Muscles of the back Flashcards
How are the posterio-axioappendicular muscles divided into groups?
- Superficial -> Trapezius and Latissimus Dorsi
- Deep -> Levator Scapulae and Rhomboids major and minor
- Scapulo-humeral -> Deltios, teres major and rotator cuff
What are the three parts of trapezius, and what do each of them do?
- Superior -> Elevates scapula (shrugging)
- Middle -> retracts scapula (squaring)
- Inferior-> depresses shoulder
What part does the trapezius play in scapular rotation?
-Superior and inferior parts work together to rotate scapula upwards and outwards (elevates glenoid cavity) with aid by serratus anterior
What movement does rotation of the scapula allow?
-Abduction of the arm above 90 degrees
What muscle is responsible for abduction of the arm above 90 degrees?
-Trapezius
What is trapezius innervated by?
-Thoracic segment of accessory nerve
What are the functions of Latissimus Dorsi?
- Extension of the arm
- ADduction of the arm
- Medial rotation
What innervates latissimus dorsi? What is the blood supply to latissimus dorsi?
- Thoracodorsal nerve
- Thoracodorsal artery
What cord does the thoraco-dorsal nerve arise from on the brachial plexus?
-Posterior cord
What are the functions of levator scapulae?
- Elevate the scapula
- Rotate the scapula to depress glenoid cavity
What nerve innervates levator scapulae?
-Dosrsal scapular nerve
What nerve root contributes to dorsal scapula nerve?
-C5
What are the functions of the rhomboids?
- Retract the scapula
- Rotate the scapula to depress glenoid cavity
What innervates the rhomboids? What is their blood supply?
- Dorsal scapular nerve
- Dorsal scapular artery
What are the three parts of the deltoid and their respective functions?
- Anterior fibres -> flex the arm
- Middle fibres -> aBduct the arm from 15-90 degrees
- Posterior fibres -> extend the arm
