UE Myology - Shoulder to Brachium Flashcards
What are the muscles in the thoracoappendicular group?
Pectoralis major, pectoralis minor, subclavius and serratus anterior
Origin, insertion and innervation of pectoralis major
O: Anterior clavicle, sternum, costal cartilages, aponeuroses external abdominal oblique
I: Lateral edge of intertubercular groove of humerus
IN: Medial AND Lateral pectoral nerves
What are the actions of the pectoralis major
ADduct and medially rotate humerus
Protract and depress scapula
Flex humerus and extend flexed humerus
Origin, insertion, innervation and action of pectoralis minor
O: Ribs 3-5
I: Coracoid process
IN: Medial pectoral Nerve
Action: Stabilize scapula - protract and depress
Origin, insertion, innervation and action of subclavius
O: 1st rib (costochondral joint)
I: Subclavian groove of inferior clavicle
IN: Nerve to subclavius
Action: Stabilize and depress clavicle
Origin, insertion, innervation and action of serratus anterior
O: Lateral surface of ribs 1-8
I: Anterior surface medial border of scapula
IN: Long thoracic nerve
Action: Protract and stabilize scapula against thoracic wall, rotate glenoid cavity superiorly
Winging of scapula
Paralysis of serratus anterior or injury to long thoracic nerve causes scapula to wing away from thoracic wall
Makes ABducting upper limb difficult
What muscles from the back act on the scapula or humerus?
Layer 1 - Trapezius and latissimus dorsi
Layer 2 - Levator scapulae, rhomboid minor, rhomboid major
What are the scapulohumeral muscles?
Deltoid, subscapularis, supraspinatus, infraspinatus, teres minor, teres major
Origin, insertion, innervation of deltoid
O: Lateral clavicle, acromion, scapular spine
I: Deltoid tuberosity of humerus
IN: Axillary nerve
What are the actions of the deltoid?
Anterior: Flex and medially rotate humerus
Medial: ABduct humerus
Posterior: Extend and laterally rotate humerus
Origin, insertion, innervation, and action of subscapularis
O: Subscapular fossa
I: Lesser tubercle of humerus
IN: Superior and inferior subscapular nerves
Action: ADduct and medially rotate humerus, hold humeral head in the glenoid cavity
Origin, insertion, innervation and action of supraspinatus
O: Supraspinous fossa
I: Greater tubercle
IN: Suprascapular Nerve
Action: ABduct humerus
Origin, insertion, innervation and action of infraspinatus
O: Infraspinous fossa
I: Greater tubercle
IN: Suprascapular nerve
Action: Laterally rotate humerus
Origin, insertion, innervation and action of teres minor
O: Lateral border scapula
I: Greater tubercle
IN: Axillary nerve
Action: Laterally rotate humerus
Origin, insertion, innervation and action of teres major
O: Inferior angle scapula
I: Medial edge of intertubercular groove of humerus
IN: Inferior subscapular nerve
Action: Medially rotate and ADduct humerus
What muscles make up the rotator cuff?
Supraspinatus, infraspinatus, subscapularis, teres minor
Which muscle in the rotator cuff is most commonly injured?
Supraspinatus
What is the purpose of the rotator cuff?
Stabilize glenohumeral joint! Keep humeral head in the glenoid cavity
What are the muscles in the anterior compartment of the brachium?
Coracobrachialis, brachialis, biceps brachii (long and short head)
Origin, insertion, innervation and action of coracobrachialis
O: coracoid process
I: Medial aspect in the middle of the humerus
IN: Musculocutaneous nerve
Action: Flex humerus (arm) and ADduct
Origin, insertion, innervation and action of brachialis
O: Distal humeral body
I: Coronoid process of ulna and ulnar tuberosity
IN: Musculocutaneous nerve
Action: Flex forearm
What are the heads of the biceps brachii and what are their origins?
Long head - O = Supraglenoid tubercle
Short head - O = Coracoid process
Insertion, innervation and action of biceps brachii
I: Radial tuberosity and antebrachial fasica via bicipital aponeurosis
IN: Musculocutaneous nerve
Action: Flex humerus, flex supine forearm, supinate forearm
(short head can resist shoulder dislocation)
