ms anatomy: thigh

this is the second lecture on the bottom half of the body and covers the muscles, nerves, and bones of the thigh region. muscles are grouped according to the actions they produce on the knee joint (extension of the knee is the kicking motion) and the hip joint (extension of the hip is pulling the leg back).

the flexors of the hip include the pectineus, rectus femoris, sartorius, and adductor longus and brevis. the extensors of the hip are the hamstrings: the biceps femoris (long head only, because the short head originates on the femur's linea aspera), the semimembrinosus, the semitendinosus, and the adductor magnus. the adductors are: the adductor longus and brevis, adductor magnus, gracilis, pectineus. the muscles that flex the knee are: sartorius, biceps femoris (both heads), semitendinosus, and semimembrinosus.

the femoral and obturator nerves are looked at briefly- both originate in the lumbar plexus at the L2,3,4 level. the femoral nerve passes through the femoral triangle and innervates the quadriceps, sartorius, iliacus, and pectineus. the obturator nerve passes through the obturator canal and innervates the gracilis, 1/2 of the adductor magnus, and the adductors (besides the pectineus)

a few details about the knee region: the "goose's foot" is a convergence of tendons on the medial upper tibia from the tendons of the sartorius, gracilis, and semitendinosus. two ligaments that stabilize the knee joint: the anterior cruciate ligament goes from the anterior tibia to the inner medial condyle of the femur and limits hyperextension. the posterior cruciate ligament goes from the posterior tibia to the inner lateral condyle of the femur and prevents anterior displacement of the femur.


questions
origins, insertions, actions, innervations...
1. sartorius
2. quadriceps femoris
3. pectineus
4. adductor longus and brevis
5. gracilis
6. adductor magnus
7. semitendinosus
8. semimembranosus
9. biceps femoris

10. where does the femoral nerve originate and where does it pass through?
11. what does the femoral nerve innervate?
12. where does the obturator nerve originate and where does it pass through?
13. what does the obturator nerve innervate?

which muscles produce these actions...
14. flexion of femur
15. extension of femur
16. lateral rotation of femur
17. adduction of femur
18. flexion of knee

19. what constitutes the pes anserinus? what else is it called?
20. what are the tibial plateaus?
21. is the fibula head part of the knee joint?
22. where does the anterior cruciate ligament attach to? what does it do?
23. where does the posterior cruciate ligament attach to? what does it do?

answers
1. O: ASIS, I: medial surface of the upper tibia, N: femoral nerve, A: flex, laterally rotate femur
2. O: rectus femoris-ASIS, vastus lateralis and medialis-linea aspera, vastus intermedius- upper anterior femur, I: tibial tuberosity via patella, N: femoral nerve, A: extend leg, flex femur.
3. O: pubis, I: linea aspera, N: femoral nerve, A: adduct, flex femur
4. O: pubis, I: linea aspera, N: obturator nerve, A: adduct, flex femur
5. O: pubis, I: medial upper tibia, N: obturator nerve, A: adduct femur, flex leg
6. O: pubis, ischium, I: linea aspera, adductor tubercle, N: obturator and sciatic nerve, A: adduct and extend femur
7. O: ischial tuberosity, I: upper medial tibia, N: tibial nerve, A: extend femur, flex and medially rotate leg
8. O: ischial tuberosity, I: medial condyle of tibia, N: tibial nerve, A: extend femur, flex and medially rotate leg
9. O: ischial tuberosity / linea aspera, I: head of fibula, N: tibial nerve and common fibular (long head/short head), A: flex and laterally rotate leg, and extend femur (long head only)

10. L234, passes through femoral triangle
11. iliacus, sartorius, quadriceps, pectineus
12. L234, passe through obturator canal
13. adductors (except pectineus), 1/2 of adductor magnus, gracilis.

14. rectus femoris, sartorius, pectineus, adductor longus and brevis.
15. adductor magnus, biceps femoris long head, semitendinosus, semimembrinosus.
16. sartorius
17. pectineus, adductor longus/brevis, gracilis, adductor magnus
18. sartorius, biceps femoris (long and short heads), semitendinosus, semimembrinosus.

19. "goose's foot" is made up of the common tendon insertions for gracilis, sartorius, semitendinosus.
20. the flat surfaces of the tibia which articulate with the femoral condyles.
21. no
22. anterior tibia to inner surface of lateral femoral condyle. limits hyperextension of knee and posterior displacement of femur on tibia
23. posterior tibia to inner surface of medial femoral condyle, prevents anterior disaplacement of femur.