ATTR 219 1st Edition Lecture 8HamstringsBiceps FemorisOrigin of long head: ischial tuberosityShort head: lineaaspera and proximal 2/3 of lateral supracondylar lineInsertion: head of fibula, lateral condyle of tibia, deep fascia on lateral lower legAction: flexion of knee/lower leg, extends hip/thigh, external rotates hip/lower legNerve to long head: tibial branch of sciaticShort head: peroneal branch of sciaticArtery: profundafemoris and poplitealSemitendinosusOrigin: ischial tuberosity and tendon of bicep femorisInsertion: upper anterior medial tibial condyleCommon pes anserine insertion (tendon not bone)Action: flexion of knee/lower leg, extension of thigh/hip, internal rotation of hip/lower legNerve: tibial branch of sciaticArtery: profundafemoris and popliteal *Pes anserine insertion is common insertion for semitendinosus, gracilis and Sartorius*SemimembranosusThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Origin: ischial tuberosityInsertion: posterior surface of medial condyle of tibiaAction: flexion of knee/lower leg, extension of thigh/hip, internal rotation of hip/lower legNerve: tibial branch of sciaticArtery: profundafemoris and popliteal-all hamstring muscles flex the knee and lower leg-all but bicep femoris: short head extend hip and thigh-all are innervated by tibial nerve- except short head of bicep (innervated by common peroneal)Vascular StructuresPopliteal artery branches off femoral-femoral runs through adductor magnus-lateral to popliteal artery is popliteal vein and lateral to vein is the tibial nerve-popliteal branches off to form 5 different arteries in the knee- Super medial genicular- distal femur, knee joint, patella- Superior lateral genicular-(supplies blood to same places as superior medial)- Inferior medial genicular- knee and proximal tibia- Inferior lateral genicular- knee joints and gastrocs- Middle genicular- ligaments of knee and synovial membrane-popliteal branches off then to form the anterior and posterior tibial arteriesFrom top to bottom: Femoral- Popliteal- Anterior/posterior tibial arteriesSynovium-synovial membrane lines joint cavity of the knee- secretes synovial fluid for joint lubrication-lubricates articular hyaline cartilage of bone ends- Creates smoother movements/motions in the knee-the knee is the largest synovial joint in the body- contains less than 1 mL of fluid (1/3 of an ounce)- synovium however, can expend to hold 80 mL of fluid (24 oz)-synovial capsule is 2 finger widths- superior to patella and posteriorly to origin of gastrocks- laterally to LCL and medially to MCL-synovial membrane is the innermost later of the joint that houses synovial membraneExternal Ligaments of the KneeLateral (fibular) Collateral Ligament (LCL): lateral epicondyle of femur to the head of fibula-major lateral stabilizer of the knee-2 in long and rounded cord-like structure-easy to palpate-directly under tendon of bicep femoris near fibular attachment-lateral side of femoral condyle, the LCL attachment is located between gastroc and popliteus*LCL and MCL can only be injuried in close chained position*Close chained= while bearing weightOpen chained= while flexing/extendingMedial (tibial) Collateral Ligament (MCL)- medial epicondyle of femur to condyle of tibia-also extends distally past medial tibial condyle-major medial stabilizer of the knee-MCL is divided into superficial and deep layers-MCL is 4 and ½ inches long and is a broad, flat band-deep fibers of the MCL attach to the following structures:- Joint capsule (posterior portion of MCL)- Medial meniscus- Coronary ligaments- Retinaculum of vastusmedialis-with 30 degrees flexion, anterior fibers of the MCL are taut (tight), and with 0 degrees of extension, posterior fibers of MCL are tautPatellar Ligament (tendon)-direct extension of quadriceps tendon-quadriceps tendon are superior to patella-patellar tendon is inferior to the patella-patellar tendons then inserts into tibial tuberosity-average length of patellar tendon is 3 inches-posterior and on each side of patellar tendon from distal patella to tuberosity are the infrapatellar fat pads: shock absorbers and nutrition provider for tendon, attached to anterior portion of meniscusCruciate Ligaments-cruciate always means to cross*always remember in relation to tibia*Posterior Cruciate Ligament (PCL)-posterior tibia to anterior femur-passes superior, anterior and medial from its tibial attachment and attaches to the lateral surface of the medial femoral condyle- prevents posterior displacement of the tibia-shorter, thicker and stronger than the ACL-most PCL tears occur in car accidents from sitting position landing forward on flexed kneeAnterior Cruciate Ligament (ACL)-anterior tibia to posterior femur-passes posterior and lateral from its tibial attachment-fans out to accommodate its attachment to the medial margin of lateral femoral condyle-prevents anterior displacement of tibia-average length is 1 and ¼ inch, average width is ½ inch-fibers of ACL are taut in full extension-typically torn with rotational mechanism-blood supply from middle genicular artery and fat pad-both ACL and PCL contained within their own fibrous sheath-keeps them out of direct contact with synovial fluid*all cruciates are either torn of not torn, there is no in between or partial tear*-can’t be repaired, only reconstructedCoronary LigamentsAlso known as meniscetibial ligaments and attach meniscus to tibial plateaus-assist in limiting excessive motion of meniscusTransverse Genicular Ligament: ties medial and lateral meniscus together