- O: External occipital protuberance, medial 1/3 of superior nuchal line, ligamentum nuchae and spinous process of the 7th cervical vertebra
- I: Lateral 1/3 of clavicle and acromion process
- A: Elevates the scapula as in shrugging the shoulders. Rotates the scapula upwards so the glenoid cavity faces superiorly, when acting with the other sections of the trapezius it retracts the scapula
- NS: Spinal accessory and ventral rami of C3,4
- S: Levator scapulae, clavicular head of the SCM, middle and lower trapezius
*REVERSED O-I ACTION: Laterally flexes head and neck to side of contraction. Rotates head and neck away from side of contraction. Action bilaterally, extends the head and neck.