Nerves of the lower limb Flashcards
What is the lumbar plexus?
A network of nerve fibres that supplies the skin and musculature of the lower limb. Located within the lumbar region it sits within the substance of psoas major. Its roots are the anterior rami of L1-L4 with some innervation from T12
What are the branches of the lumbar plexus
iliohypogastric nerve ilioinguinal nerve Genitofemoral nerve lateral cutaneous nerve of the thigh obturator nerve femoral nerve
What are the roots of the iliohypogastric nerve
What are its motor functions?
What are it sensory innervation’s?
L1 (with contributions from L12)
Innervates the internal oblique and transverses abdominis
Innervates posterolateral gluteal skin in the pubic region
What are the roots of the ilioinguinal nerve
What are its motor functions?
What are it sensory innervation’s?
L1
Innervated the interal oblique and transversus abdominis muscle
Innervates skin on the upper medial thigh. In males it also supplies the skin of the root of the enis, in females the labia majora
What are the roots of the genitofemoral nerve
What are its motor functions?
What are it sensory innervation’s?
L1, L2
The genital branch innervates the cremasteric muscle
The genital branch innervates the skin of the anterior scrotum or the skin over the mons pubis and labia majora. Also does upper anterior thigh
What are the roots of the lateral cutaneous nerve of the thigh
What are its motor functions?
What are it sensory innervation’s?
L2, L3
None
Innervates the anterior and lateral thigh down to the level of the knee
What are the roots of the obturator nerve
What are its motor functions?
What are it sensory innervation’s?
L2,L3,L4
Innervates the muscles: obturator externus, pectineus, adductor longus.adductor brevis adductor magnus and gracilis
Describe the anatomical course of the obturator nerve
Travels past the psoas major and past the common ilaic arteries before going along the pelvic wall and out the obturator foramen of the obturator canal. Very small nerve with little branching
What are the roots of the femoral nerve
What are its motor functions?
What are it sensory innervation’s?
L2,L3,L4
Innervates the iliacus, pectineus, sartorius and muscles of quadriceps femoris
Innervates skin on the anterior thigh adn medial leg
Describe the anatomical course of the femoral nerve
Largest branch of the lumbar plexus, runs down the psoas major muscle of the posterior abdominal wall. Travels under the inguinal ligament into the femroal triangle
Runs down the medial aspect of the thigh where is terminal branches terminate around the branch of the knee
Desribe the sciatic nerve
The sciatic nerve is a major nerve of the lower limb. It is a thick flat band, approximetely 2cm wide- largest nerve in the body
What are the roots of the sciatic nerve
What are its motor functions?
What are it sensory innervation’s?
L4-S3
Innervates muscles of posterior thigh, indiractly innervates all the muscles of the leg and foot through its branches
No direct sensory functions
Describe the anatomical course of the sciatic nerve
Arises from lumbosacral plexus. Leaves pelvis and enters gluteal region. Emerges underneath piriformis and travels inferiorly. Terminates int eh popliteal nerve where its gives rise to the tibial and common fibular nerves
What is piriformis syndrome?
Compression of the sciatic nerve, also known as deep gluteal syndrome. Includes pain, numbness muscle wekaness and buttocks tenderness.
Describe the tibial nerve
What are its roots?
What are its motor functions?
What are it sensory innervation’s?
posterior branch of the sciatic nerve
L4-S3
innervates posterior leg and majority of intrinsic foot muscles
Skin of posterolateral leg, lateral and sole of foot
Describe the anatomical course of the tibial nerve
Runs straight don the back of the leg pretty much in a straight line
Describe the common fibular nerve
What are the roots of the common fibular nerve?
What are its motor functions?
What are it sensory innervation’s?
Begins at the apex of the popliteal fossa, branch of sciatic nerve. Very short nerve that wraps around the knee
L4-S2
Inenrvates short head of biceps femoris
Skin over upper and lateral and lower posterolateral leg
What happens during damage to the common fibular nerve
Very common during fracture of the fibula or use of a tight plaster cast
Causes patients to lose the ability to dorsiflex the foot
Describe the superficial fibular nerve
What are the roots of it
What are its motor functions?
What are it sensory innervation’s?
Branch of common fibuar that runs medially down from knee to foot
L4-S1
Inenrvates muscles in lateral compartment of leg
Supplies the vast majority of the skin over the dorsum of the foot. Also anterior and lateral aspect of inferior third of leg
What can ankle sprains lead to
Stretching of the superficial fibular nerve leading to pain and paraesthesia over the lower leg and dorsum of foot
Describe the deep fibular nerve
What are the roots of the femoral nerve
What are its motor functions?
What are it sensory innervation’s?
Branch of ccommon fibular, starts at knee and runs straight down the leg through the middle of the ankle into the foot
L4- S1
Innervates muscles of anterior leg as well as some intrinsic msucles of the foot
Supplies the triangluar region of the skin between 1st and 2nd toes
