Lumbosacral Plexus and Blood Supply to Lower Limb- Wilson Flashcards
Spinal nerves do not give rise to the lumbosacral plexus. What does?
ventral primary rami
What is comprised of the lumbar plexus?
L1, L2, L3, L4
What is comprised of the sacral plexus?
L4, L5, S1, S2, S3, S4
Limb muscles develop from what 2 myotomic cell groups?
- dorsal muscle mass (extensors)
- ventral muscle mass (flexors)
Which myotome does the dorsal and ventral muscle mass come from?
hypomere
Damaged nerve from what division of the brachial plexus will you get wrist drop?
posterior division
extensors of the hand are innervated by radial nerve
Lateral femoral cutaneous nerve is derived from what roots of the lumbar plexus?
L2, L3
innervates the skin of the lateral thigh, hip joint
The mixed femoral nerve is derived from what roots of the lumbar plexus?
L2, L3, L4 (posterior division)
innervates the anterior compartment muscles of the thigh:
- psoas major (innervated by direct branches of lumbar plexus)
- iliacus
- vastus medialis
- vastus intermedius
- vastus lateralis
- rectus femoris
- sartorius
The obturator nerve is derived from what roots of the lumbar plexus?
L2, L3, L4 (anterior division)
innervates the medial compartment of the thigh:
- pectineus
- obturator externus
- adductor brevis
- adductor longus
- adductor magnus
- gracilis
The lumbosacral trunk that joins to sacral plexus is consisted of what roots?
L4 and L5
L5 has no distribution to the lumbar plexus
The upper limb rotates _________.The lower limb rotates medially. Thus the extensors are _________and the flexors are _________, opposite to the upper limb.
laterally
anterior
posterior
The posterior division of the lumbar plexus innervates what compartment of the thigh?
anterior compartment of thigh which are the extensors
The anterior division of the lumbar plexus innervates what compartment of the thigh?
MEDIAL compartment of thigh which are adductors
The tibial nerve is derived from which part of the lumbar plexus?
NONE
tibial nerve is derived from the SACRAL plexus not the lumbar plexus
The femoral nerve goes through what ligament?
inguinal ligament
femoral nerve gives fibers that innervate the skin and muscles of the anterior compartment of the thigh
The obturator nerve goes through foramen?
obturator foramen
obturator nerve gives fibers that innervate the skin and muscles of the medial compartment of thigh
Why is there a lumbosacral plexus?
axons from L4 and L5 can be distributed within the sacral plexus
The posterior division from L4 to S2 of the sacral plexus gives rise to what nerves?
common fibular branch of the sciatic nerve which innervates short head of the biceps femoris
What are the nerves that are derived from the common fibular nerve?
- superior gluteal nerve (L4, L5, S1) –> gluteus medius, gluteus minimus, tensor fascia lata
- Inferior gluteal nerve (L5, S1, S2)–> gluteus maximus
- nerve to the piriformis (S1, S2)
The anterior division from L4 to S2 of the sacral plexus gives rise to what nerves?
tibial branch of the sciatic nerve: innervates the posterior muscle mass of the thigh and leg THIGH -semimembranosus -semitendinousus -long head of the biceps femoris
Tibial nerve for the LEG
- gastrocnemius
- soleus
- plantaris (long tendon!!)
- popliteus
- tibialis posterior
- flexor hallucis longus
- flexor digitorum longus
The common fibular nerve branches into what nerves?
- superficial fibular nerve
- deep fibular nerve
What are the nerves derived from the tibial nerve?
nerve to obturator internus: superior gemellus and obturator internus m.
nerve to quadratus femoris: inferior gemellus and quadratus femoris
Spasms and hypertrophy of the piriformis will cause dysfunction of axons in this nerve due to the pressure placed on it. What nerve emerges into the gluteal inferior to the piriformis?
sciatic nerve
The two divisions of the sciatic nerve are still separate even as they form one sciatic nerve. True or false?
True!!!!
The tibial division of the sciatic nerve innervates the ____________compartment of the thigh.
posterior
As the sciatic nerve goes down the thigh, it passes this region where it divides into the common fibular and tibial nerves.
popliteal fossa behind the knee joint
The common fibular nerve goes off laterally to wrap around the fibula to reach the anterior lateral compartment of the lower limb. The common fibular nerve crosses the neck of the fibula becoming what?
- deep fibular nerve
2. superficial fibular nerve
What does the deep fibular and the superficial fibular nerve innervate respectively?
-deep fibular nerve innervates the anterior compartment of the LEG:
tibialis anterior, extensor hallucis longus, extensor digitorum longus, fibularis tertius
-superficial fibular nerve innervates the lateral muscle compartment of the leg:
fibularis longus, fibularis brevis
The common fibular and the tibial nerve give off the lateral cutaneous branch and the medial cutaneous branch respectively to form this nerve which innervates the posterior skin of the leg?
sural nerve ???
After crossing behind the medial malleolus, the tibial nerve terminates as what?
