Limbs 4 Flashcards
What are the two routes of venous return in the lower limb?
- deep (accompanying arteries)
- superficial (close to limb surface)
What do many of the deep distal veins form?
Venae comitantes
What are the main deep veins of the lower limbs?
- femoral vein
- deep femoral vein
- anterior tibial vein
- posterial tibial vein
- popliteal vein
- peroneal vein
What are venae comitantes?
Multiple veins forming a network of smaller veins with arteries which they accompany
What are the benefits of veins forming venae comitantes?
- heats exchange
- arteries promote venous flow
What allows only distal to proximal blood flow in the lower limb veins?
Valves in the veins
What is the calf pump?
- deep veins are sandwiched between layers of calf muscles
- contraction of muscles squeezes deep veins pushing blood towards heart
What are the main superficial veins of the lower limb?
Long and short saphenous vein
Where do the superficial veins arise from?
Dorsal venous network of the foot
What do the saphenous veins drain into?
- long = femoral vein
- short = popliteal vein
Where does the long saphenous vein run from?
- on medial side of leg
- passes anterior to the medial malleolus at the ankle
- continues superiorly and medially in the leg
- more posteriorly at the knee
- medial in the thigh until the vein passes anterior to the femoral triangle
- drains into the femoral vein through the saphenous opening in fascia lata
Where does the short saphenous vein run from?
- lateral side of leg
- passes posteriorly to the lateral malleolus at the ankle
- runs superiorly on the posterior
- drains into the popliteal vein after piercing the fascia over the popliteal fossa
What can the superficial veins of the lower limb be used for?
Can be harvested for venous grafts, mostly coronoary artery bypass grafts
What happens if the valves which allow blood flow from superficial to deep veins are compromised?
- varicose veins
- blood is pushed from deep to superficial veins
- deep venouse return is slowed down
What do varicose veins increase the risk of?
DVT due to sluggish deep venous return
What are the two areas of nodes on the lower limb?
- popliteal nodes
- inguinal nodes
What do the popliteal nodes drain?
Distal limb (legs, toes)
What do the inguinal nodes drain?
- lower limb
- pudendal region
- perineum
- anus
- parts of lower abdomen
What is the superficial drainage of the lymphnodes?
- posterior lymph vessels run with short saphenous vein
- drain into popliteal nodes in popliteal fossa
- lymph nodes continue in association with femoral vein
- vessels running with long saphenous vein drain into superficial inguinal nodes in inguinal region close to saphenous opening and inguinal ligament
What is the deep lymphatic drainage of the lower limb?
- most drainage of the distal lower limb drains into the deep inguinal nodes
- some also drains into popliteal nodes
Where does lymphatic drainage of the lower limb go up to?
Drainage via iliac vessels passing through iliac nodes
What are the important anatomical spaces of the lower limb?
- femoral triangle
- popliteal fossa
What are the borders of the femoral triangle?
.
What is the femoral triangle covered by?
Skin and deep fascia (fascia lata)
What runs through the opening in the fascia lata?
Long saphenous vein entering the triangle to drain into femoral vein
What does the femoral triangle contain?
- femoral nerve
- femoral artery
- femoral vein
- superficial and deep lymphnodes
What happens when the femoral nerve enters the femoral triangle?
Branches into many smaller nerves to supply its muscular and cutaneous targets
What can be palpated in the femoral triangle?
Arterial pulse
What can the femoral artery and vein be accessed for in the femoral triangle?
Catheterisation for procedures involving coronary arteries or other parts of the heart
What is the popliteal fossa?
Diamond shaped opening in the back of the knee
What are the borders of the popliteal fossa?
.
What does the popliteal fossa contain?
- tibial and common peroneal nerves
- popliteal artery and vein
- popliteal lymph nodes
What can be palpated at the popliteal fossa?
Pulse of the popliteal artery
Which nerve leaves the popliteal fossa at the head of the fibula and what does it divide into?
- common fibular nerve
- divides into superficial and deep fibular nerves
What forms the tibial and common peroneal nerves?
Bifurcation of the sciatic nerve
What is the adductor canal?
- muscle-lined gutter
- starts at the inferior apex of the femoral triangle and ends at the hiatus of adductor magnus
What passes through the adductor canal?
- saphenous nerve
- femoral artery and vein
What is the tarsal tunnel?
- channel between the medial malleolus and the calcaneus
- overlayed by flexor retinaculum
Which vessels enter the foot via the tarsal tunnel?
Posterior tibial artery and tibial nerve
Label this diagram of the tarsal tunnel
-
What is the clinical importance of the arteries of the lower limb?
- supply blood to tissues
- can be used to assess vascular health
- can be used to access the heart for cardiac procedures e.g angioplasty, angiography
Which arteries supply most of the lower limb?
- left and right iliac arteries
- found in the iliac regions of the pelvis
How does the abdominal aorta give rise to the iliac arteries?
- abdominal aorta bifurcates into left and right common iliac arteries
- common iliac arteries bifurcate into internal and external iliac arteries
What does the internal iliac artery supply?
- buttock and lateral thigh
- smaller branch of common iliac artery
What does the external iliac artery supply?
- forms femoral artery
- supplies rest of the limb and medial thigh
- larger branch of the common iliac artery
What are the arteries of the hip, buttock and thigh?
- external iliac artery
- deep femoral artery
- femoral artery
- popliteal artery
- superior and inferior gluteal arteries
Where does the external iliac artery become the deep femoral artery?
