Limbs 4 Flashcards
What is the name of the plexus which innervates the lower limb
Lumbosacral plexus
What are the three main nerves of the lumbar plexus
- Lateral cutaneous nerve of the thigh
- Femoral nerve
- Obturator nerve
What are the roots of the lumbosacral trunk and what is its purpose?
L4 and L5
- Provides fibres to the sacral plexus
Name nerves 1-6 on this diagram of the sacral plexus?
1) Superior Gluteal Nerve
2) Inferior gluteal nerve
3) Sciatic nerve
4) Common peroneal part
5) Tibial part
6) Posterior cutaneous nerve of the thigh
What does the femoral nerve supply?
Anterior compartment of the thigh
- Iliacus
What does the obturator nerve supply?
Medial adductor compartment of the thihg
How does the obturator nerve pass into the lower limb?
Passes inferiorly through the obturator foramen, by piercing obturator memebrane
How does the sciatic nerve reach the LL?
Passesfrom the interior of the pelvis through the greater sciatic forament into the gluteal nerve
Here it gives fibres to the piriformis
Then it travels deep to the gluteus max. and then to posterior thigh.
What is the terminal branch of the femoral nerve and describe its course and what does it supply
The saphenous nerve
- The adductor canal
- Cutaneous nerve supplying the anteromedial knee, leg and the medial foot
What is the passage of the femoral nerve?
- Descends through the pelvis
- Passes under the inguinal ligament into the femoral triangle where it divides to give its branches
WHat do the anterior and posterior branches of the obturator nerve supply?
The adductor muscles and an area of skin on the medial surface of the thigh
WHat is the relation of the superior gluteal nerve to the piriformis
Superior to piriformis
(opposite w inferior gluteal nerve)
What structures does the superior gluteal nerve supply?
- Gluteus medius and minimus
- Tensor fasciae latae
What structures does the inferior gluteal nerve supply?
- Gluteus maximus ONLY
What is the anatomical relation between the sciatic nerve, posterior cutaneous nerve of the thigh and the piriformis?
SCiatic nerve and PCN are inferior to the piriformis
Which nerve supplies the hamstring muscles
Sciatic nerve
What are the terminal branches of the sciatic nerve?
- Common peroneal nerve
- Tibial nerve
How do the terminal branches of the sciatic nerve enter the leg?
Pass in the popliteal fossa (space behind knee)
Where does the sciatic nerve split into its terminal branches
The distal part of the thigh
What is the course of the common peroneal nerve and what is its clinical significance?
- Leave popliteal fossa
- Courses laterally to wind around the neck of fibula just inferior to its head
- Here it can be palpated and is susceptible to injury
Where does the common peroneal nerve bifurcate and what is the names of its terminal branches
At the head of the fibula
Superficial peroneal nerve
Deep peroneal nerve
What does the superficial peroneal nerve supply?
- Lateral muscles of leg
- Skin of dorsum of foot
What is the supply of the deep peroneal nerve?
- Anterior muscles of leg
- Skin of cleft between 1st and 2nd toes
How does the tibial nerve pass into the leg
Through the popliteal fossa
What does the tibial nerve supply in the leg?
- Both superficial and deep muscle compartments of the posterior leg
What happens to the tibial nerve at the ankle?
- Veers medially, posterior to medial malleolus,
- passes under plantar aponeurosis
- where it bifurcates to form its termnal branches
What are the terminal branches of tibial nerve?
Lateral and medial plantar nerves
What are autonomous sensory zones?
Regions of non-overlapping sensory supply from an individual spinal root
~~~
```What is the clinical importance of autonomous snesory zones?
Pain and abnormal sensation in each zone can be attributed to a single spinal root
What does the Nerve to quadratus supply?
- External rotators
- Inferior gemellus
What does the nerve to obturator internus supply?
External rotators
Superior gemellus
Which nerve supplies the hamstring part of adductor magnus with origin on the ischial tuberosity?
