Name.

Position.

Origin.

Insertion.

Action.

Nerve Supply.

Rhomboid

minor

Lies obliquely on back from last cervical vertebra to root of scapula.

Lower part ligamentum nuchae, seventh cervical and first dorsal spines.

Root of spine of scapula.

Draws lower angle of scapula back and up.

Fifth cervical.

Second

Rhomboid

major

Immediately below rhomboid minor.

Four or five upper dorsal spines, supra - spinous ligament.

Vertebral border scapula between spine and lower angle.

Draws lower border of scapula back and up.

Fifth cervical.

Layer

Splenius : (1) Capitus. (2) Collis.

Back of neck and upper part of dorsal region.

Lower half ligamentum nuchae, last cervical and six upper dorsal spines

(1) Mastoid process, ridge of occiput. (2) Transverse processes three upper cervical vertebrae.

(1) Draws head back. (2) Keeps neck erect.

Posterior primary branch cervical and dorsal.

Third

Serratus posticus superior.

Upper part of back.

Last cervical, two upper dorsal spines, lower part ligamentum nuchae.

Second, third, fourth, and fifth ribs beyond

angles.

Raises ribs in inspiration.

Posterior primary branch dorsal.

Layer

Serratus posticus inferior.

junction of dorsal and lumbar regions.

Two last dorsal, two upper lumbar spines.

Four lower ribs beyond angles.

Draws ribs down in expiration.

Posterior primary branch dorsal.

Third Layer

Erector spinae ; divides into seven parts.

From the lower part of sacrum to the cranium.

Crest of ilium, posterior iliac spines, sacral, lumbar, & three dorsal spines.

Divides at last rib into outer and middle column.

Keeps spine erect.

Posterior primary branch sacral.

Third layer

a. Ilio-costalis orsacro-lumbalis, outer column.

Lower six or seven ribs.

Outer portion of common mass of erector spinae.

Six or seven lower ribs near their angles.

Keeps spine erect.

Posterior branches lumbar and dorsal.

Fourth Layer

b. Musculus accessorius.

All ribs about their angles.

Angles six or seven lower ribs internal to ilio-costalis.

Angles six. upper ribs.

Keeps spine erect.

Posterior branch dorsal.

Fourth layer

c. Cervicalis ascendens.

From inner side of accessorius up to the neck.

Angles of fourth, fifth and sixth ribs.

Tubercles of the transverse processes, fourth, fifth, sixth cervical vertebras.

Keeps spine erect.

Posterior branches four lower cervical.

Fourth layer

d. Longissimus dorsi. Middle column.

All ribs on the inner side of ilio-costalis.

Middle portion of common mass of erector spinae.

By two series : (1) Transverse processes of all lumbar and dorsal vertebras. (2) Articular processes of all lumbar vertebrae, lumbar fascia and ten lower ribs.

Keeps spine erect.

Posterior branches lumbar and dorsal.

Fourth Layer

e. Transversalis cervicis.

Inner side of longissimus dorsi, upper dorsal region up to the neck.

Transverse processes four or five upper dorsal vertebrae.

Transverse processes cervical vertebrae except first and last.

Keeps spine erect.

Posterior branches dorsal and cervical.

f. Trachelo-mastoid.

Inner side of transversalis ascendens.

Transverse processes upper dorsal and lower cervical vertebrae.

Back of mastoid process.

Steadies head and draws it back.

Posterior branches dorsal and cervical.

g. Spinalis dorsi. Inner column.

Inner side of longissimus dorsi.

Two upper lumbar and lower dorsal spines.

Upper dorsal spines, four to nine.

Keeps spine erect.

Dorsal.

Fourth Layer

Complexus.

Upper and back part of neck.

Transverse processes seventh cervical, three upper dorsal articular processes, fourth to sixth cervical vertebrae.

Occiput each side ligamentum nuchae.

Strengthens continuations of erector spinae in the neck. Draws head back.

Branches of cervical.

Multifidus

spinae.

Fills the grove on either side of spinous processes of the vertebra from sacrum to axis.

Back of sacrum, spine of ilium, transverse and articular processes of lumbar, dorsal, cervical vertebrae, sacro-sciatic ligament.

The whole series of spinous processes.

Keeps erect and rotates spinal column.

Posterior branches cervical, dorsal, lumbar, sacral.

Fifth Layer