Skeleton Flashcards
How many cervical vertebrae do mammals have?
7
How many cervical vertebrae do avians have?
8-25
How many thoracic vertebrae do dogs have?
13
How many thoracic vertebrae do horses have?
18
How many thoracic vertebrae do cows have?
13
How many thoracic vertebrae do pigs have?
14-16
How many lumbar vertebrae do dogs have?
7
How many lumbar vertebrae do horses have?
5-6
How many lumbar vertebrae do cows have?
6
How many lumbar vertebrae do sheep have?
6-7
How many lumbar vertebrae do pigs have?
6-7
How many sacral vertebrae do dogs have?
3
How many sacral vertebrae do horses have?
5
How many sacral vertebrae do cows have?
5
How many sacral vertebrae do sheep/goats have?
4 sheep
5 goats
How many sacral vertebrae do pigs have?
4
How many caudal vertebrae do dogs have?
20-23
How many caudal vertebrae do horses have?
20
How many caudal vertebrae do bovine have?
18-20
How many caudal vertebrae do sheep have?
16-18
How many caudal vertebrae do pigs have?
20-23
How many caudal vertebrae do avians have?
5-6
How many thoracic vertebrae do avians have?
3-10
What is the shape of the caudal thoracic vertebrae to the tail?
A straight horizontal line (generally)
What is the shape created by the thoracic vertebrae?
A downward slope.
Why is the downward slope in the thoracic vertebrae not visible?
Due to the hight of the spinous processes of thoracic vertebrae.
How does the shape of the sternum vary?
- Cylindrical in dogs
- Wide/flat in ruminants
- Ventral keel in equine
How many articulations do ribs make with the vertebral column?
2
What are the functions of the vertebral column?
1) Protection of spinal cord
2) Weight bearing + muscle insertion
3) Locomotion
What animal has the spinal column very involved in locomotion?
Cats - flexibility of vertebral column is involved in motion
What is the motion allowed in the cervical region of the spine?
- Mainly flexion/extension
- Some lateral movement
- No rotation (except in C1/C2 joint)
What is the motion allowed in the thoracic region of the spine?
- Lots of axial rotation
- Flexion/extension in all directions
What is the motion allowed in the lumbar region of the spine?
- Mainly medial/lateral flexion/extension
- Some dorsal/ventral
- Little axial rotation
What are characteristics of cervical vertebrae?
- Short spinous process
- Branching transverse process
- Articular processes mainly in dorsal/ventral plane to allow flexion and extension
What animals have more rotation in their cervical region?
Birds due to having more cervical vertebrae
What vertebrae does not have a body?
Atlas (C1)
The ____ of the atlas interact with the ____ of the skull.
Indentations, occipital condyles
Which animals lack a transverse foramen in their atlas?
Cows, pigs, and sheep.
What is the dens?
A spout projection of C2 that fits against the ventral part of C1.
It is embryonically a portion of C1 that has fused with C2.
Where does the axial rotation of the head come from?
The joint between atlas and axis.
What are the features of thoracic vertebrae?
- Long spinous process
- Stubby transverse processes
- Costal facets for rib articulation
What is the function of tall spinous processes in thoracic vertebrae?
More muscle action
How does costal cartilage change with age?
More flexible in younger animals.
What is the manubrium?
The most cranial sternebra.
How does the shape of the manubrium vary between species?
- Rod shaped in dogs/cats
- Laterally compressed in large species
Which vertebrae are most variable between species?
Lumbar
What are the features of lumbar vertebrae?
Short spinous processes, long flat transverse processes, longer body
The sacral vertebrae form the…
Dorsal wall of the pelvic cavity.
How can the number of fused sacral vertebrae be determined?
- If spinous processes are visible, the number of spinous processes
- Sacral foramen
What are features of caudal vertebrae?
- Appear like smaller lumbar vertebrae but become more rod-like as they progress caudally
- Hemal arch (chevron) -ventral structure that protects the caudal artery, not present in all species
What is a feature of the avian pelvis?
