Thoracic Muscles OIA

Deltoideus m. (scapular part): Origin

spine of the scapula

Deltoideus m. (acromial part): Origin

acromion

Deltoideus m.: Insertion

deltoid tuberosity of the humerus

Deltoideus m.: Action

flex the humeral joint (and abduction of leg)

Supraspinatus m.: Origin

supraspinous fossa of the scapula 

Supraspinatus m.: Insertion

greater tubercle of the humerus 

Supraspinatus m.: Action

laterally stabilize the humeral joint; extend the humeral joint

Infraspinatus m.: Origin

infraspinous fossa of the scapula 

Infraspinatus m.: Insertion

greater tubercle of the humerus 

Infraspinatus m.: Action

laterally stabilize the humeral joint. 

Subscapularis m.: Origin

subscapular fossa of scapula 

Subscapularis m.: Insertion

lesser tubercle of humerus 

Subscapularis m.: Action

medially stabilize the humeral joint 

Teres major m.: Origin

caudal border of scapula 

Teres major m.: Insertion

teres major tuberosity of humerus 

Teres major m.: Action

flex the humeral joint

Coracobrachialis m.: Origin

coracoid process of scapula 

Coracobrachialis m.: Insertion

crest of the lesser tubercle of humerus

Coracobrachialis m.: Action

medially stabilize the humeral joint 

Biceps brachii m.: Origin

supraglenoid tubercle 

Biceps brachii m.: Insertion

radial and ulnar tuberosities 

Biceps brachii m.: Action

flex the cubital joint; extend the humeral joint 

Brachialis m.: Origin

brachial groove of humerus 

Brachialis m.: Insertion

proximal radius and/or ulna 

Brachialis m.: Action

flex the cubital joint 

Triceps brachii m. (long head): Origin

caudal border of scapula 

Triceps brachii m. (medial, lateral and accessory heads): Origin

proximal humerus

Triceps brachii m. (all heads): Insertion

tuber olecrani

Triceps brachii m. (long head): Action

extend the cubital joint; flex the humeral joint

Triceps brachii m. (medial, lateral and accessory heads): Action

extend the cubital joint

Tensor fasciae antebrachii m.: Origin

latissimus dorsi and associated fascia 

Tensor fasciae antebrachii m.: Insertion

tuber olecrani 

Tensor fasciae antebrachii m.: Action

extend the cubital joint (and tense the deep antebrachial fascia) 

Anconeus m.: Origin

caudal aspect of distal humerus 

Anconeus m.: Insertion

tuber olecrani 

Anconeus m.: Action

extend the cubital joint and tense the joint capsule 

Extensor carpi radialis m.: Origin

lateral epicondyle of the humerus (and its crest) 

Extensor carpi radialis m.: Insertion

dorsal base of 2nd and 3rd metacarpal bones 

Extensor carpi radialis m.: Action

extend the carpal joints (and flex cubital joint)

Common digital extensor m.: Origin

lateral epicondyle of the humerus 

Common digital extensor m.: Insertion

extensor processes of distal phalanges 

Common digital extensor m.: Action

extend the carpal joints; extend the digital joints 

Lateral digital extensor m.: Origin

lateral epicondyle of the humerus 

Lateral digital extensor m.: Insertion

phalanges of the lateral-most digits 

Lateral digital extensor m.: Action

extend the carpal joints; extend the digital joints of the lateral-most digits 

Ulnaris lateralis m.: Origin

lateral epicondyle of the humerus 

Ulnaris lateralis m.: Insertion

accessory carpal bone; lateral base of 5th metacarpal bone 

Ulnaris lateralis m.: Action

awkwardly flex the antebrachiocarpal joint; abduct the manus 

Supinator m.: Origin

lateral epicondyle of the humerus 

Supinator m.: Insertion

body of radius 

Supinator m.: Action

supination of the manus 

Abductor digiti I longus m.: Origin

body of the ulna (in the carnivore) 