When it passes into the thigh behind the deep inguinal ligament
Where does the deep femoral artery become the popliteal artery?
When it goes from running anteriorly down thigh to posteriorly into the popliteal fossa
What is the deep femoral artery a branch of?
The femoral artery
What is the main artery of the thigh?
Deep femoral artery
What is the hiatus of adductor magnus?
Opening in the adductor magnus muscle which gives rise to the adductor canal
What is the blood supply of the head of the femur?
- lateral and medial circumflex arteries (mostly medial)
- ligament of the head of the femur
At what stage in life is the artery of the head of the femur important?
In children, helps with growing bone
What can happen when the head of the femur has an intracapsular fracture?
- arteries become damaged
- avascular necrosis of the femoral head
What are the main arteries of the knee, leg and foot?
- femoral artery
- popliteal artery
- genicular (knee) branches
- tibial artery
- anterior tibial artery
- posterior tibial artery
- peroneal artery
- medial plantar artery
- lateral plantar artery
- dorsal pedis artery
Label this diagram of the arteries of the knee, leg and foot
Which pulses can be palpated in the knee, leg and foot?
- popliteal pulse
- medial tibial pulse
- dorsalis pedis pulse
- determine vascular health of the lower limb
What does the dorsalis pedis artery give rise to?
Arcuate artery
What do the lateral and medial plantar arteries give rise to?
Plantar arch
What is a nerve plexus?
- network of nerves
- formed when peripheral spinal nerve roots merge and split
- new multi-segmental peripheral nerves arise from plexus
What is the main plexus which supplies the lower limb?
Lumbo-sacral plexus
Which three nerves arise form the lumbar part of the lumbo-sacral plexus?
- lateral cutaneous nerve of the thigh
- femoral nerve
- obturator nerve
Fibres from which level form the lumbosacral trunk?
L4 and L5
Which nerves of the sacral part of the lumbosacral plexus supply the lower limb?
- superior and inferior gluteal nerves
- posterior cutaneous nerve of the thigh
- sciatic nerve
What is the sciatic nerve made up of?
- common peroneal part
- tibial part
What does the superior gluteal nerve supply?
L4-S1
What does the inferior gluteal nerve supply?
L5-S2
What does the femoral nerve supply?
L2-L4
Where does the femoral nerve fun from?
- descends through pelvis
- passes under inguinal ligament into pelvic triangle laterally
- divides into a number of muscular and cutaneous branches to the anterior thigh
- terminal branch is the saphenous nerve
- travels through adductor canal then superficially to anteromedial ascpects of the knee, leg and foot
What does the obturator nerve supply?
L2-L4
Where does the obturator nerve run from?
- emerges on medial border of the psoas muscle
- runs inferiorly and anteriorly in the pelvis
- passes through obturator foramen to supply adductor muscles of the medial compartment
Which nerve supplies the hamstring part of the adductor magnus?
Tibial part of the sciatic nerve
What does the sciatic nerve supply?
L4-S3, biggest nerve in the body
What does the sciatic nerve divide into?
Tibial and fibular nerves
Which nerve runs close to the sciatic nerve?
Posterior cutaneous nerve of the thigh
What is the piriformis muscle?
- one of the lateral rotator groups of gluteal muscles
- important landmark for the nerves and vessels of the gluteal region
How does the piriformis act as a landmark for the nerves and vessels of the gluteal region?
Nerves and vessels pass from the buttock into the interior pelvis either superiorly or inferiorly to the piriformis
Where does the superior gluteal nerve enter the pelvis and what does it innervate?
- above piriformis through greater sciatic foramen
- innervates gluteus medius, minimus and tensor fascia lata
What does the inferior gluteal nerve supply?
L5-S2
Where does the inferior gluteal nerve enter the pelvis and what does it innervate?
- inferior to the piriformis via the greater sciatic foramen
- gluteus maximus only
Which other nerves enter the pelvis inferior to the piriformis?
Sciatic nerve and posterior cutaneous nerve of the thigh
What are the main nerves of the anterior and lateral leg?
- common peroneal (fibular) nerve
- bifurcates into superficial and deep peroneal nerves
What does the superficial peroneal nerve innervate?
- lateral muscles
- skin of dorsum of foot
What do the deep peroneal nerves innervate?
- anterior muscles
- skin of cleft between first and second toes
Where does the common peroneal nerve run from?
- leaves popliteal fossa laterally
- winds around head of fibula
- bifurcates into deep and superficial peroneal nerves
What are the main nerves of the posterior leg and foot?
- tibial nerve
- branches into medial and lateral plantar nerves
What does the tibial nerve innervate?
Superficial and deep muscle compartments of the posterior leg
Where does the tibial nerve run from?
- passes distally through popliteal fossa into posterior leg
- runs on surface of tibialis posterior
- travels posteriorly to the medial malleolus
- passes under plantar aponeurosis where it divides into lateral and medial plantar nerves
Why are the dermatomes of the anterior lower limb distorted, resulting in the anterior dermatome running obliquely?
Twisting of lower limb during fetal development
What is the general pattern of the dermatomes of the anterior lower limb?
L3 to the knee, L4 to the floor
What are autonomous sensory zones?
Regions of non-overlapping sensory supply from an individual spinal root
What is useful to know about innervation of the lower limb?
The dermatomes and peripheral cutaneous nerve fields do not match
Why do the dermatomes and cutaneous nerve fields not match?
- cutaneous nerves are formed in a plexus
- cutaneous nerves will have fibres from multiple spinal nerves
