Vertebral Column and Thoracic Cage Notes

Vertebral Column

• 33 bones in infants• 26 bones in adults• 5 sections:

– Cervical (7 bones) – Thoracic (12 bones)– Lumbar (5 bones)– Sacrum (5 fused bones)– Coccyx (4 fused bones)

Vertebral Curvatures

Primary – those presentat birth:• thoracic• pelvicSecondary – developafter birth: • cervical – develops as

baby holds head up• lumbar – develops as child

begins to stand

Features of Typical Vertebrae

body – for supportintervertebral arch – for articulation of next vertebraesup. & inf. articulating processes – for articulation w/vert. above or below

Features of Typical Vertebrae

rib facet – for articulation w/ribstransverse process-for muscle attachment;project laterally

spinous process - sharp projection for muscle attachment projects posteriorly

lamina – 2 plates that fuse to become spinous processpedicle – projection from bodyvertebral foramen – opening for s.c.intervertebral disc – composed of cartilage for cushion

Features of Atlas (C1)

Atlas – supports skull• Fovea dentis – notch for dens• Facet for articulation w/occipital condyles• No body

Features of Axis (C2)

Axis – pivot point

• Dens (odontoid

process); fits into

C1 for rotation

of the skull

Cervical Vertebrae (7)

Features:• smallest• most dense• transverse foramina – for arteries to brain• bifid (forked) spinous process (C2-C5)- (for muscle attachment)

• C7 –

vertebra prominens (landmark)

Thoracic Vertebrae (12)

Features:• larger than cervical• long spinous process

projects posteriorlyand inferiorly

• facets for ribs

Lumbar Vertebrae (5)

Features:• Largest, strongest

bodies• Transverse process

thinner & project laterally• Spinous process

short, thick, nearly horizontal

Sacrum & Coccyx

Sacrum – triangular-shaped bone at base of vert. column•Consists of 5 fused vertebrae•Sacral foramen – for b.v. & nerves•Sacral canal – s.c. travels through•Sacral hiatus – where spinal cord exitsCoccyx (tailbone) – consists of 4 fused vertebrae

Thoracic Cage Includes ribs, thoracic vert., sternum & costal cartilage

Support upper limbs, protect organs & aid in breathing Sternum – 3 parts: manubrium body xiphoid process

Features of Sternum

• Sternal angle – union of manubrium & body; at 2nd rib (anatomic landmark)

• Clavicular notch – junction of clavicle & sternum

• Sternal puncture – aspiration of red marrow for diagnosis

Ribs – 12 pair

3 types:

vertebrosternal- true ribs (1st 7pair)

vertebrochondral –

false ribs (next 3 pr.)

vertebral – floating (last 2 pair)

Male vs. Female PelvisFemale Structure (All related to female pelvis functioning as a birth canal):• Iliac bones more flared• Angle of pubic arch greater• > distance b/t ischial

spines• Sacral curvature shorter

& wider• Bones lighter