Nerves + Vessels LL Flashcards
Which Spinal nerves make out the Lumbo-sacral pexus?
(L1)L2-S3
How many pairs of spinal nerves are there?
How are they classified?
„There are 31 pairs of spinal nerves
- 8 Cervical
- 12 Thoracic
- 5 Lumbar
- 5 Sacral
- 1 Coccygeal
“
Where do autonomic fibres fom the spinal chord emerge?
They emerge from cranial nerves (PNS)+
- T1-L2 (SNS)
- S2-S4 (PNS)
Which spinal nerve generally supply the lower limb?
L2-S2
Which spinal nerves generally supply the perineum?
S2-C1
Which spinal nerves generally supply the upper limb?
C5-T1
Explain the involvement of the anterior and posterior rami in the lumbo-sacral plexus
The anterior rami of the spinal nerves merge and give rise to the lumbar plexus
The posterior rami (much smaller) normally cutaneous innervation
Explain the formation and route of the femoral nerve
L2-L4
- leaves the pelvis under the inguinal ligaments
- runs in the femoral triangle, in anteriomedial part of the thigh
- gives rise to many brances, one of them is the saphenous nerve (green in picture)
What is the motor and sensory function of the femoral nerve?
Which spinal nerves are involved?
Motor
It supplies all muscles in the anterior compartment of the thigh
- also gives branches to iliacus, psoas and pectineus
- –> extention of the knee
Sensory
- skin on anterior thigh+ medial side of leg and foot (though saphenous nerve)
Explain the route of the obturator nerve
Which spinal nerves are involved in its formation?
L2-L4
- descends along posterior abdominal wall
- passes through the obturator canal/foramen
Explain the motor and sensory innervation of the obturator nerve
L2-4
Motor
- medial compartment of the thigh (except pectineus)
- obturator externus
Sensory
- sin upper medial aspect of thigh
Explain the route of the sciatic nerve from the hip to the thigh
Whhich spinal route are inoveled in its formation?
L4-S3
- leaves pelvis through greater sciatic foramen, around piriformis,
- passes through gluteal region (inferior)
- runs down posterior side of thigh
- gives rise to posterior cutaneous nerve of thigh
Explain the route of the sciatic nerve in the polpiteal fossa
It devides into
- Tibial nerve (runs
- Common peroneal nerve
Explain the route of the tibial nerve
- emerges from the sciatic nerve in the polpiteal fossa
- runs down posterior leg
- travels behind medial malleolus and enters foot
What does the sciativ nerve supply?
Where does it get its spinal nerves from?
L3-S3
- supplies
- posterior compartment of tigh
- leg and foot via tibial and fibular nerve
What does the tibial nerve supply?
Which spinal nerves are involved?
Branch of the sciatic nerv L3-S3
- supplies posterior compartment of leg
- intrinsic muscles of the foot
Explain the route of the common fibular nerve in the leg
What does it supply?
Branch of the sciatic nerve, runs laterally along the fibula where it is suspectible to damage!
Is soon subdevides into
- superficial peroneal nerve (L4-S1)
- runs down laterally and supplies the lateral compartment of the leg
- deep fibular nerve (L5-S2)
- runs down anteriorly and supplies anterior compartment of leg
Explain the function and route of the superior gluteal nerve
Which spinal nerve contribute to its formation?
L4-S1
- supplies gluteal medius and minimus and tensor faccia lata
Explain the function and route of the inferior gluteal nerve
Which spinal nerve contribute to its formation?
L5-S2
- supplies gluteus maximus
Explain the use of the words anteriro and posterior devisions of the lumbar plexus in the lower limb
Anterior devisions–> supply posterior LL (e.g. sciatic nerve)
Posterior devisions –> supply anteiror LL (e.g. femoral nerve)
- due to permanent pronation during development
Explain the segmental motor supply in the (lower) limb
What are its kex characteristics?
- Muscles are supplied by two adjacent segments
- Same action on joint = same nerve supply
- Opposing muscles 1-2 segments above or below
- More distal in limb = more caudal in spine
What is the segmental motor supply to the hip?
