Serratus posterior superior muscle :-
muscle details :-
a thin, quadrilateral muscle, situated at the upper and back part of the thorax, deep to the rhomboid muscles.
Nuchal ligament (or ligamentum nuchae) and the spinous processes of the vertebrae C7 through T3.
The upper borders of the 2nd through 5th rib .
2nd through 5th intercostal nerves.
Elevates ribs 2-5 .