Equine Skeletal System Flashcards
What is the vertebral column formula?
Cervical - 7
Thoracic - 18
Lumbar - 6
Sacral - 5
Caudal - 15 to 20
What are the 10 forelimb bones and joints?
- scapula
- shoulder
- humerus
- elbow
- radius and ulna
- knee (carpus)
- cannon and 2 splint bones (metacarpals)
- fetlock
- long pastern, short pastern and pedal bone (3 phalanges)
- sesamoid bones (2 sesamoid)
What are the 10 hindlimb bones and joints?
- pelvis
- hip
- femur
- stifle joint and patella
- tibia and fibula
- hock (tarsus)
- cannon and 2 splint bones (metatarsals)
- fetlock
- long pastern, short pastern and pedal bone (3 phalanges)
- sesamoid bones (2 sesamoid)
What are the 4 synovial joints?
Spheroidal (ball and socket)
Hinge
Plane
Pivot
What is the spheroidal joint?
(ball and socket)
- the most moveable joint
- shoulder and hip joints
What is the hinge joint?
- allows movement in 1 plane only
- pedal bone, short pastern and long pastern bones
What is the plane joint?
- the least moveable, slide over each other
- carpal (knee) and tarsal (hock)
What is the pivot joint?
- allows movement round 1 axis and rotational movement
- joint between axis and atlas, allows head to rotate to a limited extent
What are tendons?
- tendons are fibrous cords of connective tissue that attach skeletal muscles to bones, they are relatively inelsatic but are made up of crimped fibres giving slight ability to lengthen
Where do tendons originate?
- they originate from bone and attach to bone
What are ligaments?
- the suspensory ligament of the horse differs from other ligaments in that it is a modified muscle
- meaning its more elastic than other ligaments
What are the 4 ligaments?
Supporting or suspending
Annular
Inter-osseous
Funicular (or cord like)
What is an example of a supporting/suspending ligament?
- suspensory ligament
What is an example of an annular ligament?
- broad bands composed of deep fascia, which fold around tendons to maintain alignment and in effect, direct the pull on a tendon
What is an example of an inter-osseous ligament?
- it ties bones together
- for example the pedal and navicular bones
What is an example of a funicular ligament?
- holds bones together
- collateral ligaments, which are of the funicular type, are situated at the side of a joint
What are the 4 types of tendons?
Common digital extensor tendon
Lateral digital extensor tendon
Deep digital flexor tendon
Superficial digital flexor tendon
What is the origin and insertion of the common digital extensor tendon?
Origin - distal humerus
Insertion - phalange all bones 1, 11 and 111
What is the action for the common digital extensor tendon?
- extends the lower limb and foot
- flexes the elbow
What is the origin and insertion of the lateral digital extensor tendon?
Origin - lateral elbow
Insertion - phalangeal bone 1
What is the action of the lateral digital extensor tendon?
- helps to straighten and extend the lower leg
What is the origin and insertion of the deep digital flexor tendon?
Origin - medial humerus and ulna
Insertion - palmar aspect of phalangeal bone 111 (pedal bone)
What is the action for the deep digital flexor tendon?
- flexes the joints of the lower leg
- extends the elbow
What is the origin and insertion of the superficial digital flexor tendon?
Origin - medial humerus and caudal radius
Insertion - back of long and short pastern bones (phalangeal bones 1 and 11)
What is the action of the superficial digital flexor tendon?
- extends the elbow
- flexes the carpus and phalangeal bones
What is the stay apparatus?
- this is a group of ligaments, tendons and muscles which lock joints in the limbs of the horse
What does the stay apparatus allow?
- allows the horse to enter a light sleep while standing
- allows for each limb to rest
What is the suspensory apparatus?
- this is part of the stay apparatus which supports fetlock and prevents it form falling to the ground
- also supports the pastern joint
What does the suspensory apparatus consist of?
- it consist of intraosseous muscle which has been replaced by fibrous material to form the suspensory ligament
Where is the suspensory ligament located?
- it lies between the deep digital flexor tendon and the cannon bone
- it splits at the level of the sesamoid bone
What does the suspensory ligament do?
- it joins the common digital extensor tendon at the front of the pastern
- it prevents over extension of the fetlock joint
What is the stifle locking stifle?
- found in the hind leg
- allows the horse to immobilise the stifle joint
What happens in the stifle locking system?
- to lock the stifle the joints extend past certain points and then cartilage hooks onto trochlea tubercle, and medial and patella ligaments are stabilised over the medial ridge
- this locks the join tin plate without any effort
Where does the stifle locking system occur?
- trochlear groove of femur and patella
-> 3 patella ligaments and medial patella cartilage
-> medial ligaments attaches to this cartilage
What is the reciprocal?
- the final component of the stay apparatus
- when the stifle is in extension the hock is also in extension due to muscle attachments
- when the femur moves caudal the distal limb moves causally and vice versa
What are the 5 functions of muscles?
- carry out intricate manoeuvres
- contract and initiate movement
- stabilise joints
- maintain posture
- aid temperature control (shivering)
What are intramuscular injection sites?
- superficial gluteal
- biceps femoris
- abdominal oblique
- medial gluteal
- quadriceps femoris
- gastrocnemius
