SERRATUS
POSTERIOR
• Origin
Serratus Posterior Superior:
• Nuchal ligament, spinous processes of C7–T3.
Serratus Posterior Inferior:
• Spinous processes of T11–L2.
• Insertion
Serratus Posterior Superior:
• Superior borders of ribs 2–5 (just lateral to their angles)
Serratus Posterior Inferior:
• Inferior borders of ribs 9–12 (just lateral to their angles)
• Agonist(s)
Superior:
- External intercostals (assist with rib elevation during inhalation).
Inferior:
- Internal intercostals and abdominal muscles (assist with forced expiration and rib depression).
• Antagonist(s)
Superior:
- Internal intercostals (depress the ribs during expiration).
Inferior:
- Diaphragm,
- External intercostals (elevate ribs during inspiration).
• Function
Serratus Posterior Superior: Assists in elevating ribs 2–5 during deep or labored inhalation.
Serratus Posterior Inferior: Assists in depressing ribs 9–12 during forced expiration.
May play a proprioceptive role due to high density of muscle spindles.
Assists in stabilizing the lower thoracic and upper lumbar rib cage during breathing.
TRIGGER POINT(S)
• Location
Serratus Posterior Superior:
Trigger points are often found just lateral to the spine in the region of the upper thoracic vertebrae (T2–T5), deep beneath the rhomboids
Serratus Posterior Inferior:
Trigger points are commonly located near the thoracolumbar junction, lateral to the lower thoracic and upper lumbar vertebrae (T11–L2), beneath the latissimus dorsi.
• Pain Referral Pattern
Superior:
Pain may be felt deep in the upper back or posterior shoulder region, and sometimes mimics interscapular or rhomboid pain.
Inferior:
Referred pain may present as a dull, aching discomfort in the lower back or flank, often mistaken for kidney or visceral pain.
Pain Pattern
💢
Potential Causes
• Poor breathing mechanics and chronic shallow breathing.
• Repetitive overhead lifting or pulling motions.
• Prolonged forward head posture or slouching.
• Chronic coughing or labored breathing (asthma, bronchitis).
• Weak core stability leading to overuse of accessory breathing muscles.
✅
Prevention Tips
• Practice deep diaphragmatic breathing to reduce reliance on accessory respiratory muscles.
• Address postural imbalances through strengthening and stretching programs.
• Avoid overuse of upper thoracic muscles during lifting or exercise.
• Use appropriate ergonomic setup during seated tasks.
• Strengthen core and lumbar stabilizers to support lower back mechanics.
