Proximal Intrinsic Forelimb Muscles Flashcards
what are extrinsic forelimb muscles?
those that link the trunk to the scapula/humerus
what are intrinsic forelimb muscles
those that originate in the forelimb
muscles that actuate the shoulder joint originate on the ____ and insert on the ____.
originate on the scapula
insert on the humerus (or more distal)
which action has more muscles associated with it in the proximal forelimb? why?
flexion
flexion is used to bring the leg backward on the ground –> working with whole body weight
extension is used to swing leg forward –> only working with weight of limb
what is the primary action of the deltoideus?
where are the origins and insertions?
flex shoulder
scapular part: O = spine of scapula; I: deltoid tuberosity
acromial part: O = acromian process; I = deltoid tuberosity
what is the primary action of the infraspinatus?
where is the origin and insertion?
flexion of shoulder
O = infraspinous fossa of scapula
I = greater tubercle of humerus
what is the primary action of the teres minor?
where is the origin and insertion?
flex shoulder
O = caudal border of scapula
I = teres minor tuberosity of humerus
what is the primary action of the supraspinatus?
where is the origin and insertion?
extend shoulder
O = supraspinous fossa of scapula
I = greater and lesser tubercles of humerus
what is the primary action of the subscapularis?
where is the origin and insertion?
extend shoulder
O = subscapular fossa of scapula
I = lesser tubercle of humerus
what is the primary action of the teres major?
where is the origin and insertion?
flex shoulder
O = caudal border of scapula
I = teres major tuberosity of humerus
what is the primary action of the coracobrachialis?
where is the origin and insertion?
flex shoulder
O = coracoid process of scapula
I = lesser tubercle of humerus
what is the primary action of the triceps brachii?
where are the origins and insertions?
extend elbow
all insert onto olecranon
long head O = caudal edge of scapula
all other originate on humerus
what is the primary action of the tensor fascia antebrachii?
where is the origin and insertion?
extend elbow
O = latissimus dorsi
I = olecranon and antebrachial fascia
what is the primary action of the anconeus?
where is the origin and insertion?
extend elbow
O = olecranon fossa
I = olecranon
what is the primary action of the biceps brachii?
where is the origin and insertion?
flex elbow and extend shoulder
O = supraglenoid tubercle of scapula
I = radial tuberosity
what is the primary action of the brachialis?
where is the origin and insertion?
flex elbow
O = brachial groove of humerus
I = radius
what do the deltoideus and supraspinatus work together to do?
abduct the shoulder joint
what is the rotator cuff made of?
SITS
supraspinatus, infraspinatus, teres minor, subscapularis
what is the function of the rotator cuff?
to provide stability while bearing weight
what is mm 3?

supraspinatus
what is mm 9?

subscapularis
what is mm 2?

teres major
what is mm 10?

coracobrachialis
what is mm 11?

tensor fascia antebrachii
what is mm 6?

long head of the triceps brahii
what is mm 6”?

medial head of the triceps brachii
what is mm 12?

biceps brachii
what is mm 2?

teres major
what is mm 4?

scapular head of the deltoideus
what is mm 4’?

acromial head of the deltoideus
what is mm 3?

supraspinatus
what is mm 6?

long head of the triceps brachii
what is mm 6’?

lateral head of the triceps brahii
which head of the triceps is unique to dogs?
accessory head of the triceps
what is mm 12?

lacertus fibrosus
what is mm 1?

teres minor
what is mm 4?

