Transcript The Vertebral Column - Harrison County Schools

The Vertebral Column
General Characteristics
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Formed from 26 irregular bones
Axial support of trunk
Surrounds and protects spinal chord
Provides attachment points for ribs and
muscles of back
Divisions and Curvatures
• 70 cm (28 in) long
• 5 divisions: 7 vertebrae are cervical, the next 12 are
thoracic, and the 5 supporting the lower back are
lumbar, the sacrum is inferior to the lumbar, and the
coccyx or tail bone
• Has an S or springlike shape
Cervical Vertebrae
• Identified as the first 7 vertebrae c1 to c7
• Smallest and lightest
• Typical features of c3 to c7 vertebrae
– Body is oval
– The spinous is short, projects directly back and is bifid (split at its
tip) except c7
– The vertebral foramen is large and generally triangular
– Each transverse process contains a transverse foramen through
which the vertebral blood vessels pass to brain
– C7 is larger than other cervical vertebrae, spinous process is
visible through skin and is used to count (called vertebra
prominens)
Cervical Vertebrae Continued
• C1 and c2 vertebrae (the atlas and axis) have no intervertebral disc
between them
• C1 the atlas, has no body and no spinous process, it is a ring of
bone consisting of anterior and posterior arches and a lateral mass
on each side. It carries the skull and the superior articular facets
receive the occipital condyles allowing you to nod
• C2 the axis, has a body, spine, and other typical vertebral
processes. Has a knoblike dens (odontoid process) projecting
superiorly from body. Forms a joint that allows you to shake head
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Thoracic Vertebrae
• 12 vertebrae (T1 to T12) all articulate with ribs
• Increase in size from first to last
• Characteristics
– Roughly heart shaped, have two facets on each side that receive the
head of ribs
– Have a circular vertebral foramen
– The spinous process is long and points sharply inferiorly
– Except T11 & T12, the transverse processes have facets that articulate
with the tubercles of ribs
Lumbar Vertebrae
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Commonly called small of back, receives most stress
5 vertebrae (L1 to L5)
Massive bodies and kidney shaped
Characteristics
– The pedicles and laminae are shorter and thicker than other vertebrae
– The spinous processes are short, flat, and hatchet shaped and are
easily seen when a person bends. Processes project backward for
attachment of back muscles
– The vertebral foramen is triangular
– The orientation of the facets of the articular processes of the lumbar
vertebra lock the vertebrae together and keeps the rotation of the
lumbar spine
Sacrum
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Roughly heart shaped
Formed by 5 fused vertebrae
Strengthens and stabilizes the pelvis
Forms the sacroiliac joint with hip bones
The sacral promontory, the anterosuperior margin of the first sacral
vertebra, bulges into pelvic cavity. It is used as a landmark for
obstetricians and the body’s center of gravity lies about 1 cm
posterior to it
Coccyx
• The tail bone “cuckoo” because looks like birds beak
• Small triangular bone, consisting of four vertebrae fused
together
• Articulates superiorly to the sacrum
• Useless bone, only provides slight support to pelvic
organs
Disease of Vertebrae
• Scoliosis: “twisted disease”
– An abnormal lateral curvature of spine
– Common late childhood, especially in girls
– Result from abnormal vertebral structure, lower
limbs of unequal length, or muscle paralysis
– Severe cases must be treated with braces or
surgery before growth ends to prevent
permanent deformity and breathing difficulties
Vertebrae Disease Continued
• Kyphosis
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“hunchback”
A dorsally exaggerated thoracic curvature
Common in elderly due to osteoporosis
May also be due to to tuberculosis of spine, rickets, or osteomalacia
• Lordosis
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“Swayback”
Accentuated lumbar curvature
Caused by spinal tuberculosis or rickets
May be temporary: “beer guts” in men, pregnancy in women
• Prolapsed disc
– Herniated disc caused by trauma to back
Kyphosis
Lordosis
Prolapsed Disk
Vertebrae Disease continued
• Spina Bifida
– “Cleft Spine”
– Congenital defect of the vertebral column in which the vertebral laminae
fail to fuse medially
– May result in impairment of neural functioning and may cause nervous
system infections
Spina Bifida