Tibial part of the sciatic nerve
Which nerves supply cutaenous innervation to 1-4
1) Obturator nerve
2) Femoral nerve (anterior cutaneous nerves of thigh)
3) Femoral nerve (saphenous nerve)
4) Common peroneal (fibular) nerve
Which nerves supply cutaenous innervation to 5-8
5) Medial plantar nerve
6) Lateral cutaneous nerve of thigh (lumbar plexus)
7) Posterior cutaneous nerve of thigh (from sacral plexus)
8) Common peroneal nerve (lateral cutaneous nerve of calf)
Which nerves supply cutaenous innervation to 9-12
9) Common fibular nerve (SUPERficial branch)
10) Tibial nerve (sural nerve)
11) Lateral plantar nerve
12) Posterior rami (L1 to L3)
Which nerves supply cutaenous innervation to 13-17
13) Posterior rami (S1 to S3)
14) Obturator nerve
15) Femoral nerve (saphenous nerve)
16) Tibial nerve (sural nerve)
17) Tibial nerve (medial calcaneal branches)
What is the clinical importance of the lower limb arteries?
- Assessing vascular health
- Angiograms
- Angioplasty
What is the root of most of the lower limb arteries?
Left and right iliac arteries
How do the left and right common iliac arteries arise?
Bifurcation of the abdominal aorta at the iliac crest
Which arteries does the bifurcation of the common iliac arteries form?
Internal and external iliac arteries
What structures does the internal iliac artery supply?
The medial thigh and buttock
What are the structures which the external iliac artery supplies?
Remainder of lower limb not supplied by internal iliac
Describe the passage of the external iliac artery through the lower limb?
Passes under inguinal ligament where it becomes the femoral artery
Describe the passage of the femoral artery?
1) Passes anteriorly, deep to sartorius, where it supplies some tissues
2) Mainly travels in the adductor canal
2) More distally, passes posteriorly to enter popliteal fossa where it becomes the popliteal artery
What is the main branch of the femoral artery?
Deep femoral artery (Profunda femoris artery)
Describe the passage of the deep femoral artery
- Branches from the femoral artery in the femoral triangle
- Immediately gives of the lateral and medial circumflex arteries
- The artery passes inferiorly, medial to the femoral shaft, giving off perforating branches.
What are the main branches of the internal iliac artery?
- Superior gluteal arteries
- Inferior gluteal arteries
- Obturator artery
Where do the superior and inferior gluteal arteries emerge?
Superiorly and inferiorly to piriformis
Which muscles do the superior and inferior gluteal arteries supply?
Gluteal compartment
Describe the passage of the obturator artery?
Passes from internal iliac artery in the pelvis trhoiugh the obturator foramen and into the medial compartment
Which muscles does the obturator artery supply
Medial muscles of the medial compartment
Where is the femoral pulse felt?
Just distal to the inguinal ligament
How does the femoral artery become the popliteal artery?
Femoral artery passes through the hiatus of adductor magnus to enter the popliteal fossa where it becomes the popliteal artery
What is the hiatus of adductor magnus?
Gap in the broad attachment of posterior femur
Describe the blood supply to the head of the femur?
- Deep femoral artery gives off two branches: Lateral and medial circumflex femoral arteries
- Obturator artery gives off the acetabular branch of the obturator artery
- These supply the head of the femur
How do the medial and lateral circumflex femoral arteries supply the head of the femur?
Encircle the proximal femur and give off branches to its head
How does the acetabular branch of the obturator artery supply the head of the femur?
Passes through in the ligament of the head of the femur
What is the difference between the acetabular branch of the obturator artery in children compared to adults
children - Provides most of the supply to HOF
adults - Provides small fraction of supply
What is the clinical significance of difference between child and adult blood supply to HOF?
Adult blood supply comes from more distal regions therefore in hip injury there is greater chance of avascular necrosis
How is avascular necrosis caused in hip injury?
If femoral neck sustains inreacapsular fractur, blood supply can be cut off leading to avascular necrosis of the femoral head
Where is the popliteal pulse felt?
Behind the knee, in the popliteal fossa
What does the genicular branches of the popliteal artery supply?
Knee
When the popliteal artery leaves the P.fossa what does it become?
Tibial artery
What structures does the posterior tibial artery and fibular arteries supply?