Abductor digiti I longus m.: Insertion

base of 1st metacarpal bone 

Abductor digiti I longus m.: Action

abduct the 1st digit 

Brachioradialis m. (better developed in cat): Origin

lateral epicondyle of the humerus 

Brachioradialis m. (better developed in cat): Insertion

fascia near the carpus 

Brachioradialis m. (better developed in cat): Action

supination of the manus 

Flexor carpi radialis m.: Origin

medial epicondyle of the humerus 

Flexor carpi radialis m.: Insertion

palmar base of 2nd and 3rd metacarpal bones 

Flexor carpi radialis m.: Action

flex the carpal joints

Flexor carpi ulnaris m. (humeral head): Origin

medial epicondyle of the humerus

Flexor carpi ulnaris m. (ulnar head): Origin

olecranon of the ulna 

Flexor carpi ulnaris m. (2 heads: humeral and ulnar): Insertion

accessory carpal bone 

Flexor carpi ulnaris m. (2 heads: humeral and ulnar): Action

flex the antebrachiocarpal joint 

Superficial digital flexor m.: Origin

medial epicondyle of the humerus

Superficial digital flexor m.: Insertion

palmar bases of the middle phalanges 

Superficial digital flexor m.: Action

flex the carpal joints; flex the metacarpophalangeal joints; flex the proximal interphalangeal joints 

Deep digital flexor m. (humeral head): Origin

medial epicondyle of the humerus 

Deep digital flexor m. (radial head): Origin

body of the radius 

Deep digital flexor m. (ulnar head): Origin

body of the ulna

Deep digital flexor m. (3 heads: humeral, radial, ulnar): Insertion

flexor tubercles of the distal phalanges

Deep digital flexor m. (3 heads: humeral, radial, ulnar): Action

flex the carpal joints; flex the digital joints 

Pronator teres m.: Origin

medial epicondyle of the humerus 

Pronator teres m.: Insertion

body of radius

Pronator teres m.: Action

pronation of the manus 

Pronator quadratus m.: Attachments

apposed surfaces of the radius and the ulna 

Pronator quadratus m.: Action

pronation of the manus

Interossei mm. (4 total): Origin

palmar base of respective metacarpal bone 

Interossei mm. (4 total): Insertion

proximal sesamoid bones & palmar base of respective proximal phalanx (tendon of common digital extensor dorsally via extensor branch)

Interossei mm. (4 total): Action

Supports and flex metacarpophalangeal joint 

Superficial pectoral m. (descending and transverse pectoral muscles): Origin

cranial part of sternum 

Superficial pectoral m. (descending and transverse pectoral muscles): Insertion

crest of greater tubercle & cranial humeral border (ulna in cat) 

Superficial pectoral m. (descending and transverse pectoral muscles): Action

adduct thoracic limb

Deep (ascending) pectoral m.: Origin

sternum and costal cartilages 

Deep (ascending) pectoral m.: Insertion

greater and lesser tubercles of humerus 

Deep (ascending) pectoral m.: Action

adduct thoracic limb and pull it caudally 

Brachiocephalicus m.: Origin

clavicular intersection / clavicle 

Brachiocephalicus m. (cleidobrachialis): Insertion

distal in body of humerus (ulna in cat) 

Brachiocephalicus m. (cleidomastoideus): Insertion

mastoid process of temporal bone 

Brachiocephalicus m. (cleidocervicalis): Insertion

dorsal midline of neck 

Brachiocephalicus m.: Action

pull thoracic limb cranially; depress and pull head and neck laterally 

Omotransversarius m.: Cranial-most attachment

wing of the atlas

Omotransversarius m.: Caudal-most attachment

distal spine of the scapula 

Omotransversarius m.: Action

pull thoracic limb cranially; depress and pull head and neck laterally 

Trapezius m. (cervical part): Origin

dorsal midline of neck 

Trapezius m. (thoracic part): Origin

dorsal midline of thorax 

Trapezius m.: Insertion

spine of the scapula 

Trapezius m.: Action

elevate the thoracic limb, adduct the dorsal border of the scapula, abduct the limb

Rhomboideus capitis m.: Origin

nuchal crest of occipital bone 

Rhomboideus thoracis m.: Origin

dorsal thorax