Anatomy Of The Dog: Muscle Actions And Innervations

Front 1

Superficial pectoral m.'s

Back 1

Action: To adduct the limb when it is not bearing weight; to prevent the limb from being abducted when weight bearing

Innervation: Cranial pectoral nerves (C7, C8)

Front 2

Deep pectoral m.

Back 2

Action: When the limb is advanced and fixed, to pull the trunk cranially and to extend the shoulder joint. When the limb in not weight bearing, to draw the limb caudally and flex the shoulder joint. To adduct the limb.

Innervation: Caudal pectoral nerves (C8, T1)

Front 3

Brachiocephalicus m.

Back 3

Action: To advance the limb; to extend the shoulder joint and draw the neck and head to the side

Innervation: Accessory nerve and ventral branches of cervical spinal nerves

Front 4

Sternocephalicus m.

Back 4

Action: To draw the head and neck to the side

Innervation: Accessory nerve and ventral branches of cervical spinal nerves

Front 5

Sternohyoideus m.

Back 5

Action: To pull the tongue and larynx caudally

Innervation: Ventral branches of cervical spinal nerves

Front 6

Sternothyroideus m.

Back 6

Action: To draw the tongue and larynx caudally

Innervation: Ventral branches of cervical spinal nerves

Front 7

Omotransversarius m.

Back 7

Action: To advance the limb or flex the neck laterally

Innervation: Accessory nerve

Front 8

Trapezius m.

Back 8

Action: To elevate and abduct the forelimb

Innervation: Accessory nerve

Front 9

Rhomboideus m.

Back 9

Action: To elevate the forelimb and draw the scapula against the trunk

Innervation: Ventral branches of cervical and thoracic spinal nerves

Front 10

Latissimus dorsi m.

Back 10

Action: To draw the free limb caudally as in digging; to flex the shoulder joint

Innervation: Thoracodorsal nerve (C7, C8, T1)

Front 11

Serratus ventralis cervicis and thoracis m.'s

Back 11

Action: To support the trunk and depress the scapula

Innervation: Ventral branches of cervical spinal nerves and the long thoracic nerve (C7)

Front 12

Deltoideus m.

Back 12

Action: To flex the shoulder

Innervation: Axillary nerve

Front 13

Infraspinatus m.

Back 13

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 shoulder laterally. To prevent medial rotation when weight bearing and provide stability to the shoulder joint.

Innervation: Suprascapular nerve

Front 14

Supraspinatus m.

Back 14

Action: To extend and stabilize the shoulder joint

Innervation: Suprascapular nerve

Front 15

Subscapularis m.

Back 15

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

Front 16

Teres major m.

Back 16

Action: Flex the shoulder, rotate the shoulder medially, and prevent lateral rotation when weight bearing.

Innervation: Axillary nerve

Front 17

Tensor fasciae antebrachii m.

Back 17

Action: To extend the elbow

Innervation: Radial nerve

Front 18

Long head of the triceps brachii m.

Back 18

Action: To extend the elbow and flex the shoulder

Innervation: Radial nerve

Front 19

Lateral head of the triceps brachii m.

Back 19

Action: To extend the elbow

Innervation: Radial nerve

Front 20

Accessory head of the triceps brachii m.

Back 20

Action: to extend the elbow

Innervation: Radial nerve

Front 21

Medial head of the triceps brachii m.

Back 21

Action: To extend the elbow

Innervation: Radial nerve

Front 22

Anconeus m.

Back 22

Action: To extend the elbow

Innervation: Radial nerve

Front 23

Biceps brachii m.

Back 23

Action: To flex the elbow and extend the shoulder

Front 24

Brachialis m.

Back 24

Action: To flex the elbow

Innervation: Musculocutaneous nerve

Front 25

Extensor carpi radialus m.

Back 25

Action: To extend the carpus

Innervation: Radial nerve

Front 26

Common digital extensor m.

Back 26

Action: To extend the joints of the 4 principal digits and the carpus

Innervation: Radial nerve

Front 27

Lateral digital extensor m.

Back 27

Action: To extend the carpus and joints of digits III, IV, and V

Innervation: Radial nerve

Front 28

Ulnaris lateralis m.

Back 28

Action: To abduct the carpal joint and support the carpus when extended to support weight

Innervation: Radial nerve

Front 29

Supinator m.

Back 29

Action: To rotate the forearm laterally so that the palmar side of the paw faces medially (supination); to flex the elbow

Innervation: radial nerve

Front 30

Pronator teres m.

Back 30

Action: To rotate the forearm medially so that the palmar side of the paw faces the ground (pronation); to flex the elbow

Innervation: Median nerve

Front 31

Flexor carpi radialis m.

Back 31

Action: To flex the carpus

Innervation: Median nerve

Front 32

Superficial digital flexor m.

Back 32

Action: To flex the carpal, metacarpophalangeal, and proximal interphalangeal joints of digits II, III, IV, and V

Innervation: Median nerve

Front 33

Flexor carpi ulnaris m.

Back 33

Action: to flex the carpus

Innervation: Ulnar nerve

Front 34

Deep digital flexor m.

Back 34

Action: To flex the carpal and metacarpophalangeal joints and the proximal and distal interphalangeal joints of the digits

Innervation: Median and ulnar nerves

Front 35

Pronator quadratus m.

Back 35

Action: To pronate the paw

Innervation: Median nerve