The serratus anterior eccentrically decelerates adduction and medial rotation of the inferior angle of the scapula.
Actions will change, depending on the origin or insertion being fixed. With the arm static, movement occurs at the ribcage, accelerating or decelerating the ribs as required (e.g. forced exhalation).
Pain will be experienced on the side of the ribcage, traveling into the armpit and posteriorly to the medial aspect of the inferior angle of the scapula. Pain is often mistaken for C8 nerve problems, as pain is referred down the inside of the arm into the palm, fifth digit (little finger), and fourth digit. As this muscle has many digitations, careful assessment is required in order to locate active central myofascial trigger points.
The serratus anterior forms the medial wall of the axilla, along with the upper five ribs. It is a large muscle composed of a series of finger-like slips. The lower slips interdigitate with the origin of the external oblique.
Outer surfaces and superior borders of upper eight or nine ribs, and fascia covering their intercostal spaces.
Anterior (costal) surface of medial border of scapula and inferior angle of scapula.
Rotates scapula for abduction and flexion of arm. Protracts scapula (pulls it forward on chest wall and holds it closely to chest wall), facilitating pushing movements such as push-ups or punching. Antagonists: rhomboids, trapezius.
Long thoracic nerve, C5, 6, 7, 8.
Note: A lesion of the long thoracic nerve will result in the medial border of the scapula falling away from the posterior chest wall, resulting in a “winged scapula” (resembling an angel’s wing). A weak muscle will also produce a winged scapula, especially when holding a weight in front of the body.
Basic Functional Movement
Example: reaching forward for something barely within reach.
Serratus Anterior - Common Trigger Point Sites
Trigger Point Referred Pain Patterns
Local: where each digitation attaches to rib.Central: rib (6–8), localized pain, radiating anteriorly and posteriorly in a 5–10 cm patch. Pain inferior angle of scapula. Pain in ulnar aspect of upper extremity.
Chest pain which does not abate with rest, breast pain and sensitivity, panic attacks, dyspnea, chronic cough, asthma, renal tubular acidosis, scapula winging, chronic “stitch” on running, stress, “stitch” in the side of rib cage, pain on deep breathing, breast sensitivity, heart attack-type pain.
Severe coughing attack (maybe correlated with emphysema), overuse in sports (e.g. tennis, swimming, boxing, pull-ups and push-ups, weight lifting, gymnastics), prolonged lifting of large heavy objects, anxiety.
T7/T8 intercostal nerve entrapment. Herpes zoster. Local vertebral alignment. Rib lesions. Breast pathologies. Reflex-sympathetic dystrophy.