Intrinsic Muscles of the Forelimb

Question 1

What muscles are on the lateral scapular and shoulder

Answer 1

ISDTL
Infraspinatus
Supraspinatus
Deltoideus
Teres minor
Lateral scapula and shoulder

Question 2

What muscles are on the medial scapula and shoulder

Answer 2

MSTC
Mum stop tickling char
Medial scapula and shoulder
Subscapularis
Teres major
Coracobrachialis

Question 3

What muscles are on the caudal arm

Answer 3

CATTA
Tensor fasciae antebrachii
Triceps brachii
Anconeus

Question 4

What muscles are on the cranial arm

Answer 4

Cranial BB
Biceps brachii
Brachialis

Question 5

What muscle are on the cranial and lateral forearm

Answer 5

Ellie calls lads ugly suck A
Extensor carpi radialis	
Common digital extensor	
Lateral digital extensor	
Ulnaris lateralis	
Supinator	
Abductor digiti I longus

Question 6

What muscles are on the caudal and medial forearm

Answer 6

CMPPFFDS
Pronator teres	
Pronator quadratus
Flexor carpi radialis	
Flexor carpi ulnaris
Deep digital flexor	
Superficial digital flexor

Question 7

Deltoideus
OIAI
About

Answer 7

O= spine and acromion process
I = Deltoid Tuberosity
A = Flex shoulder
I = Axillary nerve

Question 8

what are the heads of the triceps called

Answer 8

Long head
Lateral Head
Medial Head
Accessory Head

Question 9

Tricep long head DOG

OIAI

Answer 9

Consists of four heads instead of the
usual three muscle with a common tendon of insertion to olecranon tuber. This muscle covers the bulk of humerus.
1. Long head: Two bellies
O: The caudal border of scapula
I: Olecranon tuber
A: To extend the elbow and flex the shoulder.
I = Radial Nerve

Question 10

Triceps LAteral head

Answer 10

1’ Lateral head: Two bellies: transect to expose underlying accessory head and medial
O: deltoid tuberosity/ The tricepital line of humerus
I: Olecranon tuber
A: To extend the elbow
Innervation – Radial Nerve

Question 11

Acessory head and medial head

Answer 11

Accessory: O = Neck of humerus Medial: O = crest of the lesser tubercle near tres major tuberosity
Accessory I = Olecranon tuber Medial = olecranon
A = Extend elbow
I = Radial nerve

Question 12

Supraspinatus OIAI

Answer 12

O = supraspinous fossa
IN = greater tubercle of humerus, by a thick tendon
A: extension of the shoulder and the tendon acts as a lateral collateral ligament to stabilise the shoulder joint.
I= suprascapular nerve

Question 13

Infraspinatus

Answer 13

O = infraspinous fossa
I = small, circumscribed area in the lateral side of the greater tubercle of the humerus
Action – can flex or extend the
shoulder joint depending on limb
position.
Tendon acts as lateral collateral
ligament to stabilise shoulder joint.
Innervation – suprascapular nerve

Question 14

Teres Minor

Answer 14

Origin: caudal angle and adjacent caudal border of scapula
Inserts: Teres major tuberosity of humerus
Action – flex shoulder, rotate shoulder medially, prevent lateral rotation when weight bearing
Innervation – axillary nerve

Question 15

Deltoideus

Answer 15

Origin and insertion – 
has 2 parts: spinous part that
arises from the scapular spine,
and an acromial part arising from
the acromion. Both parts unite to
insert on the deltoid tuberosity of
the humerus.
Action – flexor of the shoulder
Innervation – axillary nerve

Question 16

Subscapularis

Answer 16

O: subscapular fossa. - described as being multipennate
(pennate = feather shaped, where the fibres approach the tendon from different directions).
I: short strong tendon on lesser tubercle of the humerus.
Action – adduct, extend and medially stabilize shoulder joint

Innervation – subscapular nerve

Question 17

Teres Minor

Answer 17

O: infraglenoid tubercle and distal third of the caudal border of the scapula
I: Teres major tuberosity of humerus
Action – flex shoulder, rotate laterally adn prevent medial rotation when bearing weight
Innervation – axillary nerve

Question 18

Biceps Brachii

Answer 18

Origin and Insertion – originates by way
of a long tendon on the supraglenoid
tuberosity, it then crosses the shoulder
joint, runs craniomedially down the
brachium and inserts, by way of 2
tendons onto the radius and ulna.
Action – flexor of the elbow, extensor of
the shoulder.
Innervation – musculocutaneus nerve

Question 19

Brachialis

Answer 19

Origin and insertion – originates on
the proximal caudal humerus and
inserts on the proximal ulna
Action – flexor of the elbow
Innervation – musculocutaneus nerve

