Department of Human AnatomyKNMU THE NERVES AND VESSELS OF THE PELVIC GIRDLE AND FREE LOWER LIMB Slide-lecture for students of the 6 Faculty of Medicine Lector – associate professor Zharova Nataliya 2015
PLAN: • LUMBAR, SACRAL, COCCYGEAL SPINAL NERVES • THE LUMBAR PLEXUS • THE SACRAL PLEXUS • THE COCCYGEAL PLEXUS • ARTERIES OF THE PELVIC GIRDLE • ARTERIES OF FREE LOWER LIMB • VEINS OF THE PELVIC GIRDLE • VEINS OF FREE LOWER LIMB
LUMBAR, SACRAL, COCCYGEAL SPINAL NERVES • Each spinal nerve arise in the area of the intervertebral foramen as the result of merging of the anterior and posterior roots of the spinal cord. The principal trunk of spinal nerve escapes from the intervertebral foramen and gives rise to 4 branches: – anterior, posterior, meningeal, communicating. Lumbar spinal nerves: • anterior branches form lumbal plexus, • posterior branches – medial – supply m. multifidus, m.interspinalis; – lateral – supply m. sacrospinalis, mm. intertransversarii; • meningeal branches – returns to the vertebral canal to supply the spinal meninges; • communicating branches – pass to the ganglia of sympathetic trunk.
THE LUMBAR PLEXUS, PLEXUS LUMBALIS (Тh12 — L4) • The lumbar plexus is formed from the anterior branches of three upper lumbar spinal nerves and a part of the anterior branches 12-th thoracic spinal nerve and anterior branches 4-th lumbar spinal nerve. • It resides within the lumbar region in between the transverse processes of related lumbar vertebrae posterior and in depth of the psoas major. • Inferiorly, the lumbar plexus communicates with the sacral plexus. Most of the rami arise from behind the lateral border of the psoas major; one ramus traverses the muscle (the genitofemoral nerve) and one branch arises from behind the medial border of the muscle (the obturator nerve).
The branches of the lumbar plexus • muscular branches • iliohypogastric nerve • ilioinguinal nerve • genitofemoral nerve • lateral cutaneous nerve • of thigh • obturator nerve • femoral nerve
Clinical applications Injury to the femoral nerve leads to paralysis of the quadriceps femoris and thus to inability to extend the knee joint. When walking, the victim is unable to with hold extension of leg and the foot strikes against the ground with its entire surface. Injury to the obturator nerve affects abduction of thigh and crossing of legs.
THE SACRAL PLEXUSTopography of the sacral plexus • The sacral plexus is the greatest of all nervous plexuses in the human body. It arises from merged upper four sacral nerves, the fifth lumbar nerve and a part of the fourth lumbar nerve, the fourth and the fifth lumbar nerves merge into a single lumbosacral trunk, that descends to the lesser pelvis cavity and joins the sacral nerves. The lowest portion of the sacral plexus formed of the fifth sacral nerves and the coccygeal nerve is the coccygeal plexus. • The sacral plexus appears as a thick triangular plate adherent to the pelvic wall (namely to the piriformis). The branches given quit the lesser pelvis via the suprapiriform and the infrapiriform foramina as the short and the long branches. • The greatest nerve of the plexus is the sciatic nerve.
Topography of the sciatic nerve The nerve quits the lesser pelvis cavity via the infrapiriform foramen and runs on below the gluteus maximus. Somewhat below the escape point, the nerve enters in between the ischialtuberosity and the greater trochanter, proceeds onto the quadratuslumborum surface and finally becomes evident within the thigh region, arising from under the lower border of the gluteus maximus. Within the thigh region, the nerve runs deep in between the neighboring muscles. Clinical applications. Chilling of the area related to the nerve results in neuritis of the sciatic nerve (sciatica). The state features painful sensation within the ischial area and the posterior portion of the thigh. The condition may even feature sensory and motor disorders.
On reaching the upper angle of the popliteal fossa, the nerve splits into the terminal branches: -the tibial nerve and - the common fibular nerve. • Topography of the tibial nerveThe tibial nerve arises directly from the sciatic nerve and runs vertically down to the popliteal fossa. Within the fossa, the nerve occupies the most superficial position with respect to neighboring popliteal artery and popliteal vein. From the popliteal fossa, the nerve proceeds to the cruropopliteal canal. On escaping from the canal, the nerve loops around the medial malleolus and gives some branches to the ankle joint.
Below the flexor retinaculum, the tibialnerve gives off its terminal branches— the medial and the lateral plantar nerves.
Clinical applications • Injury to the tibial nerve results in paralysis of pertaining flexors. The foot thus becomes permanently extended and the toes may resemble the claws.
Topography of the common fibular nerve • From the arise point, the nerve runs laterally to reach the head of fibula. At that point, the nerve enters between the heads of the fibularislongus and slits into the superficial and the deep fibular nerves. • Yet within the poplitealfossa, the nerve gives the lateral suralcutaneous nerve that merges with the medial suralcutaneousnerve to form the sural nerve. Very often, the nerves merge at the lower third of shin or even run separately. • Clinical applications • Injury to the fibular nerve leads to inability to extend and to pronate the foot. The foot in this case hangs down and laterally.