Posterior and lateral compartements of the leg
What happens to the tibial artery as it is formed below the popliteal fossa?
Splits into anterior and posterior tibial artery
What is the 1st major branch of the posterior tibial artery
Fibular artery
Describe the course of the anterior tibial artery?
It pierces the superior part of the interosseous membrane to pass into the anterior compartment of the leg and travel inferiorly to the ankle
Which muscles do the anterior tibial artery supply?
Anterior compartment of the leg
What does the anterior tibial artery become when it crosses the ankle? What is the clinical significance of this artery?
Dorsalis pedis artery
- Dorsalis pedis pulse
How is the arcuate artery formed?
From dorsalis pedis artery turning laterally
Describe the passage of the posterior tibial artery?
1) Travels posteriorly to medial malleolus
2) and divides
What are the two arteries that the posterior tibial artery divides into?
- Medial plantar artery
- Lateral plantar artery
What structure do the medial and lateral plantar arteries form?
Plantar arterial arch
Why am i not covering passage of deep veins?
They are the fucking same as the arteries duh
Describe the relation of the deep leg veins to calf muscles?
- Calf muscles sandwiched between layers of calf muscles
- Contraction of muscles squeezes deep veins pushing blood towards heart
- This is the calf pump
What direction flow of blood do lower limb vein valves allow?
Distal to proximal
How does prolonged inactivity cause DVT and how is it prevented?
- Prolonged inactivity causes decreased efficient venous return between the foot and leg leading to DVT
- Compession socks compress the vein acting as contracting muscles and therefore increasing venous return.
What are the 2 major superficial veins of the LL and how do they arise
- Long and short saphenous veins
- Arise from dorsal venous network at ankle
How does the long saohenous vein pass the medial malleolus?
Anteriorly
How does the short saphenous vein pass the lateral malleolus?
Posteriorly
Where does the long saphenous vein drain into?
Femoral vein through saphenous opening in fascia lata
Where does the short saphenous vein drain into and how ?
Popliteal vein by piercing popliteal fascia over p.fossa
Describe the drainage of the foot (superficial)
- Small veins in digits and foor drain into superficial dorsal venous network and plantar
- At ankle these networks drain into long and short saphenous veins
What is the clinical significance of superficial veins?
Harvested for venous grafts -> coronary artery bypass
How are the superficial and deep veins connected?
Perforating veins with valves which allow passage of blood from superficial to deep veins
If the valves in perforating veins are compromised…
blood is pushed from deep to superficial leading to varicose veins
When deep venous return is sluggish….
DVT more likely to form
Where do lymph vessels in distal limb drain?
Popliteal -
Which areas are drained by the inguinal nodes?
- LIMB
- Pudendal region
- Perineum
- Anus
- Parts of lower abdomen
Where are the inguinal nodes?
saphenous opening
How is the femoral triangle outlined?
- SUPERIORLY - inguinal ligament
- MEDIALLY - adductor longus
- LATERALLY - sartorius
WHat does the femoral triangle contain
- Femoral nerve
- Femoral artery
- Femoral vein
- Superficial and deep lymph nodes
- Femoral canal
How is the popliteal fossa outlined?
SUPERIORLY : the tendons of the hamstrings (semimembranosis and biceps femoris)
INFERIORLY: the lateral and medial heads of
gastrocnemius (also plantaris muscle belly laterally).
What does the popliteal fossa contain?
- Tibial and common peroneal nerves
- Popliteal artery and vein
- Popliteal lymph nodes
What is the adductor canal?
This canal is a muscle-lined gutter starting at the inferior apex of the femoral triangle and ending at the hiatus of adductor magnus.
What does the adductor canal contain
femoral artery, vein, and the saphenous nerve.
What is the tarsal tunnel
the channel between the medial malleolus and the calcaneus (heel).
What structure overlays the tarsal tunnel
flexor retinaculum.
What are the contents of the tarsal tunnel?
- tendon of tibialis posterior
- tendon of flexor digitorum longus
- posterior tibial artery
- associated veins
- the tibial nerve
- the tendon of flexor hallucis longus.
How do the posterior tibial artery and tibial nerve enter the foot
Via the tarsal tunnel
