11.2 Musculature and Movements of the Pectoral Girdle and Shoulder Flashcards
What are the three parts of the deltoid?
- Clavicular part (attaches to clavicle)
- Middle part
- Spinal part (scapular spine)
Origin and insertion of latissimus dorsi
Origin: T7-T12 (5 = big, like sciatic nerve), thoracolumbar fascia, iliac crest
Insertion: Medial floor of intertubercular groove of humerus
Origin and insertion of trapezius
Origin: Base of skull, nucchal ligament, and C7-T12 spinous processes
Insertion: Spine of scapula, lateral third of clavicle
Origin and insertion of the rhomboids
Minor origin: Nucchal ligament, C7-T1 spinous processes
Major origin: T2-T5 spinous processes
Insertion (both): medial border of scapula
Origin and insertion of levator scapulae
Origin: C1-C4
Insertion: superior angle of scapulae
Which nerve innervates levator scap and the rhomboids?
The dorsal scapular nerve
Which nerve innervates the latissimus dorsi?
Thoracodorsal nerve
Origin and insertion of teres major
Origin: inferior angle of the scapula
Insertion: Medial lip of intertubercular groove of the humerus (posterior to lat)
Action: Medially rotates and extends shoulder joint
Origin, insertion, and action of deltoid
Origin: clavicle, acromion, and spine of scapula (three parts)
Insertion: deltoid tuberosity of lateral humerus
Action: shoulder abduction/flexion/extension (depending on which fibres contract; much like glute medius)
List the four muscles of the rotator cuff and their story cues
- Supraspinatis (the rich kid)
- Infraspinatus (friends with teres minor)
- Teres minor (friends with infraspinatus)
- Subscapularis (the loner)
List the action of each of the rotator cuff muscles
- Subscapularis: protraction
- Supraspinatus: initiates abduction (then deltoid rocks up and does all the hard work)
- Infraspinatus and teres minor: retraction of scapula
What nerves innervate the rotator cuff muscles? List the common root of all of them.
- Infra/supraspinatus muscle: suprascapular nerve
- Teres minor (axillary)
- Subscapularis (subscapular nerve)
Common root: C5-C6
Origin, insertion, and action of serratus anterior.
Origin: lateral surface of ribs 1-9
Insertion: medial border of scapula
Action: protraction, depression, and elevation of the scapula (much like glute medius and deltoid; depends on which fibres contract)
Which nerve innervates serratus anterior?
Long thoracic nerve
Origin, insertion, and action of pectoralis major
Origin: sternocostal head and clavicular head
Insertion: Lateral lip of intertubercular groove of humerus
Which nerve(s) innervate pec major and pec minor?
Lateral and medial pectoral nerve
Origin, insertion, innervation, and action of coracobrachialis
Origin: Coracoid process
Insertion: humeral shaft
Innervation: musculocutaneous nerve
Action: flexion and adduction
Origin, insertion, and action of pec minor
Origin: Ribs 2-5
Insertion: Coracoid process
Action: scapula protraction
What is the course & action of subclavius? Why is its innervation “fancy”?
- Runs under clavicle, pulls it down into sternoclavicular joint
- Fancy because it has its won subclaviun nerve from brachial plexus
Where does the long/short head of the biceps brachii originate? Where does it insert? What are the actions of the muscle? How is it innervated?
Long: supraglenoid tubercle
Short: coracoid process
Insertion: radial tuberosity and biccipital aponeurosis
Actions: flexion and supination
Innervation: musculocutaneous nerve
Origin, insertion, innervation, and action of brachialis
Origin: anterior humerus
Insertion: Ulnar tuberosity
Action: elbow flexion
Innervation: musculocutaneous nerve
Origin, insertion, action, and innervation of triceps
Origins: infraglenoid tubercle (long head), posterior humerus (medial and lateral heads)
Insertion: Distal olecranon
Action: elbow extension
Innervation: radial nerve
