yogabook / muscles / serratus anterior
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Serratus anterior
Arises laterally at the front of the 1st-9th rib and attaches to various areas of the shoulder blade
- pars superior attaches to the upper medial edge of the shoulder blade,
- pars intermedia attaches to the entire medial edge of the shoulder blade,
- pars inferior attaches to the lower medial edge of the shoulder bladeand turns the shoulder blade outwards at the bottom and pulls it forwards
All 3 parts pull the scapula forward(antagonist: rhomboid muscles). Pars superior and inferior together press the scapula against the rib cage (synergists: Mm. rhomboidei). Pars inferior pulls the angulus inferior of the scapula forward for elevation of the arm. Conversely, if the scapula is fixed, they can also serve as inspiratory respiratory support muscles.
Origin: Pars superior: 1st – 2nd rib; Pars intermedia: 2nd – 3rd rib; Pars inferior (convergens): 4th – 9th rib
Attachment:
- Pars superior: Angulus superior of the scapula
- Pars intermedia: Margo medialis of the scapula
- Pars inferior: Margo medialis and angulus inferior of the scapula
Innervation: Nervus thoracicus longus from Plexus brachialis
Antagonists: Rhomboideus major and rhomboideus minor
Movement: tilts and pulls the shoulder blade forward into protraction and supports elevation with the pars superior
Tests
Serratus anterior Kraft Test, Scapular-assistance-Test