inferior ramus of the pubis until it slips into the obturator foramen. After entering the obturator foramen, the needle is advanced 3-4 cm in the dorsolateral direction. Paresthesias are rare and should not be intentionally induced. Enter 10-20 ml of anesthetic solution.

D. Complications. The most common complications are a failed blockade and patient discomfort during manipulation.

obturator nerve is a branch of the lumbar plexus (L2-L4), exits the pelvic cavity through the obturator canal in front of the vessels of the same name. Inside the canal, it divides into anterior and posterior branches. The anterior branch is located between the short and long adductor muscles, innervates the anterior group of adductors and the skin on the medial side of the thigh, the posterior branch - between the external obturator and short adductor muscles, innervates the deep group of adductors, the upper inner surface of the knee joint and the hip joint.
As an independent blockade obturator nerve can be used for anesthesia in hip arthropathy.

terminal fibers of the posterior branches of the obturator nerve can be blocked by subcutaneous crescent-shaped infiltration along the inner surface of the thigh in the region of the distal third. This consumes approximately 15 ml of a low concentration anesthetic solution.

Blockade of the external cutaneous nerve of the thigh

External femoral cutaneous nerve(L2-L3) - a branch of the lumbar plexus - located under the fascia covering the external oblique muscle of the abdomen at the anterior superior iliac spine. The nerve descends to the thigh under the lateral part of the inguinal ligament and after a few centimeters, and sometimes immediately through the wide fascia of the thigh, almost completely exits into the subcutaneous fatty tissue.

Need for carrying out therapeutic blockade of the external cutaneous nerve of the thigh can occur with the so-called paresthetic meralgia (Roth-Bernhardt disease). Sometimes this block is done in addition to a femoral nerve block.

Injection site for thin needles 4-5 cm long is determined under the inguinal ligament, retreating 2.5 cm medially from the anterior superior iliac spine. The needle is inserted at a right angle to the skin. After the puncture of the fascia, 5-7 ml of a 0.5% solution of xicaine or prilocaine or a 1% solution of trimecaine with adrenaline are injected. Then the same amount of anesthetic is fan-shapedly injected medially to the point of initial injection and also under the fascia.

Ulnar nerve block

Method 1. Blockade in the area of the ulnar canal.
blockade technique. To the medial epicondyle humerus the ulnar flexor of the wrist is attached. Part of the tendon fibers is thrown from the medial epicondyle of the shoulder to the olecranon of the ulna in the form of a transverse ligament. A bone-fibrous canal arises: from above - a transverse ligament, from the side - a bone, from below - joint capsule. The ulnar nerve passes through this canal. Arm extended to elbow joint, laid on the table so that the inner epicondyle was on top. Feel the top of the internal epicondyle of the humerus. The needle is injected in the direction from the olecranon of the ulna to the medial epicondyle of the humerus, the skin, subcutaneous tissue and ligament are pierced. The volume of the injected solution is 2-3 ml.

Method 2. Blockade in the area of the carpo-ulnar canal. In the distal part of the forearm, the ulnar nerve passes through the carpo-ulnar canal (canalis carpi ulnaris). The dorsal wall of it is the palmar ligament of the wrist, the ventral wall is the retinaculum of the flexor tendons, and the medial wall is the pisiform bone. A narrow triangular gap is formed between these ligaments and the pisiform bone.

blockade technique. Feel for the pisiform bone and the apex of the styloid process radius. A connecting line is drawn between them. 5 mm medially to the pisiform bone, the skin, subcutaneous tissue, and flexor tendon retinaculum are pierced in layers along the indicated line. The tip of the needle is turned in the distal direction and advanced 1-1.5 cm. The dorsal branch is blocked distal to the styloid process 1.5-2 cm below. The volume of the administered anesthetic solution is 2-2.5 ml.

Rice. 17-19. femoral nerve block

(Fig. 17-20). A 9 cm long, 22 G needle is used for spinal puncture. A local anesthetic solution is used to infiltrate the skin 2 cm laterally and below the pubic symphysis. Through the skin nodule, the needle is advanced medially to the inferior branch of the pubic bone, while a small amount of anesthetic is injected to reduce the discomfort experienced by the patient. When the needle reaches the periosteum, it is advanced down the inferior ramus of the pubis until it slips into the obturator foramen. After entering the obturator foramen, the needle is advanced 3-4 cm in the dorsolateral direction. Paresthesias are rare and should not be intentionally induced. Enter 10-20 ml of anesthetic solution.

D. Complications. The most common complications are a failed blockade and patient discomfort during manipulation.

Blockade of the lateral femoral cutaneous nerve

A. Indications. Selective blockade of the lateral femoral cutaneous nerve is performed during interventions on the proximal lateral sections

thigh, for example in a muscle biopsy. In combination with the blockade of other nerves, the technique is used when applying a pneumatic tourniquet, as well as during operations on the hip joint, thigh and knee.

B. Anatomy. The nerve is formed in the thickness of the psoas major muscle from the spinal nerves L 1, L 2 and L 3. Coming out from under the lateral edge of the psoas major muscle (sometimes passing through its thickness), the nerve follows forward and laterally to the anterior superior iliac spine and passes medially to the thigh under the inguinal ligament. Distal to the inguinal ligament, the nerve gives off sensitive branches to the skin of the lateral surface of the gluteal region and thigh to the level of the knee joint.

B. Blockade technique(Fig. 17-21). The patient lies on his back. Palpate the inguinal ligament and the anterior superior iliac spine. Above the inguinal ligament, at a point located a finger width medially and below the spine, the skin is infiltrated and a needle is inserted. A needle 4 cm long and 22 G in size is used. When the fascia is punctured, a click is felt well, and when the needle is advanced deeper, a loss of resistance is detected. Straightaway

Rice. 17-20. Obturator nerve block

dorsal to the ligament, 10-15 ml of an anesthetic solution is fan-shaped, including in the direction of the periosteum of the anterior superior iliac spine. Paresthesias may occur but should not be intentionally induced. If severe burning pain occurs during an anesthetic injection, the position of the needle should be changed to avoid nerve injury.

D. Complications. Complications such as patient discomfort, failed blockade and persistent paresthesias with intraneural injection are possible.

Sciatic nerve block

A. Indications. The sciatic nerve should be blocked in all operations on the lower extremity. If a surgical intervention on the lower limb does not require the use of a pneumatic tourniquet and passes outside the zone of innervation of the femoral nerve, then the blockade of the sciatic nerve provides full anesthesia. Blockade of the sciatic nerve can be performed at the level of the hip joint, popliteal fossa and ankle joint (terminal branches).

B. Anatomy. The sciatic nerve is formed by the fusion of branches spinal nerves L 4 -S 3 at the level of the upper edge of the entrance to the pelvis. From the pelvic cavity to the gluteal region, the sciatic nerve exits through the subpiri-shaped foramen. The nerve passes distally past several permanent anatomical landmarks. So, if the leg is in a neutral position, then the nerve lies immediately behind the upper sections of the lesser trochanter of the femur (Fig. 17-22). The lesser trochanter of the femur is an anatomical landmark for blockade of the sciatic nerve from the anterior approach. In the position of the patient on his side with a bent hip, the nerve is located in the middle between the most protruding part of the greater trochanter and the posterior superior iliac spine. The level of division of the sciatic nerve into the tibial and common peroneal nerves varies greatly, which is an argument in favor of the most proximal implementation of the blockade.