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
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.
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
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
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.