Popliteal Fossa

Popliteal Fossa Popliteal Fossa Is a diamond-shaped intermuscular space situated at the back of the knee Boundaries Laterally: Above Biceps femoris Below Lateral head of gastrocnemius and Plantaris Medially: Above Semimembranosus and semitendinosus Below Medial head of gastrocnemius Lateral The floor (anterior wall) of the fossa is formed by: Popliteal surface of the femur Capsule of the knee joint Popliteus muscle The roof is formed by: Skin Superficial fascia Deep fascia Contents of popliteal fossa: 1- Popliteal artery 2-Popliteal vein 3- Common fibular nerve (lateral popliteal nerve) 4- Tibial nerve (medial popliteal nerve) 5- Small saphenous vein (termination) 6- Connective tissue 7- Lymph nodes Tibial nerve Common fibular nerve Popliteal vein Popliteal artery At the middle of the fossa The popliteal artery is the deepest structure While the vein is intermediate and the tibial nerve is most superficial Small saphenous vein Femoral artery Popliteal artery Popliteus  Enters the popliteal fossa through the adductor hiatus as a continuation of the femoral artery  The deepest structure in the fossa  It ends at the level of the lower border of the popliteus muscle by dividing into anterior and posterior tibial arteries Gives genicular branches to knee joint Anterior tibial artery Posterior tibial artery The popliteal fossa is a good example of the value of thinking anatomically when considering the differential diagnosis of a mass situated in a particular anatomical area. When examining a lump in the popliteal region, think of these possibilities: Skin and soft tissues—sebaceous cyst, lipoma Vein—varicosities of the short saphenous vein in the roof of the fossa Artery—popliteal aneurysm Lymph nodes—infection secondary to suppuration in the foot Knee joint—joint effusion Tendons—enlarged bursae, especially those beneath semimembranosus and the heads of gastrocnemius Bones—a tumour of the lower end of femur or upper end of tibia A baker’s cyst (or popliteal cyst) refers to the inflammation and swelling of the semimembranosus bursa Tibial nerve Origin : From sciatic nerve at the lower third of the thigh Course: It enters popliteal fossa from upper angle and leaves it at its lower angle to enter the posterior compartment of the leg Termination: It ends deep to flexor retinaculum by dividing into medial and lateral plantar nerves. Sciatic nerve Tibial nerve Common fibular nerve Femoral vein Femoral artery Small saphenous vein Sural nerve The small saphenous vein pierces the popliteal fascia to empty into the popliteal vein The sural nerve pierces the deep fascia Small saphenous vein Sural nerve  Supplies skin on posterolateral side of lower part of leg and lateral side of foot  The sural nerve accompanies the small saphenous vein behind the lateral malleolus Sural nerve The small saphenous vein  Starts at the lateral side of the dorsal venous arch in the foot  Passes behind the lateral malleolus  Ascends vertically in the superficial fascia on the back of the leg  Penetrates the deep fascia at the back of the knee Drains into popliteal vein Sciatic nerve Tibial nerve enters the posterior compartment of the leg by passing beneath the soleus muscle Popliteus Tibial nerve Tibial nerve Medial plantar nerve Lateral plantar nerve Medial calcaneal Sural Saphenous Medial plantar Lateral plantar (Tibial nerve) (Tibial nerve) (Tibial nerve) Medial calcaneal nerve (Tibial nerve) Muscular Sensory All muscles in posterior compartment of thigh (except short head of biceps), all muscles in posterior compartment of leg, most intrinsic muscles of the foot Sural nerve: Supplies skin on posterolateral side of lower part of leg and lateral side of foot Medial calcaneal branch: Supplies the skin over the medial surface of the heel. Medial plantar nerve: sensory to Medial 2/3 of sole and medial three and a half toes. Lateral plantar nerve: sensory to Lateral 1/3 of sole and lateral one and a half toes Also Motor to most intrinsic muscles of the foot Tibial nerve injury Motor Paralysis of all muscles in the posterior compartment of the leg Paralysis of most intrinsic foot muscles Loss of plantar-flexion at the ankle Weakness of inversion Foot is dorsiflexed and everted Sensory Sensory loss from: Posterolateral side of lower part of leg Sole of the foot Injury to tibial nerve Because of its deep and protected position, its rarely injured Complete damage results in: Paralysis of all muscles in the back of the leg and most intrinsic muscles of the foot The anatagonistic muscles (dorsiflexors and evertors) will take over leading to an attitude called: (Calcaneovalgus) Foot is dorsiflexed and everted Common fibular nerve Origin: From sciatic nerve at the lower third of the thigh Course: It descends from the superior to the lateral angle of the popliteal fossa close to the medial border of biceps femoris. Termination: It ends at the neck of fibula where it divides into superficial and deep fibular nerves Branches: Sciatic nerve Tibial nerve Common fibular nerve Muscular Sensory Short head of biceps femoris 1- Sural communicating branch 2- Lateral cutaneous nerve of the calf: supplies the skin on the upper part of the lateral side of the leg Lateral cutaneous nerve of the calf Lateral cutaneous nerve of the calf Superficial fibular nerve Common fibular nerve Deep fibular nerve Superficial fibular nerve Muscular Sensory Muscles of lateral compartment of leg Supplies skin on anterolateral side of lower part of leg Supplies skin of intermediate part of dorsum of foot Superficial fibular nerve Deep fibular nerve Muscular Sensory Muscles of anterior compartment of leg Skin between big toe and second at dorsum of foot Some of the intrinsic muscles of foot The superficial fibular nerve Also called the musclocutaneous nerve of the leg Supplies two muscles in the lateral compartment of the leg and then becomes cutaneous where it supplies the skin over the anterolateral side of lower part of leg and the intermediate part of dorsum of foot (except the cleft of skin between the 1st and 2nd toes) Common fibular nerve injury Cause: most common cause is fracture neck of fibula Motor Sensory Paralysis of muscles of the anterior and lateral compartments of the leg Sensory loss from: Anterolateral side of lower part of leg Loss of dorsiflexion at the ankle Foot drop Loss of eversion Inversion of the foot is weakened Foot is plantarflexed and inverted Intermediate area of dorsum of foot Foot drop Dorsum of the toes except the lateral side of the little toe Common fibular nerve is in an exposed position as it leaves the popliteal fossa and winds around the neck of fibula Injury to common fibular nerve Paralysis of extensor muscles (supplied by deep fibular nerve) This means loss of dorsiflexion of the foot Paralysis of fibularis muscles (supplied by superficial fibular nerve) This means loss of eversion of the foot The anatagonistic muscles (plantar-flexors and invertors) will take over leading to an attitude called: (Equinovarus) Foot drop and inversion Injury to common fibular nerve Plantarflexion (Foot drop) and inversion of foot Injury to superficial fibular nerve Inversion of foot Injury to deep fibular nerve Plantarflexion (Foot drop) Injury to tibial nerve Dorsiflexiom and eversion of foot Lat cutaneous nerve of the calf Saphenous nerve Superficial fibular nerve Deep fibular nerve Lat cutaneous nerve of the calf Sural nerve Superficial fibular nerve Deep fibular nerve Post cutaneous nerve of the thigh Saphenous nerve Lat cutaneous nerve of the calf Sural nerve Medial calcaneal nerve