Muscles of the Spinal Column Chapter 12

Cervical Muscles

Splenius (capitis and cervicis) Origin: Cervicis – spinous process of T3-T6 Capitis - lower half of ligmentum nuchea & spinous process of C7 and T1-3. Insertion: Cervicis - transverse process of C1-C3. Capitis – mastoid process and occipital bone Actions: Whole 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: Whole – Cervical Flexion Half - Cervical Lateral Flexion (help with inhalation during exercise)

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 branch

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: I: Lesser trochanter of femur Action: 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 (during exercise)

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 Rib (with Intercostal Muscles) Diaphragm Expiration

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 2. External Intercostals 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.

Muslces of Expiration Muscles of Inspiration *Sternocleidomastoid *Scalenes *Internal Intercostals External Intercostals *Rectus Abdominus Diaphragm *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.