deep muscles of the back 10

deep muscles of the back 10

 

~r. menury me uu-ee O0lI.II1ll1! or me erector spmae

muscle (L. erector, one who erects) (Fig. 1.10):

' Spinalis muscle forms the medial column of the

erector spinae muscle. The inferior attachments of

the spinalis muscle are on spinous proceses. Its

superior attachments are also on spinous proceses.

The spinalis muscle is present at lumbar, thoracic

and cervical vertebral levels.

' Longissimus muscle (L. bngissimus, the longest) is

the intermediate column of the erector spinae mus-

cle. Its inferior attachment is on the sacrum and its

superior attachments are the transverse proceses

of the thoracic and cervical vertebrae. Note that its

most superior portion, the longissimus capitis

muscle, attaches to the mastoid proc of the tem-

poral bone.

' lliooostnlis muscle is the lateral column of the

erector spinae muscle. Its inferior attachment is the

ilium (iliac crest) and its superior attachments are

on ribs (L. mm, rib).

5. All three columns of the erector spinae muscle extend

the vertebral column when both sides work together.

If only one side is active, the erector spinae muscle

bends the vertebral column laterally toward the side

that is active.

TRANSVERSOSPINAI. GROUP OF MUSCLES [G 31 Z; N 159;

R Z1 5; C 41 1]

The mmsversospinal group of muscles '5 located deep

to the erector spinae muscle. The muscles in the transver-

sospinal group attach to transverse proceses and spinous

The order of dissection will be as follows: the deep muscles of
the posterior neck (splenius and semispinalis capitis) will be
studied. The erector spinae muscle will be dissected and its com-
ponent parts will be identified

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Dissection Instructions
SPLENIUS MUSCLE [G 309; N ‘I57; R Z12; C 408]
1. Identify the splenius muscle (Gr. splmion, bandage).
The splenius muscle lies deep to the trapefius muscle
and its fibers course obliquely across the neck. The
troximal attachment of the splenius muscle is the
nuchal ligament and the spinous processes of verte-
lrae C7 to T6.
2. The splenius muscle has two parts that are named
according to their distal attachments:
° Splenius capitis muscle (L. mput, head) is
attached to the mastoid process of the temporal
bone and the superior nuchal line of the occipital
bone.
° Splenius oervicis muscle  cervix, neck) is
attached to the transverse processes of the verte-
lrae Cl to C4.
3. Detach the splenius muscle from the nuchal ligament
and the spinous processes of vertebrae C7 to T6.
4. Reflect the muscle laterally, leaving its distal attach-
ments undisturbed.