Muscles of Thoracic Limb Flashcards
Superficial pectoral
Origin-first 3 sternebrae; median fibrous raphae at the ventral midline
Insertion-crest of the greater tubercle of the humerus Action-adduct limb (non-weight bearing); prevent abduction of the limb (weight-bearing)
Deep pectoral
Origin-ventral part of the sternum; median fibrous raphae at the ventral midline
Insertion-lesser tubercle of humerus (major point of insertion); also greater tubercle and 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
Braciocephalicus
Origin-clavicular intersection
Insertion-distal end of cranial humerus (cleidobrachialis); middorsal fibrous raphae of neck (cleidocervicalis); mastoid part of temporal bone (cleidomastoideus) Action-advance the limb; extend shoulder; draw head and neck to the side
Omotransversarius
Origin-wing (transverse process) of the atlas (cervical vertebrae 1)
Insertion-distal end of the spine of the scapula Action-advance the limb; flex the neck laterally
Trapezius
Origin-median fibrous raphae of the neck; supraspinous ligament
Insertion-spine of the scapula Action-elevate and abduct limb
Rhomboideus
Origin-base of skull; median fibrous raphae of neck; spinous processes of thoracic vertebrae
Insertion-dorsal border of scapula Action-elevate limb; draw scapula against trunk
Latissimus dorsi
Origin-thoracolumbar fascia; last few ribs
Insertion-teres major tuberosity of the humerus via the teres major tendon Action-draw limb caudally (digging); flex shoulder
Serratus ventralis
Origin-ribs; transverse processes of cervical vertebrae
Insertion-serrated face of scapula
Action-support trunk; depress scapula
Deltoideus
Origin-spine and acromion of the scapula
Insertion-deltoid tuberosity of humerus Action-flex shoulder
Infraspinatus
Origin-infraspinous fossa of scapula
Insertion-lateral side of the greater tubercle of humerus Action-laterally stabilizes the shoulder (prevents medial rotation while weight bearing); abduct and laterally rotate the shoulder
Teres minor
Origin-infraspinous fossa of scapula
Insertion-teres minor tuberosity of humerus
Action-laterally stabilizes shoulder (prevents medial rotation while weight-bearing); laterally rotate shoulder; flex shoulder
Supraspinatous
Origin-supraspinous fossa of scapula
Insertion-greater tubercle of humerus Action-laterally stabilizes the shoulder (prevents medial rotation while weight-bearing); extend shoulder
Subscapularis
Origin-subscapular fossa of the scapula
Insertion- lesser tubercle of humerus Action-medially stabilizes the shoulder (prevents lateral rotation while weight-bearing); adduct shoulder; extend shoulder
Teres major
Origin-caudal angle and caudal border of scapula; subscapularis muscle
Insertion-teres major tuberosity of the humerus Action-flex shoulder
Coracobrachialis
Origin-coracoid process of scapula
Insertion-crest of the lesser tubercle of the humerus (near the teres major tuberosity) Action-mainly a shoulder stabilizer
Tensor fascia 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 shoulder; flex elbow
Brachialis
Origin-brachialis groove (proximal and lateral aspect of humerus)
Insertion-radial and ulnar tuberosities Action-flex elbow
Extensor carpi radialis
Origin-lateral supracondylar crest of humerus
Insertion-metacarpal tuberosities (dorsal aspect) of MC II and III Action-extend carpus
Common digital extensor
Origin-lateral epicondyle of the humerus
Insertion-extensor processes of the distal phalanx of digits 2, 3, 4, and 5
Action-extend the joints of the four principal digits (2, 3, 4, 5)
Lateral digital extensor
Origin-lateral epicondyle of humerus
Insertion-extensor processes of the distal phalanx of digits 3, 4, and 5 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 of MC V; accessory carpal bone
Action-abduct carpus; flex carpus
Supinator
Origin-lateral epicondyle of humerus
Insertion-cranial aspect of proximal radius Action-supination (rotate antebrachium laterally so that the palmar surface of paw faces medially)
Pronator teres
Origin-medial epicondyle of humerus
Insertion-medial border of radius Action pronation (rotate the antebrachium medially so that the palmar surface of paw faces the ground)
Abductor pollicis longus
Origin-lateral an cranial border of the ulna; interosseus membrane between radius and ulna
Insertion-proximal end of metacarpal I
Action-abduct digit I
Flexor carpi radialis
Origin-medial epicondyle of the humerus
Insertion-palmar surface of 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 humerus; olecranon
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
Pronator quadratus
Action-pronate the antebrachium
Triceps brachii
Origin: long head: caudal border
of scapula. Other heads:
tricipital line, proximal
humerus
Insertion: olecranon of ulna (in common with tensor fascia antebrachii)
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 aspects of ulna
Action: extend elbow
Biceps brachii
Origin: supraglenoid tubercle of scapula
Insertion: radial and ulnar tuberosities
Action: extend shoulder, flex elbow
