Extrinsic muscles of the forelimb Flashcards
Cervical part of Trapezium muscle
Origin: Median fibrous raphe of the neck,from the 3rd cervical to 7th cervical vertebra.
Insertion: scapular spine
Innervation: dorsal branch of the accessory
Action: Elevate and draw limb foreward
Thoracic part of Trapezium muscle
Origin: From the supraspinous ligament and thoracic dorsal spines 1-9.
Insertion: scapular spine
Innervation: dorsal branch of the accessory
Action: Elevate and draw limb foreward
Cervical part of Serratus Venrtalis
Origin: transverse processes of the last 3 cervical vertebrae
Insertion: serrated face of scapula
Innervation: ventral branches of the last 3 cervical spinal nerves.
Action: passive trunk support
Thoracic part of the Serratus Ventralis
Origin: Lateral surface of the first 8 ribs
Insertion: serrated face of scapula
Innervation: long thoracic nerve of the brachial plexus
Action: move scapula forward and backward
Omotransversarius
Origin: wing of the atlas
Insertion: Lower spine of scapula
Innervation: Accessory nerve
Action: Draws the scapula forward
Rhomboideus Capitis
Origin: Occipital bone of skull
Insertion: dorsal edge of scapula
Innervation: Ventral branches of 3‐7 cervical and 1‐6 thoracic spinal nerves.
Action: elevate the limb, move the scapula forward and pull it close to the trunk.
Rhomboideus (cervical)
Origin: Tendinousraphe of neck from the 3
rd cervical to the 7th cervical vertebrae; and spines of 1‐3 thoracic vertebrae.
Insertion: dorsal edge of scapula
Innervation: Ventral branches of 3‐7 cervical and 1‐6 thoracic spinal nerves.
Action: elevate the limb, move the scapula forward and pull it close to the trunk.
Rhomboideus (thoracic)
Origin: spines of 4th-6th thoracic vertebrae
Insertion: dorsal edge of scapula
Innervation: Ventral branches of 3‐7 cervical and 1‐6 thoracic spinal nerves.
Action: elevate the limb, move the scapula forward and pull it close to the trunk.
Latissiumus dorsi
Origin: From thoracodorsal fascia via an aponeurosis (and indirectly from the spinous
processes of the last 7 thoracic through lumbar vertebrae), lateral surface of the last 2‐3
ribs.
Insertion: Mainly to the teres tubercle on the medial shaft of the humerus.
Nerve supply: Mainly the thoracodorsal nerve from the brachial plexus.
Action:Draw the limb backwards, and flex the shoulder joint.
Brachiocephalicus (cleidobrachialis, cleidocervicalis, cleidomastoideus)
Attachments: Distal part of the humeral crest, to the cranial half of the cervical fibrous
raphe, and to the mastoid part of the skull.
Nerve supply: The cleidobrachialis part is supplied by a nerve from the brachial plexus
(brachiocephalicus), the cleidocephalicus is supplied by ventral branches of several cervical
nerves as well as the accessory (CNXI) nerve (specifically to the cleidomastoid part)
Action: extension of the limb and flexion of the neck
Superficial pectoral muscle (descending and transverse)
Origin: 1st 2 sternebrae and associated costal cartilage.
Insertion: Crest of major tubercle of the humerous.
Innervation: cranial pectoral nerve.
Action: adduction
Deep pectoral muscle
Origin: From all the sternebrae.
Insertion: Both greater and lesser tubercles of humerus.
Nerve supply: Mainly caudal pectoral nerves.
Action: Mainly adduction of the limb. Also pulls limb back and trunk forward.
