Week 4 - The Shoulder Muscles Flashcards
Which muscles belong to the intrinsic shoulder muscle group?
What is the alternative name for this group?
Deltoid, teres major, and 4 rotator cuff muscles
Also called scapulohumeral group
Which muscles belong to the extrinsic group of shoulder muscles?
Which are superficial, and which are deep?
Deep - levator scapulae and the rhomboids (major and minor)
Superficial - trapezius and latissimus dorsi
Give the innervation of the trapezius.
Accessory nerve
Proprioreceptor fibres from C3 and C4 spinal nerves
What are the actions of trapezius muscle?
Upper fibres - elevate scapula
Middle fibres - retract scapula
Lower fibres - depress scapula
What nerve innervates latissimus dorsi?
The thoracodorsal nerve
What are the actions of latissimus dorsi?
Medial rotation, adduction and extension of the humerus at the shoulder joint
What nerve innervates levator scapulae?
Dorsal scapular nerve
What is the action of levator scapulae?
Elevates the scapula
What nerve innervates the rhomboid muscles?
The dorsal scapular nerve
What is the action of the rhomboid muscles?
Retract and rotate the scapula
Think 2 muscles beginning with R do the 2 R movements
What nerve innervates the deltoid?
Axillary nerve (C5 + C6)
What are the actions of the deltoid?
Anterior part flexes the arm at the shoulder
Middle part abducts the arm past 15*
Posterior part extends the arm at the shoulder
What nerve innervates teres major?
Lower subscapular nerve
What are the actions of teres major?
Medial rotation of arm
Extension of arm
Adduction of arm
What 4 muscles make up the rotator cuff?
What is their collective action?
Supraspinatus Infraspinatus Teres minor Subscapularis Pull the head of the humerus into the glenoid fossa