The pubic bones are not fused.
Which animals do not have an acromion?
Pigs and horses
Which species has an intermediate tubercle?
Equine
What is the order of metacarpal bones?
1 is most medial
What species has an enlarged medial condyle of the femur?
Equine - part of passive stay
What does the word girdle refer to?
Structures attaching the limbs to the axial skeleton
The ____ has no bony articulation with the axial skeleton.
Forelimb
The pectoral girdle is designed for…
range of motion
The pelvic girdle is designed for…
propulsion.
What bone is absent in most domestic species?
The clavicle, it can be present as a small rod in dogs/cats (more often in cats)
What is the hamate process?
A fold of bone coming off the acromion. Seen in dogs and cats.
What animals have a suprahamate?
Cats
How much motion is there in the sacroiliac joint?
Not much
The flexion surface of the femur and humerus are…
in opposite directions.
Larger “bumps” on bones allow for…
stronger muscle attachment.
How does the greater trochanter vary between species?
- Roughly at the same level of the head of femur in dogs.
- The greater trochanter is taller than the head of femur in horses and cows.
The ___ has a constant diameter while the ___ thins distally.
The radius has a constant diameter while the ulna thins distally.
What is the main weight bearing bone?
Tibia
What becomes the main weight bearing bone in larger species?
The radius due to fusion with the ulna.
The fibula is reduced in…
cows and horses.
What animal has the most complete skeleton of carpal bones?
Pigs
Which metacarpal is most commonly lost?
1
How many rows of carpals and tarsals?
Carpals = 2 rows
Tarsals = 3 rows
Small animals may have an additional…
acetabular bone.
What contributes to the acetabulum?
The ilium, ischium and pubis all contribute.
In large animals, ilium brings the sacroiliac joint more…
above hip joint so weight of the trunk is more focused on the hip.
The girdle dimensions are more important in species that…
carry a single large offspring.
Reduction of the ulna is greatest in what animal?
Horse
Most movement in the forelimb occurs at
the antebrachio-carpal level.
There is virtually no movement at…
the carpometacarpal level or between neighbouring bones in a row.
Less metacarpal bones is associated with…
increased thickness of the remaining metacarpal bones.
What is the dewclaw?
The 1st digit in dogs/cats which is non-functional.
What are the functions of a skeleton?
- Mechanical - Protection, passive support (muscles = active support), motion
- Physiological - Homeostasis, hematopoesis (marrow produces blood cells)
What are the two types of bone growth?
1) Intramembranous
* Grows directly in connective tissue
* Bones grow in response to underlying soft tissue
* Most cranial bones, clavicle, scapula
2) Endochondral
* Template of cartilage ossifies
* Centers of ossification -where cartilage cells calcify
* Growth plates allow bone to grow
* Some cranial bones
What is the diagnostic value of growth plates?
Reveals approx age in X-ray based on when growth plates fuse.
What are the cons of endochondral bone growth?
Growth plates are weaker than bone, takes longer than intramembranous.
What are the different stances?
Plantigrade: walk on full length of foot (to tarsals)(humans, bears)
Digitigrade: walk on all digits (dogs, cats)
Unguligrade: walking on hooves (ruminants, horses)(horses most extreme)
How is stance related to function?
Plantigrade = stability
Unguligrade = running more efficient (longer strides)
The distal surface of the talus is flattened in…
horses.
What is the difference between metatarsals and metacarpals?
Metatarsals are 20% longer than metacarpals and more rounded in cross-section.
Which carpal bones are fused in canines?
Radial and intermediate
Which carpal bones are fused in equines?
1+2
Which carpal bones are fused in bovine?
2+3, there is no carpal 1
Which carpal bones are fused in porcine?
None
Which tarsal bones are fused in canines?
None
Which animals have the same number of tarsal bones?
Dogs and pigs.
Which tarsal bones are fused in equines?
1+2
Which carpal bones are fused in bovines?
2+3