4.6 Muscles Crossing hip and knee joints

Question 1

What is the role of the differnt muscles in knee joints?

Answer 1

Most anterior (quads): flex femus at hip, extend leg at knee

posterior (hamstring): extend thigh, flex leg (backswing walking)

Medial: adducts: all adduct

*all 3 groups enclosed by fascia lata

Question 2

prime mover of hip joint flextion

Answer 2

Thigh flexors (pass in front of hip joint)

include: illiopsoas (iliacus and psoas major)

Question 3

Iliopsoas

Answer 3

composite of iliacus and psoas major

• fibers pass under inguinal ligament to insert via common tendom on femur

Question 4

iliacus

Answer 4

• more laterial of iliospaoas

O: iliac fossa and crest

I: femur

*prime mover for flexing thigh or flexing trunk of thigh during bow

Question 5

Psoas major

Answer 5

*psoa = loin muscle

• longer, thicker and more medial of iliospoas muscles

O: lumbar vertebrae and T12

I: femur

*like iliacus, also prime mover for flexing thigh or trunk on thigh

also flexes vertebral column laterally

Question 6

Sartorius

Answer 6

• straplike superficial muscle running obliquly across anterior surface of thigh
• Longest muscle in body - crosses hip and knee joints

O: iliac spine

I: tibia

*flexes, abducts and laterally rotates thigh

Question 7

Answer 7

Question 8

What muscles are thigh extensors, abductors and rotators?

Answer 8

Gluteus medius, gluteus minimus, gluteus maximum

• piriformis
• obturator externus and internus

Gemellus

Question 9

Gluteus maximus

Answer 9

• O: dorsal ilium ,sacrum and coccyz

I: femur, iliotibial tract

*major extenor of thigh - most effective then thigh is flexed

* laterally abducts and rotates thigh

Question 10

Gluteus medius

Answer 10

*site for intramesuclar inj

• O: ilium

I: femur

*abducts and medially rotates thigh important in walking)

*holds pelvis

Question 11

Gluteus minimus

Answer 11

• small and deep

O: ilim

I: femur

*same function of glut medius - abducts and medially rotates thigh

Question 12

Answer 12

Question 13

Answer 13

Question 14

What muscles are the lateral rotatators?

Answer 14

Piriformis

obturator externus

obturator internus

Gamellus

Quadratus femoris

Question 15

Piriformis

Answer 15

Piri = pear, formis = shape

0 located on posterior aspect of hip joint, inferior to glu min

• O: sacrum

I: femur

*rotates extended thigh laterally - helps abduct

Question 16

Obturator externus

Answer 16

• flat, trangular muscle, deep in supermedial aspect of thigh
• O: margins of obturator foramen
  i: femur

*same action as piriformis: rotates extended thigh laterally and helps to abduct thigh, stabilizes hip joint

Question 17

obturator internus

Answer 17

• surrounds obturator foramen within pelvis

O: obturator foramen

I: greater trochanter

(same function as piriformisa & obtur ext: rotates extended thigh laterally and help abduct thigh when hip is flexed)

Question 18

Gamellus

Answer 18

• has a superior and inferior *gemin = twin
• O: ischial spine

I: femus

*same function as piriformis, and obturators: rotates and extends thigh laterally, helps abduct thigh when hip is flexed

Question 19

Quadratus femoris

Answer 19

• short, thick and most inferior lateral rotator muscle
• extends laterally from pelvis

O: ischial tuberosity

I: femur

*rotates thigh laterally and stablizes hip joiny

Question 20

Answer 20

Question 21

Answer 21

Question 22

Quadriceps femoris

Answer 22

• arise from four seperate heads, form flesh of front and side of thigh
• insert into quadricepts tendon that inserts into patella via patellar ligament into tibial tubersosity

*Powerful knee extensor

Question 23

Rectus femoris

Answer 23

*rectus = straigh, femoris = femur

• superficial muscle
• O: iliac spine

I: patella and tibial tuberosity

*extends leg and flexes thigh at hip

Question 24

Vastus lateralis

Answer 24

• largest head of the quadricepts femoris, forms lateral aspect of thigh

*common IM inj site

• O: linae aspera (femur)

I: patella and tibial tuberosity

*extends and stabilizes the leg

Question 25

Vastus mediallis

Answer 25

* part of quadricepts femoris

• forms inferomedial aspect of thigh

O: linea aspera (femur)
I: patella and tibial tuberosity

*extends leg

Question 26

Vastus intermedius

Answer 26

*part os quadricepts femoris

• obscured by rectur femoris, lies between vastus lateralis and vastus medialis on anterior thigh

O: femur shaft

I: patella and tibial tuberosity

*extends leg

Question 27

Tensor fascia lata

Answer 27

Tensor: to make tense, fascia: band, lata: wide

0 enclosed between fascia laters

O: iliac crest

I: iliotibial tract (thickened alteral protion of Fascia lata)

*steadies leg an trunk on thihg by making iliotibial tract taut

*flexes and abducts thigh, rotates thigh medially

Question 28

Answer 28

Question 29

What are the hamstrings, what muscles are part of them

Answer 29

• fleshy muscles posterior thigh

*cross hip and knee joints

*prime movers of thigh extension and knee felxion

contains: biceps femoris, semitendinous and semimembransous

Question 30

Biceps femoris

Answer 30

• most lateral muscle of hamstrings, arises from two heads

O: ischial tuberosity (long head) and femur (short head)

I: fibula and tibia

*extends thigh and flexes leg,

*laterally rotates leg esp when knee is flexed

Question 31

Semitendinosus

Answer 31

• part of hamstrings
• lies ledially to biceps femoris
• largely tendinous, but also quite fleshy: long and slender

O: ischial tuberosity

I: tibial shaft

*extends thigh and flexes leg

*w/ semimembranosus medially rotates leg

Question 32

Semimembranous

Answer 32

*muscle of hamstrings

• deep to semitendinosus

O: ischial tuberosity

I: tibia

*extends thigh and flexes leg

*medially rotates leg w/ semitendinosus

Question 33

Answer 33