5. Rectus abdominis informally known
as the abs muscle, is a long muscle of
the anterior abdominal wall.
Originating from the pubic crest
(between pubic tubercle and pubic
symphysis) at the lower end the
muscle inserts with the help of fibers
to the 5th to 7th coastal cartilage and
the xiphoid process of the sternum. It
acts to flex the spinal column, tense
the anterior wall of the abdomen and
assist in compressing the contents of
the abdomen.
Rectus abdominis
(ABDOMINAL MUSCLE)
6. Internal abdominal oblique is a broad thin
muscular sheet found on the lateral side of
the abdomen. Going from superficial to
deep, the external abdominal oblique,
internal abdominal oblique and transversus
abdominis comprise the three distinct
layers of the lateral abdominal wall. This
muscle supports the abdominal wall, assists
in forced respiration, aids in raising
pressure in the abdominal area, and rotates
and turns the trunk with help from other
muscles.
INTERNAL OBLIQUE
(ABDOMINAL MUSCLE)
7. The external oblique muscle is one of the
outermost abdominal muscles, extending
from the lower half of the ribs around and
down to the pelvis.Together, the external
oblique muscles cover the sides of the
abdominal area, being large and sitting on
the top surface of the abdomen right below
the subcutaneous fat and skin.
External
Oblique
External
Oblique
10. The erector spinae muscles make up most
of the postural muscles of the back.The
erector spinae are actually many muscles that
are located between individual vertebrae or
between the vertebrae and the ribs.These
separate muscles are grouped into long strap
muscles known collectively as the erector
spinae.There are three major groups of
erector spinae muscles: the spinalis, the
longissimus, and the iliocostalis.
POSTURAL MUSCLES
11. The spinalis is a portion of the erector
spinae, a bundle of muscles and tendons,
located nearest to the spine. It is the most
medial erector spinae muscles
It is divided into three parts:
• Spinalis capitis muscle originates from
the spinous processes of C7-T1 vertebrae
and inserts into the midline of the
occipital bone.
• Spinalis colli muscle originates from the
same points as spinalis capitis, but also
from the nuchal ligament. It inserts to
the spinous processes of C2-C4
vertebrae.
• Spinalis thoracis muscle extends from
the spinous process of T11-L2 vertebrae
until the spinous process of T2-T8
vertebrae.
SPINALIS
(POSTURAL MUSCLE)
12. The longissimus muscles are the central erector
spinae muscles. They are also the thickest and
the longest. It is divided into three parts:
• Longissimus capitis muscle originates from
the transverse processes of vertebrae C4-T5
and inserts into the mastoid process of
temporal bone.
• Longissimus colli muscle extends between
the transverse processes of vertebrae T1-T5
and transverse processes of vertebrae C2-C6.
• Longissimus thoracis muscle consists of
thoracic and lumbar parts. The thoracic part
travels from the L1-L5 vertebrae, sacrum and
posterior iliac crest until the thoracic
vertebrae and inferior six ribs. The lumbar
part extends between the region
surrounding the anteromedial aspect of
ilium and L1-L5 vertebrae.
LONGISSIMUS
(POSTURAL MUSCLE)
13. The iliocostalis muscles are the most lateral
erector spinae muscles. It is a deep muscle of
the back. It is located laterally within the
erector spinae muscle complex and can be
divided into three parts:
• Iliocostalis colli muscle originates from the
angle of ribs 3 to 6 and inserts into the
transverse processes of vertebrae C4-C6.
• Iliocostalis thoracis muscle arises from the
angles of ribs 7-12 and attaches to the
angles of ribs 1-6 and transverse process of
vertebra C7.
• Iliocostalis lumborum muscle originates
from three points; lateral crest of sacrum,
medial end of iliac crest and thoracolumbar
fascia. It attaches to the angle of ribs 5-12,
transverse processes of vertebrae L1-L4 and
adjacent thoracolumbar fascia.
ILIOCOSTALIS
(POSTURAL MUSCLE)
15. The superficial muscle layer is composed of the
splenius muscles (spinotransversales muscles),
which are the splenius capitis and splenius cervicis.
These flat muscles are located on the posterolateral
aspect of the neck and the posterior upper thorax,
overlying the deep muscles of the neck. The
splenius muscles both originate from the spinous
processes of cervical and thoracic vertebrae:
The splenius capitis arises from the spinous
processes of vertebrae C7-T3 and the lower half of
the nuchal ligament. It then passes superolaterally
to insert on the mastoid process and the lateral
third of the superior nuchal line of the occipital
bone.
The splenius cervicis arises from the spinous
processes of vertebrae T3-T6 and inserts onto the
transverse processes of vertebrae C1-C3 or C4.
SUPERFICIAL
(POSTURAL MUSCLE)
16. The intermediate layer contains the large erector
spinae muscles which are sometimes called the
long muscles of the back. This muscle group is the
largest of the deep back muscles and lies on either
side of the vertebral column between the spinous
processes of the vertebrae and the angles of the
ribs.
The muscles are composed of three vertical
columns of muscle that lie side by side. From lateral
to medial, these are the iliocostalis, longissimus
and the spinalis muscles. Each muscle column is
subdivided into regions (lumborum, thoracic,
cervicis, capitis) based on which region of the axial
skeleton it attaches to superiorly.
INTERMEDIATE
(POSTURAL MUSCLE)
