Bones and Skeletal System

Bone Tissue:

Bone Cross Section
Bone Cross-Section
Microscopic View, Bone Cross Section
Microscopic View of Bone Cross-Section
Many people are familiar with a hambone as a cross-section of a typical bone. The center of the bone is filled with marrow, and this is surrounded by the hardened bone tissue itself. If you would examine a bit of this hard bone tissue under a microscope, it would look like the picture to the right. In bone, the extracellular matrix is composed of collagen with Ca3(PO4)2 deposited in it. Note that since vitamin C is needed for collagen synthesis, getting a little extra while a broken bone is healing would probably be a good idea. Bone tissue is composed of repeating, circular units called Haversian systems. Within each Haversian system, there is a central canal where blood vessels and nerves can be found. This is surrounded by concentric layers of the matrix material called lamellae. The darkly-stained spots are spaces called lacunae which contain the osteocytes.


Bones of the Human Skeleton:

Skeleton
Here’s a skeleton
(edited from Corel Presentations 8)

The main bones in the human skeleton include:

cranium
the bones of the skull surrounding the brain, not including the face bones; the bone just above/in front of the ear is the temporal bone
mandible
the jaw bone, so the hinge of the jaw is the temporo-mandibular joint, and problems with malfunctioning of this joint are known as TMJ
vertebrae
bones which make up the spine, which include:
cervical vertebrae
the vertebrae in the neck region
thoracic vertebrae
the vertebrae with ribs attached
lumbar vertebrae
the vertebrae in the lower back
sacrum
five fused vertebrae which are joined to the pelvis
coccyx
four fused vertebrae which comprise the tailbone
ribs
bones protecting the chest cavity (we all have twelve pairs)
sternum
the breastbone
clavicle
the collar bone
scapula
the shoulder blade
humerus
the top of the arm
ulna
the little finger side of the lower arm which also forms the elbow
radius
the thumb side of the lower arm; the Radius Rotates around
carpals
the wrist bones
— Watch out for sound-alike words (Thanks to a very observant student for catching this!): “carpal” refers to a wrist bone, while “carpel” refers to a female flower part.
metacarpals
the palm of the hand
phalanges
the fingers and toes
(os) coxa
Hip Bones
Hip Bones (clipart edited from Corel Presentations 8)
the hip bones, which include:
ilium
the big bone on top that we think of as the hip bone — Watch out for sound-alike words: “ilium” refers to a hip bone, while “ileum” refers to the last section of the small intestine.
ischium
the bones on which you sit
pubis
the lower front hip bone
ways to tell male pelvis from female:
  1. spread of ilium: female more flared and cradle-like with anterior iliac spines farther apart vs. more straight “up-and-down” in male
  2. shape of hole in ischium: smaller and triangular in female vs. larger and rounded in male
  3. angle across pubic symphysis = pubic arch: less than 90° (acute angle) and more sharply angled in male, greater than 90° (obtuse angle) and more rounded in female
  4. inner diameter and distance between ischia larger in female — big enough for head of baby to pass through
femur
the thigh bone
patella
the kneecap
tibia
the thick, inside (big-toe side) shinbone
The root word “tibia” means “flute.” There is a Celtic song “The Two (Twa) Sisters” or “The Wind and the Rain” about a woman who was drowned by a jealous sister. Most versions of this song tell of a minstrel who made her hair and breastbone into a harp which sang of her death. However, I have heard a version (I’m having trouble finding out who recorded it — does anyone out there have any info?) in which, when her bones washed ashore, the man made a flute out of her tibia, which then sang the song of her murder.
fibula
the thin, outer (little-toe side) shinbone
tarsals
the heel bones
metatarsals
the arch of the foot, the sole
phalanges
the fingers and toes
Copyright © 1996 by J. Stein Carter. All rights reserved.
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