The vertebral column Flashcards
function of vertebral column
• Functions: o supports weight of head and trunk o protects spinal cord o allows spinal nerves to exit spinal cord o site for muscle attachment o permits movement of the head and trunk
Regions of vertebrae column
o abbreviated by capital letter that indicates the region
o followed by a number that indicates the specific vertebra
• starts with lowest number at the cranial end and highest number at the caudal end of the region
o cervical (C1-C7)
o thoracic (T1-T12)
o lumbar (L1-L5)
o sacral (S1-S5) – only one in the adult
o coccygeal (Co1-Co5) – variable number but only one in the adult
Spinal curves
o most body weight lies in front of vertebral column and curvatures bring weight in line with body axis and center of gravity
o 4 in adult but appearance changes from fetus to adult due to change in posture
Type of spinal curves
o cervical – curves ventrally
o thoracic – curves dorsally
o lumbar – curves ventrally
o sacral – curves dorsally
abnormal spinal curvature
o conditions and events that damage bones, muscles and nerves distorts shape and impairs function of vertebral column
o may be temporary condition or may be due to disease or congenital defect
example of abnormal spinal curvature ?
o kyphosis = exaggerated dorsal curvature of thoracic region
• most common in post-menopausal women (“dowager’s hump”) resulting from compression fractures
o lordosis (“swayback”) = exaggeration of ventral curve of lumbar region
• pregnancy or obesity resulting in weakness of abdominal muscles
o scoliosis = lateral and rotational curvature of the vertebral column
• most common distortion of spine
• can result from developmental problems or muscle paralysis affecting one side of back
• idiopathic scoliosis – when underlying cause not known
• appears in girls during adolescence
• treatment includes: exercise, braces, and surgical straightening with implanted rods
body
= bony disk that is weight-bearing portion
o articulates with neighbouring vertebrae - interconnected by ligaments and separated by intervertebral discs
vertebral foramen
large opening surrounded by arch and together with foramina of other vertebrae forms vertebral canal
o contains the spinal cord and cauda equine
• vertebral arch
projects posteriorly from body
• pedicle part of vertebral arch
part attached to the posterolateral margins of the body
• vertebral arch : lamina
thin plate that joins with lamina from other half of vertebrae to make the arch
• contain intervertebral notches
• vertebral arch : transverse process
extends laterally from each side of the arch
vertebral arch : spinous process
extends posteriorly from the junction of the two lamellae
• seen and felt as series of lumps down the midline of the back
• superior (2) and inferior (2) processes
at junction between pedicles and laminae
o overlap of superior from one vertebra and inferior process from vertebra above increases rigidity of vertebral column
o articular facet
on end of each process
• intervertebral foramina
formed by articulation from processes and from notches of adjacent pedicle
o allows spinal nerves to exit spinal cord
Intervertebral disc : fibrocartilage
located between bodies of adjacent vertebrae
o provide additional support and prevent vertebral bodies from rubbing against each other
• compress with age so distance between vertebrae decreases – overall height of individual decreases, and more prone to herniation (portion squeezed out of place)
Cervical vertebrae
- extend from occipital bone of skull to thorax
* have very small bodies – dislocations and fractures more common in this area
• typical cervical vertebrae (C3-C7) have:
o bifid (split) spinous processes o transverse foramen in each transverse process - only present in cervical vertebrae • passageway for vertebral arteries and veins supplying the brain
C-1
atlas (holds up the head) (Fig 6.22) – has no body and no spinous process
o has large superior articular facets where it articulates with the occipital condyles at the base of the skull
• permits nodding (“yes”) movement but prevents twisting
c-2
axis (Fig 6.22) – contains the dens - a modified process on superior side of its small body
o fits into the large vertebral foramen of the atlas and held in place by transverse ligament
• allows head to rotate
c-7
has most prominent spinous process (vertebral prominens)
o ligamentum nuchae – large elastic ligament begins here and extends cranially to insert along external occipital crest
whiplash
= traumatic hyperextension of the cervical vertebrae
o may result in fracture of spinous processes or herniated disc putting posterior pressure on spinal cord, spinal nerves, muscles, tendons and ligaments
Thoracic vertebrae
• body thicker and heart shaped
• have long thin spinous processes directed inferiorly
• articular facets articulate with ribs
o T1-T8 have superior and inferior costal facets on border of body and pedicle
o T9-T-12 have only single facet
o T1-T10 have transverse costal facets on transverse process to articulate with tubercles of ribs
lumbar vertebrae
- large, thick oval-shaped bodies
* rectangular spinous and transverse processes
sacrum
- adult = 5 fused sacral vertebrae – with fusion complete ~age 25
- curved with convex dorsal surface
sacrum : apex
narrow caudal portion
sacrum :base
broad superior surface
sacrum : median sacral crest
partially fused spinous processes of first four sacral vertebrae
o sacral canal – extends the length of the sacrum
o sacral hiatus = end of sacral canal – often site for injection of anesthetics
sacrum :sacral foramina
lateral to midline
sacrum : auricular surfaces
lateral ear-shaped wings that join with the pelvic bones
Coccyx
- adult = 3-5 fused coccygeal vertebrae
- most inferior portion of vertebral column
- small and have no vertebral foramina or processes
- attachment site for ligaments and muscle
Spina Bifida
developmental condition of vertebral arches
• most common neural tube defect (NTD) associated with heredity and maternal diet
o low folic acid intake associated with NTD
• pregnant women – recommended intake 400 micrograms daily
• region affected and severity of condition vary widely
o most commonly involves 3-6 vertebrae in inferior thoracic, lumbar, or sacral region
• vertebral arch is incomplete so do not contain spinous process
• meninges surrounding spinal cord bulge outward
rib cage
– semi-rigid chamber that protects vital organs in thorax
= ribs and associated costal cartilages and sternum (thoracic cage includes thoracic vertebrae)
• increases and decreases in volume of thoracic cavity during respiration
ribs
12 pairs of that articulate with the thoracic vertebrae
ribs :head
articulates with bodies of two adjacent ribs
ribs : tubercle
articulates with transverse process of inferior vertebra
ribs : • body (shaft
main part of rib,
o angle = point of greatest curvature and weakest point that can be fractured in crushing injury
o sternal end = attaches to costal cartilage
o costal groove along inferior and medial border = bath for blood vessels and nerves
ribs : true ribs
attach directly via their costal cartilages to the sternum
ribs : false ribs
(5 pairs) – 8th, 9th, 10th attach by common cartilage to the seventh ribs
ribs : floating ribs
11th and 12th do not attach to sternum
sternum
flat bone that forms anterior midline of thoracic cage
sternum has 3 parts ?
o manubrium
o body
o xiphoid process
sternum : manubrium
most cranial portion - articulates with clavicle and 1st rib
• jugular notch – located on superior margin and easily palpated
• sternal angle –prominence where inferior margin of manubrium and body of sternum meet
sternum :body
middle portion
sternum :xiphoid process
most caudal portion and no ribs attach here
• connection to body of sternum can be broken creating a spear of bone that can severely damage the liver
