Vertebral Column

Thoracic vertebrae contains how many bones?

T1-T12

Sacrum and coccyx contains how many bones?

S1-S5

tectorial membrane: Slides 72-75

upward continuation of posterior longitudinal ligament (on anterior wall of vertebral canal) extends from posterior surface of body of axis to occipital bone (above foramen magnum) lies posterior to dens, apical ligament, alar ligaments, and cruciform ligament

in articulated spine, superposition of vertebral foramina creates :

vertebral canal > main contents: spinal cord and its surrounding membranes (meninges) and roots of spinal nerves

Joints Between Vertebral Arches: interspinous ligament: refer to slides 53-55

fills space between two adjacent spinous processes limits separation of spinous processes during flexion

Primary curvature are known as:

(kyphoses) > develop during fetal period due to flexed fetal position > convex posteriorly > located in thoracic and sacral regions > maintained throughout life as a consequence of differences in height between anterior and posterior parts of vertebrae

Secondary curvatures are known as:

(lordoses) > begin to appear during fetal period, but do not become obvious until infancy > concave posteriorly > located in cervical and lumbar regions > maintained primarily by differences in thickness between anterior and posterior parts of intervertebral discs

vertebral arch consists of:

2 pedicles > form sides of vertebral foramen > fuse anteriorly with vertebral body 2 laminae > close vertebral foramen posteriorly > meet each other in posterior midline

Atlas C1 - atypical vertebrae refer to slide 19

1. atypical cervical vertebra with no body and no spinous process 2. consists of anterior and posterior arches and 2 lateral masses 3. anterior arch is shorter > has a tubercle in midline of its anterior surface (anterior tubercle) and an articular facet for dens (of C2) in midline of its posterior surface (takes part in median atlanto-axial joint) 4. posterior arch is longer > has a tubercle in midline of its posterior surface (posterior tubercle) and a groove for vertebral artery immediately posterior to each lateral mass 5. each lateral mass has 2 articular facets >superior articular facet articulates with occipital condyle (takes part in atlanto-occipital joint) > inferior articular facet articulates with superior articular facet of C2 (takes part in lateral atlanto-axial joint)

vertebral arch gives rise to 7 processes:

1. spinous process projects posteriorly in midline from junction of 2 laminae 2. transverse processes project laterally from junction of laminae and pedicles 3. spinous and transverse processes serve as levers and receive attachments of muscles and ligaments 4. articular processes (2 superior and 2 inferior) > project superiorly and inferiorly from junction of laminae and pedicles > articulate with articular processes of vertebrae above and below 5. superposition of vertebrae in articulated spine creates intervertebral foramina 6. intervertebral foramina transmit spinal nerves out of vertebral canal (spinal nerves can be compressed at intervertebral foramina causing peripheral motor and/or sensory problems) also transmit blood vessels in and out vertebral canal 7. boundaries of intervertebral foramen: superior: pedicle of vertebra above inferior: pedicle of vertebral below anterior: intervertebral disc and small parts of bodies of both vertebrae posterior: inferior articular process of vertebra above and superior articular process of vertebra below (together form a zygapophysial/facet joint)

1. Name the regions of the vertebral column and indicate the number of vertebrae found in each region 2. Describe the anatomical features of a typical vertebra 3. Describe the normal curvatures of the vertebral column and its most common abnormalities 4. Describe the anatomical features of typical cervical, thoracic and lumbar vertebrae 5. Describe the anatomical features of the atlas, axis, vertebra prominens, sacrum and coccyx

6. Discuss common disorders affecting the vertebral column 7. Describe the joints between adjacent vertebral bodies and adjacent vertebral arches 8. Describe the articular surfaces, ligaments, and movements of the atlanto-occipital and atlanto-axial joints 9. Describe the ligaments connecting the axis and the occipital bone 10. Describe the movements of the vertebral column and their regional variations

which cervical vertebrae are atypical?

C1, C2,C7

cervical vertebrae contains how bones? and what are the names of the first two?

C1-C7 C1 Atlas C2 Axis

Lumbar vertebrae contains how many bones?

