Intrinsic Muscles of the forelimb

Question 1

Deltoideus m.

All parts, Action, Innervation

Answer 1

2 Parts:
Spinous- covers the infraspinatus m.
Acromial- arises from the acromion process and has fusiform shape

ACTION: to flex the shoulder

INNERVATION: Axillary nerve

Question 2

Infraspinatus m.

Insertion, Action, Innervation

Answer 2

Lies in the infraspinous fossa and is fusiform in shape.

INSERTION: A small, circumscribed area on the lateral side of the greater tubercle of the humerus.

ACTION: To extend or flex the joint, depending on the degree or position of the joint. To abduct the shoulder and rotate humerus laterally. Also to prevent medial toation when weight bearing and lateral stability of shoulder joint.

INNERVATION: Suprascauplar nerve

Question 3

Teres minor m.

Action, Innervation

Answer 3

Small, wedge-shaped muscle, covered superficially by the deltoideus

ACTION: To flex the shoulder, rotate the shoulder laterally, and prevent medial rotation when weight bearing.

INNERVATION: Axillary nerve

Question 4

Supraspinatus m.

Insertion, Action, Innervation

Answer 4

INSERTION: The greater tubercle of the humerus, by a thick tendon.

ACTION: To extend and stabilize the shoulder joint.

INNERVATION: Suprascapular nerve

Question 5

Subscapularis m.

Insertion, Action, Innervation

Answer 5

INSERTION: The lesser tubercle of the humerus

ACTION: To adduct, extend, and medically stabilize the shoulder joint. Also to rotate the shoulder joint medially and prevent lateral rotation when bearing weight. Very important in stabilizing the shoulder joint in addition to the infraspinatus and teres minor caudally, as well as supraspinatus cranially.

INNERVATION: Subscapular nerve

Question 6

Teres Major m.

Action, Innervation

Answer 6

ACTION: To flex the shoulder joint, rotate the shoulder medially, and prevent lateral rotation when weight bearing.

INNERVATION: Axillary nerve

Question 7

Coracobrachialis m.

Action, Innervation

Answer 7

ACTION: To adduct, extend, and stabilize the shoulder joint.

INNERVATION: Musculocutaneous nerve

Question 8

Tensor Fasciae Antebrachii m.

Action, Innervation

Answer 8

ACTION: To extend the elbow joint

INNERVATION: Radial nerve

Question 9

Triceps Brachii m.

All parts, Origin, Insertion, Action, Innervation

Answer 9

4 heads in the dog, common tendon to the olecranon tuber. Only the long head arises from the scapula, the other three from the proximal end of the humerus.

Long head:
ORIGIN: Caudal border of scapula
INSERTION: the Olecranon tuber
ACTION: To flex the shoulder joint and extentend the elbow joint.
INNERVATION: Radial nerve

Lateral Head:
ORIGIN: Tricipital line of the humerus
INSERTION: The Olecranon tuber
ACTION: To extend the elbow joint
INNERVATION:  Radial nerve

Accessory Head:
ORIGIN: The neck of the humerus
INSERTION: The olecranon tuber
ACTION: to extend the elbow joint
INNERVATION:  Radial Nerve

Medial Head: 
ORIGIN: The crest of the lesser tubercle near the teres major tuberosity
INSERTION: the olecranon
ACTION: To extend the elbow joint
INNERVATION: radial nerve

Question 10

Anconeus m.

Action, Innervation

Answer 10

Small muscle, located almost completely in the olecranon fossa.

ACTION: To extend the elbow joint

INNERVATION: Radial nerve

Question 11

Biceps Brachii m.

ORIGIN, INSERTION, ACTION, INNERVATION

Answer 11

Has only one head, long fusiform muscle that lies on the medial and cranial surfaces of the humerus.

ORIGIN: The supraglenoid tubercle of the scapula
INSERTION: The ulnar and radial tuberosities
ACTION: to flex the elbow and extend the shoulder joint
INNERVATION: Musculocutaneous nerve

Question 12

Intertubercular Bursa

Answer 12

Also known as the Bicipital Bursa, extension of the shoulder joint that lies within the intertubercular groove, acts as a synovial sheath for the bicipital tendon.

