Lumbar and lumbosacral plexus Flashcards
*The entire lower limb is supplied by which 2 somatic nerve plexi?
1) Lumbar plexus (ventral rami of L1-L4)
2) Lumbosacral plexus (ventral rami of L4 and L5 joining the ventral rami from S1-S4)
*What does the lumbar plexus innervate?
Lumbar plexus (ventral rami of L1-L4) innervates – skin and muscles of the lower abdominal wall
- skin covering the root of the penis and anterior scrotum and the skin over the mons pubis and anterior portion of the labia majora
- skin and muscles in the anterior and medial compartments of the thigh
- skin of the lateral thigh
- skin of the medial side of the leg.
*What does the lumbosacral plexus innervate?
lumbosacral plexus (ventral rami of L4 and L5 joining the ventral rami from S1 to S4) innervates
- the skin and muscles of the gluteal region
- the skin and muscles of the perineum
- the skin and muscles of the posterior thigh
- the skin and muscles of the anterior, lateral, and posterior leg and the muscles of the medial leg
- the skin and muscles in the foot.
*Which plexus innervates the foot muscles?
lumbosacral (ventral rami of L4 and L5 joining the ventral rami of S1 to S4)
*Which plexus innervates the glute muscles?
lumbosacral (ventral rami of L4-L5 joining with S1-S4)
*Which plexus innervates the skin of the medial side of the leg?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the muscles of the anterior thigh?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the muscles of the medial thigh?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the skin of the anterior thigh?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the skin of the medial thigh?
lumbar plexus (ventral rami of L1-L4)
*Which plexus innervates the skin of the gluteal region?
lumbosacral plexus (L4-L5 and S1-S4)
*Which plexus innervates the foot skin?
lumbosacral plexus (L4-L5 and S1-S4)
*Which plexus innervates the muscles of the posterior thigh?
lumbosacral plexus (L4-L5 and S1-S4)
*Which plexus innervates the skin of the posterior thigh?
lumbosacral plexus (L4-L5 and S1-S4)
*Which plexus innervates most of the leg muscles and leg skin?
lumbosacral plexus (L4-L5 and S1-S4)
*What do the clunial nerves do?
provide cutaneous innervation to the skin of the gluteal region.
*What are the different groups of clunial nerves?
1) Superior clunial nerves (dorsal rami of L2, L3)
2) Middle clunial nerves (dorsal rami of S2, S3, S4)
3) Inferior clunial nerves (branches from posterior cutaneous nerve of the thigh– ventral rami of S2, S3)
*What are the superior clunial nerves and what do they supply?
derived from dorsal rami of L2, L3, L4. Supply the skin over the central and superior portion of this region.
*What are the middle clunial nerves and what do they supply?
derived from dorsal rami of S2, S3, and S4. Supply medial portion of the buttock.
*What are the inferior clunial nerves and what do they supply?
branches from posterior femoral cutaneous nerve of the thigh (which is a branch from the ventral rami of the sacral plexus). Inferior clunial nerves (S2 and S3) supply skin covering inferior portion of the buttock.
*Each paravertebral ganglion in the lumbar and sacral portion of the sympathetic chain is connected to a lumbar or sacral ventral ramus via?
grey ramus
*The lumbar and lumosacral plexi are what? What are they responsible for?
The lumbar and lumbosacral plexi are somatic nerve plexi responsible for supplying cutaneous sensaton from the skin and motor innervation to the muscles of the entire lower limb.
*What is responsible for the cremaster reflex? What is the cremaster reflex used for?
The L1 spinal nerve (the genital branch of the genitofemoral nerve off of the lumbar plexus) is responsible for the cremaster reflex. This reflex is used to determine integrity of the L1 spinal nerve. The cremaster muscle should contract (causing the testicles to retract lightly) if the L1 dermatome is stimulated (either by rubbing the skin of the anterior scrotum or upper thigh).
*Which is the largest nerve plexus in the body?
lumbosacral or sacral plexus