Nerve supply

• What is the lumbosacral plexus ?

  an interweaving of neurons from different levels/segments of the spinal cord, into final destination nerves that are either motor, sensory or mixed
• what are motor neurons ?


  they fire muscles
• what are sensory nerves ?


  they provide information to the CNS from the periphery of the body, usually the skin and specialised organs
• what is Hilton’s Law?


  a nerve which supplies a muscle also supplies the joint the muscle acts across
• how does every nerve start?

  every nerve at every level of the spinal cord starts out the same way how every the limbs have grown out from the trunk with several levers of nerves in them, where the neurons from neighbouring segments mix together and group into proper nerves
• where doe the plexus start ?

  at the ventral ramus
• what is the characteristic of every nerve of the body ?

  every nerve in the body is paired - there is a left and right nerve
• what is the lumbar and sacral plexus joined by ?

  the lumbosacral trunk (L4 and L5)
• Where does the full plexus interweave from ?

  L1 to S5
• what does the lumbosacral trunk cross?

  the sacral Ala where it adds the L4 and L5 segments to the sacral plexus
• What nerve is the start of the lower limb nerves ?

  sciatic nerve
• what is the pathway of sciatic nerve ?

  • exits pelvis via the greater sciatic foramen beneath Piriformis
  • travels between the lateral rotators and glut max between the ischial tuberosity and greater trochanter
  • continues between the hamstrings and adductor Magnus
• what is this nerve ?

  sciatic nerve

  
• what are the two branches of the sciatic nerve?

  • common fibular nerve
  • tibial nerve
• what is this tibial and common fibular nerve bound by?

  bound by fascia
• where do the tibial and common fibular nerve seperate ?

  popliteal fossa
• what is this nerve?

  tibial nerve

  
• What is the pathway of the tibial nerve?

  • beneath deep fascia
  • goes medial
  • supplies plantaris, gastrocnemius, popliteus, soleus, TP, FDL, FHL
  • passes medial to ankle joint, behind the medial malleolus through the tarsal tunnel
• what are the branches of the tibial nerve?

  calcaneal nerve
• What does the calcaneal nerve supply?

  • provides sensation from the skin of an area over the heel
  • it is damaged when heel experiences damage
• what are the two types of calcaneal nerves?

  Medial and lateral calcaneal nerves
• what are the branches of the calcaneal nerve?

  • medial plantar nerve
  • lateral plantar nerve
• what is this nerve ?

  lateral plantar nerve

  
• what is this nerve?

  medial lateral nerve

  
• what is the supply of the medial and lateral plantar nerve?

  • pass beneath the flexor retinaculum, medially
  • if vessels or muscles of the tarsal tunnel become inflamed, they could be damaged
  • provide sensation from the skin of the sole
• what is this supply of the medial and lateral plantar nerves?

  motor to the plantar intrisic muscles of the foot
• What is this nerve ?

  common fibular nerve

  
• what is the pathway of the common fibular nerve?

  • travels around the neck of fibula
  • sends motor branch to short head biceps femoris
  • passes deep to FL
• What are the branches of the common fibular nerve?

  • superficial fibular nerve
  • deep fibular nerve
  • cutaneous (Sensory) sural nerve
• what is this nerve?

  superficial fibular nerve

  
• what is the pathway of the superficial fibular nerve ?

  • arises deep near the neck of fibula
• what is the supply of the superficial fibular nerve?

  • supplies lateral leg muscles - FL and FB
  • provides sensation from the skin over lateral leg and dorsum of the foot
• what is this nerve ?

  deep fibular nerve

  
• what is the pathway of the deep fibular nerve?

  • runs down from the front surface of the Interosseus membrane of the leg, so protects the nerve from damage
  • passers anterior to ankle joint and deep to extensor retinaculum
• what is the supply of the deep fibular nerve?

  • supplies anterior compartment muscles - TA, EHL, EDL, FT
  • sends one branch to provide sensation form between great and 2nd toe
  • sends another branch that supplies muscles in the dorsum of the foot - EDB, EHB
• what is this nerve?

  cutaneous (sensory) sural nerve

  
• what is the supply of the cutaneous sural nerve?

  it is superficial and provides sensation from an area of skin over the proximal lateral leg
• What is a nerve originating from the lumbar plexus ?

  femoral nerve
• what is this nerve ?

  femoral nerve

  
• what is the pathway of the femoral nerve?

  • travels through Psoas major
  • passes beneath the Inguinal lig into the femoral triangle where it is lateral to the femoral artery
  • continues down the adductor canal and becomes purely sensory saphenous nerve
  • sends sensory branches to the anterior and medial thigh