Page 334 - Kinesiology of the musculoskeletal system foundations for physical rehabilitation

310 Section III Axial Skeleton laminae, and articular processes, collectively referred to as
external occipital protuberance to the base of the mastoid posterior elements (also referred to as the “vertebral arch” or
process of the temporal bone. This thin but distinct line “neural arch”). The pedicles, the third section, act as bridges
marks the attachments of several extensor muscles of the head that connect the body with the posterior elements. Thick and
and neck, such as the trapezius and splenius capitis muscles. strong, the pedicles transfer muscle forces applied to the
The inferior nuchal line marks the anterior edge of the attach- posterior elements forward, for dispersion across the vertebral
ment of the semispinalis capitis muscle. body and intervertebral discs. Table 9-2 provides greater
details on the structure and function of the components of a
Relevant Osteologic Features typical midthoracic vertebra.

Tem• pMoraasl tBoiodneprocess RIBS
Oc••••••ci pIEOSFBintouxaacfrstpecleaierlirmBapirnoiroieoatrnpnalrnelaonmurcctucocahcnighpadnaliytullalmilelnisnpeerotuberance Twelve pairs of ribs enclose the thoracic cavity, forming a
protective cage for the cardiopulmonary organs. The poste-
The foramen magnum is a large circular hole located at the rior end of a typical rib has a head, a neck, and an articular
base of the occipital bone, serving as the passageway for the
spinal cord. A pair of prominent occipital condyles projects Vertebral artery Sympathetic ganglion
from the anterior-lateral margins of the foramen magnum, Ventral nerve root Transverse process
forming the convex component of the atlanto-occipital joint. Superior articular (anterior tubercle)
The basilar part of the occipital bone lies just anterior to the Spinal nerve
anterior rim of the foramen magnum. facet root
Ventral ramus of
VERTEBRAE: BUILDING BLOCKS OF THE SPINE Spinal cord spinal nerve
In addition to providing vertical stability throughout the Dura mater Transverse process
trunk and neck, the vertebral column protects the spinal cord, (posterior tubercle)
ventral and dorsal nerve roots, and exiting spinal nerve roots Dorsal ramus of
(Figure 9-4). The relationship between the spinal cord and spinal nerve
exiting nerve roots throughout the entire vertebral column is
schematically shown in Figure III-1 in Appendix III, Part A. Dorsal root ganglion

The midthoracic vertebrae demonstrate many of the essen- Dorsal nerve root
tial anatomic and functional characteristics of any given ver-
tebra (Figure 9-5). As a general orientation, a given vertebra FIGURE 9-4. A cross-section of a spinal cord is shown. Note the
can be subdivided into three sections. Anteriorly is the large relationship among the neural tissues, components of the cervical
vertebral body—the primary weight-bearing component of a vertebra, and the vertebral artery. (Modified with permission from
vertebra. Posteriorly are the transverse and spinous processes, Magee DL: Orthopedic physical assessment, ed 3, Philadelphia,
1997, Saunders.)

Lateral view

Superior articular facet Superior articular process

Transverse process Superior costal demifacet Superior view
Costal facet Spinous process
T6 Transverse process
Intervertebral foramen Intervertebral Laminae
Apophyseal joint disc 6th rib Costal
facet
Spinous process T7
Pedicle
Vertebral
canal

Pedicle Costotransverse joint Superior costal
Superior articular facet T6 facet
Inferior Inferior
costal
A articular B Costocorporeal joint Body
process demifacet

FIGURE 9-5. The essential characteristics of a vertebra. A, Lateral view of the sixth and seventh vertebrae (T6
and T7). B, Superior view of the sixth vertebra with right rib.