Vertebral Column Structure, Regional Differences, and the Bony Thorax

(pages 154-158)

Body or centrum

disclike, weight-bearing part of the vertebra facing anteriorly in the vertebral column

Vertebral arch

arch formed from the joining of all posterior extensions, the laminae and pedicles, from the vertebral body

Vertebral foramen

canal through which the spinal cord passes

Transverse processes

two lateral projections from the vertebral arch

Spinous process

single projection arising from the posterior aspect of the vertebral arch (actually the fused laminae)

Superior and inferior articular processes

paired projections lateral to the vertebral foramen, allowing a vertebra to form joints with adjacent vertebrae

Cervical Vertebrae

the seven vertebrae (C1 to C7) that form the neck region of the spine

atlas (C1)

the first cervical vertebra that has no body and contains depressions that receive the occipital condyles of the skull

axis (C2)

the second cervical vertebra that acts as a pivot for the rotation of the atlas (and skull) above

dens

a large upright process on the axis that acts as the pivot point

typical cervical vertebrae

C3 through C7, which are the smallest and lightest vertebrae, and most often their spinous processes are short and divided into two branches

foramina

openings in the transverse processes of the cervical vertebrae through which the vertebral arteries pass on their way to the brain

Thoracic Vertebrae

The 12 thoracic vertebrae (T1 to T12) that are the only vertebrae to articulate with the ribs

costal facets

articulating surfaces on the body of thoracic vertebrae which receive the heads of the ribs

Lumbar Vertebrae

The five lumbar vertebrae (L1 to L5) that have massive, blocklike bodies and are the sturdiest of the vertebrae

Sacrum (sa′krum)

composite bone formed by the fusion of five vertebrae

alae

winglike lateral parts of the sacrum that articulate with the hip bones, forming the sacroiliac joints

median sacral crest

the roughened posterior midline surface of the sacrum, formed by the fused spinous processes

sacral canal

the continuation of the vertebral canal inside the sacrum

sacral hiatus

a large inferior opening where the sacral canal terminates

Coccyx

formed from the fusion of three to five tiny, irregularly shaped vertebrae, often called the human “tailbone”

bony thorax

composed of the sternum, ribs, and thoracic vertebrae, routinely called the thoracic cage

thoracic cage

protective, cone-shaped cage of slender bones around the organs of the thoracic cavity

Sternum (breastbone)

a typical flat bone and the result of the fusion of three bones

manubrium (mah-nu′bre-um)

the superior bone fused to form the sternum

body

the middle bone fused to form the sternum

xiphoid (zif′oid) process

the most inferior bone fused to form the sternum

jugular notch

concave upper border of the manubrium, easily palpated

sternal angle

results where the manubrium and body meet at a slight angle, serving as a reference point for counting ribs

xiphisternal (zi′fe-ster″nal) joint

the point where the sternal body and xiphoid process fuse, lying at the level of the ninth thoracic vertebra

true ribs

the first seven pairs of ribs that attach directly to the sternum by costal cartilages

False ribs

the next five pairs of ribs that either attach indirectly to the sternum or are not attached to the sternum at all

floating ribs

the last two pairs of false ribs, which lack sternal attachments