Week 13 Posterior Thigh PDF

Posterior Compartment of the Thigh Muscles of the posterior thigh  Biceps Femoris o Origin:  long head: ischial tuberosity  short head: linea aspera and lateral supracondylar line of femur o Insertion: two heads join and...

Posterior Compartment of the Thigh Muscles of the posterior thigh  Biceps Femoris o Origin:  long head: ischial tuberosity  short head: linea aspera and lateral supracondylar line of femur o Insertion: two heads join and common tendon inserts into head of fibula o Nerve supply:  long head: tibial division of sciatic nerve  short head: common fibular (peroneal) division of sciatic nerve o Action:  flexion and lateral rotation of leg at knee joint  extension of thigh at hip joint (long head only)  Semitendinosus o Origin: ischial tuberosity o Insertion: by a long tendon into upper part of medial surface of shaft of tibia (part of pes anserinus together with sartorius and gracilis) o Nerve supply: tibial division of sciatic nerve o Action:  flexion and medial rotation of leg at knee joint  extension of thigh at hip joint  Semimembranosus o Origin: ischial tuberosity  o Insertion:  posterior aspect of medial condyle of tibia  tendon gives rise to fibers that pass superiorly and laterally to reinforce posterior aspect of capsule of knee joint (oblique popliteal ligament) o Nerve supply: tibial division of sciatic nerve o Action:  flexion and medial rotation of leg at knee joint  extension of thigh at hip joint Blood Supply of the Posterior Compartment of the Thigh  there is no major artery in posterior compartment of thigh  main source of blood supply: perforating branches of profunda femoris artery  perforating arteries anastomose with each other and 1st perforating artery takes part in cruciate anastomosis (with inferior gluteal and medial and lateral circumflex femoral arteries) and 4th perforating artery anastomoses with branches of popliteal artery that supply distal parts of hamstring muscles and in this way, a line of anastomoses is established along posterior thigh, from gluteal region to popliteal fossa Sciatic Nerve  as it leaves gluteal region, it passes deep to long head of biceps femoris  descends along midline of posterior thigh, overlapped posteriorly by adjacent margins of biceps femoris and semimembranosus  related anteriorly to adductor magnus  in lower ⅓ of thigh, it ends by dividing into tibial and common fibular (peroneal) nerves (division may occur at a higher level)  branches (in posterior thigh):  tibial and common fibular (peroneal)  muscular branches to long head of biceps femoris, semitendinosus, semimembranosus and hamstring part of adductor magnus (from tibial division) and muscular branch to short head of biceps femoris (from common fibular [peroneal] division) Popliteal Fossa  diamond-shaped space located posterior to knee joint  boundaries:  superolateral: biceps femoris  superomedial: semitendinosus and semimembranosus  inferolateral: lateral head of gastrocnemius and plantaris  inferomedial: medial head of gastrocnemius  anterior wall (floor): popliteal surface of femur, articular capsule of posterior aspect of knee joint, popliteus muscle  posterior wall (roof): deep fascia over popliteal fossa (popliteal fascia) and continuous superiorly with fascia lata and inferiorly with crural fascia (deep fascia of leg)  contents:  popliteal artery and vein  terminal part of small saphenous vein  tibial and common fibular (peroneal) nerves and their branches  terminal part of posterior cutaneous nerve of thigh  genicular branch of obturator nerve (terminal part of its posterior branch)  popliteal lymph nodes  adipose tissue Popliteal Artery  begins at adductor hiatus as a continuation of femoral artery  terminates at inferior border of popliteus muscle by dividing into anterior and posterior tibial arteries  most deeply located structure in popliteal fossa and lies in contact with fossa’s floor (vulnerable in supracondylar fractures of femur)  in midline of popliteal fossa, popliteal vein lies posterior to popliteal artery and tibial nerve lies posterior to popliteal vein  branches:   muscular branches: to gastrocnemius, soleus, plantaris and distal parts of hamstring muscles  genicular branches (supply knee joint and participate in arterial anastomosis around it): 2 superior (medial and lateral), 2 inferior (medial and lateral) and 1 middle  superior medial and superior lateral genicular arteries: curve around distal femur, superior to femoral condyles, to reach anterior aspect of knee joint  inferior medial and inferior lateral genicular arteries: curve around proximal tibia to reach anterior aspect of knee joint  middle genicular artery: unpaired branch and arises from anterior aspect of popliteal artery opposite back of knee joint and pierces oblique popliteal ligament and supplies cruciate ligaments and synovial membrane inside joint Popliteal Vein  formed by union of anterior and posterior tibial veins at inferior border of popliteus muscle  terminates at adductor hiatus, where it becomes femoral vein  ascends through popliteal fossa posterior to popliteal artery and anterior to tibial nerve  tributaries:  veins that correspond to branches of popliteal artery (share same name)  small saphenous vein  Popliteal Lymph Nodes  embedded in connective tissue and fat of popliteal fossa  receive superficial lymph vessels from lateral part of foot and leg (accompany small saphenous vein)  receive deep lymph vessels accompanying anterior and posterior tibial vessels (drain all deep structures of foot and leg)  e erent vessels from popliteal lymph nodes accompany popliteal and femoral vessels and terminate in deep inguinal lymph nodes Tibial Nerve   originates in lower ⅓ of thigh from sciatic nerve and descends almost vertically through popliteal fossa, posterior to popliteal artery and vein  leaves popliteal fossa and enters posterior compartment of leg by passing deep (anterior) to tendinous arch of soleus muscle  branches in popliteal fossa:  muscular branches for medial and lateral heads of gastrocnemius, soleus, plantaris and popliteus  articular branches to knee joint  branches in popliteal fossa:  sural nerve:  cutaneous branch of tibial nerve: descends between 2 heads of gastrocnemius and pierces crural fascia (deep fascia of leg) in upper to mid-parts of posterior leg and is joined by sural communicating branch (from lateral sural cutaneous nerve) at a variable level (some authors call the nerve “medial sural cutaneous” as it originates from tibial nerve and “sural” after it joins communicating branch)  sural nerve accompanies small saphenous vein and passes posterior and then inferior to lateral malleolus and continues along lateral border of foot and little toe as lateral dorsal cutaneous nerve  sural nerve supplies skin over inferolateral part of posterior aspect of leg and along lateral borders of foot and little toe Common Fibular (Peroneal) Nerve  originates in lower ⅓ of thigh from sciatic nerve  runs inferiorly and laterally in popliteal fossa, following medial border of biceps femoris  leaves popliteal fossa by passing superficial to plantaris and lateral head of gastrocnemius  passes posterior to head of fibula and then lateral to neck of fibula, deep to uppermost fibers of fibularis longus muscle (common injury site), where it divides into 2 terminal branches: superficial and deep fibular (peroneal) nerves  branches in popliteal fossa:  lateral sural cutaneous nerve: supplies skin of upper lateral part of leg and gives o sural communicating branch that joins sural nerve  articular branches to knee joint