Question 20

Coracobrachialis

Answer 20

Origin: coracoid process of the scapula
Insertion: crest of lesser tubercle of the humerus, proximal to teres major tuberosity
Action – adduct, extend and stabilize shoulder joint
Innervation - musculocutaneus nerve

Question 21

Anconeus

Answer 21

Ancon = elbow
Origin: lateral supracondylar crest and lateral and medial epicondyles of the humerus
Inserts: olecranon
Action – elbow extensor and capsular muscle of the elbow
Innervation – radial nerve

Question 22

Tensor Fascia Antebrachii

Answer 22

Origin: arises from the fascia latissimus dorsi
Inserts: olecranon.
Action – extend elbow
Innervation – radial nerve

Question 23

Extensor Carpi Radialis

Answer 23

Origin and Insertion:
Originates from the lateral
supracondylar crest of humerus.
Inserts on the proximo-dorsal surface
of metacarpal II & III.
Action – Extensor of the carpus, flexor
of the elbow
Innervation – radial nerve

Question 24

Common Digital Extensor

Answer 24

Origin and Insertion – originates from the
lateral epicondyle of the humerus, and
inserts on the distal phalanges of digits II to V.
Action – extends carpus and digits II to V
Innervation – radial nerve

Question 25

Lateral Digital Extensor

Answer 25

Origin and Insertion – originates from the
proximal radius and ulna and inserts on the
distal phalnges of digits III, Iv and V.
Action – Extension of digits II, IV and V
Innervation – radial nerve

Question 26

Ulnaris Lateralis

Answer 26

Origin and Insertion – originates from the
lateral epicondyle of the humerus and
inserts on the proximal end of metacarpal
V.
Action – Extension or flexion of the carpus,
depending on the position of the limb.
Innervation – radial nerve

Question 27

Supinator

Answer 27

Origin and insertion – this muscle lies
laterally on the cranial surface of the
elbow. It arises from the lateral
collateral ligament and the lateral
epicondyle of the humerus. It inserts
on the cranial surface of the radius.
Action – rotation of the paw so that
the palmer surface faces medially
Innervation – radial nerve

Question 28

Abductor Pollicis Longus

Answer 28

pollex = thumb
Origin and Insertion –
Originates from craniolateral surface of
Ulna
Inserts on the medial aspect of the
proximal end of metacarpal I/II. It has
a small sesamoid near the point of
insertion.
Action – Extends carpus and abduct
the first digit
Innervation – radial nerve

Question 29

Pronator Teres

Answer 29

Origin and Insertion – this muscle lies
medially on the cranial surface of the
elbow. It originates from the medial
epicondyle of the humerus and
inserts on the cranial radius.
Action – rotation of the paw so that
the palmer surface is in contact with
the ground
Innervation – median nerve

Question 30

Flexor Carpi Radialis

Answer 30

Origin and insertion – originates from the
medial epicondyle, inserts on the palmer
aspect of metacarpals II and III.
Action – flexor of the carpus
Innervation – median nerve

Question 31

Superficial Digital FLexor

Answer 31

Origin and Insertion – originates from the
medial epicondyle of the humerus, inserts
on the palmer proximal edge of the middle
phalanx of all digits.
Action – flexor of the digits
Innervation - median nerve

Question 32

Flexor Carpi Ulnaris

Answer 32

Origin and insertion – this muscle has two heads –
a weaker ulnar head that originates from the
proximal ulna, and a strong humeral head that
arises from the medial epicondyle of the humerus.
Both insert onto the accessory carpal cone.
Action – flexor of the carpus
Innervation – ulnar nerve

Question 33

Deep Digital Flexor

Answer 33

Origin and insertion –
This muscle has 3 heads. The humeral head
is the strongest and itself consists of 3 bellies.
It arises from the medial epicondyle of the
humerus. The radial head is the weakest
division and arises from the medial border of
the radius. The third head is the ulnar head.
It arises from the caudal border of the ulna.
All three heads unite to form the strong
tendon which then splits and inserts on the
distal phalanges of all digits.
Action – flexor of the digits
Innervation – median nerve

Question 34

Pronator Quadratus

Answer 34

Origin and Insertion – this muscle fills the
space between the radius and ulna. It arises
on the ulna and inserts on the radius.
Action – to rotate the paw inwards
Innervation – median nerve

Question 35

Interosseousei/ Interossei

Answer 35

4 in total lying on the palmer aspect of metacarpal bones II, III, IV and IV.
Distally, each muscle divides into 2 short tendons that attach to the proximal end of P1.
Each tendon has a sesamoid embedded in it.
Action : flexion of metacarpophalangeal joints
Innervation : Ulnar nerve