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 present at birth: thoracic pelvic Secondary – develop after birth: cervical – develops as baby holds head up lumbar – develops as child begins to stand

Features of Typical Vertebrae body – for support intervertebral arch – for articulation of next vertebrae sup. & inf. articulating processes – for articulation w/vert. above or below

Features of Typical Vertebrae rib facet – for articulation w/ribs transverse process- for muscle attachment; project laterally

spinous process - sharp projection for muscle attachment projects posteriorly lamina – 2 plates that fuse to become spinous process pedicle – projection from body vertebral 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 posteriorly and 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 exits Coccyx (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 Pelvis Female 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