‘Delts’ are teardrop shaped and have three parts, anterior, medial and posterior. They control the flexion, abduction and extension of the humerus.
Made up of four muscles (see below) – the supraspinatus, infraspinatus, teres minor and subscapularis. These help to stabilise the shoulder joint and assist with the abduction, adduction and rotation of the humerus. Due to their location, they are prone to small tears and impingements.
Supraspinatus – This helps to hold the humerus in place and to lift the arm.
Infraspinatus – This is the main muscle for rotation and extension of the shoulder.
Teres minor – This is the smallest of the rotator cuff muscles and its main role is to help with the rotation of the arm away from the body.
Subscapularis – This is what holds the humerus to the shoulder blade and aids the rotation of the arm and allows you to hold your arm straight out and to lower it.
This helps with the elevation of the shoulder blade.
These allow your scapula to elevate, retract and depress.
These can be found under your trapezium and help with the elevation and retraction of the scapula.