L1-L5

refer to slide 9, 10

Top part of the superior view is anterior and the spinous process is the posterior view. The lamine form the posterior arch. Tranverse processes are apart of the transverse costal facet. The processes pose as the muscle attachment. The joints that are form between the processes is the synovial joint. What type of joint is interverteral joint? Fibrous cartilage?

Axis C2 refer to slide 21

atypical cervical vertebra has a bony prominence that projects superiorly from vertebral body > dens (odontoid process) > articulates with facet on anterior arch of atlas at median atlanto-axial joint superior articular facets are located on each side of base of dens > articulate with inferior articular facets of lateral masses of atlas at lateral atlanto-axial joints

scoliosis

abnormal curvature of vertebral column in coronal (frontal) plane (to right or left)

excess thoracic kyphosis (clinically shortened to "kyphosis")

abnormal exaggeration of primary curvature in thoracic region (humpback or hunchback)

excess lumbar lordosis (clinically shortened to "lordosis")

abnormal exaggeration of secondary curvature in lumbar region (hollow back or sway back) "pregnancy"

what are intervetebral disc? refer to slide 41 and 43

account for 20-25% of length of vertebral column thickest in cervical and lumbar regions (greater range of motion) parts: peripheral part anulus fibrosus central part nucleus pulposus allow movement between adjacent vertebrae and serve as shock absorbers when load on vertebral column is increased

lumbar curvature (lordosis) becomes apparent when:

an infant begins to assume upright posture, standing and walking

cervical curvature (lordosis) becomes fully evident when:

an infant begins to raise (extend) head while prone or to hold head erect while sitting

Vertebra Prominens C7 refer to slide 22

atypical cervical vertebra long, non-bifid spinous process (used as landmark to count spinous process) foramina transversaria are usually smaller than in other cervical vertebrae (usually do not transmit vertebral arteries)

what is the name of the joint that is between vertebral bodies? refer to slide 39

bodies of adjacent vertebrae are connected to each other by intervertebral discs (cartilaginous joints) symphasis bc it is made of fibro cartilage intervertebral discs provide strong attachments between vertebral bodies, uniting them into a continuous semi-rigid column also form part of anterior border of intervertebral foramina intervertebral discs are reinforced by anterior and posterior longitudinal ligaments

Joints Between Vertebral Arches: intertransverse ligament: refer to slides 53-55

connects transverse processes of two adjacent vertebrae (functionally not very important)

Anulus fibrosus refer to slide 41 and 43

composed of fibrocartilage with collagen fibers arranged in concentric layers or sheets (lamellae) in each lamella, bundles of collagen fibers have same orientation (65º with respect to vertical) in consecutive lamellae, collagen fibers are oriented perpendicular to each other

Joints Between Vertebral Arches: ligamentum flavum: refer to slides 53-55

connects laminae of adjacent vertebrae composed almost entirely of elastic tissue (yellowish color when fresh) limits separation of laminae during flexion and helps to restore erect posture

Atlanto-axial Joints transverse ligament of atlas: slides 66-68

connects medial surfaces of lateral masses of atlas retains dens in position preventing impingement of spinal cord thought to be most important ligament of craniovertebral complex of joints

Atlanto-axial Joints lateral atlanto-axial joints:slides 66-68

established between inferior articular facets of lateral masses of atlas and superior articular facets of axis

Craniovertebral Joints

established between occipital bone, atlas and axis specially adapted for head movements there are no intervertebral discs between occipital bone and atlas or between atlas and axis includes: 2 atlanto-occipital joints 3 atlanto-axial joints (1 median and 2 lateral)

alar ligaments (one on each side): Slides 72-75

extend from sides of dens to medial surfaces of occipital condyles

Posterior Longitudinal Ligament refer to slide 49-50

extends along posterior aspects of vertebral bodies and intervertebral discs (anterior wall of vertebral canal) from C2 to sacrum limits flexion of vertebral column in lower thoracic and lumbar regions posterior longitudinal ligament is denticulated narrower over vertebral bodies and wider over intervertebral discs

