Secondary to serratus anterior palsy, a winged scapula is also caused by trapezius and rhomboid palsy involving the accessory nerve and the dorsal scapular nerve, respectively.
12.
Note that some muscles are not usually involved in these synergy patterns and include the lattisimus dorsi, teres major, serratus anterior, finger extensors, and ankle evertors.
13.
Though the most common causes of a winged scapula is due to serratus anterior palsy, and less commonly trapezius and rhomboid palsy, there are still other circumstances that present the ailment.
14.
A lesion of the nerve paralyses the serratus anterior to produce winged scapula, which is most prominent when the arm is lifted forward or when the patient pushes the outstretched arm against a wall.
15.
The chest wall has 10 layers, namely skin, superficial fascia, deep fascia, serratus anterior, layer for ribs ( containing intercostal muscles ), and endothoracic fascia from superficial to deep.
16.
The five superior serrations increase in size from above downward, and are received between corresponding processes of the serratus anterior muscle; the three lower ones diminish in size from above downward and receive between them corresponding processes from the latissimus dorsi.
17.
It originates from the axillary artery and follows the lower border of the Pectoralis minor muscle to the side of the chest, supplies the Serratus anterior muscle and the Pectoralis major muscle, and sends branches across the axilla to the axillary lymph nodes and Subscapularis muscle.
18.
The serratus anterior is occasionally called the " big swing muscle " or " boxer's muscle " because it is largely responsible for the protraction of the scapula that is, the pulling of the scapula forward and around the rib cage that occurs when someone throws a punch.
19.
The evolution of the serratus anterior itself has resulted in ( 1 ) grouping of its distal and proximal fibers, ( 2 ) size reduction of its intermediate fibers, and ( 3 ) the insertion of its dominant superior and inferior parts onto the superior and inferior angles of the scapula.
20.
In primitive life forms, the main function of the axioscapular group is to control the movements of the vertebral border of the scapula : fibers concerned with the dorsal movement of scapula evolved into the rhomboids, those with ventral motion into serratus anterior, and those with cranial movements into levator scapulae.
