Unit 2 - Chest + Upper Arm Flashcards
- Actions - Innervations - Proximal Attachment - Distal Attachment
Origin (prox. attachment) – surpaspinatus m.
supraspinous fossa of scapula
Insertion (dist. attachment) – supraspinatus m.
superior facet of greater tubercle of humerus
Innervation – supraspinatus m.
suprascapular n. (C4, C5, C6)
Action – supraspinatus m.
- initiates & helps deltoid abduct shoulder joint
- acts w/ other rotator cuff muscles
Origin (prox. attachment) – infraspinatus m.
infraspinous fossa of scapula
Insertion (dist. attachment) – infraspinatus m.
middle facet of greater tubercle of humerus
Innervation – infraspinatus m.
suprascapular nerve (C5, C6)
Action – infraspinatus m.
- laterally rotates arm
- acts w/ other rotator cuff muscles
Origin (prox. attachment) – teres major m.
posterior surface of inferior angle of scapula
Insertion (dist. attachment) – teres major m.
medial lip of intertubercular sulcus of humerus
Innervation – teres major m.
lower subscapular n. (C5, C6)
Action – teres major m.
adducts & medially rotates arm
Origin (prox. attachment) – teres minor m.
middle part of lateral border of scapula
Insertion (dist. attachment) – teres minor m.
inferior facet of greater tubercle of humerus
Innervation – teres minor m.
axillary n. (C5, C6)
Action – teres minor m.
laterally rotates arm
- rotator cuff muscle
Origin (prox. attachment) – pectoralis major m.
- clavicular head = anterior surface, medial half of clavicle
- sternocostal head =
- anterior surface of sternum
- superior 6 costal cartilage
- aponeurosis of external oblique
Insertion (dist. attachment) – pectoralis major m.
lateral lip of intertubercular sulcus of humerus
Innervation – pectoralis major m.
lateral & medial pectoral nerves
clavicular head = C5 and C6
sternocostal head = C7, C8, T1
Action – pectoralis major m.
- adducts & medially rotates humerus
- draws scapula anteriorly and inferiorly
- Alone = [clavicular] flexes humerus; [sternocostal] extends humerus
Origin (prox. attachment) – pectoralis minor m.
3rd - 5th ribs near costal cartilages
Insertion (dist. attachment) – pectoralis minor m.
medial border & superior surface of coracoid process of scapula
Innervation – pectoralis minor m.
medial pectoral n. (C8, T1)
Action – pectoralis minor m.
- draws scapula inferiorly and anteriorly against thoracic wall = stabilizes scapula
Origin (prox. attachment) – serratus anterior m.
lateral external surfaces of 1st - 8th ribs
Insertion (dist. attachment) – serratus anterior m.
anterior surface medial border of scapular
Innervation – serratus anterior m.
long thoracic n. (C5, C6, C7)
Action – serratus anterior m.
- protracts scapula
- holds it against thoracic wall
- rotates scapula
Origin (prox. attachment) – deltoid m.
lateral third of clavicle; acromion and spine of scapula
Insertion (dist. attachment) – deltoid m.
deltoid tuberosity of humerus
Innervation – deltoid m.
axillary n. (C5, C6)
Action – deltoid m.
- clavicular = flexes & medially rotates arm
- acromial = abducts arm
- spinal = extends and laterally rotates arm
Origin (prox. attachment) – subscapularis m.
subscapular fossa
Insertion (dist. attachment) – subscapularis m.
lesser tubercle of humerus
Innervation – subscapularis m.
upper and lower subscapular n. (C5, C6, C7)
Action – subscapularis m.
- medially rotates arm
- rotator cuff muscle
- helps hold head of humerus in glenoid cavity
Innervation – coracobrachialis m.
musculocutaneous n. (C5, C6, C7)
Action – coracobrachialis m.
helps flex & adduct arm
* resists shoulder dislocation
Origin (prox. attachment) – biceps brachii m.
- short head = tip of coracoid process of scapula
- long head = supraglenoid tubercle of scapula
Insertion (dist. attachment) – biceps brachii m.
radial tuberosity and fascia of forearm via bicipital aponeurosis
Innervation – biceps brachii m.
musculocutaneous n. (C5, C6, C7)
Action – biceps brachii m.
- supinates forearm
- flexes forearm in supine
- short head = resists shoulder dislocation
Origin (prox. attachments) – brachialis m.
distal 1/2 of anterior surface of humerus
Insertion (dist. attachment) – brachialis m.
coronoid process & tuberosity of ulna
Innervation – brachialis m.
musculocutaneous n. ; radial n.
(C5 and C7)
Action – brachialis m.
flexes forearm in all positions
Origin (prox. attachment) – brachioradialis m.
proximal 2/3 of lateral supracondylar ridge of humerus
Insertion (dist. attachment) – brachioradialis m.
lateral surface of distal end of radius; proximal to styloid process
Innervation – brachioradialis m.
radial n. (C5, C6, C7)
Action – brachioradialis m.
- relatively weak elbow joint flexion
- maximal when forearm is midpronated position
Origin (prox. attachment) – triceps brachii m.
Long head = infraglenoid tubercle of scapula
Lateral head = posterior surface of humerus, superior to radial groove
Insertion (dist. attachment) – triceps brachii m.
- Proximal end of olecranon of ulna
- forearm fascia
Innervation – triceps brachii m.
radial n. (C6, C7, C8)
Action – triceps brachii m.
- chief extensor of elbow joint
- long head = extends shoulder joint, resists humerus dislocation
Innervation – anconeus m.
Radial n. (C7, C8, T1)
Action – anconeus m.
- helps triceps in extending elbow joint
- stabilizes elbow joint
- abduct ulna during pronation