Vertebral Column

body

- disc-shaped The anterior portion of the vertebra - is the weight-bearing region of the vertebra.

transverse ridge

- lines that cross the anterior surface of the sacrum marking lines of fusions of sacral vertebrae

transverse costal facet

-articulates with tubercle of rib - located on transverse processes

anterior sacral foramina

passageways for ventral rami of spinal nerves

inferior costal facet

receive the head of the ribs on the inferior side; only in thoracic vertebrae

superior costal facet

receive the head of the ribs on the upper side; only in thoracic vertebrae

median sacral crest

- located on the midline of the posterior surface of the sacrum -represents the fused spinous processes of the sacral vertebrae.

nucleus pulposus

- the inner sphere in an intervertebral disc -is gelatinous and acts like a rubber ball, enabling the spine to absorb compressive stress

lateral sacral crest

-, representing the tips of the transverse processes of the sacral vertebrae

sacral hiatus

-The laminae of the fifth (and sometimes the fourth) sacral vertebrae fail to fuse medially, leaving an enlarged external opening -Opening at inferior end of sacrum on posterior side Used as a route to administer an epidural anesthetic

vertebral foramen

-The large hole encircled by the body and vertebral arch is the -Successive structures of these of the articulated vertebrae form the long vertebral canal, through which the spinal cord and spinal nerve pass

posterior longitudinal ligament

-The posterior longitudinal ligament, which is narrow and relatively weak, attaches only to the intervertebral discs. This ligament helps to prevent hyperflexion (bending the vertebral column too sharply forward).

vertebral column

-also called the spinal column or spine, consists of 26 bones connected into a flexible, curved structure. -The main support of the body axis, the vertebral column extends from the skull to the pelvis, where it transmits the weight of the trunk to the lower limbs. -It also surrounds and protects the delicate spinal cord and provides attachment points for the ribs and for muscles of the neck and back.

laminae

-are flat, bony plates that complete the vertebral arch posteriorly, extending from the transverse processes to the spinous process.

pedicles

-are short, bony walls that project posteriorly from the vertebral body and form the sides of the vertebral arch

vertebral arch

-forms the posterior portion of the vertebra. It is composed of two pedicles and two laminae -protects the spinal cord and spinal nerves located in the vertebral foramen.

Coccyx

-four vertebrae fused together to form the tailbone - lowest part of the vertebral column

anterior longitudinal ligament

-is a wide ligament and attaches strongly to both the bony vertebrae and the intervertebral discs. Along with its supporting role, this thick anterior ligament prevents hyperextension of the back

spinous process

-is the median, posterior projection arising at the junction of the two laminae -site for muscles and ligaments that move and stabilize the vertebral column.

transverse foramen

-only found in the cervical vertebrae and allow passage of the vertabral artery, vein, and nerve - These vessels ascend and descend through the neck to help serve the brain.

superior articular processes

-project upward from one vertebra's pedicle-lamina junction and meets inferior articular processes from the vertebra above -- form moveable joints between each successive vertebrae

transverse process

-s projects laterally from each pedicle-lamina junction. are attachment sites for the muscle and ligaments.

Atlas

-the first cervical vertebra (C1) -lacks a body and a spinous process -it is a ring of bone consisting of anterior and posterior arches, plus a lateral mass on each side. -superior articular facets receive the occipital condyles of the skull -These joints participate in flexion and extension of the head on the neck, as when you nod "yes." The inferior articular facets form joints with the axis

posterior sacral foramina

-which transmit the dorsal rami of the sacral spinal nerves

lumbar vertebrae

5 vertebrae in lower back

cervical vertebrae

7 vertebrae of the neck

vertebra prominens

C7 -the spinous process is not forked and is much larger than those of the other cervical vertebrae

-The vertebrae become progressively larger from the cervical to the lumbar region as the weight they must support progressively increases

How does the size of vertebrae change as you go down the vertebral column?

-The discs are thickest in the lumbar (lower back) and cervical (neck) regions of the vertebral column

How does the thickness of the intervertebral discs vary?

-In the fetus and infant, the vertebral column consists of 33 separate bones, or vertebrae (ver′te-bre). -Inferiorly, nine of these eventually fuse to form two composite bones, the sacrum and the tiny coccyx (tailbone). -The remaining 24 bones persist as individual vertebrae separated by intervertebral discs.

How many vertebrae are in infants and how many are present in adults?

-Their bodies are massive and appear kidney-shaped from a superior view -The pedicles and laminae are shorter and thicker than those of other vertebrae. • The spinous processes are short, flat, and hatchet-shaped, and they project straight posteriorly. These processes are robust for the attachment of large back muscles. • The vertebral foramen is triangular. - transverse processes are thin and tapered • The superior articular facets face posteromedially (or medially), - the inferior articular facets face anterolaterally (or laterally) , oriented approximately in the sagittal plane. Movement:Flexion and extension; some lateral flexion; rotation prevented

What are the characteristics of Lumbar vertebrae

inferior articular processes

articular processes that protrude below from the pedicle lamina junctions - form moveable joints between each successive vertebrae

sacrum

bone formed from five vertebrae fused together near the base of the spinal column -articulates with the hip bones of the pelvis.

sacral canal

continuation of vertebral canal -central canal transmitting the dorsal and ventral roots of spinal nerves S1 to S6 and the coccygeal spinal nerve.

