Dance Anatomy & Kinesiology

250 Dance Anatomy and Kinesiology

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

Posterior muscles (continued)

Hamstrings (continued)

Semimembranosus

(sem-ee-mem-brah-NO-sus)

Ischial tuberosity Medial condyle of tibia Knee flexion

Knee internal rotation

(Hip extension)

(Hip internal rotation)

Popliteus

(pop-LIT-ee-us)

Tripartite tendon:

1. Lateral femoral condyle


2. Head of fibula


3. Posterior aspect of lateral
   meniscus

Medial posterior aspect of

upper tibia

External rotation of

femur (when foot fixed)

Internal rotation of tibia

(when foot free)

“Unlocking” knee

Additional secondary muscles

Gracilis Just below symphysis

on pubis, inferior rami of

ischium and pubis

Medial surface of upper

tibia (pes anserinus)

Knee flexion

(Hip adduction)

(Hip flexion)

Sartorius Anterior superior iliac spine

(ASIS) and area just below

Medial surface of upper

tibia (pes anserinus)

Knee flexion

(Hip flexion)

(Hip abduction)

(Hip external rotation)

Tensor fasciae latae Anterior outer crest of ilium,

lateral aspect of anterior

superior iliac spine

Tibia via iliotibial band Lateral support of knee

(Terminal knee extension)

(Knee external rotation)

(Hip abduction)

(Hip flexion)

(Hip internal rotation)

Gastrocnemius Medial and lateral femoral

condyles

Calcaneus (foot) via

Achilles tendon

Knee flexion

(Ankle plantar flexion)

*Special circumstances for action or action at other joints given in parentheses

Knee Alignment and Common Deviations

Knee alignment can be evaluated relative to the

frontal, sagittal, or transverse plane. Appropriate

alignment of the bones involved in the knee joint can

have important implications in terms of how stresses

are borne and the resultant injury predispositions,

as well as for one’s ability to meet the performance

and aesthetic demands of dance. Common align-

ment deviations include valgus angulation, genu

recurvatum, and tibial torsion.

Valgus Angulation

As discussed in chapter 4, when one views the legs

from the front or back, the shafts of the femur are not

totally vertical but rather angle slightly inward, with

the knees more medial than either the femoral head

or greater trochanter. Due to this femoral obliquity

in the frontal plane, it is normal for the tibia to angle

outward slightly relative to the femur. This angula-

tion functions to help establish an approximately

vertical positioning of the tibia, desirable for transfer

of body weight. The angle between the femur and

tibia, which opens out laterally, is termed a valgus

angle or valgus angulation. In adults, an angle of

about 170° to 174° is considered normal (Magee,

1997; Smith, Weiss, and Lehmkuhl, 1996), and such a

normal alignment of the tibia relative to the femur is

termed genu rectum (L. genu, knee + rectus, straight)

as seen in figure 5.11A.

Genu Valgum

However, in some cases this relative lateral deviation

of the tibia is exaggerated and the angle between the

TABLE 5.1 Summary of Attachments and Primary Actions* of Knee Muscles (continued)