- Flexion= L2-3
- Extension= L4-5
What is the segmental motor supply to the knee?
Extension= L3,4
Flexion= L5,S1
Explain the segmental motor supply to the ankle
- Dorsiflexion = L4,5
- Plantarflexion= S1,2
- inversion= L4
- Eversion= L5,1
- toe flexion= L5,S1
- toe extension= S1,2
Explain the Main dermatomes in the LL
Anterior:
- “L3 to the knee, L4 to the floor” –> work you other way around it
Posterior:
- Medial= S2
- Lateral= S1, seperated by axial line
What is an autonomous sensory zone?
Normally: spinal neres largely overla when it comes to cutaneous sensory supply (e.g dermatomes)
But ther are some zones where overlap is minimal, called autonomous sensory zones
Name some of the clinically significant sensory autonomous zones of the LL
„L3 – front of the thigh (“L3 to the knee”)
L4 – front of the leg (“L4 to the floor”)
L5 – dorsum of the great toe
S1 – lateral aspect of the foot
S2-4 – perineum and perianal region“
Explaint the route of the lateral cutaneous branch of the thigh and its result in compression
- passes superficially 2cm medial to the anterior superior iliac spine at the level of the inguinal ligament.
- It can be compressed at this level causing meralgia paraesthetica.“
What is the saphenous nerve?
What happens in damage?
Branch of the femoral nerve suppying cutaneous sensory innervation in the medial leg and foot
- might be damaged at the medial malleolus
- or at knee (both: often linkes to medical procedures)
Explaint the route of Arteries from the aorta into the LL
- Aorta into
- Common iliac artery
- into
- interal iliac artery
- obturator artery
- external iliac artery
- becomes femoral artery at the inguinal ligament
- interal iliac artery
Explain the route of the femoral artery in the thigh
- passes inguinal ligament at mid-inguinal point
- just below the inguinal ligament it gives rise to the
- the superficial circumflex iliac artery
- the superficial epigastric artery
- the superficial external pudendal artery
- the deep external pudendal artery
- Below that it gives of big branch the profunda femoris artery
- perforating artery
- medial+ lateral circumflex artery
- Superficial femoral artery passes through adducturo hiatus and becomes the polpiteal artery
Explain the route of the polpiteal artery
- runs in polpiteal fossa
- bifurcates into
- anterior tibial artery
- passes anterior in leg, becomes dorsalis pedis at foot (anterior)
- posterior tibial artery
- gives off peroneal artery that runs laterally
- rest: runs posteriorly in leg and entery foot posterior to medial malleolus
*
- anterior tibial artery
What are the main arteries of the foot?
Where do they originate from?
- Anterior tibial artery gives rise to dorsalis pedia
- posterior tibial artery gives rise to medial plantar artery
What are the main superficial veins of the LL
Explain their route
- Great saphenous vein
- forms dorsal venous arch
- runs anterior to medial malleolus
- runs medially, in the leg, goes slightly posterior in knee,runs up mediall in thigh and
- joins femoral vein at the saphenous-femoral junction
- Short saphenous vein
- forms from dorsal venous arch
- runs posterior to lateral malleolus
- runs up the leg posteriorly and
- joins the polpiteal vein in the polpiteal fossa
Explain the organisation of deep veins in the LL
- most of them as venae comitantes along the arteries
- some can be named e.g.
- anterior and posterior tibial veins
- polpiteal vein (where SSV joins)
- femoral vein (where LSV joins)
- profunda femoris vein
- external iliac vein
What are the characteristics of venae comitatnes?
- •Multiple veins form a network of smaller veins with arteries which they accompany
- often they are inter-connected
Explain the venous blood flow in the lower limb and how this might lead to problems
Generally
- Venous blood flow is suppoerted by muscular pump+ arterial pump
- Blood flow is from superficial to deep veins, regulated by valves
- in valve damage: blood flows from deep to superficial leading to varicose veins
