MBS 212 Human Movement

1. MBS 212 Human Movement Lecture 8 LOWER LIMB Skeleton Prof. Thomas K. Monsees 2008 Prof. Monsees

2. Lower limb anchored to axial skeleton • Lower limb is directly anchored to axial skeleton by sacroiliac joint + strong ligaments, which link pelvis bone to sacrum • Pelvic bone is separated from abdomen, back, and perineum by a continuous line (red) that joins/pass different bony landmarks Prof. Monsees

3. Abdomen, Pelvis and Perineum Prof. Monsees

4. Regions of the lower limb • Gluteal • Posterolateral btw iliac crest + gluteal fold of buttock • Thigh • Anteriorly btw inguinal lig + knee joint • Leg • Btw knee + ankle joint • Foot • Distal to ankle point Prof. Monsees

5. Bones of the lower limb Bones • Pelvic bone (link to sacrum) • Femur (largest bone of body) • Tibia (medial) • Fibula (lateral) • Bones of the foot Joints • Hip joint (ball & socket) • Btw pelvic bone + femur • Knee joint w patella (hinge) • Btw femur + tibia Prof. Monsees

6. Os coxae • or coxal bones or hip bones or pelvic bones • Right + left coxal bones join each other anteriorly + sacrum posteriorly  pelvic girdle • Pelvis (= basin) includes pelvic girdle + coccyx Prof. Monsees

7. Sacrum + Coccyx • Distal parts of axial skeleton • Highly modified vertebrae • 5 sacral vertebrae fused into single bone, sacrum • Coccyx, or tailbone, consist of 3-5 more or less fused vertebrae Prof. Monsees

8. Pelvic girdle Prof. Monsees

9. Pelvis • Each coxal bone is formed by fusion of 3 bones during development: Ilium, Ischium, and Pubis • Iliac crest + spine: superior part of ilium • Sciatic notch: post side of ilium, sciatic nerve passes here • Ischial tuberosity: attachment of post thigh muscles • Pubic crest + tubercle: attachment of abdominal muscles • Pubic crest can be felt anteriorly • Pubic symphysis: joint between both coxal bones Prof. Monsees

10. Coxal bone Prof. Monsees

11. Acetabulum • Fossa located on surface of each coxal bone • Articulates with femur  hip joint • Articular surface is crescent shaped and occupies only the sup + lat aspects of the fossa • Acetabulum means a shallow vinegar cup, a common household item in ancient times Prof. Monsees

12. Gluteal injections • Large gluteal muscle common site for intramuscular injection • Large sciatic nerve lies deep  injection in superolateral region of hip • Landmarks are anterior superior iliac spine + tubercle of iliac crest Prof. Monsees

13. Gateways to lower limb Prof. Monsees

14. Summary: Pelvic girdle • Place of attachment for lower limbs • Supports the weight of body • Protects internal organs • Is complete bony ring  much more stable than shoulder girdle but less mobility • Protects developing fetus in woman+ forms passageway for fetus during delivery Prof. Monsees

15. Differences btw Male and female pelvis Ilium Ischium Prof. Monsees

16. Right Femur Prof. Monsees tibia anterior posterior

17. Femur • Long bone of thigh having • Proximal head • Greater + lesser trochanters • Shaft w linea aspera posteriorly • Distal end w medial + lateral condyles • Head articulates with acetalbulum forming hip joint • Condyles articulate w • tibia forming tibiofemoral joint • Patella forming patellofemoral joint • Both being part of knee joint Prof. Monsees

18. Stages of ossification in femur • Primary ossification in utero • upper epiphysis head at 1 y • greater trochanter at 4 y • lesser trochanter at 12 y Prof. Monsees

19. Patella • Large sesamoid bone located within tendon of quadriceps femoris muscle group • Articulates w patella groove of femur • Holds tendon away from distal end of femur  change tendon angle thus increasing forces that can applied on muscle to tibia less muscle contraction is required to move tibia Prof. Monsees

20. Prof. Monsees Talus

21. Tibia • medial bone of leg having • Proximal expanded tibial condyles • Shaft w tibial tuberosity anteriorly and sharp • Lateral facing interosseus border • Distal end w medial malleous • Proximally med + lat tibial condyles articulate w • Medial + lateral femoral condyles forming knee joint • Facet below lateral condyle articulates w head of fibula forming superiortibiofibular joint • Distally articulates w • Fibula  inferior tibiofibular joint • Talus  ankle joint Prof. Monsees

22. Fibula • lateral bone of leg having • Proximal head • Irregular shaft w sharp medial facing interosseous border • Expanded distal end w lateral malleolus projecting inferiorly • articulates w • tibia  superior + inferior tibiofibular joint • Talus  ankle joint Prof. Monsees

23. Surface anatomy showing bones of lower limb Prof. Monsees

24. Bones of the foot Bones • Phalanges • Metatarsals • Tarsal bones • 7 in 2 rows + 1 bone in between Joints Ligaments Deep transverse metatarsal ligament Prof. Monsees

25. Bones of the foot Prof. Monsees

26. How to learn the 7 tarsal names? • Talus • Calcaneus • Navicular • Cuneiforms: medial, intermediate, lateral • Cuboid Mnemonic for distal row is MILC: medial, intermediate, lateral cuneiforms + Cuboid Mnemonic for proximal 3 bones is: No Thanks Cow That is Navicular, Talus, Calcaneus Prof. Monsees

27. Bones of foot do not lie flat in single plane  • Longitudinal + transverse arches of the foot • Arches are flexible; absorb and transmit forces during standing and walking Prof. Monsees