Trunk and Neck Muscle Actions (Quiz 3)

Neck Flexion (Bilateral)

• Sternocleidomastoid

• Anterior scalene

• Longus capitis

• Longus colli

Neck Extension (bilateral)

• Splenius Capitis

• Splenius Cervicis

Neck Rotation- Opposite side (Unilateral)

• Sternocleidomastoid

• All scalenes

Neck Rotation- Same side (Unilateral)

• Splenius capitis

• Splenius cervicis

Neck Lateral Flexion- same side (unilateral)

• Sternocleidomastoid

• All scalenes

• Splenius capitis

• Splenius cervicis

Trunk Flexion (Bilateral)

• Rectus abdominis

• External obliques

• Internal obliques

Trunk Extension (Bilateral)

• Erector Spinae group (Iliocostalis, Longissimus, spinalis)

• Multifidi and Rotatores

• Semispinalis Capitis

Trunk Rotation- Opposite side (unilateral)

• External obliques

• Multifidi

• Rotatores

Trunk Rotation- Same side (unilateral)

Internal obliques

Trunk Lateral Flexion- Same side (unilateral)

• External obliques

• Internal obliques

• Erector spinae group (Iliocostalis, Longissimus, spinalis)

• Quadratus lumborum

Primary breathing- Inhilation

External intercostals: assist with inhilation by making thoracic space bigger by ELEVATING ribs.

Primary breathing- Forced exhalation

Internal intercostals: Assist with forced exhalation by making thoracic space smaller (draw ribs inferiorally).

Abdominal Compression/Stability

Transverse abdominus, obliques help