1. The Vertebral Column

2. General Characteristics
Formed from 26 irregular bones
Axial support of trunk
Surrounds and protects spinal chord
Provides attachment points for ribs and muscles of back

3. 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

4. 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)

5. 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 no

6. 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

7. Lumbar Vertebrae 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

8. Sacrum 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

9. 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

10. 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

12. Vertebrae Disease Continued
Kyphosis
“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
“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

13. Kyphosis

14. Lordosis

15. Prolapsed Disk

16. 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

17. Spina Bifida