Origin and Insertion of Thoracic Limb Flashcards
Superficial pectoral muscle
Origin: first three sternebrae; median fibrous raphe at the ventral midline
Insertion: crest of the greater tubercle of the humerus
Action: adduct limb (non-weight bearing) prevent abduction of limb (weight-bearing)
Deep pectoral muscle
Origin: ventral part of sternum; median fibrous raphe at the ventral midline
Insertion: Lesser tubercle of the humerus (major portion of insertion); greater tubercle and the crest of the humerus via aponeurosis
Action: pull trunk cranially when limb is advanced and fixed; extend shoulder; draw limb caudally when not supporting weight
Brachiocephalicus
Cleidobrachialis
Cleidocephalicus
Origin: Clavicular intersection
Insertion: distal end of cranial humerus; middorsal fibrous raphe of the neck; mastoid part of the temporal bone
Action: advance the limb; extend shoulder; draw head and neck to the side
Omotransversarius
Origin : wing (transverse process) of the atlas (cervical vertebra 1)
Insertion: distal end of the spine of the scapula
Action: to advance the limb or flex the neck laterally
Trapezius
Origin: the median fibrous raphe of the neck and the supraspinous ligament
Insertion: the spine of the scapula
Action: to elevate and abduct the forelimb
Rhomboideus
Rhomboideus cervicis (to the neck) Rhomboideus capitis (to the head) Rhomboideus thoracis (to the thorax)
Origin: base of the skull (nuchal crest of occipital bone); median fibrous raphe of neck; spinous process of thoracic vertebra
Insertion: the dorsal border of the scapula
Action: to elevate the forelimb and draw the scapula against the trunk
Latissimus dorsi
Origin: the throacolumbar fascia; last few ribs
Insertion: the teres major tuberosity of the humerus via the teres major tendon
Action: to draw the free limb caudally as in digging; to flex the shoulder joint
Serratus ventralis
Serratus ventralis cervicis
Serratus ventralis thoracis
Origin: ribs; transverse process of cervical vertebrae
Insertion: the serrated face of the scapula
Action: to support the trunk and depress the scapula
Deltoideus
Origin: spine and acromion of the scapula
Insertion: deltoid tuberosity of the humerus
Action: flex shoulder
Infraspinatus
Origin: infraspinous fossa of the scapula
Insertion: lateral side of the greater tubercle of the humerus
Action: laterally stabilizes the shoulder (prevents medial rotation while weight-bearing); abduct and laterally rotate shoulder; assists other muscles in the extension of flexion of shoulder
Teres Minor
Origin: infraglenoid tubercle of the scapula; distal caudal border of the scapula
Insertion: teres minor tuberosity of the humerus
Action: laterally stabilizes the shoulder (prevents medial rotation while weight-bearing) ; laterally rotate shoulder; flex shoulder (assists other muscles)
Supraspinatus
Origin: supraspinous fossa of the scapula
Insertion: greater tubercle of the humerus (thick tendon)
Action: laterally stabilized the shoulder (prevents medial rotation while weight-bearing); extend shoulder
Subscapularis
Origin: Subscapular fossa of the scapula
Insertion: lesser tubercle of the humerus
Action: medially stabilizes the shoulder (prevents lateral rotation while weight-bearing); adduct shoulder; extend
Teres Major
Origin: caudal angle and caudal border of the scapula; subscapularis muscle
Insertion: teres major tuberosity of the humerus
Action: flex shoulder; rotate limb medially
Coracobrachialis
Origin: coracoid process of the scapula
Insertion: crest of the lesser tubercle of the humerus, near the teres major tuberosity
Action: mainly a shoulder stabilizer, but can assist in adduction and/or extension of the shoulder
Tensor fasciae antebrachii
Origin: fascia covering the lateral surface of the latissimus dorsi muscle
Insertion: olecranon of the ulna, in common with the tendon of insertion of the triceps brachii muscle
Action: extend elbow
Triceps brachii
Origin: long head-> caudal border of scapula. Other heads-> tricipital line, proximal humerus (neck, lesser tubercle, and crest of the lesser tubercle)
Insertion: olecranon of ulna
Action: flex shoulder (long head); extend elbow (all heads)
Anconeus
Origin: lateral supracondylar crest of the humerus; lateral and medial epicondyles of the humerus
Insertion: proximal and lateral aspect of the ulna
Action: extend elbow
Biceps Brachii
Origin: supraglenoid tubercle of scapula
Insertion: radial and ulnar tuberosity
Action: extend shoulder; flex elbow
Brachialis
Origin: brachialis groove (proximal and lateral aspect of the humerus)
Insertion: radial and ulnar tuberosity
Action: flex elbow
Extensor carpi radialis
Origin: lateral supracondylar crest of the humerus
Insertion: metacarpal tuberosities (dorsal aspect) of MCII and III
Action: extend carpus
Common digital extensor
Origin: lateral epicondyle of the humerus
Insertion: extensor process of the distal phalanx of digits 2,3,4,5 (extensor process of distal phalanges II, III, IV, and V)
Action: extend the joints of the four principal digits (2, 3, 4, and 5)
Lateral digital extensor
Origin: lateral epicondyle of the humerus
Insertion: extensor process of the distal phalanx of digits 3, 4, and 5 (extensor process of distal phalanges III, IV, and V) proximal ends (base) of all phalanges of same digits
Action: extend the joints of digits 3, 4, and 5
Ulnaris Lateralis
Origin: lateral epicondyle of the humerus
Insertion: lateral aspect of the proximal end (base) of MC V; accessory carpal bone
Action: abduct carpus; flex carpus
Supinator
Origin: lateral epicondyle of the humerus
Insertion: cranial aspect of proximal radius
Action: supinator (rotate antebrachium laterally so that the palmar surface of the paw faces medially)
Pronator teres
Origin: medial epicondyle of the humerus
Insertion: medial border of the radius
Action: pronation
Abductor pollicis longus
Origin: lateral and cranial border of the ulna; interosseus membrane between the radius and ulna
Insertion: proximal end of the metacarpal I
Action: abduct digit I
Flexor carpi radialis
Origin: medial epicondyle of the humerus; medial border of the radius
Insertion: palmar surface of the proximal aspect (base) of MC II and III
Action: flex carpus
Superficial digital flexor
Origin: Medial epicondyle of the humerus
Insertion: palmar surface of the proximal aspect (base) of the middle phalanges of digits 2, 3, 4, and 5
Action: flex carpus; flex digits 2-5
Flexor carpi ulnaris
Origin: medial epicondyle of the humerus; olecranon caudal and medial aspect
Insertion: accessory carpal bone
Action: flex carpus
Deep digital flexor
Origin: medial epicondyle of humerus; ulna; radius
Insertion: flexor tubercle (palmar surface of the base) of the distal phalanx of each digit
Action: flex carpus; flex digits
