Intrinsic Muscles of the Thoracic Limb Flashcards
Deltoideus m.
Scapular part
Attachments:
(O) Spine of scapula and (I) deltoid tuberosity
Acromial part
Attachments:
(O) Acromion and (I) deltoid tuberosity
Action:
Flexion of the shoulder
Innervation:
Axillary n.
Blood Supply:
Caudal circumflex humeral a. and v.
Supraspinatus m.
Attachments:
(O) Supraspinous fossa & (I) greater tubercle of the humerus
Actions:
Stabilize & extend the shoulder
Advancement of the limb
Innervation:
Suprascapular n.
Blood Supply:
Suprascapular a. & v.
Infraspinatus m.
Attachments:
(O) Infraspinous fossa & (I) greater tubercle of the humerus (area of infraspinatus)
Actions:
Extend the shoulder joint
Stabilize the shoulder joint
Abduct the shoulder joint
Rotate the shoulder joint
Innervation:
Suprascapular n.
Blood Supply:
Caudal circumflex humeral a. and v.
Cranial circumflex humeral a. and v.
Abductor digiti I longus m.
(Carnivores only!)
Carnivores only!
Attachments:
(O) Craniolateral surface of the radius and ulna - interosseous ligament
(I) proximal MC I (medial)
Actions:
Abduct digit I
Extend the carpal joint
Innervation:
Radial n.
Deltoideus m.
(Horses & Pigs)
No acromial part of the muscle
Teres minor m.
Attachments:
(O) Distal caudal border of the scapula and infraglenoid tubercle of the scapula
(I) the teres minor tuberosity of the humerus
Actions:
Flex the shoulder joint,
Rotate the shoulder joint
Innervation:
Axillary n.
Blood Supply:
Primary–> Cranial circumflex humeral a. & v.
Caudal circumflex humeral a. and v.
Subscapularis m.
Attachments:
(O) Subscapular fossa & (I) the lesser tubercle of the humerus
Actions:
Extend the shoulder joint,
Stabilize the shoulder joint,
Adduct the shoulder joint,
Rotate the shoulder joint
Innervation:
Subscapular n.
Axillary n.
Blood Supply:
Subscapular a. & v.
Teres major m.
Attachments:
(O) Caudal angle and border of the scapula and (I) the teres major tuberosity
Actions:
Flex the shoulder joint,
Stabilize the shoulder joint,
Medially rotate the shoulder joint
Innervation:
Axillary n.
Blood Supply:
Thoracodorsal a. and v.
Caudal circumflex humeral a. & v.
Coracobrachialis m.
Attachments:
(O) Coracoid process of the scapula and (I) proximal medial surface of the humerus
Actions:
Extend the shoulder joint,
Adduct the shoulder joint
Innervation:
Musculocutaneous n.
Blood Supply:
Caudal circumflex humeral a. and v.
Cranial circumflex humeral a. and v.
Tensor fasciae antebrachii m.
Attachments:
(O) Fascia of latissimus dorsi and (I) the olecranon
Actions:
Extend the elbow joint
Innervation:
Radial n.
Blood Supply:
Collateral ulnar a. and v.
Triceps brachii m.
Attachments:
Medial, lateral, long, and accessory (only dogs) heads-
(O) caudal border of scapula (long head)
(O) proximal medial and lateral surface of the humerus
(I) the olecranon
Actions:
Extend the elbow joint,
Flex the shoulder (long head)
Innervation:
Radial n.
Blood Supply:
Deep brachial a. and v. (middle of triceps brachii m.)
Caudal circumflex humeral a. and v. (proximal )
Collateral ulnar a. and v. (distal)
Anconeus m.
Attachments:
(O) Lateral supracondylar crest of the humerus & (I) the olecranon
Actions:
Extend the elbow joint
Innervation:
Radial n.
*Partially hidden under the distal portion of the lateral head of the triceps brachii m.
Biceps brachii m.
Attachments:
(O) Supraglenoid tuberosity, radial and ulnar tuberosity, & tendon of the extensor carpi radialis m. (lacertus fibrosus in equine)
*Transverse humeral retinaculum holds bicipital tendon in place in bicipital groove*
Actions:
Flex the elbow joint,
Extend the shoulder joint
Stabilization of the shoulder joint during standing
Innervation:
Musculocutaneous n.
Blood Supply:
Bicipital a. and v. (distal portion)
Cranial circumflexhumeral a. & v. (proximal part)
Brachialis m.
Attachments:
(O) Caudal surface of proximal humerus & (I) radial and ulnar tuberosity
Actions:
Flex the elbow joint
Innervation:
Musculocutaneous n.
Extensor carpi radialis m.
Attachments:
(O) Lateral supracondylar crest & dorsal tuberosities
(I) base of metacarpals dorsal aspect
(dogs- II and III)
(horse- III)
(ruminants- III and IV)
Actions:
Extend the carpal joint
Innervation:
Radial n.
Blood Supply:
Cranial interosseous a. & v.
Transverse cubital a. & v.
First extensor cranial view
Common digital extensor m.
Attachments:
(O) Lateral supracondylar crest of the humerus & (I) the extensor process of distal phalanx or phalanges (Carnivores- digits II-V)
(Horse- digit III)
(Ruminants- medial head (medial digital extensor or proper extensor of digit III) digit III, lateral head (middle digital extensor or common extensor of digit III and IV) digits III and IV)
Actions:
Extend the carpal joint
Extend the digits
Innervation:
Radial n.
Blood Supply:
Common interosseous a. & v. (cranial & caudal)
Transverse cubital a. and v.
Deep antebrachial a. & v.
Lateral digital extensor m.
Attachments:
(O) Lateral supracondylar crest of the humerus & (I) the extensor process of distal phalanx or phalanges
(Carnivores- digits III-V, joins the common digital extensor tendon)
(Horse- digit III, joins the common digital extensor tendon)
(Ruminant- digit IV, joins lateral head of common digital extensor tendon)
Actions:
Extend the carpal joint,
Extend the digital joints
Innervation:
Radial n.
Blood Supply:
Cranial interosseous a. & v.
Deep antebrachial a. & v.
Deep digital flexor m.
(3 heads)
Attachments:
Humeral head- (O) medial humeral epicondyle and (I) the flexor surface of phalanx or phalanges
Radial head- (O) caudal surface of proximal radius and (I) the flexor surface of phalanx or phalanges
Ulnar head- (O) caudal surface of proximal ulna and (I) the flexor surface of phalanx or phalanges
Actions:
Flex the carpal joint
Flex the digital joint
Innervation:
Median n. (radial head)
Ulnar n. (humeral & ulnar head)
Blood Supply:
Humeral Head:
- Deep antebrachial a. & v.
- Ulnar a. & v.
- Cauldal interosseous a. and v.
Ulnar Head:
- Deep antebrachial a. & v.
- Ulnar a. & v.
- Cauldal interosseous a. and v.
Radial Head:
- Cauldal interosseous a. and v.
- Deep antebrachial a. & v.
Supinator m.
(Only in carnivores and pigs)
Attachments:
(O) Lateral humeral epicondyle and (I) the cranial surface of the radius
Actions:
Lateral rotation of the forearm (supination of the forepaw)
Flex the elbow joint
Innervation:
Radial n.
Blood Supply:
Transverse cubital a. and v.
Pronator teres m.
Attachments:
*Mostly in carnivores, inconsistently present in others*
(O) Medial humeral epicondyle and (I) the cranial surface of the radius
Actions:
Medial rotation of the forearm (pronation of the forepaw)
Flex the elbow joint
Innervation:
Median n.
