Nerves of Lower Limb Flashcards
From where do the limb buds develop?
Out of lateral side of cavity
What do the limb buds take with them as they develop?
Ventral rami supplying that strip of wall
What are the two plexi that supply the lower limb?
Lumbar
Sacral
Where does the lumbar plexus divide?
Within substance of psoas major
Which ventral rami feed into the lumbar plexus?
L1-4
What do the anterior fibres of the lumbar plexus supply?
Flexor compartment in posterior aspect
What do the posterior fibres of the lumbar plexus supply?
Extensor compartment in anterior aspect
Which nerves of the lumbar plexus emerge from the lateral border of psoas?
Ilioinguinal and iliohypogastric nerves
Lateral cutaneous nerve of thigh
Femoral nerve
Which vertebral segments supply the ilioinguinal and iliohypogastric nerves?
L1
Which vertebral segments supply the lateral cutaneous nerve of thigh?
L2
L3
Which vertebral segments supply the femoral nerve?
L2
L3
L4
Posterior division fibres
Which nerves of the lumbar plexus emerge onto the anterior surface of psoas?
Genitofemoral nerve
Which vertebral segments supply the genitofemoral nerve?
L1
L2
Which nerves of the lumbar plexus emerge from the medial border of psoas?
Obturator nerve
Which vertebral segments supply the obturator nerve?
L2
L3
L4
What do the ilioinguinal and iliohypogastric nerves supply?
Lower part of anterior abdominal wall
What is another name for the lateral cutaneous nerve of thigh?
Lateral femoral cutaneous nerve
Why is the genitofemoral nerve like two nerves in one sheath?
Has
- Genital branch
- Femoral branch
Which muscle do the ilioinguinal and iliohypogastric nerves emerge onto?
Quadratus lumborum
What is the course of the ilioinguinal and iliohypogastric nerves in the anterior abdominal wall?
Slip into neurovascular plane of anterior abdominal wall - between internal oblique and transversus abdominis
Track into anteroinferior direction towards groin region
Supplies conjoined tendon that forms roof of inguinal canal
Passes directly beneath McBurney’s point
Which nerve emerges more superiorly onto psoas: ilioinguinal or iliohypogastric?
Iliohypogastric
What is the course of the lateral femoral cutaneous nerve of thigh after emerging from psoas?
Swings wide onto iliacus
Goes with iliacus beneath inguinal ligament and into lower limb
Tucks under inguinal ligament where it attaches to anterior superior iliac spine
What can happen to the lateral femoral cutaneous nerve of thigh in very obese, and classically, in pregnant women?
Can be impinged by inguinal ligament and anterior superior iliac spine
What does impingement of the lateral femoral cutaneous nerve of thigh cause?
Tingling and numbness on lateral side of thigh
What is the course of the femoral nerve after emerging from psoas?
Tucks into gutter between iliacus and psoas
Beneath inguinal ligament
Divides into terminal branches just distal to ligament all at once
What is the nerve supplying the anterior compartment of the thigh?
Femoral nerve
What is the course of the genitofemoral nerve after emerging from psoas?
Splits very quickly into genital and femoral branches
Femoral branch goes straight beneath inguinal ligament
Genital branch enters inguinal canal via deep ring
Which nerve supplies the skin over the femoral triangle?
Femoral branch of genitofemoral nerve
What type of nerve is the femoral branch of the genitofemoral nerve?
Sensory
What fibres is the obturator nerve carrying: anterior, posterior, or both?
Anterior division fibres
Which nerve supplies the medial compartment of the thigh?
Obturator nerve
From what are the muscles of the medial compartment of the thigh derived from, and what does this imply about their nerve supply?
Flexor musculature, therefore supplied by anterior division fibres
What part of the sacrum does piriformis arise from?
Anterolateral aspect
Which muscle do S1-4 ventral rami emerge onto?
Anterior surface of piriformis
Where is the sacral plexus formed?
