Postcranial (Axial) Flashcards
1
Q
Axial Skeleton
A
Skull, vertebrae, ribs, sternum
2
Q
Evolutionary Trends
A
- Some vertebral elements enlarge while others regress
- The vertebral elements displace the notochord as the primary mechanical axis
- Vertebral segments differentiate
Fish: Trunk, caudal
Tetrapods: Cervical, thoracic, lumbar, sacral, caudal
3
Q
Function of vertebrae?
A
- protect spinal chord and dorsal aorta
- later on became attachment points for trunk muscles and to support for swimming
- in tetrapods, include suspension against gravity and withstand force
4
Q
Aspondyly (# of centrum)
A
No centra
5
Q
Monospondyly
A
1 centra
6
Q
Dispondyly
A
2 centra
7
Q
Polyspondyly
A
Multiple centra
8
Q
Amphicoelous
A
- both ends concave
- limited motion (fish)
9
Q
Procoelous
A
- anterior end concave, posterior convex
- extensive motion (snakes)
10
Q
Opisthocoelous
A
- anterior end convex, posterior end concave
- extensive motion (hoofed mammals)
11
Q
Acoelous
A
- both ends flat
- limited motion, good to receive compressive force (most mammals)
12
Q
Heterocoelous
A
- saddle shaped
- allow for flexion, but prevent rotation (birds)
13
Q
Diapophysis
A
Rib attachment on neural arch for tuberculum of dorsal rib
14
Q
Parapophysis
A
Rib attachment on centrum for capitulum of dorsal rib
15
Q
Basapophysis
A
attachment for ventral rib
16
Q
Cervical Region
A
- neck region
- amphibians: only 1
- aves: 12 -25
- reptiles and mammals: 6-9 (mammals have 7)
17
Q
Thoracic Region
A
anterior trunk with ribs
18
Q
Lumbar Region
A
posterior trunk without ribs
19
Q
Sacral Region
A
vertebrae attached to pelvic girdle
20
Q
Caudal Region
A
Tail region posterior to sacrum
21
Q
Rib Function
A
- muscle attachment
- protective case for organs
- respiration in tetrapods
22
Q
Rib Development
A
sclerotome within myosepta
23
Q
A
