What is normal Scapulohumeral rhythm?
Scapulohumeral rhythm is the rhythm in which our scapula moves, in relation with the humerus in the glenohumeral joint as a means for shoulder mobility. The standard ratio is often recognized as 2:1. This means for every 2 degrees the humerus moves, the scapula moves 1 degree.
What joint does Scapulohumeral rhythm action occur?
During shoulder abduction, there is 120 degrees of movement that occurs at the glenohumeral joint, while 60 degrees occurs at the scapulothoracic joint, creating a 2 to 1 ratio (2:1). This movement is known as the scapulohumeral rhythm (SHR) of shoulder abduction.
What happens during shoulder flexion?
A shoulder flexion is when you move your arms anywhere from a resting position by your sides to straight above your head. An extension is when you move your arms and stick them out behind you. The muscles involved in the flexion movement include the anterior deltoid, pectoralis major and coracobrachialis.
How many phases are there in Scapulohumeral rhythm?
By dividing the arc of motion into the four phases, the linearity of movement could be determined. The scapulohumeral rhythm is calculated as a ratio, essentially dividing the glenohumeral elevation or abduction angle by the scapulothoracic angle (amount of upward scapula rotation).
What muscles are involved in Scapulohumeral rhythm?
Latissimus Dorsi and m. Levator Scapulae, shortening of the posterior joint capsule and/or lack of coordination between essential muscles like the m. Serratus Anterior, m. Trapezius and Rotator cuff muscles.
What muscles elevate the scapula?
The elevation is accomplished by the trapezius, levator scapulae, and rhomboid muscles. Depression is accomplished through the force of gravity and the actions of the latissimus dorsi, serratus anterior, pectoralis major and minor, and the trapezius muscles.
Is Scapulohumeral rhythm a force couple?
Muscles that control the scapula and are involved in this rhythm are the following; trapezius, serratus anterior, rhomboids, levator scapulae and pectoralis minor. These muscles work in co-ordinated “force couples” to control movement of the scapula.
How do you perform flexion?
Lumbar flexion in a sitting position; Sit in a chair with your knees open and your feet on the floor. Lean forward, bending at your low back. Reach your hands down towards the floor between your knees, and hold this position for two to three seconds. Return to the starting position.
What is elbow extension and flexion?
When your forearm moves toward your body by bending at your elbow, it’s called elbow flexion. The opposite movement is called elbow extension. The three bones involved in elbow flexion are the: humerus, in your upper arm. ulna, on the little finger side of your forearm.
How do you train Scapulohumeral rhythm?
Hold a barbell with the hand placed as far away as comfortably possible. This will place the arm in some abduction and the scapula in upward rotation. Slowly elevate the scapula towards the ear. Perform three sets of 20 slow repetitions with a hold.
What muscles medially rotate the humerus?
The subscapularis, along with the teres major, another intrinsic muscle that is not part of the rotator cuff, and extrinsic muscles like the pectoralis major and latissimus dorsi, is responsible for medial, or internal, rotation of the arm.
What muscles medially rotate the shoulder?
The deeper subscapularis medially rotates the shoulder with help from the more superficial teres major, latissimus dorsi and anterior fibers of the deltoid. The supraspinatus originates in the supraspinous fossa, which means superior to the spine of the scapula.