front leg muscles Flashcards
Deltoideus
Origins: spine and acromial process of the scapula
Insertion: the deltoid tuberosity
Action: to flex the shoulder
Innervation: axillary nerve
Infraspinatus
Origins: infraspinatus fossa of scapula
Insertion: the lateral side of the greater tubercle of the humerus
Action: to extend or flex the joint, depending on the degree of extension or position of the joint when the muscle contracts. To abduct the shoulder and to rotate the humerus laterally. To prevent medial rotation when weight bearing and provide lateral stability to the shoulder joint
Innervation: suprascapular nerve
teres minor
Origins: infraglenoid tubercle and distal third of the caudal border of the scapula
Insertion: the teres minor tuberosity of the humerus (near greater tubercle)
Action: to flex the shoulder, rotate the shoulder laterally and prevent medial rotation when bearing weight
Innervation: axillary nerve
supraspinatus
Origins: the supraspinous fossa of the scapula
Insertion: the greater tubercle of the humerus, by a thick tendon
Action: to extend and stabilize the shoulder joint
Innervation: suprascapular nerve
Subscapularis
Origins: the subscapular fossa
Insertion: the lesser tubercle of the humerus
Action: to adduct, extend, and medially stabilize the shoulder joint. To rotate the shoulder medially and prevent lateral rotation when bearing weight
Innervation: subscapular nerve
teres major
Origins: the caudal angle and adjacent caudal border of the scapula; the caudal surface of the subscapularis
Insertion: (medial side near lesser tubercle) teres major tuberosity on humerus
Action: flex the shoulder joint, rotate the shoulder joint medially, and prevent lateral rotation when bearing weight
Innervation: axillary nerve
tricpes brachii Long head
Origins: caudal border of the scapula
Insertion: the olecranon tuber
Action: to extend the elbow and flex the shoulder joint
Innervation: radial nerve
triceps brachii lateral head
Origins: tricipital line of the humerus (lateral side between teres minor and deltoid tuberosity)
Insertion: the olecranon tuber
Action: to extend the elbow
Innervation: radial nerve
triceps brachii accessory head
Origins: neck of the humerus
Insertion: the olecranon tuber
Action: to extend the elbow
Innervation: radial nerve
Triceps brachii medial head
Origins: the crest of the lesser tubercle near the teres major tuberosity
Insertion: the olecranon tuber
Action: to extend the elbow
Innervation: radial nerve
Anconeus
Origins: the lateral supracondylar crest of the lateral and medial epicondyles of the humerus
Insertion: the lateral surface of the proximal end of the ulna (olecranon)
Action: to extend the elbow
Innervation: radial nerve
Brachialis
Origins: the proximal third of the lateral surface of the humerus
Insertion: the ulnar and radial tuberosities (medial near head)
Action: to flex the elbow joint
Innervation: musculocutaneous nerve
biceps brachii
Origins: the supraglenoid tubercle of the scapula
Insertion: the ulna and radial tuberosities (medial side of bones)
Action: to flex the elbow joint and extend the shoulder joint
Innervation: musculocutaneous nerve
extensor carpi radialis
Origins: the lateral supracondylar crest of humerus
Insertion: the small tuberosities of the dorsal surfaces of the base of the metacarpals II and III
Action: to extend the carpal joint
Innervation: radial nerve
Common digital extensor
Origins: the lateral epicondyle of the humerus
Insertion: the extensor processes of the distal phalanges of digit II, III, IV and V
Action: to extend the joints of the four principal digits and the carpus
Innervation: radial nerve
lateral digital extensor
Origins: the lateral epicondyle of the humerus
Insertion: the proximal ends of all the phalanges of digits III IV V but mainly the extensor processes of the digital phalanges of these digits
Action: to extend the carpal joints of the carpus and digits III, IV and V
Innervation: radial nerve
Ulnaris lateralis
Origins: the lateral epicondyle of the humerus
Insertion: the lateral aspect of the proximal end of the metacarpal V and the accessory carpal bone
Action: to abduct the manus and flex the carpal joints and support the carpus when extended to support weight
Innervation: radial nerve
Supinator
Origins: the lateral epicondyle of the humerus
Insertion: the cranial surface of the proximal fourth of the radius
Action: to rotate the forearm laterally so that the palmar side of the paw faces medially to flex the elbow joint
Innervation: radial nerve
Extensor carpi obliquus
Origins: the lateral border and cranial surface of the body of the ulna; the interosseous membrane
Insertion: the proximal end of the metacarpal
Action: to abduct the first digit or pollex and extend the carpal joints
Innervation: radial nerve
pronator teres
Origins: the medial epicondyle of the humerus
Insertion: the medial border of the radius between the proximal and middle thirds
Action: to rotate the forearm medially so that the palmar side of the paw faces the ground, to flex the elbow
Innervation: median nerve
flexor carpi radialis
Origins: the medial epicondyle of the humerus and the medial border of the radius
Insertion: the palmar side of the base of metacarpals II and III
Action: to flex the carpal joints
Innervation: median nerve
superficial digital flexor
Origins: the medial epicondyle of the humerus
Insertion: the palmar surface of the base (proximal end) of the middle phalanges of digits II, III, IV, and V
Action: to flex the carpal, metacarpophalangeal and proximal interphalangeal joints of digits II, III, IV, and V
Innervation: median nerve
Flexor carpi ulnaris ulnar head
Origins: the caudal border and medial surface of the olecranon
Insertion: the accessory carpal bone
Action: to flex the carpus
Innervation: ulnar nerve
flexor carpi ulnaris humeral head
Origins: the medial epicondyle of the humerus
Insertion: the accessory carpal bone
Action: to flex the carpus
Innervation: ulnar nerve
Cleidocephalicus
pars mastoidea
Origin: clavicular intersection
Insertion: the mastoid part of the temporal bone with the sternomastoideus muscle
Action: Draw the neck and head to the side, to advance the limb, to extend the shoulder joint.
