Bones of the Back Region

Question 1

OCCIPITAL

Answer 1

the bone forming the posterior surface of the skull

it articulates superolaterally with the parietal bones through the lambdoid suture, anteroinferiorly with the temporal bone and anteriorly with the body of the sphenoid bone

Structures: external occipital protuberance, inferior nuchal line, superior nuchal line, occipital condyle

Question 2

external occipital protuberance (Occipital)

Answer 2

a low process on the external surface of the occipital bone in the midline

it is an attachment site for the ligamentum nuchae; the superior nuchal lines of the two sides meet in the midline at the external occipital protuberance; also known as: inion

Question 3

inferior nuchal line (Occipital)

Answer 3

a low ridge that runs transversely on the external surface of the squamous part of the occipital bone inferior to the superior nuchal line

it is an attachment site for deep neck muscles

Question 4

superior nuchal line (Occipital)

Answer 4

a low ridge that runs transversely on the external surface of the squamous part of the occipital bone

it is an attachment site the for the trapezius and splenius mm.

Question 5

occipital condyle (Occipital)

Answer 5

a low, wide projection from the inferior surface of the lateral part of the occipital bone

paired; it articulates with the atlas

Question 6

VERTEBRAE

Answer 6

one of a series of irregular bones that form the spine

a vertebra has two parts: the vertebral body and the vertebral arch; there are 33 vertebrae total: 7 cervical, 12 thoracic, 5 lumbar, 5 fused to form the sacrum, 4 coccygeal; features of a typical vertebra include: body, pedicles, transverse processes, laminae, articular processes, spinous process

Question 7

vertebral body (Vertebra)

Answer 7

the largest part of the vertebra

it is shaped like a short cylinder; adjacent vertebral bodies articulate through a symphysis

Question 8

vertebral arch (Vertebra)

Answer 8

the ring of bone formed by the paired pedicles and paired laminae of the vertebra

the transverse processes and spinous process are attached to the neural arch; the neural arch protects the spinal cord

Question 9

pedicle (vertebra)

Answer 9

short strong process that extends posteriorly from the posterolateral surface of the vertebral body

paired; it connects the body with the transverse process; it is marked by superior & inferior vertebral notches;

Question 10

transverse process (Vertebra)

Answer 10

a lateral process the extends from the junction of the pedicle and the lamina of the vertebra

a site for muscle attachment and rib articulation

Question 11

lamina (Vertebra)

Answer 11

a broad flat plate of bone located between the transverse process and the spinous process of the vertebra

paired; it is flattened markedly in the anteroposterior direction; ligamenta flava span the interval between the laminae of adjacent vertebrae

Question 12

articular processes (Vertebra)

Answer 12

processes that project inferiorly and superiorly from the junction of the lamina and pedicle of the vertebra

two pair on each vertebra (superior and inferior); the superior articular processes of one vertebra articulate with the inferior processes of the adjacent vertebra through synovial joints

Question 13

intervertebral notch (Vertebra)

Answer 13

a notch on the superior and inferior surface of the vertebral pedicle

the superior intervertebral notch of one vertebra combined with the inferior intervertebral notch of the adjacent vertebra forms the intervertebral foramen

Question 14

intervertebral foramen (Vertebra)

Answer 14

an opening between the pedicles of adjacent vertebrae

adjacent intervertebral notches form the intervertebral foramen; an opening for passage of the spinal nerve

Question 15

vertebral canal (Vertebra)

Answer 15

the opening formed by the combination of the body and the vertebral arch

it contains the spinal cord, meninges, epidural fat and the internal vertebral plexus of veins

Question 16

spinous process (Vertebra)

Answer 16

a posterior midline process arising from the junction of the two laminae of the vertebra

it projects inferiorly; it is an important site of muscle attachment; spinous processes of cervical vertebra 2-6 are bifid

Question 17

CERVICAL VERTEBRAE

Answer 17

the seven vertebrae of the neck

cervical vertebrae have the features of the typical vertebra plus all have transverse foramina (for passage of the vertebral artery); C2-C6 have bifid spinous processes; cervical vertebrae have relatively small bodies; several cervical vertebra are named: atlas, axis, vertebra prominens

