Spinal Osteology Flashcards
Vertebrae- number of each
Total: 33 7 cervical 12 thoracic 5 lumbar 5 sacral (fused) 4 coccygeal (usually fused)
Note: Sacral fusion patterns vary in approximately 5% of the population:
Sacralization- fusion of the fifth lumbar vertebra with the sacrum
Lumbarization- lack of fusion of the first sacral vertebra with the sacrum.
Vertebrae become larger inferiorly in accordance with the increase in the weight bearing function.
Typical vertebra: Body
largest, most anterior portion
composed of spongy (cancellous) bone covered with a thin layer of compact (cortical) bone.
cylindrically shaped having roughened ends covered with hyaline cartilage
epyphyseal rim (uncus)- thickening of compact bone located at the extreme cylindrical margin of the superior and inferior ends of the vertebral bodies.
Clinical correlation: demineralization of the spongy bone
the structural integrity of the vertebra is compromised resulting in compression fractures.
Typical vertebra: vertebral arch
Pedicles- posterolateral processes which project from teh body bilaterally.
- Vertebral notches- superior and inferior indentations of the pedicle. When articulated these indentations on contiguous vertebrae help from intervertebral foramina which allow for passage of the spinal nerves and vessels.
Laminae- continuation of pedicles posteromedially; fuse win the midline to complete the vertebral arch and enclose the vertebral foramen.
Typical vertebra: processes
a. Transverse bilateral extensions of bone directed lateralward from the junction of the pedicle and lamina
b. Articular- four in number, two superior and two inferior, located at the junction of the pedicle and lamina; orientation of articular facets determine regional movement.
c. Spinous- posteriorly directed extension of bone formed by the union of two laminae
Cervical vertebrae: body
Body- small, lateral dimension is greater than anterior/ posterior dimension
Cervical vertebrae: transverse proceses
Arises from the junction of the pedicle and articulating processes,
directed anterolateral,
anteriorly attached to costal processes which project from the body of the vertebra thereby forming the COSTOTRANSVERSE FORAMEN (TRANSVERSE CERVICAL FORAMEN),
osseous connection between the costal process and transverse process is grooved on its superior surface for passage of the spinal nerve
Articulating processes: located posterior to the transverse process, facets are flat and oval shaped and oriented obliquely in the coronal plane, superior facets are directed upward and backward, inferior facets are directed downward and forward
What items traverse the costotransverse foramen
(= transverse cervical foramen)
The vertebral artery, vein, and sympathetic nervous plexus
Costal and transverse processes end laterally by forming…
anterior and posterior tubercles, respectively, which provide sites for attachment of neck and superficial back musculature
Cervical vertebrae spinous processes
short, bifid, downward projecting
Cervical vertebral arch or foramen
TRIANGULARLY shaped with apex directed posteriorly
Atlas
The first cervical vertebra does not possess a body. Instead it is constructed of two lateral masses connected by anterior and posterior arches.
Anterior arch of atlas
tubercle, facet for dens of CV2 (axis)
Posterior arch of atlas
tubercle, sulcus for vertebral artery
Atlas: lateral masses
large articulating facets.
Superior- articulate with the occipital condyles of the skull
Inferior- articulate with the superior articulating facets of the axis.
Transverse process- well developed to provide attachment sites for muscles which rotate the head.
Transverse crvical foramina are large, located close to the articulating facets and have continuity with the sulcus for the vertebral artery on the superior surface of hte posterior arch.