THE COCCYGEAL PLEXUS • The coccygeal plexus is composed of the anterior branches of the fourth and fifth sacral and the cocygeal nerves. It gives rise to the thin anococcygeal nerves which join with the posterior branch of the coccygeal nerve and innervate the skin at the top of the coccyx and of the anus.
THE COMMON ILIAC ARTERY The abdominal aorta diverges at sharp angle (60-70°) to give rise to the common iliac arteries. Each artery descends laterally to reach the respective sacroiliac joint. There, the arteries give rise to the external and internaliliac arteries.
THE INTERNAL ILIAC ARTERY Relations of the internal iliac artery • The internal iliac artery arises from the common iliac artery and descends to the lesser pelvis. The artery is the principal nourishing vessel for this region. • The artery gives off numerous branches, both • parietal and visceral.
THE EXTERNAL ILIAC ARTERY The external iliac artery descends on the medial aspect of the psoas major and quits the lesser pelvis via the vascular space. Within the femoral triangle, the artery becomes continuous with the femoral artery. The external iliac artery gives the branches as follows: - the inferior epigastric artery arises from the main trunk above the inguinal ligament and then ascends medially along the internal surface of the anterior abdominal wall occupying the lateral umbilical ligament. Then the artery enters the rectus sheath and ascends along its posterior surface to reach the umbilical ring. Here it anastomoses with the superior hypogastric artery. In the beginning, the artery gives off - the pubic branchanastomoses with the same branch of the obturator artery; • a. cremasterica (in male) or a. ligamentumteres uteri (in female); • the deep circumflex iliac artery runs laterally along the inguinal ligament and the iliac crest. It supplies the iliacus and the muscles of abdominal wall.
THE FEMORAL ARTERY, ARTERIA FEMORALIS • The femoral artery arises directly from the external iliac artery. The arteries are delimited by the inferior border of the inguinal ligament. • On leaving the vascular space, the artery appears within the femoral triangle together with the femoral nerve (found laterally) and the femoral vein (found medially). • Pulsation of the artery is palpable below the inguinal ligament in the area related to the vascular space. Within the femoral triangle, the artery runs along the iliopectineal groove and then along the femoral groove. From the femoral groove, the artery proceeds to the adductor canal, which leads it to the poplitealfossa. Here it becomes continuous with the popliteal artery.
Clinical applications. The deep artery of thigh is of great importance for collateral circulation. Intrinsic anastomoses and intersystem anastomoses (with the internal iliac and popliteal arteries) provide good conditions for collateral circulation, which is vital in occlusions of femoral artery.
The branches of the femoral artery: 1. The superficial epigastric artery arises near the very beginning of the femoral artery and passes in front of the inguinal ligament under the skin to the region of the navel. 2. The superficial circumflex artery runs along the inguinal ligament to the skin in the region of the superior anterior iliac spine. 3. The external pudendal arteries usually two in number, branch out in the region of the hiatus saphenus and lead medially to the skin of the external genital organs and lower surface of the abdomen. 4. The descending artery of the knee branches off from the femoral artery on its way in the adductor canal and, exiting through the anterior wall of this canal with n. saphenus, supplies m. vastusmedialis with blood and participates in the formation of the arterial network of the knee joint. 5. The deep femoral artery is the main vessel through which the thigh is supplied with blood.
The branches of the deep femoral artery: 1) a. circumflexa femoris medialispasses medially and upward and gives off the branches to the m. pectineus, to the adductor muscles, to the hip joint, to m. iliopsoas, m. obturatorius externus, m. piriformis, m. quadriceps femoris. 2) a. circumflexa femoris lateralispasses laterally under m. rectus femoris and gives off the branches to m.quadriceps, m. sartorius and to the knee joint. 3) aa. perforantes(three in number) branch off the posterior surface of the deep femoral artery and supply posterior muscles of the thigh. Clinical applications. The deep artery of thigh is of great importance for collateral circulation. Intrinsic anastomoses and intersystem anastomoses (with the internal iliac and popliteal arteries) provide good conditions for collateral circulation, which is vital in occlusions of femoral artery.
THE POPLITEAL ARTERY, ARTERIA POPLITEA The popliteal artery is a direct continuation of the femoral artery. It occupies the poplitealfossa together with the vein of the same name (it runs laterally and posteriorly). Upon reaching the leg region, the artery enters the cruropopliteal canal and gives off its two terminal branches — the anterior and posterior tibial arteries. The popliteal artery gives off five genicular arteries.
The popliteal artery gives off five genicular arteries: 1. the superior (medial and lateral) genicular arteries arise above the femoral epicondyles. Each artery rounds the respective epicondyle and passes to the anterior surface of knee joint. Their branches form the genicular anastomosis; 2. the middle genicular arterypenetrates the posterior wall of the joint capsule of knee joint and terminates within the cruciform ligaments; 3. the inferior (medial and lateral) genicular arteriesarise below the femoral epicondyles. Each artery rounds the respective epicondyle and passes to the anterior surface of knee joint. The genicular arteries supply the knee joint and neighboring muscles. They form a wide anastomosis around the knee joint — the genicular anastomosis.