Question 18

atlas (C1) (Cervical vertebrae)

Answer 18

the first cervical vertebra

it is called atlas in comparison the mythological Greek Titan Atlas, who bore the weight of the world on his shoulders; it has no vertebral body, only anterior & posterior arches; it articulates with the odontoid process of the axis

Question 19

axis (C2) (Cervical vertebrae)

Answer 19

the second cervical vertebra

the odontoid process (dens) projects superiorly from its body; it articulates with the anterior arch of the atlas

Question 20

vertebra prominens (Vertebrae)

Answer 20

the seventh cervical vertebra

it has a long, non-bifid spinous process which is prominent at the nape of the neck, hence its name

Question 21

THORACIC VERTEBRAE

Answer 21

the 12 vertebrae associated with the thoracic region

thoracic vertebrae have the features of a typical vertebra plus they are characterized by long slender spines that project inferiorly; they have facets for articulation with ribs; thoracic vertebrae have bodies of intermediate size

Question 22

costal articular facet on the body (Thoracic vertebrae)

Answer 22

small smooth areas at the junction of the body and the vertebral arch

most thoracic vertebrae have 2 costal facets on each side (one superior and one inferior); the superior costal facet of one vertebra and the inferior costal facet of the adjacent vertebra both articulate with the head of the same rib; also known as demifacets

Question 23

costal articular facet on the transverse process (Thoracic vertebrae)

Answer 23

a small smooth area on the transverse process of the thoracic vertebra

it articulates with the articular facet on the tubercle of the rib

Question 24

LUMBAR VERTEBRAE

Answer 24

the 5 vertebrae located in the lumbar region

lumbar vertebrae have the features of a typical vertebra plus they are characterized by short, blunt spines that project posteriorly; lumbar spines do not overlap making the lumbar level a good one for spinal tap; lumbar vertebrae are built strong and have the largest bodies of all vertebrae

Question 25

SACRUM

Answer 25

a triangular bone that is the posterior skeletal element forming the pelvis

it is formed by 5 fused vertebrae; the sacrum and two os coxae bones form the pelvis

Question 26

Anterior sacral foramina (Sacrum)

Answer 26

an opening in the anterior surface of the sacrum

there are four pairs; each transmits the ventral primary ramus of the respective sacral spinal nerve; branches of the lateral sacral aa. enter the sacral canal through these openings

Question 27

posterior sacral foramina (Sacrum)

Answer 27

an opening in the posterior surface of the sacrum

there are four pairs; each transmits the dorsal primary ramus of the respective sacral spinal nerve

Question 28

promontory (Sacrum)

Answer 28

a projection of the superior part of the sacrum in an anterior direction

the body of the fifth lumbar vertebra sits on the sacral promontory and articulates with it through a symphysis

Question 29

sacral canal (Sacrum)

Answer 29

the opening in the center of the sacrum

it is the continuation of the vertebral canal at sacral vertebral levels

Question 30

articular surface (Sacrum)

Answer 30

the roughened area located on the lateral surface of the sacrum

this surface articulates with the ilium in the sacroiliac articulation

Question 31

body (Sacrum)

Answer 31

the central portion of the sacrum

the body is equivalent to the bodies of the other vertebra

Question 32

base (Sacrum)

Answer 32

the superior surface of the sacrum

the base of the sacrum articulates with the fifth lumbar vertebra through an intervertebral disk

Question 33

sacral hiatus (Sacrum)

Answer 33

an opening in the posterior surface of the sacrum in the midline

it is a normal feature that results from the failure of fusion of the laminae of the fifth sacral segment (and sometimes the fourth) during development

Question 34

Ala (Sacrum)

Answer 34

the lateral portion of the sacrum

paired; it projects laterally from the body of the sacrum; it represents the fused costal and transverse processes of the first sacral vertebra

Question 35

COCCYX

Answer 35

the most inferior portion of the vertebral column

the coccyx results from the fusion of the four coccygeal vertebrae; it may be a single bone or the first coccygeal vertebra may be separated from the other three; it articulates with the fifth sacral segment; coccygeal vertebrae are reduced in complexity, having no pedicles, laminae or spines