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)
How do you elicit the bicipital myotactic reflex and what happens?
Place thumb over bicipital tendon and strike it with reflex hammer - forearm should flex slightly
What is the bicipital myotactic reflex testing?
Musculocutaneous nerve or C5/C6 anterior rami
What is biceps tendinitis?
Repetitive movement of the tendon of long head biceps brachii within the intertubercular groove can make it susceptible to inflammation or crepitus
What is crepitus
Crackling sound
What is a popeye deformity?
When the tendon of long head biceps brachii dislocates from the intertubercular groove or even separates completely from the supraglenoid tubercle;
causes the muscle to BALL UP in the middle of the arm!!
What are the posterior compartment muscles in the brachium?
Triceps brachii and anconeus
Origin, insertion, innervation and action of anconeus
O: Lateral humeral epicondyle
I: Lateral aspect of olecranon
IN: Radial nerve
Action: Extend forearm and stabilize elbow joint
What are the three heads of the triceps brachii?
Long head, lateral head, medial head
Origin of long head triceps brachii
Infraglenoid tubercle
Origin of lateral head triceps brachii
Posterior humerus superior to radial groove
Origin of medial head triceps brachii
Posterior humerus inferior to radial groove
Insertion, innervation, action of triceps brachii
I: Olecranon
IN: Radial nerve
Action: extend forearm (long head - resists shoulder dislocation)
What muscles resist shoulder dislocation in the brachial muscles?
Short head of biceps brachii and long head of triceps brachii
What muscles make up the triangular space?
Teres minor, teres major, long head triceps brachii
What is housed in the triangular space?
Circumflex scapular A. and V.
What muscles make up the quadrangular space?
Teres minor, teres major, long head and lateral head of triceps brachii
What is housed in the quadrangular space?
Posterior humeral circumflex A. and V. and axillary nerve
What muscles make up the triangular interval?
Teres major, long head and lateral head of triceps brachii
What is housed in the triangular interval?
Deep brachial A. and V. and radial nerve
