Sphenoid bone is located under the shoulder and symmetrically distributed on both sides of the back, which can play a role in connecting the upper limbs on both sides. Butterfly bone is a kind of bone that can support the brain, so it is named after it looks like a butterfly with open wings.
Under normal circumstances, when the arm is raised, the scapula remains basically motionless for the first 30 to 60 degrees, and then it begins to rotate steadily upward, and it also rotates downward when the arm falls. It is not normal that the medial edge or lower corner of the scapula obviously protrudes backward (winged scapula), or that the whole scapula is stuck or excessively lifted during exercise.
If the position or function of the scapula is abnormal, the risk of shoulder and neck pain or difficulty in lifting the arm will also increase. This is because the big arm is directly "hung" on the scapula, and the arm can keep its position normal, extend in all directions, move up and down, back and forth by the scapula, and rotate in time.
The scapula is mainly pulled and fixed on the back by 17 muscles. These muscles are perfectly matched, so that the scapula lies flat and does not tilt, which is flexible and efficient when assisting the arm. This kind of cooperation is often disturbed by the bad posture of sitting in front of the computer for a long time and the action or work of raising your arms above your head.