Lumbosacral plexus Flashcards
Wilson
Which anterior rami supply the Lumbosacral plexus?
Lumbar Plexus (L1-L4)
Sacral Plexus (L4-S4)
Limb buds develop from two myotomic groups.
What are they?
dorsal muscle mass
Ventral muscle mass
Dorsal muscle mass of limb development give rise to which muscles?
Extensors
Ventral muscle mass give rise to which muscles?
Flexors
The mass of cells between the dorsal and ventral muscle mass is a precursor for?
Precursor for bones and tedons
Anterior division of the lumbar and sacral plexus procide innervation for?
Flexors
The posterior division of the lumbar and sacral plexi provide innervation for?
Extensors
The femoral n. receives ventral primary rami from which divisions?
Posterior divisions
It will supply extensor muscles
The obturator n. receive ventral primary rami from which divisions?
anterior divisions
It will supply flexor muscles
Common fibular n. receive ventral primary rami from which divisions?
Posterior divisions
It will supply extensors
Tibial n. receive ventral primary rami from which divisions?
anterior division
What are the branches of the Lumbar plexus (L1-L4)?
Iliohypogastric n. (L1)
Ilioinguinal n. (L1)
genitofemoral n. (L1 and L2)
Lateral femoral cutaneous n. ( L2 and L3) - posterior division
Femoral nerve, which is mixed (L2, L3, and L4) - posterior division
Obturator n., which is mixed ( L2, L3, and L4) - anterior division
Lumbosacral trunk, to sacral plexus (L4 and L5)
What is the different about the lower limb rotation during fetal development compared to the upper limb
Lower limb rotates medially, whereas the upper limb rotate laterally
EXTENSORS - Anterior portion of lower limb
FLEXORS - posterior portion of lower limb
(THIS IS OPPOSITE COMPARED TO UPPER LIMB)
Posterior and anterior division of the lumbar plexus innervate which compartment of the thigh?
Posterior division - anterior compartment of thigh
Anterior division - medial compartment of thigh
Femoral n. innervates which compartment of the thigh?
Anterior compartment of the thigh
The obturator n. innervates which compartment of the thigh?
Medial compartment of the thigh
The posterior division of the sacral plexus come from which ventral primary rami?
L4-S2
The anterior divisions of the sacral plexus come from which ventral primary rami?
L4-S3
Superior gluteal n. recieves nerve branches from which ventral primary rami?
Posterior division of L4-S1
The inferior gluteal n. recieves nerve fibers from which ventral primary rami?
Posterior division of L5-S2
The nerve to piriformis recieves nerve fibers from which ventral primary rami?
Posterior divison of S1 and S2
Which two nerves come together to form the sciatic nerve?
Common fibular nerve (Posterior division L4-S2)
Tibial nerve (Anterior division L4-S3)
The nerve to obturator internus and superior gemellus recieves nerve fibers from which ventral primary rami?
Anterior division of L5 + S1
The nerve to quadratus femoris and inferior gemellu recieves nerve fibers from which ventral primary rami?
Anterior division of L4 + L5
What is the course of the sciatic nerve?
leaves the pelvis -> gluteal region via greater sciatic foramen -> emerges inferiorly to the piriformis muscle and descends in an inferolateral direction.
As the nerve moves through the gluteal region, it crosses the posterior surface of the superior gemellus, obturator internus, inferior gemellus and quadratus femoris muscles. It then enters the posterior thigh by passing deep to the long head of the biceps femoris.
Within the posterior thigh, the nerve gives rise to branches to the hamstring muscles and adductor magnus. When the sciatic nerve reaches the apex of the popliteal fossa, it terminates by bifurcating into the tibial and common fibular nerves.
Why is the piriformis an important landmark in the body?
The sciatic nerve emerges into the gluteal inferior to the piriformis
Damage/inflammation of the piriformis can cause Sciatica
The tibial division of the sciatic nerve innervates which part of the thigh?
Posterior compartment of the thigh
(Hamstrings)
What is the exception of the hamstring muscles and their nerve innervation?
All muscles of the hamstring are innervated by the tibial division of the sciatic nerve except the short head of biscep, which is innervated by the common fibular division of sciatic nerve.
Where does the sciatic nerve divided into the common fibular and tibial nerves?
In the popliteal fossa
Tibial nerve goes straight down and the common fibular nerve curves laterally at the neck of the fibula to go to the anterior compartment.
The common fibular nerver goes anteriorly at the neck of the femur and spilts into two branches. What are they?
Deep fibular n.
Superficial fibular n.
The deep fibular nerve innervates where?
The anterior compartment of the leg (Extensors)
The superficial fibular nerve innervates where?
Lateral compartment of leg
(Fibularis longus and brevis)
After innervating these muscles it becomes a cutaneous nerve for the lateral side of the leg