The Lumbosacral Plexus Flashcards
Where do the lower limbs receive their nerve supply via?
The lumbosacral plexus
What is the lumbar plexus formed from?
Anterior rami of L1-L4 spinal nerves
What is the lumbsacral trunk formed from?
L4 + L5 anterior rami
What nerves are in the lumbar plexus?
+ their nerve roots
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Iliolunguinal L1
Genitofermoral L1,L2
Lateral femoral cutaneous L2,L3
Obturator L2, L3, L4
Femoral L2,L3,L4
Where does the iliolinguinal nerve innervate?
Skin of genitalia + upper medial thigh
Iliolinguinal nerve roots
L1
Genitofemoral nerve roots
L1, L2
What doe the genitofemoral nerve branch into?
Genital branch
Femoral branch
Sensory function of lateral femoral cutaneous nerve
To anterolateral thigh to knee
Lateral femoral cutaneous nerve roots
L2, L3
Obturator nerve roots
L2, L3, L4
Sensory innervation of the obturator nerve
Skin over medial thigh
What does the femoral nerve branch into?
Anterior femoral cutaneous branch
Saphenous branch
Femoral nerve roots
L2, L3, L4
Where does the anterior femoral cutaneous branch of the femoral nerve innervate?
Skin of anterior thigh
Where does the saphenous branch of the femoral nerve innervate?
Skin of medial leg
What is the sacral plexus formed by?
Anterior rami of S1-S5
Receives contribution from L4+L5 via lumbosacral trunk
Nerves of the sacral plexus
+ their nerve roots
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Superior gluteal L4 , L5 S1
Inferior gluteal L5, S1, S2
Sciatic L4, L5, S1, S2, S3
Posterior femoral cutaneous S1,S2,S3
Pudendal S2, S3, S4
Superior gluteal nerve roots
L4, L5, S1
Where does the superior gluteal nerve leave the pelvis?
Greater sciatic foramen above the piriformis
What does the superior gluteal nerve innervate?
Gluteus medius
Gluteus minimis
Tensor fascia lata
Inferior gluteal nerve roots
L5, S1, S2
Where does the inferior gluteal nerve leave the pelvis?
Via the greater sciatic foramen below the piriformis
What does the inferior gluteal nerve innervate?
Gluteus maximus
Sciatic nerve roots
L4, L5, S1, S2, S3
What does the sciatic nerve branch into?
Where?
Tibial nerve
Common peroneal nerve
At popliteal fossa
Where does the tibial nerve innervate?
Posterior thigh
Semitendinosus
Semimembranosus
Biceps femoris (long head)
Ischial part of ADductor mangus
What does the common peroneal nerve innervate?
bicep femoris (short head)
Tibial nerve roots
L4-S3
Common peroneal nerve roots
L4-S3
Posterior femoral cutaneous nerve roots
S1, S2, S3
Where does the posterior femoral cutaneous nerve innervate?
Skin of posterior thigh + leg
Motor innervation of obturator nerve
- obturator externus
- pectineus
- ADuctor longus, brevis + mangus
- gracillis
