Dance Anatomy & Kinesiology

The Knee and Patellofemoral Joints 249

and internal rotation of the tibia or knee. However,

depending on the specific insertion of the muscle,

when the knee is in full extension or hyperextension,

the line of pull may pass anterior to the knee axis

such that it reverses its function to being an exten-

sor of the knee (Basmajian and DeLuca, 1985). This

may be one mechanism that dancers use for helping

maintain extension of the knee with less quadriceps

activation when raising the leg to the front.

Summary of Knee Muscle

Attachments and Actions

A summary of the attachments of the muscles that

cross the knee is provided in table 5.1, and some of

the more primary of these muscles and their attach-

ments are shown in figures 5.9, A and B, and 5.10,

A and B. From these resources, deduce the line of

pull and resultant possible actions of the primary

muscles of the knee, and then check for accuracy

by referring to figures 5.9C and 5.10C.

FIGURE 5.8 Pes anserinus (right knee, medial view).

TABLE 5.1 Summary of Attachments and Primary Actions* of Knee Muscles

Muscle Proximal attachment(s) Distal attachment(s) Primary action(s)

Anterior muscles

Quadriceps femoris (KWOD-ri-seps FEM-o-ris)

Rectus femoris

(REK-tus FEM-o-ris)

Anterior inferior iliac spine

Posterior head: just above

acetabulum

Tibial tuberosity via

patellar tendon

Knee extension

(Hip flexion)

Vastus medialis

(VAS-tus me-dee-A-lis)

Medial and posterior

surfaces of femur

Quadriceps femoris

tendon and medial border

of patella

Knee extension

Vastus intermedius

(VAS-tus in-ter-ME-dee-us)

Anterior and lateral aspects

of femur

Quadriceps femoris

tendon and superior

border of patella

Knee extension

Vastus lateralis

(VAS-tus lat-er-A-lis)

Upper lateral and posterior

surfaces of femur

Quadriceps femoris

tendon and lateral border

of patella

Knee extension

Posterior muscles

Hamstrings

Biceps femoris

(BI-seps FEM-o-ris)

Long head: ischial tuberosity

Short head: linea aspera of

femur

Head of fibula

Lateral tibial condyle

Knee flexion

Knee external rotation

(Hip extension)

(Hip external rotation)

Semitendinosus

(sem-ee-ten-di-NO-sus)

Ischial tuberosity Medial surface of upper

tibia (pes anserinus)

Knee flexion

Knee internal rotation

(Hip extension)

(Hip internal rotation)

(continued)

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