Old Exam Flashcards
Generally, muscles that contract to make the angle of a joint more narrow are:
Flexors
Generally, muscles that contract to make the angle of a joint wider are:
Extensors
If the shape of the joint allows, muscles may also move the bones sideways, toward the body:
Adductors
If the shape of the joint allows, muscles may also move the bones sideways, away from it (_____).
Abductors
Generally, extensor muscles are located on the _____ side of the limb.
Cranial and dorsal
Generally, flexor muscles are located on the _____ side of the limb.
Caudal and palmar
Muscles that move the forelimb forward:
Brachiocephalicus
Omotransversarius
Sternomandibularis
Biceps brachii
Brachialis
Extensor carpi radialis
Common and lateral digital extensors
Thoracic portion of trapezius
Subclavicus
Supraspinatus
Muscles that draw the limb backward:
Latissimus dorsi
Teres major
Superficial and deep digital flexor
Long and lateral head of triceps brachii
Subscapularis
Flexor carpi radialis and ulnaris
Rhomboideus
Biceps femoris (2 heads)
Joints and action
Hip and stifle joints
Extends hip, stifle and hock
Abductor
Common and lateral digital extensor
Joints and action
Extend carpus and foot joints
Front limb
Superficial and deep digital flexor
Flexes carpus and foot joints
Front limb
Brachiocephalicus and omotransversarius
Limb and action
Neck muscles/Front limb
Bring the limb forward
Muscles that flex the hip, extend the stifle and abduct the hind limb
Fascia glutea, superficial gluteus, and tensor fascia lata
When _____ is the main fuel = aerobic
When _____ is the main fuel = anaerobic
Oxygen - aerobic
Glycogen - anaerobic
_____ heads attach to actin and shorten the sarcomere as they contract and relax
Myosin
Horse limb anatomy is important to learn because the value of horses lies in their ability to _____
Move
Muscles can only _____ and relax.
When a muscles passes over the apex of a joint it causes the joint to _____
Contract
Extend
5 Functions of the Skeleton
Protect internal organs
Give muscles something to attach to for movement
Give the body structure
4 Functions of Skeletal muscles
Move Skeleton
Support Skeleton
Maintain joint stability
Produce heat by shivering
Define reciprocal apparatus
The hock cannot move without the stifle
Gluteal tongue - why is it important?
Gives muscle more surface area to be able to control the force and connect the hindlimb to the frontlimb so the horse can move properly and project motion from the hind limb forward to the front limb
Explain the bow and string system
The back muscles hollow the back when they contract, so in order to round the back abdominals need to contract so it holds the back taut.
The rider is the “arrow”
The back is the “bow”
Abdominals are the “string”
Muscles most important to ridden horse
Iliopsoas and psoas
Horse’s natural response to weight of a rider
Tense the psoas and iliopsoas - which prevents him from stepping under with hind legs
If these muscles do not soften and become supple, the horse will never engage his hindquarters correctly. Structures in mid-back and stifle bear brunt of power produced by hind limb muscles, which become damaged in the process
Warm-up exercises to unlock these muscles
Describe Type I muscle fibers
Slow twitch fibers
Highly oxidative
Endurance horses (slow to fatigue)
Narrow
Less power
1 motor neuron per 20-30 muscle fibers
Describe Type IIA
Fast twitch fibers
Highly oxidative
Good for race horses
High myoglobin (oxygen use)
Describe Type IIB
Fast twitch fibers
Low oxidative
Good for bursts of energy (rapidly fatigued)
Ex: Quarter horses barrel racing
White sprint muscle
1 motor neuron per 2,000 muscle fibers
Why is it hard to breed a race horse to run 1 1/4 miles
Because its longer than a sprint race and shorter than an endurance race. Horses need sprinting muscles that can last a long time. Type IIA is the best for race horses to have as it is in between.
