Extrinsic Muscles of Thoracic Limb Flashcards
Superficial pectoral splits into which two muscles?
Descending pectoral
Transverse pectoral
Superficial pectoral: origin
Origin: 1st two sternebrae; fibrous raphe btw adjacent muscles
Superficial pectoral: insertion
Insertion: whole crest of the greater tubercle of the humerus
Superficial pectoral: action
Action: adduct the limb when it is not bearing weight or to prevent the limb from being abducted when bearing weight
Deep pectoral: origin
Origin: ventral part of the sternum; median fibrous raphe at the ventral midline
Deep pectoral: insertion
Insertion: major portion partly muscular, partly tendinous on the lesser tubercle of the humerus; an aponeurosis to the greater tubercle and its crest; the caudal part to the medial brachial fascia
Deep pectoral: action
Action: limb is fixed: to pull the trunk cranially and to extend the shoulder joint.
Not supporting weight: to draw the limb caudally and flex the shoulder joint
Platysma
best developed of the cutaneous muscles of the neck and head
Brachiocephalicus breaks down into which 4 muscles?
1) Cleidobrachialis
2) Cleidocephalicus
- –3)Pars cervicalis
- –4)Pars mastoidea
Brachiocephalicus: origin
Origin: clavicular intersection
Cleidobrachialis: attachment
distal end of the cranial border of the humerus
Cleidocephalicus: attachment
cranial half of the mid dorsal fibrous raphe
Pars mastoidea: attachment
mastoid process of the temporal bone with the sternomastoideus muscle
Brachiocephalicus: action
advance the limb; to extend the shoulder joint and draw the neck and head to the side
Sternocephalicus: action
Action: draw the head and neck to the side
Omotransversarius: origin
Origin: wing, or transverse process, of atlas
Omotransversarius: action
Action: to advance the limb or flex the neck caudally
Trapezius: origin
Origin: median fibrous raphe of the neck
Trapezius: insertion
Insertion: the spine of the scapula
Trapezius: action
Action: to elevate and abduct the forelimb
Rhomboideus splits into what 3 muscles?
1) rhomboideus capitis
2) rhomboideus cervicis
3) rhomboideus thoracis
Rhomboideus: origin
1) nuchal crest of the occipital bone
2) median fibrous raphe of the neck
3) spinous processes of the first seven thoracic vertebrae
Rhomboideus: insertion
Insertion: dorsal border of the adjacent surfaces of the scapula
Rhomboideus: action
Action: To elevate the forelimb and draw the scapula against the trunk
Latissimus dorsi: origin
Origin: the thoracolumbar fascia from the spinous processes of the lumbar and the last seven or eight thoracic vertebrae; a muscular attachment to the last two or three ribs
Latissimus dorsi: insertion
Insertion: the teres major tuberosity of the humerus and the teres major tendon
Latissimus dorsi: action
Action: to draw the free limb caudally as in digging; to flex the shoulder joint
Serratus ventralis cervicis: origin
Origin: transverse process of the last five cervical vertebrae and the first seven or eight ribs ventral to their middle
Serratus ventralis cervicis: insertion
Insertion: dorsomedial third of the scapula (serrated face)
Serratus ventralis cervicis: action
Action: to support the trunk and depress the scapula
Omotransversarious: Insertion
Insertion: distal end of scapular spine