anconeus
what is lameness?
abnormal limb movements
what type of motion do muscles produce at joints?
angular motion
what are the fulcrums of the MSK?
joints
what are the levers of the MSK?
bones
what is torque?
the tendency of a force to cause an object to rotate around a certain axis
what are the external forces acting on the MSK?
gravity, ground reaction forces, friction
do muscle contractions always produce angular motion? why or why not?
no
they can resist external forces or brake to control the rotation at a joint
what is the out-lever?
where the external force and torque are applied
what is the in-lever?
where the internal (muscle) force and torque are applied
what is a first class lever? what is an example of this in the body?
fulcrum with weight on either side (teeter totter)
cranial side of atlantooccipital joint
what is a second class lever? what is an example of this in the body?
fulcrum on one side, external forces acting right beside it, and muscle forces acting beside the external forces (wheelbarrow)
distal limb joints
what is a third class lever? what is an example of this in the body?
fulcrum on one side, internal force beside that, and external force beside internal force (holding barbell)
biceps in forelimb
what is the most common lever class in the MSK system?
third class
how do muscles resist torque?
increasing muscle force or increasing lever arm
how do we define the flexor surface?
use the angle that is already less than 180 degrees based on neutral position of the two bones in the joint
what are the flexor and extensor surfaces of the shoulder?
F: caudal aspect
E: cranial aspect
what are the flexor and extensor surfaces of the elbow?
F: cranial aspect
E: caudal aspect
what are the flexor and extensor surfaces of the distal joints?
F: caudal
E: cranial
what are the flexor and extensor surfaces of the hip?
F: cranial
E: caudal
what are the flexor and extensor surfaces of the stifle?
F: caudal
E: cranial
what are the flexor and extensor surfaces of the tarsus/hock?
F: cranial
E: caudal
hyper ranges typically apply to the ___ surface
extensor
label this image

A: brachialis
B: anconeus
C: lateral head of triceps brachii
D: long head of triceps brachii
E: supraspinatus
label this image

A: medial head of triceps brachii
B: long head of triceps brachii
C: accessory head of triceps brachii
label this image

A: biceps brachii
B: medial head of triceps brachii
C: teres major
label this image

A: teres major
B: subscapularis
C: supraspinatus
D: coracobrachialis
E: tensor fascia antebrachii
F: long head of triceps brachii
G: medial head of triceps brachii
H: biceps brachii
label this image

A: supraspinatus
b: infraspinatus
label this image

A: teres minor
B: brachialis
label this image
ignore G

A: lateral head of triceps brahii
B: brachialis
C: teres minor
D: long head of triceps brachii
E: anconeus
F: infraspinatus
H: deltoideus
I: biceps brachii
J: coracobrachialis
K: medial head of triceps brachii
L: lateral head of triceps brachii
M: subscapularis
what is muscle A?

accessory head of the triceps brachii
what is muscle A?
biceps brachii
label this image
A: lateral head of triceps brachii
B: long head of triceps brachii
C: deltoideus
D: supraspinatus
E: teres major
label this image
A: subscapularis
B: teres major
C: supraspinatus
what is muscle A?
tensor fascia antebrachii
what is muscle A?
coracobrachialis
What are muscles A and B?
A: medial head of triceps brachii
B: biceps brachii
what is muscle A?
deltoideus
what is muscle A?
infraspinatus
label this image

A: supraspinatus
B: deltoideus
label mm A and B
which muscle is being held up by the glove?

A: infraspinatus
B: teres minor
glove: deltoideus
what are muscles A and B?

A: subscapularis
B: teres major
label muscles A and B

A: lateral head of the triceps brachii
B: long head of the triceps brachii
label these muscles

A: tensor fascia antebrachii
B: medial head of the triceps brachii
what structure is being pointed to?

accessory head of the triceps brachii
what structure is being pointed to?

biceps brachii
what structure is being pointed to?

brachialis
label these muscles (include ones from extrinsic forelimb)

A: omotransversarius
B: brachiocephalicus
C: rhomboideus
D: serratus ventralis
E: subclavius
F: supraspinatus
G: deltoideus
H: long head of triceps brachii
I: lateral head of triceps brachii
J: tensor fascia antebrachii
what is mm A?

cervical trapezius
what is mm A?

thoracic trapezius
what is mm A?

latissimus dorsi
this is the ventral side of the horse. what muscle is it?

pectoralis profundus
what is muscle A?
this is on the medial side of the horse. think extrinsic forelimb

superficial pectorals