2 1. What is lumbosacral plexus? Sensory and motor innervation of the whole lower limbarises from the spinal roots L1-S4Lumbal plexusSacral plexus.
3 2. How is the lumbar plexus formed? Anterior rami of upper 4 lumbar spinal nerves (+L5) and from the contribution of subcostal nerve (T12).in the lumbar region, within the psoas major muscle.
4 3. Nerves of the lumbar plexus? L1 gives rise to the iliohypogastric and ilioinguinal nervesL1 + L2 gives rise to the genitofemoral nerveL2 + L3 gives rise to the lateral femoral cutaneousL2 + L3 + L4 give rise to the femoral and obturator nervesL4 + L5 give rise to the lumbosacral trunk which joins sacral nerves to form the sacral plexus.
5 4. ...femoral nerve? (L2-L4) largest branch both motor and sensory. Emerges from the lateral border of the psoas majorFlexors of the hip and extensors of the kneeSkin of the anterior and lateral thigh, medial leg and foot.
6 5. ...saphenous nerve? largest cutaneous branch of the femoral nerve continuation of the femoral nerveSkin of medial aspects of leg and foot.
7 6. ...obturator nerve?Emerges from the medial border of the psoas majorLeaves the lesser pelvis throughthe obturator canalSkin on the superior medial thighAdductor muscles of theleg.
8 7. ...lumbosacral trunk?Descending part of the L4 nerve unites with the anterior ramus of the L5 nerve to form thelumbosacral trunk.Participates in the formation of the sacral plexus with the anterior rami of S1-S4 nerves..
9 8. ...ilioinguinal & iliohypogastric nerves? Enter the abdomen and run obliquely across the quadratus lumborum muscle behind the kidney.Abdominal musclesSkin of the inguinal and pubic regions..
10 9. ...genitofemoral nerve?uinal & iliohypogastric nerves Pierces the psoas major and emerges on its anterior surface.Skin of the middle anterior thigh; male scrotum and cremaster muscle; female labia majora.
11 10. ...lateral cutaneous nerve of the thigh? Runs inferolaterally on the iliacus and enters the thigh deep to the inguinal ligament/iliopubic tractSkin on the anterolateral surface of the thigh.
12 11....lumbar plexus & the sympathetic system? The lumbar plexus is also connected with the lumbar part of the sympathetic nervous system via two or three long communicating branches.
13 12. How is the sacral plexus formed? anterior rami of S1 to S4, and the lumbosacral trunk(L4 and L5).formed in relation to the anterior surface of the piriformis musclelocated on the posterolateral wall of the lesser pelvis..
14 13... sciatic nerve? Largest nerve in the body. The most lateral structure emerging through the greater sciatic foramen inferior to the piriformis and enters the gluteal regionPosterior aspect of the thigh and the entire leg and foot.
15 13... sciatic nerve?Leaves the gluteal region by passing deep to the long head of the biceps femoris,at the lower margin of the quadratus femoris muscleDivides into the common peroneal and tibial nerves, at a variable site above the popliteal fossa.
16 14... pudendal nerve ?Main nerve of the perineum and the chief sensory nerve of the external genitaliaEnters the gluteal region through the greater sciatic foramen inferior to the piriformis muscle & medial to the sciatic nerve.Passes through the lesser sciatic foramen to enter the perineum.no branches in the gluteal region..
17 15....superior & inferior gluteal nerves? Superior gluteal nerveleaves the pelvic cavity through the upper part of the greater sciatic foramen superior to piriformis musclegluteus medius, gluteus minimus, and tensor fasciae lataInferior Gluteal Nervegluteus maximus.
18 16....others? Nerve to Quadratus Femoris Nerve to Obturator Internus Posterior Cutaneous Nerve of ThighPerforating cutaneous nerve.