MSK Session 3- Back And Shoulder Muscles, And The Shoulder Joint Flashcards
What are the three groups of extrinsic back muscles?
- superficial
- deep
- scapulo-humeral
What are intrinsic back muscles responsible for?
Posture
What are the two superficial back muscles?
Trapezius
Latissimus dorsi
What are the 2 deep back muscles?
Levator scapulae
Rhomboids
What are the 2 scapulo-humeral muscles?
Teres major
Deltoid
What is the action of each of the parts of the trapezius?
- descending/superior fibres- elevate and rotate the scapula
- middle fibres- retract the scapula
- ascending/inferior fibres- depress the scapula
- abduction past 90 degrees
What is the innervation of the trapezius muscle?
Spinal accessory nerve
What is the action of the latissimus dorsi?
Extension, adduction and medial rotation of the upper limb.
What is the innervation of the latissimus dorsi?
Thoracodosral nerve
What is the action of the Levator scapulae muscle?
Elevates the scapula
What is the innervation to the Levator scapulae?
Dorsal scapula nerve
What is the action of the rhomboids?
Retraction and rotation of the scapula.
What is the innervation to the rhomboids?
Dorsal scapula nerve
Which rhomboid is most superior?
Minor
What is the action of the the three deltoid segments?
- anterior/clavicular fibres- flexion of the arm
- middle/acromial fibres - abduction of the arm between 15 and 90 degrees.
- posterior/spinal fibres - extension of the arm