Muscle Actions, Synergists, and Antagonists

Vocabulary flashcards covering 42 muscles, detailing each muscle’s primary action along with its synergists and antagonists.

Masseter

Action: Elevates mandible. Synergist: Temporalis. Antagonist: Digastric.

Temporalis

Action: Elevates mandible. Synergist: Masseter. Antagonist: Digastric.

Digastric

Action: Depresses mandible. Synergist: None. Antagonists: Masseter, Temporalis.

Sternohyoid

Action: Depresses hyoid. Synergist: Thyrohyoid. Antagonist: None.

Sternothyroid

Action: Depresses thyroid cartilage (larynx). Synergist: None. Antagonist: None.

Thyrohyoid

Action: Depresses hyoid bone. Synergist: Sternohyoid. Antagonist: None.

Sternocleidomastoid

Action: Flexes and rotates head. Synergist: None. Antagonist: None.

Clavo-trapezius

Action: Flexes neck laterally or elevates clavicle. Synergist: None. Antagonist: None.

Acromio-trapezius

Action: Adducts scapula. Synergist: Rhomboideus. Antagonist: None.

Spino-trapezius

Action: Depresses scapula. Synergist: Pectoralis minor. Antagonist: Levator scapulae.

Latissimus dorsi

Action: Adducts humerus. Synergist: Pectoralis major. Antagonist: Clavo-deltoid.

Clavo-deltoid

Action: Flexes and adducts humerus. Synergist: pectoralis major Antagonist: latissimus dorsi

Acromio-deltoid

Action: Abducts humerus. Synergist: Supraspinatus. Antagonist: Latissimus dorsi.

Spino-deltoid

Action: Extends humerus. Synergist: Pectoralis major. Antagonist: None.

Levator scapulae

Action: Elevates scapula. Synergist: Rhomboideus. Antagonist: Pectoralis minor.

Rhomboideus

Action: Adducts and elevates scapula. Synergist: Spino-trapezius. Antagonist: Acromio-trapezius.

Subscapularis

Action: Medial rotation of humerus. Synergist: Teres major. Antagonist: Infraspinatus.

Supraspinatus

Action: Abducts humerus. Synergist: Clavo-deltoid. Antagonists: Pectoralis major, Latissimus dorsi.

Infraspinatus

Action: Lateral rotation of humerus. Synergist: None. Antagonists: Subscapularis, Teres major.

Teres major

Action: Medial rotation of humerus. Synergist: Subscapularis. Antagonist: Infraspinatus.

Serratus anterior

Action: Anterior rotation of scapula. Synergist: None. Antagonist: None.

Pectoralis major

Action: Flexes and adducts humerus. Synergist: Clavo-deltoid. Antagonist: Spino-deltoid.

Pectoralis minor

Action: Steadies and depresses scapula. Synergist: Spino-trapezius. Antagonist: Rhomboideus.

Triceps brachii (lateral head)

Action: Extends forearm. Synergist: Triceps brachii (medial head). Antagonist: Biceps brachii.

Triceps brachii (long head)

Action: Extends forearm. Synergist: Triceps brachii (medial head). Antagonist: Biceps brachii.

Triceps brachii (medial head)

Action: Extends forearm. Synergist: Triceps brachii (lateral head). Antagonist: Biceps brachii.

Biceps brachii

Action: Flexes forearm. Synergists: Brachialis, Brachioradialis. Antagonist: Triceps brachii (medial head).

Brachialis

Action: Flexes forearm. Synergists: Biceps brachii, Brachioradialis. Antagonist: Triceps brachii (medial head).

Brachioradialis

Action: Flexes forearm. Synergists: Biceps brachii, itself. Antagonist: Triceps brachii (medial head).

Extensor carpi radialis longus

Action: Extends wrist. Synergist: Extensor carpi radialis brevis. Antagonist: Flexor carpi radialis.

Extensor carpi radialis brevis

Action: Extends wrist. Synergist: Extensor carpi radialis longus. Antagonist: Palmaris longus.

Extensor digitorum

Action: Extends digits 2-5. Synergist: None. Antagonists: Flexor digitorum superficialis, Flexor digitorum profundus.

Extensor digiti minimi

Action: Extends digit 5. Synergist: None. Antagonist: None.

Extensor carpi ulnaris

Action: Extends wrist. Synergist: Extensor carpi radialis longus. Antagonist: Palmaris longus.

Flexor carpi ulnaris

Action: Flexes wrist. Synergist: Palmaris longus. Antagonist: Extensor carpi radialis longus.

Palmaris longus

Action: Flexes wrist. Synergist: Flexor carpi radialis. Antagonist: Extensor carpi ulnaris.

Flexor carpi radialis

Action: Flexes wrist. Synergist: Palmaris longus. Antagonist: Extensor carpi ulnaris.

Flexor digitorum profundus

Action: Flexes distal phalanges of digits 2-5. Synergist: Flexor digitorum superficialis. Antagonist: Extensor digitorum.

Pronator teres

Action: Pronation of forearm. Synergist: None. Antagonist: Supinator.

Supinator

Action: Supination of forearm. Synergist: None. Antagonist: Pronator teres.

Flexor digitorum superficialis

Action: Flexes middle phalanges of digits 2-5. Synergist: Flexor digitorum profundus. Antagonist: Extensor digitorum.

Abductor pollicis brevis

Action: Abducts thumb. Synergist: None. Antagonist: None.