Posterior Shoulder & Rotator Cuff Muscles Flashcards
Which muscles are involved in movement at the shoulder joint?
Deltoid Trapezius Levator scapulae Rhomboids Rotator Cuff Muscles Teres major
Which muscles also attach to the pectoral girdle, but are not involved in shoulder movement?
Pectoralis major
Pectoralis minor
Serratus anterior
What are the roles of the three components of the Deltoid?
Posterior (Spinal) = Extension at shoulder
Middle (Acromial) = Abduction at shoulder
Anterior (Clavicular) = Flexion at shoulder
What are the roles of the components of the Trapezius?
Ascending = Scapular depression Middle = Retraction Descending = Elevation
Ascending and descending together = Superior rotation of glenoid fossa
What is the role of the Levator scapulae?
Elevation of scapula
Inferior rotation of glenoid fossa
What are the roles of the Rhomboids?
Rhomboid major and minor
Retraction of scapula
Inferior rotation of glenoid fossa
What are the Rotator Cuff Muscles and what are their roles?
Supraspinatus =
First 15 degrees of abduction at shoulder
Infraspinatus
Teres minor =
Stabilise head of humerus in glenoid
Lateral rotation at shoulder
Subscapularis =
Stabilise head of humerus in glenoid
Medial rotation at shoulder
What is the role of Teres major?
Adduction
Medial rotation at shoulder
Why is superior rotation of the glenoid required on abduction?
Prevents the greater tubercle of the humerus from impinging on the acromion of the scapula
What is the role of the tendinous “cuff” formed by the distal tendons of the rotator cuff muscles?
Blends with and reinforces the fibrous capsule of the shoulder joint
Stabilises the shallow ball and socket joint
What aerated distal insertions of the rotator cuff muscles?
Supraspinatus, infraspinatus and teres minor =
Greater tubercle of humerus
Subscapularis =
Lesser tubercle of humerus
Where does the nerve supply to the rotator cuff muscles originate?
Brachial plexus
