CVA Axial Skeleton

Lessons 9 and 10

Cranial most Sternum

manubrium

Caudal most sternum

xiphoid process

Acoelus

Ends of centrum are flat

Amphicoelus

Both ends concave

Procoelus

Cranial: concave Caudal: convex

Opisthocoelus

Cranial: convex Caudal: concave

Heterocoelus

Saddle-shaped ends

True Rib

Meet with sternum at ventral aspect

False rib

Don’t articulate with sternum

Articulate with adjacent ribs

Floating Rib

Don’t articulate with anything ventrally

Trunk Rib

Open, spider-like shape

Caudal Rib (Fish Shape)

Elongated diamond

Dorsal Ribs

Pin bones

Costo-Chondral Junction

Meeting place of ventral and sternal rib

Tuberculum

Dorsal portion of vertebral rib

Capitulum (Head)

Ventral portion of vertebral rib

Facet

Portion of vertebral body where rib articulates

Atlas

Controls nodding movement, wing shaped

Axis

Controls side to side movement, long tube shape

Pygostyle

Fused - most caudal vertebra

Cervical

Articulates vertebral column with head

• Atlas / Axis

Thoracic

Facets articulate with ribs

Lumbar

Between thoracic and sacral

Sacral

Near pelvis

Caudal

Comprises tail

Invertebral Bodies

Cushions between vertebrae

In mammals:

• Annulus fibrosis (fibrocartilage) surrounding

• Nucleus pulposus (notochord remnant)

3 origins of plastron

Clavicles (Epiplastrons), Interclavicle (Entoplastron), Gastralia (Hypoplastron and Xiphiplastron)

Uncinate Processes

Extend from rib caudally

Muscle attachment

Teleost Vertebrae - trunk

Neural spines

Ribs

No hemal spines

Teleost Vertebrae – caudal/tail

neural spine

hemal spines

no ribs

Turtle ribs and vertebrae

Thoracic vertebrae and ribs fused with carapace

Heterocoelus cervical vertebrae → movement of neck

Zygopophyses

Zygosphene and Zygantrum interlock to prevent excess twisting

Synsacrum

caudalmost thoracic

- all lumbar

- all sacral

- first caudal

Innominate Bone