Throughout the years, only a small amount of research has been conducted to study the anatomy of the lower trapezius. However, there is plenty of research regarding the role of the lower trapezius in scapula function and the association between lower trapezius dysfunction and shoulder pain. A notable study conducted in 1994 on the anatomy of the lower trapezius found that the lower trapezius begins on the spine and lengthens from the T2 to T12 vertebrae, inserting onto the spine of the scapula from the acromion process to its root. According to the anatomy study, the lower trapezius closely follows the middle trapezius which attaches to the C7 and T1 vertebrae, also attaching to the spine of the scapula. The lower trapezius is a multipennate muscle which is innervated by the accessory nerve, or the eleventh cranial nerve, and the ventral rami of the third and fourth cervical nerves along the cervical plexus.
The scapula is the foundation of all upper limb kinetic chain movements. To function effectively, it must have enough flexibility and mobility to achieve the necessary positions to allow the humerus to move smoothly, without impingement. It also needs to remain strong and stable during upper limb movements, specifically overhead sports activities to provide the proper transmission of force from the body to the hand, most important in athletic activities such as swimming, tennis and throwing sports.
The lower trapezius is a muscle that plays an essential role during scapula movement and positioning as well as dynamic scapula stability. The upward rotation, posterior tilt, and external rotation movements of the scapula function to increase the width of the subacromial space during humeral elevation. Nonetheless, a lack of proper scapula function, or scapula dyskinesis, can increase the adaptation of the humeral head, altering the position and motion of the scapula, often leading to injury.
The lower trapezius is a muscle which has been suggested to function ideally with the mechanics of the scapula. It has been acknowledged that improper mobilization of the scapula, also referred to as scapula dyskinesis, during overhead activities may lead athletes to experience sports injuries in the form of impingement, subacromial bursitis and instability. For more information, contact us at (915) 850-0900.