Dance Anatomy & Kinesiology

The Pelvic Girdle and Hip Joint 165

Individual Muscles of the Hip

Anterior Muscles of the Hip

The anterior muscles of the hip include the iliopsoas, rectus femoris, and sartorius. These muscles

cross anterior to the axis of the hip joint for flexion-extension and so share the common action of hip

flexion used in movements such as walking, running, or leaping.

Iliopsoas

The iliopsoas is actually composed of the psoas

major (G. psoa, the loins + major, the larger) and

iliacus (iliac, ilium). Since these share a common

distal attachment and appear to act together during

functional movement, they are frequently referred to

together as one muscle, the iliopsoas. The iliopsoas,

shown in figure 4.5, is approximately 16 inches (41

centimeters) long (Rasch and Burke, 1978). It runs

deep under the abdominal wall from the front of the

lower spine and inner portion of the ilium downward

to attach onto the medial side of the upper femur

at the lesser trochanter. Due to its deep location,

it is often difficult for dancers to “feel” or visualize,

and careful examination of its attachments on the

skeleton is helpful to understand its location and

function. The iliopsoas is one of the most powerful

muscles in the entire body (Michele, 1960) and can

develop a tensile pull in excess of 1,000 pounds

(454 kilograms). The iliopsoas has been shown

to be the most important muscle for hip flexion

above 90°, as evidenced by the inability to lift the

thigh above 90° when iliopsoas paralysis is pres-

ent (Smith, Weiss, and Lehmkuhl, 1996). It can also assist with hip abduction, particularly at higher

ranges. These two latter properties give the iliopsoas key importance for dance movements such as

high développés to either the front or side. The potential contribution of the iliopsoas to hip rotation

is still under debate, and although it may function as an external rotator when the femur is internally

rotated, it appears unlikely to play an important rotation role in other conditions.

Regarding its postural role, the iliopsoas is the only muscle in the human body that has attachments

on the spine, pelvis, and femur. Due to these attachments, the iliopsoas is in a unique position not

only to produce movement but also to stabilize the hip and effect the positioning of the lumbar spine.

Attachments and Primary Action of Iliopsoas

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

Iliopsoas (il-ee-o-SO-us)

Psoas major

(SO-us)

Transverse processes, bodies, and

intervertebral discs of T12-L5

Lesser trochanter of

femur

Hip flexion

Hip abduction (higher ranges)

Posture

Iliacus

(il-ee-AK-us)

Iliac fossa, crest of ilium, inner

lateral sacrum

Lesser trochanter of

femur

Hip flexion

Hip abduction (higher ranges)

FIGURE 4.5 The iliopsoas muscle (anterior view).

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