To allow the animal to move its body for a variety of reasons e.g. finding and eating food, running from danger, grooming, etc
How can the skeleton be divided?
Into the axial and appendicular skeleton
What is included in the a) axial b) appendicular skeleton?
a) Skull and vertebral column
b) Forelimb and hindlimb
Define the following terms a) protraction b) retraction c) adduction d) abduction e) flexion f) extension?
a) Movement of the limb cranially relative to the trunk
b) Movement of the limb caudally relative to the trunk
c) Movement of the limb medially relative to the trunk
d) Movement of the limb laterally relative to the trunk
e) Folding/shortening of the limb
f) Stretching/lengthening of the limb
Describe the sequence of events that occurs during locomotion to create forward propulsion of the animal
Folding of the limb = flexion
Moving the limb forwards = protraction
Stretching the limb = extension
Moving the limb backwards or fixing the limb and move the trunk forwards relative to the limb = retraction
Describe the differences in contribution from the axial skeleton/trunk in different species
Horses have a relatively rigid vertebral column so most of the propulsion/stride length results from limb movement. Cats have a flexible vertebral column which acts like a bow to increase propulsion/stride length from limbs
How do the following components contribute to the locomotor system? a) bones b) joints c) ligaments d) muscles e) tendons f) nerve supply g) blood supply
a) Act as rigid props within the limb
b) Allow movement between bones
c) Hold bones together
d) Produces movement between bones across joints
e) Attach muscles to bone across joints
f) Control of movement
g) Metabolic support
What are the different types of bone? And what are their functions?
Long - support and leverage in limbs
Flat - large surface area for attachment and protection of underlying structures
Short - large range of movement between bones, anti-concussive/shock absorbing
Sesamoid - redirect forces where there is a change in angle, reduces friction so prevents damage
Irregular - unique
What are bony bumps called?
What are smooth areas (articular surfaces) on the surface of bones covered by?
Define these physical features that are visible in long bones on radiographs
Diaphysis = shaft
Cortex = wall
Medullary cavity = hollow centre
Epiphysis = proximal or distal end (articular surfaces located here)
Metaphysis = transition zone between epiphysis and diaphysis
Where does growth of bones occur?
At the physics/growth plate
List some of the palpable features of the scapula
What does the scapular spine divide the scapular into?
The suprascapular fossa and infrascapular fossa
Why is the caudal border of the scapula not palpable?
As it is beneath muscle
What can the acromion process be used to locate?
The shoulder joint
What part of the scapula articulates with the humerus to make the shoulder joint?
The glenoid cavity
What part of the scapula provides an area of attachment for the biceps brachii muscle?
How many centres of ossification does the scapula develop from?
What process is present in cats just proximal to the acromion process?
What is present on the scapular spine of larger species?
True or false: domestic species have a clavicle?
How are the forelimbs held onto the trunk in domestic species? What is the advantage of this?
They are held onto the trunk by muscular attachments alone. This allows the scapular to rotate along the side of the trunk (scapular glide). This results in a large range of crania-caudal movement of the forelimb relative to the trunk which in turn increases stride length when running.
Which muscle forms a sling that suspends the weight of the trunk between the forelimbs?
What are tendons and why are they advantageous?
Tendons are condensation of fibrous tissue into chords. They are less bulky across joints, and only need small areas of attachments.
What is the term for two muscles which have opposing actions?
List the extrinsic muscles of the forelimb
What is the origin and insertion of Brachiocephalicus?
O = cervical vertebrae and skull
I = humerus
What is the function of Brachiocephalicus?
What is the origin and insertion of Latissimus dorsi?
O = thoracic vertebrae
I = humerus
What is the function of Latissimus dorsi?
What is the origin and insertion of Serratus ventralis?
O = thoracic wall (ribs) and cervical vertebrae
I = Proximal scapula
Where is Serratus ventralis located?
Between the forelimb and trunk (scapula and thoracic wall)
What is the function of Serratis ventralis?
Support the weight of the trunk between the forelimbs
Cranial portion - forelimb retractor
Caudal portion - forelimb protractor
What is the origin and insertion of Trapezius?
O = cervical and thoracic vertebrae
I = proximal scapular spine
What is the function of Trapezius?
What is the origin and insertion of Pectorals?
O = sternum
I = humerus
What is the function of Pectorals?
Which extrinsic forelimb muscles are antagonistic pairs?