Muscles of the thoracic limb (Intrinsic muscles) Flashcards
What are intrinsic muscles? (2)
- attachments entirely on the limb
- related to the movement across the limb/joints
Muscle acting on the entire limb (4 category, 2 muscles each)
all extrinsic muscles except serratus ventralis & rhoimboideus)
Abductors
* Trapezius m.
* Deltoideus m.
Adductors
* Superficial pectoralis m.
* Subscapularis m.
Protractors
* Brachiocephalicus m.
* Omotransversarius m.
Retractors
* Latissimus dorsi m.
* Deep pectoral m.
Flexor muscles acting on shoulder joint are (6)
- Latissimus dorsi (extrinsic)
- Deltoideus
- Infraspinatus
- Teres major
- Teres minor
- Long head of triceps brachii
Extensor muscles acting on the shoulder joint are (4)
- Brachiocephalicus (extrinsic)
- Supraspinatus
- Subscapularis
- Bicep brachii
Deltoideus is divided into 2 parts which are
- Scapular part
- Acromion part
Origin & insertion of deltoideus
- OR – Spine of scapular, and acromion
- IN – both has insertion at the deltoid tuberosity
#shoulder flexor & limb abductor
location & function of infraspinatus muscle (3)
- occupy infraspinous fossa
- lateral collateral ligament of the shoulder joint
- abductor of humerus
Origin & insertion of infraspinatus
- OR – Infraspinous fossa, spine of scapula
and caudal border of scapula - IN – distal to great tubercle of humerus
#shoulder flexor
Origin & insertion of teres major (long, flat muscle)
*OR - caudal angle/scapula
*IN - teres major tuberosity
#shoulder flexor
Origin and insertion of teres minor (round, triangular shape)
*OR - caudolateral angle of scapula
*IN - near greater tubercle & deltoid tuberosity
#shoulder flexor
Long head of tripes is divided into 4 heads in dogs & 3 heads in ruminants & horses
- Long
- Lateral
- Medial
- Accessory
Origin & insertion of long head of triceps
- OR – 2/3 caudal edge of the scapula, infraglenoid
tubercle - IN – olecranon of ulna
#shoulder flexor
Origin & insertion of supraspinatus (occupy supraspinous fossa)
*OR - supraspinous fossa, including spine of scapula
*IN - greater tubercle of humerus
#shoulder extensor
Origin & insertion of subscapularis (occupy subscapularis fossa, medial collateral ligament, adductor)
*OR - subscapularis fossa
*IN - lesser tubercle of humerus
#shoulder extensor
Origin & insertion of bicep brachii (proximal par of arm, cross shoulder & elbow joint) (single head in dogs)
*OR - supraglenoid tubercle
*IN - medial surface of olecranon of ulna
#shoulder extensor
#elbow flexor
Flexor muscles acting on the elbow joint (2)
- Biceps brachii
- Brachialis
Extensor muscles acting on elbow joint (2)
- triceps brachii
- anconeus
Origin & insertion of brachialis (proximal part of arm) ( 2 insertion tendons in dogs, 1 in horse @ radius)
*OR - caudal surface of proximal humerus
*IN - medial side, radius & ulna tuberosity
#elbow flexor
Origin (for all heads) & insertion of triceps brachii (all 4 heads involved in extension of elbow) (dissect deltoideus & lateral head to see long & accessory head)
*OR
LaH: lateral of humerus, deltoid tuberosity
LoH; edge of caudal 2/3 o scapula
AH: proximal caudal part of the humerus neck
MH: medial of humerus; teres
major tuberosity
*IN - all heads inserted @ olecranon of ulna
#elbow extensor
Origin & insertion of anconeus (tenses antebrachial fascia)
- OR – lateral epicondyle & olecranon fossa of humerus
- IN – lateral surface, proximal part of ulna
#elbow extensor
Flexor muscles acting on carpus (2)
*flexor carpi radialis
*flexor carpi ulnaris
Extensor muscles acting on carpus (2)
*Extensor carpi radialis
*ulnaris lateralis
Origin & insertion of flexor carpi ulnaris (2 bellies)
OR – medially, proximal end of ulnar and humerus
IN – accessory carpal bone (2 tendons)
#carpus flexor
#forepaw abductor
Origin & insertion of flexor carpi radialis
OR – medial epicondyle
IN – palmar side, metacarpal II and III
#carpus flexor
Origin & insertion of extensor carpi radialis (also flex elbow joint)
OR – lateral epicondyle of humerus
IN – metacarpal II & III
#carpus flexor
Origin & insertion ulnaris lateralis
OR – lateral epicondyle of humerus
IN – proximal end of fifth metacarpal
Flexor muscles acting on digit (2)
- Superficial digital flexor m.
- Deep digital flexor m.
Extensor muscles acting on digits (2)
- Common digital extensor m.
- Lateral digital extensor m.
Origin & insertion & action of superficial digital flexor
OR – medial epicondyle of humerus
IN – metacarpophalangeal joint
Action – flex proximal and middle digital joints
(four principal digits)
#digit flexor
Origin & insertion of deep digital flexor
OR – medial epicondyle of humerus
IN – distal phalanx
#digit flexor
Origin & insertion & action of common digital extensor
OR – lateral epicondyle of humerus
IN – distal phalanges of digits II-IV
Action – also extend carpal/elbow
#digit extensor
Origin & insertion & action of lateral digital extensor
OR – lateral epicondyle of humerus
IN – Proximal phalanges of digits III-IV
Action – also extend carpal/elbow
#digit extensor
Muscles involved in the rotation of arm (3)
- Pronator quadratus m.
- Supinator m.
- Pronator teres m.
Origin, insertion & action of pronator teres
OR – medial epicondyle of humerus
IN – radial tuberosity
Action - Outward rotation of forepaw
#arm rotation
Origin, insertion & action of pronator quadratus
OR – interosseous space radius and ulna
IN – radius
Action- Inward rotation (forepaw
*arm rotation
Origin & insertion of supinator
OR – lateral epicondyle of humerus
IN – radial tuberosity