Ligaments Connecting Axis and Occipital Bone apical ligament: Slides 72-75

extends from tip of dens to anterior margin of foramen magnum

superior longitudinal band: Slides 72-75

extends from transverse ligament to occipital bone

inferior longitudinal band: Slides 72-75

extends from transverse ligament to posterior surface of body of axis longitudinal bands are mostly involved in holding transverse ligament in position

Sacrum (anterior) refer to slides 32-34

formed by fusion of 5 sacral vertebrae forms most of posterior wall of pelvic cavity wedge-shaped upper end is wider (base) lower end is narrower (apex) base articulates with L5 and apex articulates with coccyx promontory anterior and median part of base that projects forward ala of sacrum lateral part of base (one on each side of S1 body) anterior (pelvic) surface is concave and has 4 pairs of anterior sacral foramina (transmit ventral rami of S1-S4 spinal nerves) posterior (dorsal) surface is rough and convex has 4 pairs of posterior sacral foramina (transmit dorsal rami of S1-S4 spinal nerves

Nucleus Pulposus refer to slides 45-47

gelatinous material containing large amount of water (70-90%), small number of collagen fibers with no uniform orientation, and a few cells (notochordal cells early in life, fibroblasts, chondrocytes) water content decreases with age remnant of notochord of embryo located slightly closer to posterior margin than to anterior margin of disc semi-fluid nature of nucleus pulposus allows it to change its shape a sudden increase in compression load of vertebral column causes nucleus pulposus to become flattened outward pressure of nucleus pulposus is accommodated by anulus fibrosus sometimes outward pressure of nucleus pulposus is too great anulus fibrosus ruptures nucleus pulposus herniates (most commonly posterolaterally into vertebral canal or intervertebral foramen)

Ligamentum Nuchae (Nuchal Ligament) refer to slide 57

homologous to supraspinous ligament in cervical region midsagittal membrane that separates right and left muscles of posterior neck and provides attachment for them posterior border is free and superficial extends from external occipital protuberance to tip of spinous process of C7 superior border attaches to external occipital crest anterior border attaches to posterior tubercle of atlas and spinous processes of cervical vertebrae helps to support weight of head when inclined forward (writing, reading) much stronger in quadrupeds

What are the 5 regions of the vertebral column?

in upper 3 regions there is movement between adjacent vertebrae > in lower 2 regions there is no movement between adjacent vertebrae: cervical > consists of 7 vertebrae (C1-C7) thoracic > consists of 12 vertebrae (T1-T12) lumbar > consists of 5 vertebrae (L1-L5) sacral > consists of 5 vertebrae (S1-S5), which fuse with each other to form a single bone (sacrum) coccygeal > usually consists of 4 rudimentary vertebrae (Co1-Co4), which fuse with each other to form a single bone (coccyx)

Lumbar Vertebrae (looks like elephant) refer to slides 28-29

large vertebral body with a kidney-shaped outline large and triangular vertebral foramen large, rectangular spinous process that projects straight posteriorly no foramen transversarium or costal facets mammillary processes > small bony prominences located on posterior border of superior articular processes accessory processes > small bony prominences located on posterior aspect of transverse processes, near their origin from vertebral arch articular facets are almost sagittally oriented orientation of articular facets facilitates flexion/extension, allows some lateral flexion, but limits axial rotation

motion occurs at all 3 atlanto-axial joints simultaneously main motion is axial rotation also allow flexion/extension and a small amount of lateral flexion

motion occurs at all 3 atlanto-axial joints simultaneously main motion is axial rotation also allow flexion/extension and a small amount of lateral flexion

Atlanto-axial Joints median atlanto-axial joint: slides 66-68

pivot joint established between dens of axis and an osteofibrous ring formed by anterior arch of atlas and transverse ligament of atlas

Sacrum (Posterior) refer to slides 32-34

posterior surface has 5 ridges: 1 median sacral crest represents tips of spinous processes 2 intermediate sacral crests represent articular processes 2 lateral sacral crests represent tips of transverse processes posterior sacral foramina are located between intermediate and lateral sacral crests on each side lateral surface of sacrum has an articular facet for hip bone (1 on each side) auricular surface takes part in sacroiliac joint sacral tuberosity irregular area posterior to auricular surface (gives attachment to interosseous sacroiliac ligament) sacrum encloses sacral canal, which ends inferiorly in sacral hiatus sacral cornua (horns): 2 bony prominences located one on each side of sacral hiatus