intervertebral discs

fibrocartilage pads that separate and cushion the vertebrae - composed of the nucleus pulposus and the anulus fibrosus

anulus fibrosis

outer collar of intervertebral disc composed of collagen and fibrocartilage -, the outer rings consist of ligament and the inner ones consist of fibrocartilage. The main function of these rings is to contain the nucleus pulposus, limiting its expansion when the spine is compressed. -However, the rings also function like a woven strap, binding the successive vertebrae together, resisting tension on the spine, and absorbing compressive forces. Collagen fibers in adjacent rings cross like an X, allowing the spine to withstand twisting.

facets

smooth joint surfaces of the articular processes covered with hyaline cartilage

intervertebral foramina

lateral openings between adjacent vertebrae for spinal nerves - created by notches between superior and inferior borders of the pedicles

-• The body is small, wide side to side (wider laterally than in the anteroposterior dimension.) • Except in C7, the spinous process is short, projects directly posteriorly, and is bifid (bi′fid; "cleaved in two"), or forked; that is, it is split at its tip. -The vertebral foramen is large and generally triangular. • Each transverse process contains a hole, a transverse foramen, through which the vertebral blood vessels pass. These vessels ascend and descend through the neck to help serve the brain. • The superior articular facets face superoposteriorly, whereas the inferior articular facets face inferoanteriorly. -Thus these articulations lie in an oblique plane. The orientation of these articulations allows the neck to carry out an extremely wide range of movements: flexion and extension, lateral flexion, and rotation. Spine region with greatest range of motion

What are the characteristics of Typical Cervical Vertebrae, C3-C7

This condition usually involves rupture of the anulus fibrosus followed by protrusion of the nucleus pulposus. -Aging is a contributing factor, because the nucleus pulposus loses its cushioning properties over time, and the anulus fibrosus weakens and tears. -This mechanical fatigue allows the nucleus to rupture through the anulus. -The anulus is thinnest posteriorly, but the posterior longitudinal ligament prevents the herniation from proceeding directly posteriorly, so the rupture proceeds posterolaterally—toward the spinal nerve roots exiting from the spinal cord

What are the characteristics of a herniated disc?

-body is larger than cervical; heartshaped; there are superior and inferior costal facets near pedicle . Laterally, each side of the vertebral body has two facets, commonly referred to as demifacets (dem′e-fas″ets). For most ribs, the head of the rib is attached to the bodies of two vertebrae, the inferior costal facet of the superior vertebra and the superior costal facet of the inferior vertebra. -Vertebra T1 differs from this general pattern in that its body bears a full facet for the first rib and a demifacet for the second rib; furthermore, the bodies of T10-T12 have only single facets to receive their respective ribs. -• The spinous process is long and points inferiorly. • The vertebral foramen is circular. • With the exception of T11 and T12, the transverse processes have facets that articulate with the tubercles of the ribs called transverse costal facets -Movements: Rotation; lateral flexion possible but restricted by ribs; flexion and extension limited

What are the characteristics of thoracic vertebrae?

(1) flexion and extension (anterior bending and posterior straightening of the spine), (2) lateral flexion (bending the upper body to the right or left), and (3) rotation, in which the vertebrae rotate on one another in the long axis of the vertebral column

What are the three general movements of the spine

-Only the thoracic and sacral curvatures are well developed at birth. Both of these primary curvatures are convex posteriorly, so that an infant's spine arches (is C-shaped) like that of a four-legged animal. -The secondary curvatures, the cervical and lumbar curvatures, are concave posteriorly and develop during the first 2 years of childhood as the intervertebral discs are reshaped -The cervical curvature is present before birth but is not pronounced until the baby starts to lift its head at 3 months, and the lumbar curvature develops when the baby begins to walk, at about 1 year.

What spinal curvatures are well developed at birth and what shape do they form?

Cervical and Lumbar curvatures- concave Thoracic and Sacral curvatures-convex

What types of curvature in the spine are concave posteriorly and convex posteriorly?

sacral promontory

Where the first sacral vertebrae bulges into pelvic cavity - anterosuperior margin into anterior cavity -The human body's center of gravity lies about 1 cm posterior to this landmar

-. Collectively, the intervertebral discs make up about 25% of the height of the vertebral column. As a result of compression and loss of fluid from the gelatinous nucleus pulposus, they flatten somewhat by the end of each day. So, you are probably 1 to 2 centimeters shorter at night than when you awake in the morning.

Why are you slightly taller earlier in the day than later in the day?

ala

Winglike tip of the outer side of the sacrum -articulate at the auricular surface with the two hip bones to form the sacroiliac (sa″kro-il′e-ak) joints of the pelvis

ligamentum flavum

a posterior ligament that connects the laminae of adjacent vertebrae -contains elastic connective tissue and is especially strong: It stretches as we bend forward, then recoils as we straighten to an erect position.

axis

the second cervical vertebra (C2) -has a body, a spinous process, and the other typical vertebral processes, is not as specialized as the atlas -Its only unusual feature is the knoblike dens ("tooth") projecting superiorly from its body. The dens is actually the "missing" body of the atlas that fuses with the axis during embryonic development -, the dens acts as a pivot for the rotation of the atlas and skull. Hence, this joint participates in rotating the head from side to side to indicate "no."

thoracic vertebrae

the second set of 12 vertebrae; form the outward curve of the spine and are known as T1 through T12