Innervation: Accessory nerve and ventral branches of cervical spinal nerves
Cleidobrachialis
Origin: clavicular intersection
Insertion: the distal end of the cranial border of the humerus. There is also a significant fascial tie into the axilla
Action: Draw the neck and head to the side, to advance the limb, to extend the shoulder joint.
Innervation: Accessory nerve and ventral branches of cervical spinal
Trapezius
Origins: median raphe of the neck and the supraspinous ligament from the level of the 3rd cervical vertebra to the level of the 9th thoracic vertebra
Insertion: spine of the scapula
Action: to elevate and abduct the forelimb
Innervation: Accessory nerve
Omotransversarius
Attachments: the distal end of the spine of the scapula; cranially the transverse process (wing) of the atlas
Action: to advance the limb or flex the neck laterally
Innervation: Accessory nerve
Superficial Pectorals
Descending
Origin: the first sternebra
Insertion: crest of the greater tubercle of the humerus
Action: To adduct the limb when it is not bearing weight or to prevent the limb from being abducted when bearing weight
Innervation: Ventral branch of spinal nerves C7 and C8
Superficial Pectorals
Transverse
Origin: the first two sternebrae and usually a part of the third; the fibrous raphe between adjacent muscles
Insertion: crest of the greater tubercle of the humerus
Action: To adduct the limb when it is not bearing weight or to prevent the limb from being abducted when bearing weight
Innervation: Ventral branch of spinal nerves C7 and C8
Deep Pectorals
Origin: ventral part of the sternum and the fibrous raphe between fellow muscles; deep abdominal fascia in the region of the xiphoid cartilage
Insertion: the major portion partly muscular, partly tendinous on the lesser tubercle of the humerus; aponeurosis to the greater tubercle and its crest; caudal part to the medial brachial fascia
Action: when the limb is advanced and fixed in a supporting position, to pull the trunk cranially and to extend the shoulder joint. When not weight bearing to draw the limb caudally and flex the shoulder joint. To adduct the limb.
Innervation: Caudal pectoral nerves (C8, T1)
Rhomboideus
Capitis, Cervicis, Thoracis
Origins: The nuchal crest of the occipital bone; median fibrous raphe of the neck; spinous processes of the first 7 thoracic vertebrae
Insertion: the dorsal border and adjacent surfaces of the scapula
Action: to elevate the forelimb and draw the scapula against the trunk
Innervation: ventral branches of cervical and thoracic spinal nerves
Latissimus Dorsi
Origins: thoracolumbar fascia from the spinous processes of the lumbar and the last 7 & 8 thoracic vertebrae; a muscular attachment to the last two or three ribs
Insertion: teres major tuberosity of the humerus and the teres major tendon (medial aspect of humerus)
Action: to draw the free limb caudally as in digging: to flex the shoulder joint
Innervation: Thoracodorsal nerve (C7, C8, T1)
Serratus Ventralis Cervicis and Thoracis
Origins: transverse processes of the last 5 cervical vertebrae and the first 7 or 8 ribs ventral to their middle
Insertion: the dorsomedial third of the scapula
Action: to support the trunk and depress the scapula
Innervation: ventral branches of cervical spinal nerves and the long thoracic nerve (C7)
Interossei 1-4
Origin: base of its respective metacarpal bone
Insertion: two tendons: base of the proximal phalanx. Imbedded in each tendon is a sesamoid bone
Action: to flex the carpal; and metacarpophalangeal joints and the proximal and distal interphalangeal joints of the digits
Innervation: median and ulnar nerve
Subclavius
origin: cranial part of the sternum
insertion: supraspinatus and shoulder fascia
action: complement the actions of the deep pectoral: suspend the trunk and stabilize the shoulder joint
innervation: pectoral nerve