Joints Between Vertebral Arches: supraspinous ligament: refer to slides 53-55

runs along midline of back connecting tips of spinous processes from C7 to sacrum limits separation of spinous processes during flexion

Cervical Vertebrae refer to slide 17

small vertebral body (compared to thoracic and lumbar vertebrae) uncinate processes elevated lateral margins of superior surface of vertebral body vertebral foramen large and triangular foramen transversarium opening in transverse process that transmits vertebral artery and accompanying veins and nerve plexus transverse processes end in anterior and posterior tubercles spinous process is short and usually bifid orientation of articular facets allows for flexion/extension, lateral flexion and axial rotation (cervical region is more mobile than thoracic and lumbar regions)

Coccyx- refer to slide 37

small, wedge-shaped bone usually formed by fusion of 4 rudimentary coccygeal vertebrae forms, with sacrum, posterior wall of pelvic cavity base upper end that articulates with apex of sacrum apex lower end 1st coccygeal vertebra has rudimentary transverse and superior articular processes (latter ones are known as coccygeal cornua/horns)

what is the Identification of Specific Vertebral Spinous Processes?

spinous process of C7 is usually visible as prominent eminence in midline at base of neck (spinous process of T1 is often more prominent than spinous process of C7) root of spine of scapula is at level of spinous process of T3 inferior angle of scapula is at level of spinous process of T7 horizontal line connecting highest points of right and left iliac crests crosses spinous process of L4 sacral dimples (mark location of posterior superior iliac spine) are at level of spinous process of S2

describe an overview of the vertebral column

strong and flexible bony column that extends from base of skull, superiorly, to pelvis, inferiorly composed of approximately 33 bones (vertebrae)

Anterior Longitudinal Ligament

strong ligament extending along anterior aspects of vertebral bodies and intervertebral discs from occipital bone to upper sacrum limits extension of vertebral column

Joints Between Vertebral Arches: what are facet (zygapophysial) joints ?

synovial joints between articular processes of adjacent vertebrae bony articular facets are covered with hyaline cartilage surrounded by an articular capsule orientation of articular facets determines type of motion possible between vertebrae innervated by dorsal rami of spinal nerves

Atlanto-occipital Joints are? refer to slide 60-64

synovial joints established between occipital condyles (convex) and superior articular facets of lateral masses of atlas (concave) each joint has its own articular capsule, but right and left joints work in unison allow mostly flexion/extension with small amounts of lateral flexion and axial rotation occipital bone and atlas are also connected by anterior and posterior atlanto-occipital membranes extend from anterior and posterior arches of atlas to anterior and posterior margins of foramen magnum, respectively (posterior atlanto-occipital membrane arches over vertebral artery)

cruciform ligament: Slides 72-75

transverse ligament of atlas + superior and inferior longitudinal bands

What are the features of a typical vertebra?

vertebral body > shaped like a short cylinder > located anteriorly vertebral arch > bony arch that forms posterior part of vertebra vertebral body and arch enclose an opening > vertebral foramen

Thoracic vertebrae (looks like giraffe) refer to slides 25-26

vertebral body is larger than that of cervical vertebrae and has a heart-shaped outline vertebral foramen is smaller than that of cervical vertebrae and is circular in shape vertebral bodies of most thoracic vertebrae have 4 costal facets (2 superior and 2 inferior) for articulation with heads of ribs (head of a typical rib articulates with bodies of 2 adjacent thoracic vertebrae body of numerically corresponding vertebra and body of vertebra above) most thoracic vertebrae (except last 2) have also costal facets on transverse processes (transverse costal facets) articulate with tubercle of numerically corresponding rib long, overlapping spinous process that projects posteriorly and inferiorly articular facets are oriented almost in coronal (frontal) plane axial rotation is favored by orientation of articular facets attachment of ribs, vertical orientation of articular facets, and overlapping spinous processes limit flexion/extension, and to some degree, lateral flexion