On anterior surface of piriformis
What is the lumbosacral trunk?
Part of L4 doesn’t feed into lumbar plexus
Heads down with L5 into pelvis
What makes up the sacral plexus?
Lumbosacral trunk
S1-4
What does the sacral plexus supply?
Pelvis
Lower limb
How do the branches of the sacral plexus supplying the lower limb exit?
With piriformis into gluteal region
What does the femoral nerve supply?
Motor to - Quadriceps - Sartorius - Pectineus Sensory to - Anterior and anteromedial thigh - via 2 separate nerves - Medial side of knee, leg, and ankle - Saphenous nerve Articular branches to - Hip - Knee
What is the innervation of iliopsoas?
Directly from lumbar plexus
For how long is the femoral nerve “the femoral nerve” for after passing below the inguinal ligament?
1 inch
To which artery and vein is the femoral nerve situated laterally?
Femoral artery and vein
Is the femoral nerve within the femoral sheath?
No
Which branch of the femoral nerve supplies sensory innervation to the anterior aspect of the thigh?
Anterior cutaneous nerve of thigh
Which branch of the femoral nerve supplies sensory innervation to the anteromedial aspect of the thigh?
Anteromedial cutaneous nerve of thigh
What nerve is the saphenous nerve a branch of?
Femoral nerve
When does the saphenous nerve become cutaneous?
Level of knee
What does the saphenous nerve supply sensory innervation to?
Skin down medial side of leg and foot up to level of 1st metatarsophalangeal joint
What does the lateral cutaneous nerve of thigh supply?
Sensory to anterolateral aspect of thigh
What is the course of the obturator nerve after emerging from psoas?
Drops into pelvis
Lateral wall of pelvis - almost direct descent
Obturator canal
Top of medial compartment of thigh
What does the obturator nerve supply?
Motor to - Adductor muscles - Pectineus Sensory to - Inferomedial thigh > just above knee - Peritoneum lining side wall of pelvis Articular branches to - Hip
Why does pectineus get a dual nerve supply from both the femoral and obturator nerves?
Transition muscle between anterior and medial compartments of thigh
Which part of adductor magnus doesn’t the obturator nerve supply?
Hamstring part
How does the obturator nerve supply the three layers of adductor muscles?
Splits into
- Anterior branch of obturator nerve - between adductor longus and brevis
- Posterior branch of obturator nerve - between adductor brevis and magnus
Which nerve supplies gracilis?
Obturator nerve
Where can pain from a pelvic pathology, classically a large ovarian cyst, be referred to, and why?
Pathology irritates parietal peritoneum
Pain referred to cutaneous distribution of obturator nerve
What is the largest nerve in the body?
Sciatic nerve
Which compartments does the sciatic nerve supply?
Posterior compartment of thigh
Everything below knee
Which vertebral segments feed into the sciatic nerve?
L4 L5 S1 S2 S3 Anterior division fibres Posterior division fibres
What are the two components to the sciatic nerve?
Tibial
Common fibular
What is the course of the sciatic nerve?
Exits pelvis via greater sciatic foramen
Emerges beneath piriformis in gluteal region
Posterior to hip, running over quadratus femoris
Descends posterior thigh under biceps femoris
Divides at apex of popliteal fossa
What does the sciatic nerve supply?
Motor to - Hamstrings Sensory - Via terminal branches only because deep nerve Articular branches to - Hip - Knee via terminal branches
Which components of the sciatic nerve supply each of the hamstring muscles?
All supplied by tibial component except short head of biceps femoris, which supplied by common fibular component
Which nerve supplies gluteus maximus?
Inferior nerves - from sacral plexus
Which vessels supply gluteus maximus?
Inferior gluteal vessels
Which nerve supplies gluteus medius and minimus?
Superior gluteal nerve
From where do the inferior gluteal nerves emerge?
Below piriformis
From where does the superior gluteal nerve emerge?