- medial plantar nerve
2. lateral plantar nerve
Flexor digitorium brevis and 1st lumbrical of the foot are innervated by what nerve?
medial plantar nerves
The medial and lateral plantar nerve are synonymous to what nerves in the hand?
- median nerve
- ulnar nerve
The anterior femoral cutaneous and the saphenous nerve are derived from what division of the lumbar plexus?
posterior division of the lumbar plexus: femoral nerve
- anterior femoral cutaneous nerve innervates the anterior portion of the thigh
- femoral nerve TERMINATES as the saphenous nerve which innervates the medial portion of the leg anteriorly and posteriorly
The cutaneous branch of this nerve innervates the adductor compartment of the thigh.
obturator nerve
Lesion of the dorsal root and or the spinal nerve results in decreased sensation in a ___________dermatome.
single
Lesions proximal to a plexus produce a sensory loss in a single dermatome.
Lesion of a ventral or dorsal primary ramus results in decreased sensation in a _________of a dermatome.
portion
The posterior femoral cutaneous nerve, also known as the posterior cutaneous nerve of the thigh, is a sensory branch of what plexus?
sacral plexus
The lateral femoral cutaneous nerve is derived from what plexus?
lumbar plexus
the only cutaneous branch from L2 and L3 to innervate the lateral portion of the thigh
A lesion of a ventral primary rami results in decreased sensation restricted to a _________of a dermatome.
portion
What does it mean if sensory loss involves 2 or more dermatomes?
you are dealing with the TERMINAL branches of the lumbosacral plexus
T10 and L1 are usually landmarks for what on the body?
T10- umbilicus
L1- inguinal ligament
The main blood supply to the lower limb arises from what?
external iliac artery
The external iliac artery changes its name to what when it passes beneath the inguinal ligament?
femoral artery
This terminates as the common iliac which divides into the external and internal iliac arteries .
abdominal aorta
Which divisions of the common iliac go to the pelvic and lower limb respectively?
- internal iliac goes to the pelvic region
- external iliac goes to the lower limb
Why is the femoral artery a good location to take pulse and catheterization?
- bissects inguinal ligament
- very superficial
- lies anterior to femoral head
- can be compressed against the femoral head to control hemorrhage
The femoral artery passes the adductor hiatus (canal) and changes name to?
popliteal artery
A catheter in the femoral artery or vein enters what side of the heart?
if placed in the femoral artery it goes to the left side of heart
-if placed in the femoral vein it goes to the right side of heart
Both hold true regardless of which left or right femoral artery/vein you place the catheter in
The femoral artery gives access to the arterial system of a patient. True or false?
TRUEEE!!!!
femoral artery is derived all the way from the aorta
What is the major branch of the femoral artery?
deep femoral artery
What is the main blood supply to the head of the femur?
medial and lateral femoral circumflex
NOTE: these arteries anastomose
What arteries are involved in the healing process of a fracture in the hip?
medial and lateral femoral circumflex arteries
Why is the cruciate anastomosis at the level of the lesser trochanter important?
it provides a collateral route if the femoral artery is occluded
What arteries are the cruciate anastomosis made up of?
Transverse limb:
- medial circumflex
- lateral circumflex
Vertical limb:
- ascending branch of the 1st perforating artery
- descending branch of the inferior gluteal artery (from the internal iliac artery)
What do the perforating arteries from the deep femoral artery supply?
the hamstrings of the thigh
Where do the medial and lateral femoral circumflex arteries go to respectively?
- medial femoral circumflex artery: medially to the neck of the femur
- lateral femoral circumflex artery: laterally to the neck of the femur
The popliteal artery is a continuation of the femoral artery after it transverses the adductor hiatus. The popliteal artery gives what branches that ANASTOMOSE around the knee?
- superior medial genicular artery
- superior lateral genicular artery
- inferior medial genicular artery
- inferior lateral genicular artery
What is the reason for anastomosis in joint or collateral route developments in joints?
kinking in joints
The popliteal artery terminates at the inferior border of the popliteus by dividing into what?
anterior tibial artery
posterior tibial artery
Why is the popliteal artery important?
it is a second good location for feeling pulse
The anterior tibial artery pierces and runs on what to supply the anterior compartment of the leg?
interosseous membrane
-anterior TIBIAL artery supplies the ANTERIOR compartment of leg
The anterior tibial artery terminates at the malleoli as what?
dorsalis pedis artery
What is the dorsalis pedis artery significant?
- it is a third location where you can feel the pulse (Examine the pulse) as it runs superficially
- can check for peripheral arterial disease from which stroke can occur
What artery supplies the posterior compartment of the leg?
posterior tibial artery which runs medially
What is the major branch of the posterior tibial artery that supplies the DEEP compartment of the leg?
fibular artery which runs laterally
The fibula is lateral.
