Bones: Names, Descriptions and Factoids

Human Skeleton

Facts About Bones

  • There are over 300 bones in a human infant.
  • Because bones fuse in childhood, there are 206 bones in a human adult.
  • Bones are metabolically active, meaning they are constantly breaking down and rebuilding.
  • Bones become stronger under stress, and weaker when they are not stressed.
  • They contain large amounts of calcium.
  • The inside of the bone is light and made of a spongy like substance.
  • The outside of the bone is very hard.
  • Bones protect organs, store minerals (such as calcium, iron, magnesium), produce blood cells, and of course allow for movement in conjunction with muscles.
  • They are held together by strong fibrous tissue called ligaments.
  • For more information on bone facts.

Definitions Needed for the Study of Bones

  • Anatomical Position: this is the position of the body that allows for easy and accurate referencing when dealing with the human body. The body is standing straight, feet slightly apart with the feet slightly pointing outwards. Head forward. Arms to the sides just slightly away from the body. And the hands turned so the palms are outward with the thumbs furthest away from the body, with the fingers spread and straight.
  • Superior: higher than something else e.g. the head is superior to the shoulders.
  • Inferior: lower than something else e.g. the mouth is inferior to the nose.
  • Anterior: towards the front e.g. the sternum is anterior to the vertebrae.
  • Posterior: towards the back.
  • Lateral: towards the outside e.g. the thumb is lateral to the middle finger.
  • Medial: in the middle.
  • Proximal: closer towards the body e.g. the elbow is proximal compared to the wrist.
  • Distal: further away e.g. the elbow is distal compared to the shoulder.

Cranium (Skull)

  • Frontal bone: at the front of the cranium.
  • Parietal bone (2): at the sides of the cranium, higher than the temporal bones.
  • Temporal bones (2): sides of cranium, just above the ears.
  • Occipital bone: at the back of the cranium.
  • Sphenoid bone: a small bone in front of the temporal bone.
  • Ethmoid bones (2): an even smaller bone just to the sides of the eyes.
  • Nasal bone: behind the nose.
  • Zygomatic bone (2): at the sides and just below the eyes.
  • Vomer bone: a tiny bone just above the upper lip.
  • Mandible: upper jaw.
  • Maxilla: lower jaw.
  • Palatine bone: the roof of the mouth.
  • Hyoid bone: at the front, between the neck and the chin. The only bone not directly attached to another bone.

Ears

  • Malleus (2).
  • Incus (2).
  • Stapes (2): smallest and lightest bone in the human body.

Thoracid Region

  • Scapula: shoulder blades, located at the upper back.
  • Clavicles: collar bones, located at the front. Connect the sternum to the shoulders.
  • Sternum: breastbone. Located at the center of the chest running up and down. Almost all the ribs attach to the sternum.
  • Manubrium: a bone at the top of the sternum.
  • Xiphoid: a small bone at the bottom of the sternum.

Vertabral Column (24)

  • Cervical vertebrae (7): immediately posterior to the cranium. Atlas (C1) is at the top. Axis (C2) is below the atlas.
  • Thoracic vertebrae (12): middle segment. Attach to ribs.
  • Lumbar vertebrae (5): lower back.
  • Sacral (5): below the lumbar. They are fused.
  • Coccyx: the last part, also known as the tail bone. They are fused.

Ribs (24):

  • At the back all ribs attach to the vertebral column, from T1 through to T12.
  • From top to bottom, at the front, ribs 1-7 attach directly onto the sternum, via cartlidge.
  • Ribs 9 and 10 attach to the cartilidge of rib 7.
  • Ribs 11 and 12 are referred as floating ribs because they do not attach to anything at the front.

Arms

  • Humerus: upper arm.
  • Radius: forearm, closest to the thumb when in the anatomical position.
  • Ulna; forearm, closest to the pinky finger when in the anatomical position.

Hands

  • Carpals (8): Small wrist bones.
    • Pisiform bone: Proximal, lateral.
    • Triquetral bone: Middle, lateral.
    • Hamate bone: Distal, lateral. Attaches to #4 & #5 Metacarpals.
    • Scaphoid bone: Proximal, medial.
    • Trapezium bone: Distal, medial. Attaches to #1 (thumb).
    • Lunate bone: Proximal, middle.
    • Capitate bone: Middle. Attaches to #3 Metacarpal.
    • Trapezoid bone: Distal, middle. Attaches to #2 Metacarpal.
  • Metacarpals (5):
    • Long bones of the palm of the hands.
    • Numbered 1 to 5, with the bone attaching to the thumb being #1.
  • Phalanges: fingers (14).
    • They are numbered 1 to 5, with the thumb being 1.
    • Each finger has 3 bones.
    • The thumb has only 2 bones.
    • Each finger is divided in 3 sections: proximal (closest to the wrist), middle, and distal (farthest from the wrist).
    • The thumb only has proximal and distal.

Lower Body

  • Pelvis: this bone is attached to the Sacrum and the femurs.
  • Femur: upper leg. Largest bone in the body. Attaches to the pelvis and makes up the anterior portion of the knee. At the knee it attaches to the Tibia.
  • Tibia: the largest of the 2 bones of the lower leg. It is the one you can feel by touch at the anterior lower leg.
  • Fibula: the smaller of the 2 bones of the lower leg. It can not be felt by touch. It is posterior to the Tibia. This bone does not attach to the femur, but rather to the Tibia, and then again to the Talus of the foot.
  • Patella: the knee cap. This is the largest sesamoid bone in the body.

Feet: from posterior to anterior:

  • Heel: back of the foot
    • Calcaneus: the heel. The part of the foot that you step on as you walk. It is inferior to the Talus.
    • Talus: Superior to the Calcaneus. It is the bone that the Tibia and Fibula attach to.
  • Tarsals:
    • Navicular: just anterior to the Talus, medial to the Cuboid bone, to the inside of the foot.
    • Cuboid: just anterior to the Calcaneus, lateral to the Navicular, to the outside of the foot.
    • Cuneiform bones (3): lateral, intermediate, and medial.
  • Metatarsals (5):
    • The long bones of the foot.
    • They are numbered 1 to 5, with #1 attaching to the big toe.
  • Phalanges: toes (14):
    • They are numbered 1 to 5, with the toe being 1.
    • Each toe has 3 bones.
    • The big toe has only 2 bones.
    • Each toe is divided in 3 sections: proximal (closest to the wrist), middle, and distal (farthest from the ankle).
    • The bigtoe only has proximal and distal.
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