12 - Posterior Leg and Popliteal Fossa Flashcards
What is the popliteal fossa?
A diamond shaped space behind the knee through which important structures pass through to get to the lower limb and foot
What are the borders of the popliteal fossa?
Superior Medial: Semitendinosus and semimembranosus
Superior Lateral: Biceps Femoris
Inferior Medial and Lateral: Medial and lateral heads of gastrocnemius
What are the contents of the popliteal fossa?
Popliteal artery and vein, tibial nerve AND common peroneal nerves (CPN veers left to fibular head so doesn’t really run through middle of fossa)
What is the deepest structure in the popliteal fossa, closest to the knee joint/tibia & femur?
The popliteal artery - this means it is the structure at most risk during a knee injury (most anterior)
Where does the small saphenous nerve run?
Above fascia q
What is a knee dislocation?
Is where a tibia and femur dissociate as the tibia is driven backwards. Emergency due to contents of popliteal fossa/neurovascular structures at risk
Most common due to dashboard injuries
Image vessels to see if they are leaky (CS) and still patent
What are the muscles of the superficial posterior compartment of the leg?
Plantaris
Gastrocnemius
Soleus
What muscles make up triceps surae?
The medial and lateral heads of gastrocnemius and soleus. NOT plantaris
What is the muscle in the posterior compartment that not everyone has/is residual?
Plantaris
- Is a small muscle with a long tendon often used for a muscle or tendon graft
- sits between gastroc and soleus
Gastrocnemius?
O:
Lateral - lateral condyle of FEMUR
Medial - medial condyle of femus
I: Posterior calcaneus via the calcaneal tendon/achilles tendon
> plantarflex ankle and flex knee
Soleus
O: Superior fibula and soelal line of tibia
I: Calcaneal tendon to posterior calcaneus
> only plantarflexes ankle
What is the nerve supply to all of the posterior compartment muscles?
Tibial Nerve
Plantaris
O: Superior and deep to lateral head gastroc on the lateral condyle of FEMUR
I: Medial Calcaneal Tendon
> plantarflexes ankle
What are the muscles of the deep posterior compartment?
Mostly mirrors anterior compartment
- Tibialis Posterior
- Flexor Digitorum Longus
- Flexor Hallucis Longus
- Popliteus
Tibialis Posterior?
O: Posterior tibia, fibula and interosseous membrane
I: navicular and medial cuneiform
> joins with tibialis anterior to INVERT and plantarflexes
Flexor Digitorum Longus
O: Middle half of TIBIA
I: Distal phalanges of lateral 4 toes
> plantarflexion and flexes toes
tendon doesn’t always go to little toe
Flexor Hallucis Longus
O: Inferior 2/3 fibula and interosseous membrane
I: Distal phalanx of big toe
> plantarflexion and flex big toe
Popliteus
O: Lateral condyle of the femur
O: Posterior superior tibia
> medially rotates tibia
How do FDL and FHL run?
FDL runs from medial tibia to lateral toes
FHL runs from lateral fibula to medial big toe
Where does the posterior compartment neurovascular bundle run?
In a fascial plane between the superficial and deep compartment (tibial nerve, peroneal and posterior tibial artery)
Where do the superficial structures run in the cross section of a leg?
- great saphenous vein and saphenous nerve run medially
- small saphenous vein and SURAL nerve run more laterally and posteriorly
What does the posterior tibial artery terminate in?
Goes around the medial malleolus and into the sole of the foot
> bifurcates into the medial and lateral plantar arteries
> there is communication between the plantar arteries and dorsalis pedis to ensure good blood flow to the foot (good as is most distal structure so runs out first)
Lumbosacral Plexus spinal nerves?
L2-S2/S3
Femoral Nerve?
- L2-L4
- anterior compartment of thigh
- branches into the saphenous nerve
Obturator Nerve?
- L2-L4
- medial compartment of thigh
- NO branches
What is the myotome of adduction?
L4
What are the spinal levels of the saphenous nerve?
L3 L4
What are the spinal levels of the sciatic nerve?
L4-S3
What are the spinal levels of the tibial nerve?
S1 S2 (plantarflexion/posterior comp)
What are the spinal levels of the deep peroneal nerve?
- anterior leg/dorsiflexion
- L4/L5
What are the spinal levels of the superficial peroneal nerve?
- lateral leg/eversion
- L5/S1
What are the spinal levels of the tibial nerve?
- posterior comp/plantarflexion
- S1/S2
What are the spinal levels of the superior gluteal nerve?
- hip abductors
- L4/L5/S1
What are the spinal levels of the inferior gluteal nerve?
- gluteus maximus
- hip extension
- L5/S1/S2
Name the order of structures going behind the medial malleolus from anterior to posterior
- Tom Dick And Very Naughty Harry Tibialis posterior flexor Digitorum longus posterior tibial Artery posterior tibial Vein tibial Nerve flexor Hallucis longus
Achilles Tendon Injuries?
- is the most commonly injured tendon
- often when going from stationary position to fast
- injury can occur at musculotendinous junction, tear the tendon, where it attaches to the calcaneous/pull off bone, or you can tear the muscle
- presentation is the inability to ‘push off’ or plantarflex
- is a loud and painful injury
Can you find 4 pulses in the lower limb? What are the landmarks?
1. Femoral Artery > half way along inguinal ligament from ASIS to Pubic Tubercle 2. Popliteal Artery > need to relax hamstrings, gastroc and soleus as is deep 3. Dorsalis Pedis > in line with 2nd MT 4. Posterior Tibial Artery > posterior to medial malloelus
