Action.

Muscle.

Origin.

Insertion.

Nerve-supply.

Flexion

Longus colli

From the bodies and transverse processes of the first three thoracic and last three cervical vertebrae

The bodies and transverse processes of the upper cervical vertebrae

Anterior primary divisions of the upper cervical nerves

Psoas

See Hip-Joint

Rectus abdominis

By two heads from the symphysis and crest of the pubis

The front of the ensi-form cartilage and seventh, sixth, and fifth costal cartilages

Anterior primary divisions of the lower six thoracic nerves

Obliquus externus abdominis (external oblique)

From the outer surfaces of the lower eight ribs interdigitating with serratus magnus and latissimus dorsi

The external lip of the iliac crest in its anterior half and into a broad aponeurosis covering the anterior abdominal wall. By this means it is attached to the pubic crest, and the lower free edge of the aponeurosis forms Poupart's ligament

Same as above

Obliquus internus abdominis (internal oblique)

From the lumbar fascia, the anterior half of the iliac crest, and the outer half of Pou-part's ligament

The outer surfaces of the last three ribs, and forming an aponeurosis into the seventh, eighth, and ninth costal cartilages and linea alba

Same as above

Trans-versalis

From the inner surfaces of the lower six costal cartilages interdigitating with the diaphragm ; the lumbar fascia, anterior half of internal lip of iliac crest, and outer third of Poupart's ligament

The fibres form an aponeurosis, which joins with that of the other side to form the linea alba; and below joins the lower part of the obliquus internus to form the conjoint tendon attached to the crest of the pubis

Same as above

Extension

Com-plexus

From the transverse processes of the upper six thoracic and lower four cervical vertebrae

Between the superior and inferior curved lines of the occipital bone near the middle line

Posterior primary divisions of the spinal nerves

Splenius capitis and cervicis

From lower half of liga-rnentum nuchae and spines of seventh cervical and upper six dorsal vertebrae

Splenius capitis into the mastoid process and outer part of superior curved line of occipital bone ; splenius cervicis into the transverse processes of the upper cervical vertebrae

Same as above

Serratus posticus superior

From the ligamentum nuchae and spines of seventh cervical and first four dorsal vertebrae

By slips into the second, third, and fourth ribs

Same as above

Serratus posticus inferior

From the spines of the last two thoracic and first two lumbar vertebrae

By slips into the last four ribs

Same as above

Erector spinae

From the posterior half of the iliac crest, the posterior sacro - iliac ligament, the back of the sacrum, and spines of all the sacral and lumbar vertebrae

Divides into three portions : (1) Ilio-costa-lis, by slips into the lower six ribs ; (2) the longissimus dorsi, by outer slips into all the ribs and inner slips into the transverse processes of the upper lumbar and all the dorsal vertebrae ; (3) spinalis dorsi, into the spines of the upper dorsal vertebrae

Same as above

Quadra.tus lumborum

Posterior part of iliac crest, ilio-lumbar ligament, and transverse processes of the lower lumbar vertebrae

Inner part of lower border of twelfth rib, and transverse processes of upper lumbar vertebrae

First three or four lumbar nerves