Abdominal Muscles
A well-functioning abdominal musculature unloads the back stress during lifting and stabilizes the spinal column, because the abdominal muscles are antagonists to the back muscles. The back muscles are always used during lifting, standing, and sitting. In the majority of people, abdominal muscles are weaker than back muscles. Strong abdominal muscles, hip flexors (iliopsoas, rectus femoris), and back extensors are very important for all sports. There are four abdominal muscles (Table 12-9 and Fig. 12-20).
TABLE 12-5 Long Back Muscles (Intermediate Layer)*
Erector Spinae
Origin
Insertion
Innervation
Action
Iliocostals (lateral column): iliocostalis lumborum, iliocostalis thoracis. and iliocostalis cervicis Longissimus (intermediate column)
Spinalis (medial column): spinalis thoracis, spinalis cervicis, spinalis capitis
Broad tendons attached interiorly to posterior iliac crest, posterior sacrum, sacroiliac ligaments, and sacral and inferior lumbar spinous processes A broad tendon attached inferiorly to posterior iliac crest, posterior sacrum, sacroiliac ligaments, and sacral and inferior lumbar spinous processes Broad tendons attached inferiorly to posterior iliac crest, posterior sacrum, sacroiliac ligaments, and sacral and inferior lumbar spinous processes
Angles of the ribs
Transverse processes of thoracic and cervical vertebrae and mastoid process of temporal bone
Extend from spinous lumbar and thoracic processes
Dorsal rami of spinal nerves of corresponding segments
Dorsal rami of spinal nerves of corresponding segments
Dorsal rami of spinal nerves of corresponding segments
Side bending and ipsilateral rotation when muscles contract unilaterally Trunk extension when muscles contract bilaterally Side bending and ipsilateral rotation when muscles contract unilaterally Trunk extension when muscles contract bilaterally Side bending and ipsilateral rotation when muscles contract unilaterally Trunk extension when muscles contract bilaterally
Semispinalis capitis Splenius capitis
Longissimus capitis Splenius cervicis
Levator scapulae Longissimus cervicis Semispinalis cervicis Iliocostalis cervicis Infraspinatus, infraspinous fascia
Spinalis thoracis Iliocostalis thoracis Longissimus thoracis Iliocostalis lumborum External oblique
Internal oblique
Semispinalis capitis Splenius capitis
Longissimus capitis Splenius cervicis

Internal oblique
Figure 12-18 Muscles of the back.
Ligamentum nuchae Splenius capitis Sternocleidomastoid Splenius cervicis Scalenus posterior
Trapezius Teres major
Serratus posterior superior Rhomboid major
Iliocostalis thoracis Latissimus dorsi Longissimus thoracis Serratus anterior Serratus posterior inferior
Thoracolumbar fascia Erector spinae
Figure 12-18 Muscles of the back.
Muscles |
Origin |
Insertion |
Innervation |
Action |
Semispinalis |
Transverse |
Medial half between |
Dorsal rami of |
For corresponding region of spine: |
capitis |
processes of |
superior and |
spinal nerves of |
ipsilateral rotation when muscles |
T1-T6 |
inferior nuchal |
corresponding |
contract unilaterally, extension | |
line |
segments |
when muscles contract bilaterally | ||
Semispinalis |
Transverse |
Spinous processes |
Dorsal rami of |
For corresponding region of spine: |
cervicis |
processes of |
of C2-C5 |
spinal nerves of |
ipsilateral rotation when muscles |
T1-T6 |
corresponding |
contract unilaterally, extension | ||
segments |
when muscles contract bilaterally | |||
Semispinalis |
Transverse |
Thoracic spinous |
Dorsal rami of |
For corresponding region of spine: |
thoracis |
processes |
processes |
spinal nerves of |
ipsilateral rotation when muscles |
of thoracic |
corresponding |
contract unilaterally, extension | ||
vertebrae |
segments |
when muscles contract bilaterally | ||
Multifidus |
Spinous processes |
Spinous processes |
Dorsal rami of |
Side bending and ipsilateral rotation |
and laminae |
spanning one to |
spinal nerves of |
when muscles contract unilaterally | |
from S4-C2 |
three vertebrae |
corresponding |
Trunk extension when muscles contract | |
vertebrae |
segments |
bilaterally, stabilizing the spinal | ||
column |
Muscles |
Origin Insertion |
Innervation |
Action |
Intertransversarii |
Uniting spinous and transverse processes |
Dorsal rami of spinal |
Laterally flex superior |
of consecutive vertebrae |
nerves of corresponding |
vertebra; help extend | |
segments |
vertebral column | ||
Interspinalis |
Uniting spinous and transverse processes |
Dorsal rami of spinal |
Help extend vertebral |
of consecutive vertebrae |
nerves of corresponding |
column | |
segments | |||
Rotatores |
Transverse process Base of spinous |
Dorsal rami of spinal |
Rotate superior |
of vertebra process of |
nerves of corresponding |
vertebra to the | |
superior vertebra |
segments |
opposite side |
*See Figure 12-19.
*See Figure 12-19.
Costotransverse ligament
Levator costae longus Levator costae brevis Rotatores thoracis
Lumbalis vertebra I, vertebral arch
Ligamenta flava
Intertransversarii mediales lumborum
Intertransversarii mediales lumborum

Intertransverse ligament
Rib IX
Multifidi
Intertransverse ligament
Lumbar vertebrae, spinous processes
Figure 12-19 Deep short muscles of the back.
Intertransverse ligament
Rib IX
Multifidi
Intertransverse ligament
-Rib XII
Lumbar vertebrae, processes costal Intertransversarii laterales lumborum Thoracolumbar fascia (deep layer)
Multifidi
Erector spinae
Lumbar vertebrae, spinous processes
Figure 12-19 Deep short muscles of the back.

Dynamic Six Pack Abs
Reasonable care has been taken to ensure that the information presented in this book is accurate. However, the reader should understand that the information provided does not constitute legal, medical or professional advice of any kind.
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