Lumbar plexus Flashcards
Anterior or posterior rami
Anterior
What are the spinal roots of the lumbar plexus
L1-4
Also receives contribution from T12
What do the spinal roots divide into
Cords
What do the cords combine to form and how many
6 branches (major peripheral nerves)
What are the branches of the lumbar plexus
Iliohypogastric, Ilioinguinal, Genitofemoral, Lateral cutaneous, Femoral (covered in separate deck) Obturator (covered in separate deck)
Roots of iliohypogastric nerve
L1 with contributions from T12
Course of iliohypogastric nerve
Runs to the iliac crest, across the quadratus lumborum muscle of the posterior abdominal wall
Then it perforates the transverse abdominis and divides into terminal branches
Motor Innervation of iliohypogastric nerve
Internal oblique muscle
Transversus abdominis muscle
Sensory Innervation of iliohypogastric nerve
Posterolateral gluteal skin of pubic region
Roots of ilioinguinal nerve
L1
Course of ilioinguinal nerve
Same as larger iliohypogastric nerve.
After Innervating musculature of anterior abdominal wall, it passes through superficial inguinal ring
Motor Innervation of ilioinguinal nerve
Internal oblique
Transversus abdominis
Sensory Innervation of ilioinguinal nerve
Skin on upper middle thigh
Skin over root of penis and anterior scrotum
Skin over mons pubis and labium majus
Roots of genitofemoral nerve
L1-2
Course of genitofemoral nerve
After leaving psoas major, it quickly divides into a genital branch and a femoral branch
Motor Innervation of genitofemoral nerve
Genital branch innervates the cremasteric muscle
Sensory Innervation of genitofemoral nerve
Genital branch - skin over anterior scrotum, mons pubis and labium majus
Femoral branch - skin over upper anterior thigh
Roots of lateral cutaneous nerve of thigh
L2-3
Where does the lateral cutaneous nerve of thigh enter the thigh
At lateral aspect of inguinal ligament
Motor Innervation of lateral cutaneous nerve of thigh
None (it’s purely sensory)
Sensory Innervation of lateral cutaneous nerve of thigh
Skin over anterior and lateral thigh down to level of knee
What is lumbosacral plexopathy
Disorders of either lumbar or sacral plexus caused by damage to nerve bundles
Main cause of lumbosacral plexopathy
Diabetic amyotrophy (lumbosacral radioplexus neurophagy) High blood glucose damages nerves
Other causes of lumbosacral plexopathy
Idiopathic plexopathy (equivalent of personage-turner syndrome of brachial plexus) Tumours/local invasions - compress plexus
When is a plexopathy suspected
If symptoms can’t be localised to a single nerve
How does a patient present with lumbosacral plexopathy
Neuropathic pain,
Numbness,
Weakness and wasting of muscles
Treatment for lumbosacral plexopathy
Depends on cause:
Tumours/space occupying lesions - removal
Diabetic/idiopathic - high dose of corticosteroids
Where is the lumbar plexus located
In the lumbar region -
Within psoas major
Anterior to transverse processes of lumbar vertebrae
