8. Knee

Question 1

Quadriceps femoris

Origin

Insertion

Action

Answer 1

short, thick muscle, most inferior of lateral rotator muscles; extends laterally from pelvis

O- ischial tuberosity

I- intertrochanteric crest of femur

A- leg extensor used in climbing, jumping, running and rising from seated position.

Question 2

Sartorius

Origin

Insertion

Action

Answer 2

straplike superficial muscle running obliquely across anterior surface of thigh to knee; longest muscle in body; crosses both hip and knee joints.

O- anterior superior iliac spine

I- winds around medial aspect of knee and inserts into medial aspect of proximal tibia

A- flexes, abducts, and laterally rotates thigh; flexes leg (weak) as in soccer kick, helps produce the cross legged position

Question 3

Gracilis

Origin

Insertion

Action

Answer 3

Long, thin, superficial muscle of medial thigh
O- inferior ramus and body of pubis and adjacent ischial ramus

I- medial surface of tibia just inferior to its medial condyle

A- adducts thigh, flexes and medially rotates leg (esp. during walking)

Question 4

Hamstrings

Origin

Insertion

Action

Answer 4

The hamstrings are fleshy muscles of the posterior thigh (biceps femoris, semitendinosus, and semimembranosus). They cross both the hip and knee joints and are prime movers of thigh extension and leg flexion. Common origin from ischial tuberorisity.

Question 5

Tensor fascia latae

Origin

Insertion

Action

Answer 5

Enclosed b/w fascia layers of anterolateral aspect of thigh; functionally associated w/medial rotators and flexors of thigh
O- anterior aspect of iliac crest and anterior superior iliac spine

I- iliotibial tract

A- steadies trunk on thigh by making iliotibial tract taut; flexes, abducts, and medially rotates thigh