Question 13

Brachialis m.

Origin, Inerstion, Action, Innervation

Answer 13

ORIGIN: The proximal third of the lateral surface of the humerus. (The muscle runs through the brachialis groove of the humerus).
INSERTION: The ulnar and radial tuberosities
ACTION: To flex the elbow joint
INNERVATION: Musculocutaneous nerve

Question 14

Extensor Capri Radialis m.

Origin, Insertion, Action, Innervation

Answer 14

ORIGIN: The lateral supracondylar crest
INSERTION: The small tuberosities on the dorsal surfaces of the bases of metacarpals II and III
ACTION: To extend the carpal joints
INNERVATION: Radial nerve

Question 15

Common Digital Extensor m.

Origin, Insertion, Action, Innervation

Answer 15

ORIGIN: The lateral epicondyle of the humerus
INSERTION: The extensor process of the distal phalanges of II,III,IV, and V
ACTION: To extend the joints of the four principal digits and carpus (functional digits)
INNERVATION: Radial nerve

Question 16

Lateral Digital Extensor m.

Origin, Insertion, Action, Innervation

Answer 16

Lies between the common digital extensor and ulnar is lateralis

ORIGIN: The lateral epicondyle of the humerus
INSERTION: The proximal ends of all the phalanges of digits III,IV, and V
ACTION: To extend the carpus and digits III,IV and V.
INNERVATION: Radial nerve

Question 17

Ulnaris Lateralis m.

Action, Innervation

Answer 17

ACTION: To abduct the manus and flex the carpal joints and support carpus when bearing weight.
INNERVATION: Radial nerve

Question 18

Supinator m.

Action, Innervation

Answer 18

ACTION: To rotate the forearm laterally so that the palmar side of the paw faces medially (supination); to flex the elbow joint.
INNERVATION: Radial nerve

Question 19

Abductor Digiti I Longs m.

Action, Innervation

Answer 19

ACTION: To abduct digit I and extend carpal joints
INNERVATION: Radial nerve

Question 20

Pronator Teres m.

Action, Innervation

Answer 20

ACTION: To rotate the forearm medially so that the palmar side faces the ground, also to flex the elbow.
INNERVATION: Median nerve

Question 21

Flexor Carpi Radialis m.

Origin, Insertion, Action, Innervation

Answer 21

ORIGIN: The medial epicondyle of the humerus and 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

Question 22

Superficial Digital Flexor m.

Origin, Insertion, Action, Innervation

Know relationship with DDF m.

Answer 22

ORIGIN: The medial epicondyle of the humerus
INSERTION: The base of the middle phalanx of digits II-V
ACTION: To flex the carpal, metacarpophalangeal, and interphalangeal joints of II-V
INNERVATION: Median nerve

Question 23

Flexor Carpi Ulnaris m. (Know all parts)

Origin, Insertion, Action, Innervation

Answer 23

2 parts: Ulnar head and numeral head

ORIGIN: Ulnar head: the caudal border and medial surface of the olecranon;
Humeral head: the medial epicondyle of the humerus
INSERTION: The accessory carpal bone
ACTION: To flex the carpus
INNERVATION: Ulnar nerve

Question 24

Deep Digital Flexor m.

Origin, Insertion, Action, Innervation

Answer 24

Humeral head is the largest, ulnar head is smaller and arises from the caudal border of the ulna, radial head is smallest and comes from the medial border of the radius.

ORIGIN: Humeral head: the medial epicondyle of the humerus
Ulnar head: small and arises from the caudal border of the ulna
Radial head: middle 1/3 medial border of the radius
INSERTION: The flexor tubercle on the palmar surface of the distal phalanx of each digit (I-V)
ACTION: To flex the carpal and metacarpophalangeal and proximal and distal interphalangeal joint
INNERVATION: Median and ulnar nerves

Question 25

Carpal Canal

Answer 25

Formed by the accessory carpal bone laterally, the palmar carpal ligament and the carpal bones dorsally, and flexor retinaculum on the palmar surface.

Question 26

Pronator Quadratus m.

Answer 26

Fills the space between the radius and the ulna.

ACTION: To pronator the paw.
INNERVATION: Median nerve