Introduction
The musculus serratus or also called M. Serratus anterior is a muscle of the shoulder girdle musculature and is therefore attributed to the upper extremities. Its origin extends with its tendons from the 1st -9th rib. However, it has three different points of attachment on the shoulder blade or scapula.
The upper part of the muscle (pars superior) starts at the upper part of the scapula (angulus superior). The middle part (pars intermedia) is attached to the middle part of the scapula (Margo medialis). And the lower part (pars inferior) is located at the lower part of the scapula and the middle section of the scapula.
Its function is mediated by the long thoracic nerve (innervated). This nerve originates from the spinal cord segment C5-C7. If an injury or lesion of this nerve occurs, it can lead to the so-called scapula alata. Here, the shoulder blade protrudes like a wing.
Function
The M. Serratus in its entirety causes a shift of the scapula to the side-front. This function in particular is extremely important, as it serves as a respiratory aid muscle for the rib elevation when the shoulder girdle is fixed. The lower part of the muscle (pars inferior) has the function of rotating the scapula and can also swing the lower corner (or angle) of the scapula sideways-forward.
This also allows the arm to be raised above an angle of 90° (degrees), which is equivalent to lifting the arm above the shoulder. The upper part (pars superior) of the Serratus muscle causes the arm to return from a 90° elevation. At the same time it is the counterpart of the pars inferior.
Stretching
The shoulder girdle involving the Serratus muscle is a complex musculoskeletal system. It is therefore especially important to stretch it before intensive training. Here are 2 examples with and without aids.
The starting position is standing upright with the right side directly against a wall. The right foot touches the baseboard of the wall, the left foot stands parallel to it about shoulder width apart. Now it is necessary to lead the right arm backwards and to stretch it through so that a stretching stimulus is perceived in the chest muscles and in the shoulder area.
The stretching stimulus can be intensified by actively or intensively pressing against the wall. However, no pain should occur at any time. This position should be held for 30 seconds, followed by a change of sides.
Stand upright, legs should be shoulder width apart. The knees should also be slightly bent. The right arm is now angled towards the left shoulder blade.
Then the angled arm is grasped at the elbow joint with the left hand and the movement is supported until a slight stretching stimulus occurs in the shoulder. This position should be held for about 30 seconds. Then the side is changed.