Above piriformis
What nerve supply is endangered in a posterior dislocation of the hip?
Sciatic nerve and all its neural supply beyond that point
Where does the sciatic nerve classically divide into its terminal branches?
2/3 of way down posterior compartment of thigh - classically at apex of popliteal fossa
What happens if the sciatic nerve divides at a point higher than usual?
Classically, tibial component still comes out beneath piriformis but common fibular component will come out through/above piriformis
What are the implications of giving an intramuscular injection in the gluteal region if the common fibular part of the sciatic nerve emerges through or above piriformis?
Injection can endanger common fibular part, so now injections give in lateral part of thigh
What do the two terminal branches of the sciatic nerve supply?
Everything below knee
What are the vertebral segments feeding the tibial nerve?
L4 L5 S1 S2 S3 Anterior division fibres
What is the course of the tibial nerve?
Continues vertical descent of sciatic nerve through popliteal fossa Beneath fibrous arch of soleus Descends on tibialis posterior in calf Posterior to medial malleolus Sole of foot
What does the tibial nerve split into on the sole of the foot?
Medial and lateral plantar nerves
What is the motor supply of the tibial nerve?
Posterior compartment of leg
Sole of foot
What is the sensory supply of the tibial nerve?
Posterior, posterolateral, and lateral leg
Sole of foot
Via which branch does the tibial nerve supply sensory innervation to the posterior, posterolateral, and lateral leg, as well as the lateral side of the foot?
Sural nerve
Via which branch does the tibial nerve supply sensory innervation to the sole of the foot?
Medial calcaneal nerve
Medial and lateral plantar nerves
Which nerve supplies the sensory innervation of the skin over the posterior aspect of the thigh, and of what is it a branch?
Posterior femoral cutaneous nerve, directly off sacral plexus
From which muscles are the lateral everter muscles of the foot derived?
Anterior extensor muscles of leg
What vertebral segments feed into the common fibular nerve?
L4 L5 S1 S2 Posterior division fibres
What is the course of the common fibular nerve?
Divides laterally from tibial nerve Heads medial to biceps femoris Superficial to lateral head of gastrocnemius Winds around neck of fibula Sinks into fibularis longus Divides into terminal branches
What is the sensory supply of the common fibular nerve?
Upper lateral leg via lateral sural cutaneous nerve
Gives communicating branch to sural nerve
What is the motor supply of the deep fibular nerve?
Anterior compartment of leg
Extensor digitorum brevis
What is the sensory supply of the deep fibular nerve?
1st toe cleft
What does the deep fibular nerve give articular branches to?
Ankle
Foot
What is the motor supply of the superficial fibular nerve?
Lateral compartment of leg
What is the sensory supply of the superficial fibular nerve?
Lower lateral leg
Dorsum of foot
Which nerve is endangered in a fracture of the neck of the fibula, or a tight plaster compressing it to the bone?
Common fibular nerve
What are the clinical features of common fibular nerve damage?
Lose motor supply to extensors of leg and toes, and everters > foot drop
What is the course of the deep fibular nerve?
Starts in fibularis longus
Descends deep to extensor digitorum longus
Anterior to interosseus membrane, beneath tibialis anterior
Beneath extensor retinaculum
Onto dorsum of foot
What is the course of the superficial fibular nerve?
Descends in lateral compartment
Which vertebral segments control hip flexion?
L2,3
Which vertebral segments control hip extension?
L4,5
Which vertebral segments control knee flexion?
L5, S1
Which vertebral segments control knee extension?
L3,4
Which vertebral segments control ankle dorsiflexion?
L4,5
Which vertebral segments control ankle plantarflexion?
S1,2
Which vertebral segments control foot inversion?
L4
Which vertebral segments control foot eversion?
L5, S1
Which vertebral segments control big toe extension?
L5, S1
Which vertebral segments control big toe flexion?
S1,2
