Bones and Muscles of Lower Extremity

Question 1

what joint of the pelvis transmit the weight of the head, upper extremities, and trunk to the lower extremities?

Answer 1

sacroiliac (SI) joint

Question 2

the patella is what type of bone?

Answer 2

sesamoid

Question 3

does the fibula participate in the knee joint?

Answer 3

no

Question 4

why are the ACL and PCL named as such?

Answer 4

ACL (anterior cruciate ligament) attaches to anterior tibia, PCL (posterior cruciate ligament) attaches to posterior tibia

Question 5

the tibia sits on the ___

Answer 5

talus

Question 6

the medial and lateral bumps on our ankles are the ___ and ____, respectively

Answer 6

medial bump is medial malleolus of tibia
lateral bump is lateral malleolus of fibula

these contain the ankle joint and ensure it is a simple hinge joint

Question 7

when your thigh is kicked out front, and your knee is bent, how do you describe these movements?

Answer 7

hip flexion, knee flexion

Question 8

when your thigh is reaching behind you, and your leg is bent straight, how do you describe these movements?

Answer 8

hip extension, knee extension

Question 9

when your thigh is kicked forward and your leg is straight, how do you describe these movements?

Answer 9

hip flexion, knee extension

Question 10

describe the origin of the psoas and iliacus in the iliopsoas muscle, and what does the iliopsoas muscle do?

Answer 10

psoas arises from lateral border of vertebral bodies, iliacus arises from iliac fossa
together, the iliopsoas muscle flexes the hip
(attach to the femur together)

Question 11

what does the gluteus maximus do

Answer 11

extends hip (think about standing up)

Question 12

what does the gluteus medius do and what is its role

Answer 12

abducts hip (away from midline), stabilizes pelvis when the opposite leg is lifted off the ground during walking

the anterior fibers also medially rotate hip

Question 13

what are the 3 muscles in the lateral rotator group of the hip?

Answer 13

piriformis (most superior), obturator internus, quadratus femoris (most inferior)

Question 14

what are the main adductors (away from midline) of the hip (2)?

Answer 14

adductor longus, adductor magnus

Question 15

what do the quadriceps do

Answer 15

extend knee

Question 16

the hamstring crosses both the hip joint and the knee joint, allowing it to do these 2 things:

Answer 16

extend the hip (moves thigh posteriorly), flex the knee (bent)

Question 17

what do the gastrocnemius and soleus do together?

Answer 17

plantar flex (point the toe)

plantar is bottom of foot

Question 18

what muscle in the leg dorsiflexes the ankle and inverts?

Answer 18

tibialis anterior (points toes up)

this keeps us from dragging our feet and tripping when we walk

invert = roll foot outwards (bottom of foot facing midline)

Question 19

what are the two muscles on the lateral leg? What do they do?

Answer 19

fibularis longus, fibularis brevis

evert the ankle (roll inward, plantar facing away from midline)

Question 20

what muscle extends the great toe?

Answer 20

extensor hallucis longus - controlled by one spinal nerve, so can be functionally useful for discriminating injury from one part of CNS to another

Question 21

what structures make up the femoral triangle

Answer 21

inguinal ligament (running from pubic tubercle to anterior superior iliac spine), medial border of sartorius, lateral border of adductor longus

Question 22

what muscles make up the adductor group of the thigh?

Answer 22

adductor longus, adductor magnus, adductor brevis, gracilis

Question 23

where does the gluteus maximus insert?

Answer 23

posterior border of the iliotibial tract

Question 24

this rim of fibrocartilage reinforces and deepens the acetabulum

Answer 24

acetabular labrum