Diamond-shaped space behind knee. (468, 481)
Upper borders are semimembranosus and semitendinosus medially and biceps femoris laterally.
- these make a hollow when the knee is flexed
- when extended they sit back against condyles and popliteal fat bulges its roof.
Lower borders are heads of gastrocnemius (they lie close together)
Roof = fascia lata strongly reinforced here by transverse fibres
- pierced by short saphenous vein and posterior femoral cutaneous nerve.
Floor (above down) = popliteal surface of femur, capsule of KJ, posterior surface of tibia and popliteus muscle covered in fascia.
Contents: popliteal artery and vein, tibial and common peroneal nerves, few popliteal lymph nodes.
- distinguish cadaveric L from R by identifying common peroneal nerve emerging from lateral boundary (but donŐt confuse it with the medial semitendinosus tendon).
Slopes down laterally (medial to biceps tendon) ¨ disappears into peroneus longus to lie on neck of fibula (palpable there). Ends by dividing into deep & superficial peroneal nerves. Branches:
Runs down in subcut fat to join sural nerve below of bellies gastrocnemius (may come off: )
Pierces roof of fossa over lateral head of gastrocnemius, supplies skin over upper peroneal / extensor compartments of leg.
¨ capsule of KJ.
Runs down fossa and passes deep between heads of gastroc ¨ then beneath fibrous arch of soleus to enter calf. Gives motor branches to all muscles arising in the fossa: plantaris, gastroc (both heads), soleus & popliteus.
Sural nerve = only cutaneous branch, emerges b/n gastroc heads, joins sural communicating nerve in the subcut fat; (nerve is usually lateral to the vein).
Articular branches are 3 genicular nerves: accompany superior and inferior medial genicular arteries ¨ medial ligament and capsule and middle medial genicular ¨ pierces oblique popliteal ligament supplying it and cruciates.
Deepest of neurovascular structures throughout PF.
Runs from adductor hiatus ¨ fibrous arch in soleus (see 482); 20cm long.
Enters PF on medial side of femur, deep & medial to sciatic nerve.
Artery is convex laterally through PF ¨ comes to lie lateral to tibial nerve; below fibrous soleal arch, as the posterior tibial artery returns to the medial side of the nerve again.
Popliteal vein lies b/n artery & nerve at all levels. Nerve & vein are closest to roof at all levels.
From above downwards: artery lies free on popliteal surface of femur ¨ fixed by popliteal ligament of KJ and by middle genicular artery ¨ free on popliteus ¨ passes below soleus and divides into anterior & posterior tibial arteries.
- rarely divides proximal to popliteus, anterior tibial then runs anterior to its muscle.
Medial head of gastroc may separate the artery from vein & nerve ¨ medial displacement ¨ popliteal artery entrapment syndrome.
2 sural branches, 1 to each head of gastroc
5 genicular arteries: upper and lower medial and lateral, and middle
- superior medial & lateral encircle lower femur proximal to gastroc attachment; medial superior lies deep to semitendinosus & semimembranosus and adductor magnus tendon; lateral superior lies deep to biceps femoris.
- inferior medial & lateral encircle upper end of tibia; medial inferior courses obliquely to medial head of gastroc & medial ligament of knee; lateral inferior runs horizontally deep to lateral head of gastroc, crosses popliteus tendon deep to lateral lig of knee.
- Middle pierces oblique popliteal ligament to supply cruciates (with genicular branch of posterior division of obturator).
These genicular arteries form an anastomosis around patella, femoral and tibial condyles, with descending genicular branch of femoral, descending branch of lateral circumflex femoral, circumflex fibular branch of posterior tibial, and anterior and posterior recurrent branches of anterior tibial (see 477).
From behind or from either side with knee partly flexed.
Posterior approach: open interval b/n heads of gastroc, retract them, avoid nerves and vein.
Lateral: pass behind iliotibial tract and lateral intermuscular septum, displacing biceps backwards.
Medial: pass behind tendon of adductor magnus, or retract medial hamstrings lower down.
Lies between artery and nerve at all levels.
May be double. Formed by union of venae comitantes of anterior & posterior tibial arteries. Receives branches equivalent to branches of popliteal artery + short saphenous vein.
Few scattered nodes in termination of small saphenous vein beneath deep fascia.
- a few small afferents run from above heel with saphenous vein to here.
Send efferents alongside popliteal and femoral vessels to deep inguinal nodes
See paper notes
Popliteal surface of tibia ¨ tendon inserting into lateral condyle of femur + tendon inserting into lateral meniscus. Innervation: tibial nerve.