Post-cranial Skeleton Flashcards
What is the post-cranial skeleton
Everything other than the cranium
What does the axial skeleton consist of
Skull (cranium)
Vertebrae
Ribs
Sternum
What does the appendicular skeleton consist of
Fins
Limbs
What are the functions of the vertebrae
Protects spinal cord and dorsal vessels
Provides muscle attachment
Suspend body
Locomotion
What is the notochord
A fluid filled, callagneous rod
Where does the notochord run from
Runs along the longitudinal axis of the body
What does the vertebral column develop around
Notochord
Where is the notochord located
Ventral to the developing spinal cord
What do fish vertebrae look like
Similar all the way down
What are the two regions of fish vertebral column
Trunk and caudal
Why are fish vertebral columns undifferentiated
Due to not supporting body
Fish vertebrae are tall and thin allowing what
Undulating movement and preventing telescoping
The centrum in fish vertebrae are typically what
Amphicoelous
In fish what does the heterocercal tail do
Generates lift
Where would you find a heterocercal tail
Chrondrichthyes
Where would you find a homocercal tail
Osteichthyes
Where is the heterocercal tail directed
Vertebrae directed dorsally
Where are homocercal tail directed
Neural spines and central directed dorsally, he also spine elongate and match them ventrally
What is regionalisation
Progression from water to land
What does regionalisation increase
Impact of gravity and force of locomotion
How many cervical vertebrae do amphibians have
One single
What does an amphibians cervical vertebrae articulate with
The skull
What is the name for the amphibian centrum
Ossified opistocoelus centrum
What does the Ossified opistocoelus centrum in amphibians allow for
Strength for weight-bearing on land
Name the 4 vertebrae in amphibians
Cervical, thoracolumbar, sacral and caudal
What does the single cervical vertebrae articulate with in amphibians
Skull
How many sacral vertebrae do amphibians have
1
The craniovertebral joint allows for what
Dorsoventral rocking (nodding)
What are the benefits of the craniovertebral joint in amphibians
Protects sense organs
Navigate terrain better
Describe reptilian vertebrae
Procoelous
Ball and socket intervertebral articulation
What are all the parts to the reptilian vertebral column
8 cervical
Thoracolumbar
2 sacral
Caudal
How many cervical vertebrae do aves have
High amount
Cervical vertebrae articulate in what way
Saddle shaped articulations
Are the thoracic vertebrae fused or not fused in aves
Fused
What parts of the vertebral are fused to the synsacrum
Thoracic, lumbar, sacral, proximal caudal vertebrae
What does the fused synsacrum in abes allow for
Provides rigidity for flight, indirectly reduces muscle bulk (makes bird lighter)
Where are the ribs found in a mammalian
Thoracic region
How many cervical vertebrae do Mammals have
7
How many thoracic vertebrae mammals have
15-20
How many sacral vertebrae do mammals have
2-3 fused
How many sacral vertebrae do humans have
5 fused
What does the intervertebral disc in mammals consist of
A central gel (nucleus pulposus), remains of notochord
When is the neural spine weaker and stronger
Bone is weak under tension/ torque forces
Stronger under compression
How do neural spines orientate themselves
Parallel to forces from cranial and caudal musculature
To increase force in neural spine what do you need to increase
Increase muscles or increase height of neural spine
What are ribs associated with in fish
The trunk region
What are the two sets of ribs in fish called
Ventral and dorsal
At amphibians ribs short or long? What is the exception
Short. Except in limbless amphibians where they play a locomotor role
Are reptilian ribs long or short
Long
What region to reptilians have ribs in
Cervical and thoracic
What type of ribs do “Draco” have
Extended ribs in the mid-thoracic region that assist in gliding
Describe avian ribs
Thin and broad
What purpose do ribs provide in an avian
Support muscle attachment needed for flight
What is the unicate process
Reinforces the rib cage aid in flight and breathing mechanics
What is unique about the first thoracic ribs in avians
They are floating
What do ribs attach to in mammals
The centrum and transverse process of vertebrae
Name the three parts to the sternum
Manubrium
Body of sternum
Xiphoid process