THE ANTERIOR TIBIALARTERY Relations of the anterior tibial artery • The anterior tibial artery arises from the popliteal artery within the cruropopliteal canal. It quits the canal via the anterior outlet (the opening in the interosseous membrane) and descends to the foot together with the deep fibular nerve. Upon reaching the ankle joint, the artery comes out from under the extensors tendons. Then the artery proceeds to the dorsal surface of foot to become continuous with the dorsal artery of foot. The branches of the anterior tibial artery: • the posterior tibial recurrent arterybecomes evident on the posterior surface of leg; it ascends to join the genicularanastomosis; • the anterior tibial recurrent arteryarises opposite to the latter artery. It also joins the genicularanastomosis; • the anterior (medial and lateral) malleolar arteries descend to the respective ankles. They participate in formation of the medial and lateral malleolar networks. • muscular branches supply the anterior muscles of the leg.
THE DORSAL ARTERY OF FOOT Relations of the dorsal artery of foot The dorsal artery of foot is a direct continuation of the anterior tibial artery. It runs between the tendons of the extensor hallucislongus and the extensor digitorumlongus. The branches of the dorsal artery of foot: 1. the lateral and 2. medial tarsal arteries run to the respective aspects of foot; 3. the arcuate arteryarises at the bases of metatarsals and runs laterally to anastomose with the lateral tarsal artery. The arch formed gives off the dorsal metatarsal arteries(2 through 5), which split into the dorsal digital arteries; the first dorsal metatarsal artery arises directly from the dorsal artery of foot. It gives off three dorsal digital arteriesto both aspects of the great toe and to the medial aspect of the second toe; 4. the deep plantar arteryis the 2nd terminal branch of the dorsal artery of foot; there it anastomoses with the lateral plantar artery to form thedeep plantar arch.
THE POSTERIOR TIBIAL ARTERY Relations of the posterior tibial artery The larger posterior tibial artery arises immediately from the popliteal artery. The artery occupies the cruropopliteal canal together with the tibial nerve. Within the canal, the artery runs along the deep muscles of leg anterior to the soleus. The artery quits the canal and passes medially from the calcaneal tendon immediately below the skin and fascia. Here, one can palpate pulsation of the artery. The artery then rounds the medial malleolus, passes under the flexor retinaculum and eventually appears on the plantar surface of foot. There it gives the lateral and medial plantar arteries. The branches of posterior tibial artery: • muscular branches supply the posterior muscles of the leg • medial malleolar branches • lateral malleolar branches • calcaneal branch • fibular artery • perforating branch
THE PLANTAR ARTERIES The posterior tibial artery gives rise to the lateral and medial plantar arteries. • The lateral plantar artery - it runs laterally to reach the lateral plantar groove. On reaching the 5th metatarsal bone, the artery declines medially and anastomoses with the deep plantar artery to form the deep plantar arch. The arch gives off four plantar metatarsal arteries which anastomose with the dorsal arteries by means of the perforating branches. The plantar metatarsal arteries become continuous with the common plantar digital arteries which in turn split into the plantar digital arteries proper. The latter arteries run along the aspects of toes. • The medial plantar artery is smaller than the lateral; it runs along the medial plantar groove and reaches the base of great toe to anastomose with the lateral plantar artery. The plantar arch thus features anastomoses related to both vertical and horizontal planes.
Clinical applications The arteries of lower limb are often affected by atherosclerosis and obliterating endarteritis, which feature pathological growth of connective tissue in the inner layer and lipid infiltration of vascular wall. The pathologies result in occlusion of the vessel affected. Collateral circulation may compensate slow progressing occlusion of the distal arteries yet occlusion of min trunks results in severe ischemia and even gangrene. Gangrene requires amputation of the limb. Treatment of the state nowadays includes various reconstructive and plastic surgeries.
THE VEINS OF LOWER LIMB • The veins of the lower limb are subdivided into the superficial and deep. The double deep veins accompany the arteries. • The superficial veins run below the skin and outside the proper fascia. The superficial veins give rise to the great and small saphenous veins. They arise from the dorsal and plantar venous networks of foot. • The great saphenous vein, arises from the medial portion of the dorsal venous network of foot and ascend along the medial aspect of the leg and thigh . In the upper third of thigh, the vein runs along its anterior surface to reach the saphenous opening. • On passing the saphenous opening, the vein joins the femoral vein. On the way to destination point, the vein receives numerous tributaries that anastomose with each other and with the tributaries of small saphenous vein and deep veins of lower limb.
The small saphenous vein,arises at the lateral aspect of foot. The vein rounds the lateral malleolus and ascends along the posterior surface of leg in between the heads of the gastrocnemius muscle. At the popliteal fossa, the muscle pierces the fascia and joins the popliteal vein. The small saphenous vein receives numerous tributaries that anastomose with the tributaries of the great saphenous vein and with the deep veins of thigh.