Anatomy of Skeletal Muscle on Lower Extremity

1. Anatomy of Skeletal Muscle on Lower Extremity SeungYeol Lee, M.D. Department of Orthopaedic Surgery, Seoul National University BundangHospital

2. Anterior Muscles of Pelvis

3. Psoas Major Origin : T12-L5 vertebra Insertion : lesser trochanter Action : powerful hip flexion

4. Psoas Minor Origin : T12 & L1 vertebra Insertion : pectineal line Action : weak flexion of trunk

5. Iliacus Origin : iliac fossa Insertion : lesser trochanter Action : powerful hip flexion

6. Gluteal Muscles

8. Gluteal Maximus Origin : ilium & dorsal sacrum Insertion 1. glutealtuberosity 2. iliotibial band Action 1. powerful extension 2. ER of hip

9. Gluteal Medius Origin:ilium between anterior & posterior gluteal lines Insertion: greater trochanter Action: 1. powerful abduction 2. IR of hip 3. Balancing during walking

10. Gluteal Minimus Origin: ilium between anterior & inferior gluteal lines Insertion: anterior greater trochanter Action: 1. abduction & IR of hip 2. Assistgluteus medius during walking

11. Trendelenburg sign

12. Piriformis • Origin: • anterior sacrum • Insertion: superior greater trochanter • Action: • 1. hip ER • 2. hip abduction during flexion

14. Obturatorinternus Origin 1. ischiopubic rami 2.obturator membrane Insertion: medial greater trochanter Action: 1. hip ER 2. hip abduction during flexion

15. Sup. & Inf. gemellus Origin: ischial spine(sup.) ischialtuberosity(inf.) Insertion: medial greater trochanter Action: 1. hip ER 2. hip abduction during flexion

16. Quadratusfemoris Origin: ischial tuberosity Insertion: intertrochanteric crest Action: hip ER

17. Posterior Femoral Muscle (Hamstrings)

19. Biceps Femoris (long head) Origin:ischialtuberosity Insertion: head of fibula Action: 1. hip extension 2. knee flexion & ER

20. Biceps Femoris (short head) Origin: 1. lineaaspera, 2. supracondylar line Insertion: fibula, lateral tibia Action: knee flexion & ER

21. Semitendinosus Origin: ischial tuberosity Insertion: proximal medial tibia Action: 1. hip extension 2. knee flexion & IR

22. Semimembranosus Origin: ischial tuberosity Insertion: posterior medial tibial condyle Action: 1. hip extension 2. knee flexion & IR

23. Rectus Femoris muscle

24. Origin : 1. AIIS 2. superior rim of acetabulum Insertion : patella, tibial tubercle Action : 1. hip flexion 2. knee extension

25. Triceps surae

26. Gastrocnemius Origin : Lateral and medial femoral condyle Insertion : Calcaneus ( via Achilles tendon) Action : Knee flexion, ankle plantar flexion

27. Soleus Origin : 1. Posterior fibula head 2. Soleal line of tibia Insertion : Calcaneus( via Achilles tendon) Action : ankle plantar flexion

28. Soleus Origin : 1. Posterior fibula head 2. Soleal line of tibia Insertion : Calcaneus( via Achilles tendon) Action : ankle plantar flexion

29. The Anterior and Lat Compartment (Extensor and Fibularis Groups)

30. Anterior Tibialis Origin : Upper 2/3 of lat. Surface of tibia Cruralinterosseous membrane Highest part of Superficial crural fascia Insertion : Medial and plantar surface of medial cuneiform Medial base of metatarsal Action : Ankle dorsiflexion Inversion

31. Fibularislongus Origin : Head of fibula Proximal 2/3 of lateral surface of fibula Insertion : Plantar side of medial cuneiform Base of first metatarsal Action : Ankle plantar flexion Eversion

32. The Posterior Compartment (Deep Flexor Groups)

33. Posterior Tibialis Origin : Cruralinterosseous membrane and adjacent borders of tibia and fibula Insertion : Tuberosity of navicular, cuneiforms, base of second fourth metatarsals Action : Ankle plantar flexion Inversion

34. Flexor Hallucislongus Origin : Distal 2/3 of posterior surface of fibula Insertion : Base of distal phalanx of big toe Action : Plantar flexion Inversion

35. Flexor Digitorumlongus Origin : Middle third of posterior surface of tibia Insertion : Base of second through fifth distal phalanges Action : Plantar flexion Inversion

36. Thank you for your attention !!!