Dance Anatomy & Kinesiology

90 Dance Anatomy and Kinesiology

FIGURE 3.20 The quadratus lumborum (posterior

view).

Summary of Spinal

Muscle Attachments and Actions

A summary of the attachments of the spinal muscles

is provided in table 3.1, and selected muscles and

attachments are shown in figures 3.21, A and B, and

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

of pull and resultant possible actions of the primary

muscles of the spine; check your results by looking

at figure 3.21D and figure 3.22C.

TABLE 3.1 Summary of Spinal Muscle Attachments and Primary Actions

Muscle Origin* Insertion** Primary action

Anterior muscles

Rectus abdominis

(REK-tus ab-DOM-i-nis)

Crest of pubis

of pelvis, pubic

symphysis

Cartilages of ribs

5-7

Spinal flexion

Spinal lateral flexion (same)

External oblique

(o-BLEEK)

Anterolateral aspect

of lower 8 ribs

Anterior crest of

ilium, crest of

pubis, and linea

alba

Spinal flexion

Spinal lateral flexion (same)

Spinal rotation (opposite)

Internal oblique

(o-BLEEK)

Thoracolumbar fascia,

anterior 2/3 of iliac

crest, lateral inguinal

ligament

Ribs 9-12,

cartilages of ribs 7-

9, and linea alba

Spinal flexion

Spinal lateral flexion (same)

Spinal rotation (same)

Transversus abdominis

(trans-VER-sus ab-DOM-i-nis)

Thoracolumbar fascia,

anterior 3/4 of iliac

crest, lateral inguinal

ligament, ribs 7-12

Linea alba, pubis Constriction of abdominal wall and

contents

Assists with spinal stabilization

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

Psoas major

(S0-us)

Transverse

processes, bodies,

and intervertebral

discs of T12-L5

Lesser trochanter

of femur

Hip flexion

Posture (maintenance of normal lumbar

curve)

Iliacus

(il-ee-AK-us)

Iliac fossa, crest of

ilium, sacrum

Lesser trochanter

of femur

Hip flexion