Human Bones Classification Lecture Notes

Introduction

• Adult human skeleton has 206 bones
• Bones classified by shape into:
  • Long bones
  • Short bones
  • Flat bones
  • Sesamoid bones
  • Irregular bones
• Sutural (Wormian) bones are minor category, found between cranial sutures

Long Bones

• Characteristics: Longer than they are wide
• Mnemonic: "L" for Limb and clavicle (collarbone)
• Examples:
  • Arms: Humerus, radius, ulna, metacarpals
  • Legs: Femur, tibia, fibula, metatarsals, phalanges
  • Clavicle (collarbone)
• Count: 90 long bones

Short Bones

• Characteristics: Cube-shaped, same length and width
• Mnemonic: "S" for Sprain (common in wrist and ankle)
• Examples:
  • Wrist: Carpal bones (scaphoid, lunate, triquetrum, hamate, capitate, trapezoid, trapezium)
  • Ankle: Tarsal bones (talus, navicular, cuboid, calcaneus, three cuneiforms)
• Count: 28 short bones

Flat Bones

• Characteristics: Thin and broad, for organ protection
• Mnemonic: "F" for Fort (protection)
• Examples:
  • Skull: Frontal, parietal, occipital, nasal, lacrimal, vomer
  • Rib cage: Sternum, ribs
  • Scapula
• Count: 36 flat bones

Sesamoid Bones

• Characteristics: Resemble sesame seeds, found within tendons
• Mnemonic: "Sesame seed" or "P" shaped (Pisiform, Patella)
• Examples: Pisiform, patella
• Count: 4 sesamoid bones (two patella, two pisiform)

Irregular Bones

• Characteristics: Odd shapes, do not fit other categories
• Mnemonic: Form an "I" shape
• Examples:
  • Hips: Hip bones
  • Spine: Vertebrae, hyoid
  • Skull: Temporal, ethmoid, sphenoid, zygomatic, maxilla, mandible, inferior nasal concha, palatine
  • Ears: Malleus, incus, stapes
• Count: 48 irregular bones

Recap of Mnemonics

• Long bones: Limbs and clavicle
• Short bones: Sprain (wrist and ankle)
• Flat bones: Fort (protection)
• Sesamoid bones: Sesame seed or P-shaped
• Irregular bones: Eye shape (location in hips, spine, skull, ears)

Conclusion

• Understanding the classification of bones helps in anatomy studies
• Varying classification systems exist, so follow the one taught in courses

Tips

• Use mnemonics to recall bone types and locations
• Review anatomy videos for detailed visuals (links provided in resources)