Pelvic Nerves Flashcards
Lumbosacral Plexus
- formed mainly by branches of L4-L7, S1-S3
- emerge from vertebral canal through intervertebral foramina, caudal to corresponding vertebra
Nerves of the Lumbosacral plexus
- Lateral cutaneous femoral
- Genitofemoral
- Femoral
- Obturator
- Sciatic
- Cranial gluteal
- Caudal gluteal
- Caudal cutaneous femoral
Lateral cutaneous femoral N.
Innervates
- skin over the lateral aspect thigh
- Stifle joint
Test site
-4cm cranial to greater trochanter
Genitofemoral N.
Innervates
- skin over the medial aspect of the thigh
- Male = prepuce and scrotum
- Female = inguinal mammary glands, skin surrounding vulva
Test site
-femoral triangle
What is the action of the quadriceps femoris muscle on the stifle joint?
extension
Femoral N.
Innervates
- Quadriceps femoris muscle - ALL 4 heads
- iliopsoas muscle
Injury to the Femoral N.
- overextension of the quadriceps femoris m = e.g. during recovery after anesthesia
- pelvic fracture -> paralysis of quadriceps femoris m. -> incapable of supporting weight
Common to amputate leg if this injury occurs
Saphenous N.
Innervates
- Sartorius m.
- skin over the medial aspect of thigh, and tarsus (metatarsus and plantar surface of the 2nd digit)
Test site
-4cm distal to the medial epicondyle of the femur
What muscles adduct the pelvic limb?
- adductor
- gracilis
- pectineus
- external obturator
Obturator N.
Innervates
-adductor muscles of the pelvic limb
No cutaneous branches
Injuries to the Obturator Nerve
- Pelvic fracture
- Compression of the nerve = cattle during calving
Lumbosacral Trunk
- formed mainly by ventral branches of L6, L7, S1, and S2
- largest part of lumbosacral plexus
- continued outside pelvis as sciatic nerve
Cranial gluteal N.
Innervates
- middle gluteal muscle
- deep gluteal muscle
- tensor fascia lata
No cutaneous branches
Caudal gluteal N.
Innervates
- superficial gluteal muscle
- (middle gluteal m., piriformis m., cranial portion of biceps femoris m.)
No cutaneous branches
Sciatic or Ischiatic N.
Innervates
- biceps femoris
- quadratus femoris
- semitendinosus
- semimembranosus muscles
- (+ deep gluteal m, internal obturator m, gemelli m)
- skin over lateral aspect of thigh (dist. 1/2), lateral and caudal aspect of the crus
Test site
-mid lateral aspect of leg at level of tibial tuberosity
Injuries to the Sciatic N.
- fractures
- misdirected intramuscular injection
- complication of hip and femoral surgery
Common fibular N.
Innervates
- flexor muscles of the tarsus
- extensor muscles of the digits
What muscles flex the tarsus?
- cranial tibial
- fibularis longus
- fibularis brevis
What muscles extend the digits?
- long digital extensor
- lateral digital extensor
Injury to the Common fibular N
Misdirected intramuscular injection
Causes dropped foot (“knuckle over”) and loss of sensation of the dorsal surface of the paw
Superficial and deep fibular N.
Innervates Skin
- on dorsolateral aspect of distal crus
- on dorsal aspects of metatarsal and digital regions
Tibial N.
Innervates
- extensor muscles of the tarsus
- flexor muscles of the digits
- interossei muscles
- skin on plantar surface of metatarsus and digits
Extensor muscles of the tarsus?
gastrocnemius muscle
Flexor muscles of the digits?
SDF and DDF