The posterior tibial artery runs with what nerve in between the tendons of flexor hallucis longus and flexor digitorum?
tibial nerve
The posterior tibial artery crosses the ankle posterior to the medial malleolus, between what two muscles?
flexor hallcius longus and flexor digitorum longus
Why is the posterior tibial artery significant?
it is a fourth location for measuring pulse at the ankle
The posterior tibial artery terminates as what?
- lateral plantar artery
- medial plantar artery
they both lie in between the 1st two muscle layers of the foot
What are the four locations where the pulse may be taken at the lower limb?
- femoral head: femoral artery
- posterior side of knee: popliteal artery
- dorsal surface of the foot: dorsalis pedis artery (termination of anterior tibial artery)
- medial ankle: posterior tibial artery
A weak pulse on one side may be a sign of what?
peripheral artery disease (PAD) or obstruction
-these could be due to the development of plaques within arteries
What is claudication and how does it develop?
pain and cramping in the muscles of the leg which is induced by exercise due to obstruction of the arteries
-tissue ischemia develops distal to a vascular lesion
Why is venous return from the lower limb often an issue?
getting blood back to the heart from the lower limb is an issue because we stand erect
- gravity pulls down on blood to go to the big foot
- same veins in the upper limb its just that gravity makes it easier in the upper limb
Veins of the lower limb are organized into what 3 groups?
- Deep veins
- Superficial veins
- Perforating veins
What are characteristics of the types of veins found in the lower limb for deep, superficial, and perforating veins?
deep veins: runs with arteries of the same name
superficial: immediately under the skin, cephalic, medial cubital; have NO arteries running with them!!
perforating vein: connects the deep and superficial vein
What are the borders of the femoral triangle?
lateral border: sartorius
medial border: adductor longus
superior border: inguinal ligament
floor formed by the iliacus, psoas major, pectineus, adductor longus
What type of vein is the femoral vein?
deep vein as it runs with the femoral artery
The lower limb has what 2 major veins that are important for thermal regulation?
- great saphenous vein
2. lesser saphenous vein
The great saphenous vein runs with what NERVE on the medial portion of the LEG?
saphenous nerve
The great saphenous vein travels from the dorsum of the foot up medially of the leg to go through the femoral triangle.
FACTS
it runs on the medial malleolus
The lesser saphenous vein travels from the lateral malleolus up the central part of the calf and terminates in the popliteal fossa by joining the popliteal vein.
FACTS!!
Why are the great and lesser saphenous vein clinically significant?
they are clinically important for vascular surgery
What are you concerned with replacing the coronary artery with the great or lesser saphenous vein?
They have valves so you would need to turn it upside down.
The saphenous nerve is a terminal branch of what nerve?
femoral nerve
What does the deep femoral nerve innervate?
NOTHINGG!!!! because there’s no such thing
there is a deep femoral ARTERY that gives rise to the perforating arteries supplying the hamstrings of the thigh
What are the hamstrings of the thigh?
- semimembranosus
- semitendonosus
- biceps femoris
- hamstring head of adductor magnus
from medial to lateral thigh
What is the purpose of valves in the perforating veins?
perforating veins connect the superficial veins with the deep veins
it allows blood flow from the superficial vein to the deep vein BUT it DOES NOT allow blood flow from deep to superficial vein
What are the mechanisms in which body returns blood from the big toe to the heart, thus overcoming the pressure of a 4, 5, or 6 ft column of blood?
- valves
- energy of the arterial pulse is transferred into the venae comitantes generating movement of blood
- venous calf pump: contraction and relaxation of muscles squeeze the vein and pumps blood towards the heart
- perforating arteries shunt blood from superficial veins to the deep veins where blood can be pumped back to the heart
The fibular vein runs with what muscle?
flexor hallucis longus
The great and lesser saphenous vein do not have the advantage of being under muscle (they are underneath the skin). So how is their blood pumped back to the heart?
- valves
- perforating veins
What occurs if the valves in the legs fail?
edema and pooling of blood in the leg
What is the importance of venae comitantes?
- they are composed of deep veins
- they are important for exchange of heat (a countercurrent system)
- uses some energy of the pulsating artery to return the blood to the heart
How is energy of the arterial pulse transferred into the venae comitantes generating movement of blood?
the expansion of the arteries during a pulse going to the big toe compresses veins enough to open valves going towards the heart
Why is the center of gravity anterior to the rotational axis of the ankles which produces a tendency to sway forward?
- readiness for flight/fight
2. calf-pump
Diseased or damaged valves in the peforating veins allow blood to pool in the superficial veins, where there is no pumping. What is the result?
varicose veins
What are factors than can predispose someone to varicoses veins?
- obesity
- dunlap disease which puts pressure on the external iliac and femoral vein restricting blood coming back to the heart
How can the diaphragm help bring blood back to the heart?
diaphragm when it contracts increases the abdominal pressure pushing fluids from high pressure to low pressure towards the heart
What nerve does the anterior tibial artery run with?
deep fibular nerve
Superior and inferior gluteal arteries branch off of what artery?
internal iliac artery
