The Lumbosacral Plexus Flashcards
What structures form the lumbosacral plexus?
The lumbosacral plexus is formed by the ventral rami of spinal nerves L1-S4.
Where is the lumbosacral plexus located in the body?
The lumbosacral plexus is located in the pelvic region, extending from the lumbar spine to the sacrum.
What are the main nerves arising from the lumbosacral plexus?
The main nerves arising from the lumbosacral plexus include the femoral nerve, obturator nerve, sciatic nerve, and their branches.
Describe the course and distribution of the femoral nerve.
The femoral nerve courses through the pelvis and thigh, supplying motor innervation to the anterior thigh muscles and sensory innervation to the anterior thigh and medial leg.
What muscles does the femoral nerve innervate?
The femoral nerve innervates muscles such as the quadriceps femoris and sartorius.
Describe the course and distribution of the obturator nerve.
The obturator nerve passes through the pelvis and innervates the medial thigh muscles, including the adductors.
What muscles does the obturator nerve innervate?
The obturator nerve innervates muscles such as the adductor longus and gracilis.
Describe the course and distribution of the sciatic nerve.
The sciatic nerve is the largest nerve of the lumbosacral plexus, supplying motor and sensory innervation to the posterior thigh, leg, and foot.
What muscles does the sciatic nerve innervate?
The sciatic nerve innervates muscles such as the hamstrings and muscles of the lower leg and foot.
What are the two main branches of the sciatic nerve?
The two main branches of the sciatic nerve are the tibial nerve and the common fibular (peroneal) nerve.
Describe the course and distribution of the tibial nerve.
The tibial nerve travels down the posterior thigh and leg, supplying motor innervation to the posterior thigh muscles and sensory innervation to the posterior leg and sole of the foot.
What muscles does the tibial nerve innervate?
The tibial nerve innervates muscles such as the gastrocnemius and soleus.
Describe the course and distribution of the common fibular (peroneal) nerve.
The common fibular (peroneal) nerve divides into the deep fibular nerve and superficial fibular nerve, supplying motor innervation to the anterior and lateral compartments of the leg, respectively.
What muscles does the common fibular nerve innervate?
The common fibular nerve innervates muscles such as the tibialis anterior and fibularis longus.
Describe the course and distribution of the superior gluteal nerve.
The superior gluteal nerve exits the pelvis and innervates the gluteus medius, gluteus minimus, and tensor fasciae latae.
What muscles does the superior gluteal nerve innervate?
The superior gluteal nerve innervates muscles responsible for hip abduction and stabilization.
Describe the course and distribution of the inferior gluteal nerve.
The inferior gluteal nerve exits the pelvis and innervates the gluteus maximus.
What muscles does the inferior gluteal nerve innervate?
The inferior gluteal nerve innervates the largest muscle of the buttocks, responsible for hip extension and lateral rotation.
Describe the course and distribution of the pudendal nerve.
The pudendal nerve exits the pelvis and innervates the perineum, including the external genitalia and anal region.
What muscles does the pudendal nerve innervate?
The pudendal nerve innervates muscles such as the external anal sphincter and bulbospongiosus.
Describe the course and distribution of the posterior femoral cutaneous nerve.
The posterior femoral cutaneous nerve travels down the posterior thigh and innervates the skin of the posterior thigh and popliteal fossa.
What areas does the posterior femoral cutaneous nerve innervate?
The posterior femoral cutaneous nerve innervates the skin of the posterior thigh, buttocks, and perineum.
Describe the course and distribution of the iliohypogastric nerve.
The iliohypogastric nerve exits the pelvis and innervates the skin of the lower abdomen, inguinal region, and gluteal region.
What areas does the iliohypogastric nerve innervate?
The iliohypogastric nerve innervates the skin over the iliac crest, pubic symphysis, and upper buttock.
Describe the course and distribution of the ilioinguinal nerve.
The ilioinguinal nerve exits the pelvis and innervates the skin of the inguinal region, mons pubis, and upper scrotum or labia majora.
What areas does the ilioinguinal nerve innervate?
The ilioinguinal nerve innervates the skin over the groin, upper thigh, and external genitalia.
Describe the course and distribution of the genitofemoral nerve.
The genitofemoral nerve exits the pelvis and innervates the skin of the genitalia and anterior thigh.
What areas does the genitofemoral nerve innervate?
The genitofemoral nerve innervates the skin over the anterior thigh and genital region.
Describe the course and distribution of the lateral femoral cutaneous nerve.
The lateral femoral cutaneous nerve exits the pelvis and innervates the skin of the lateral thigh.
What areas does the lateral femoral cutaneous nerve innervate?
The lateral femoral cutaneous nerve innervates the skin over the lateral thigh, providing sensory innervation.
