Muscles of the Spinal Column
Chapter 12
Cervical Muscles
Splenius (capitis and cervicis)

Origin:



Insertion:




Cervicis - transverse process of C1-C3.
Capitis – mastoid process and occipital bone
Actions:
Whole


Cervicis – spinous process of T3-T6
Capitis - lower half of ligmentum nuchea &
spinous process of C7 and T1-3.
Cervical Extension
Half


Cervical Rotation to the same side.
Cervical Lateral flexion
Splenius (cervicis & capitis)
Splenius
Sternocleidomastoid




O: Top of the sternum and
medial third of the clavical
I: Mastoid process
Action:
Whole
 Cervical

Flexion
Half
 Cervical
Lateral Flexion
 Cervical Rotation to the
opposite side.
Sternocleidomastoid
Sternocleidomastoid
Scalenes (or scaleni)



O: First two ribs
I: Transverse processes
of cervical vertebrae.
Actions:
– Cervical Flexion
 Half - Cervical Lateral
Flexion (help with
inhalation during exercise)
 Whole
Scalenes
Lumbar Muscles
Erector spinae muscles


O: Fascia of lower back, posterior
L, T and lower C vertebrea, and
angles of ribs.
Inesrtions




Spinalis branch - spinous process of T
and C and occipital bone
Longissimus branch - transverse
process of T and C, mastoid process.
Iliocostalis branch - angles of the ribs
and cervical transverse processes
Actions:


Whole – Extension
Half - Lateral flexion
Erector spinae muscles
Erector spinae muscles
Iliocostalis branch
Longissimus branch
Spinalis branch
Spinalis branch
Longissimus branch
Iliocostalis branc
Quadratus lumborum
O: Posterior lip of iliac
crest
 I: Lower border of 12th rib
and transverse process of
L1-4
 Actions:

 Half
- Lumbar lateral flexion
 Whole - Stabilization
Quadratus lumborum
Iliopsoas

O:




Psoas - lateral surface of T12 and
L1-5,
Iliacus - anterior surface of ilium
(iliac fossa)
I: Lesser trochanter of femur
Action:
 Whole - Lumbar flexion of trunk

[Whole - Hip flexion]
Iliopsoas
Iliopsoas
The Abdominal Muscles
4.
2.
3.
1.
Rectus abdominis




O: Crest of the pubis
I: Xyphoid process
and 5th - 7th ribs
Action:
Whole
 Lumbar

Flexion
Half
 Lumbar
lateral flexion
Rectus abdominis
External oblique



O: Lower 8 ribs.
I: Anterior iliac crest;
inguinal ligament, crest of
pubis, fascia of the rectus
abdominus
Action:
 Whole
– Lumbar flexion
 Half


Lumbar rotation to opposite side
Lumbar lateral flexion
External oblique
External oblique
Internal oblique



O: Inguinal ligament (from
anterior iliac crest to
pubis) and iliac crest
I: Costal cartilages of the
lower ribs.
Actions:


Whole – Lumbar flexion
Half
 Lumbar rotation to the
same side
 Lumbar lateral flexion
Internal oblique
Internal
The Oblique
Muscles?
Which is Internal and which is External?
External
Transverse abdominis



I: Inguinal ligament,
iliac crest, and lower 6
ribs
O: Linea alba ("white
line") and pubis crest
Functions:
 Exhalation
exercise)
(during
Transverse abdominis
MUSCLES OF RESPIRATION
Rib actions
 Respiration

III. ANATOMY
of the
RESPIRATOY
MUSCLES
Diaphragm
O: Xiphoid process,
costal cartilages,
lumbar vertebrae
 I: Central tendon
 A: Flattens, pulls
central tendon
downward

External Intercostals
O: Inferior border of the
ribs
 I: Superior border of the
next rib below
 A: Draws ribs together
and lifts the ribs


11 on each side; slant down
and forward
Internal Intercostals (p.
379)




O: Inferior border of
the ribs
I: Superior border of
the next rib down
A: Draws ribs together
and lowers ribs
slant down and
backward
MUSCLES OF RESPIRATION
Inspiration
Diaphragm
Expiration
Rib (with
Intercostal
Muscles)
I. INSPRIATION




Increase in thorasic
cage
Volume inside
increases
Pressure decreases
Air moves into the
lungs
A. Inspiration at Rest

1. Diaphragm
 Flattens
and moves
downward when
contracted
A. Inspiration at Rest

1. Diaphragm
 Flattens
and moves
downward when
contracted


2. External
Intercostals
Lift the ribs up and
out when contracted
B. Inspiration During Exercise
1. Scalenes – elevate upper ribs
 2. Sternoceidomastoid – elevate clavical
and upper ribs
 3. External intercostal muscles

II. EXPIRATION




Decrease thorasic
cage
Volume inside
decreases
Pressure increases
Air moves out of the
lungs
A. Expiration at Rest.
No muscles are involved
 Passive recoil action at rest will decrease
the thorasic cage

B. Expiration During Exercise





Internal Intercostals Rectus Abdominus – help push the diaphragm
upward.
External obliques– help push the diaphragm
upward.
Internal obliques– help push the diaphragm
upward.
Transverse abdominus– help push the
diaphragm upward.
*Sternocleidomastoid
Muslces of
Expiration
*Scalenes
*Internal Intercostals
External Intercostals
Diaphragm
*Rectus Abdominus
*External Obliques
*Internal Obliques
*Transverse Abdominus
Muscles of
Inspiration
Note:
These muscles need to trained with
exercise as any other muscle does.
 Early limitations (side aches and
breathlessness) felt during exercise may
involve the untrained state of these
muscles.
