List of bones of the human skeleton

The skeleton of an adult human consists of 206 bones. It is composed of 270 bones at birth, which decreases to 206 bones by adulthood after some bones have fused together. It consists of 80 bones in the axial skeleton (28 in skull and 52 in torso) and 126 bones in the appendicular skeleton (32 x 2 in upper extremities including both arms and 31 x 2 in lower extremities including both legs). Many small and often variable bones, such as some sesamoid bones, are not included in this count.

Introduction

The figure of 206 bones is commonly repeated, but does have some peculiarities in its method of counting. It is taken of an adult human—the number of bones in the skeleton changes with age, as multiple bones fuse,and a process which typically reaches completion in the third decade of life. In addition, the bones of the skull and face are counted as separate bones, despite being fused naturally. Some reliable sesamoid bones such as the pisiform are counted, while others, such as the hallux sesamoids, are not.

Individuals may have more or fewer bones than this owing to anatomical variations. The most common variations include additional (i.e. supernumerary) cervical ribs or lumbar vertebrae. Sesamoid bone counts also may vary among individuals.

Bones

Vertebral column

• The spinal vertebrae of the vertebral column (33 bones)
  • The cervical vertebrae (7)
  • The thoracic vertebrae (12)
  • The lumbar vertebrae (5)
  • The sacral vertebrae (5 at birth, later fused into one)
  • The coccygeal vertebrae (4 at birth, later fused into one)

Chest

• The sternum (1)
• The ribs (24, in 12 pairs), including:
  • (3) pairs (8th,9th and 10th pairs), also known as false ribs are attached anteriorly to each other and to the 7th rib by cartilages and synovial joints
  • (2) pairs of floating ribs (11th and 12th pairs), have no anterior attachment.

Head

• The skull (1)
  • The cranial bones (8)
    • The occipital bone
    • The parietal bones (2)
    • The frontal bone
    • The temporal bones (2)
    • The sphenoid bone (sometimes counted as facial)
    • The ethmoid bone (sometimes counted as facial)
  • The facial bones (15)
    • The nasal bones (2)
    • The maxillae (upper jaw) (2)
    • The lacrimal bone (2)
    • The zygomatic bone (2)
    • The palatine bone (2)
    • The inferior nasal concha (2)
    • The vomer
    • The mandible (lower jaw)
    • The hyoid bone (sometimes not counted as facial)
• In the middle ears (3 x 2=6)
  • malleus (2)
  • incus (2)
  • stapes (2)

Shoulder

• The clavicle (2)
• The scapula (2)

Arm

• The bones of the upper arm (6 bones, 3 each side)
  • The humerus
  • The ulna
  • The radius
• The hand (54 bones, 27 in each hand)
  • The carpals
    • scaphoid bone (2)
    • lunate bone (2)
    • triquetrum bone (2)
    • pisiform bone (2)
    • trapezium (2)
    • trapezoid bone (2)
    • capitate bone (2)
    • hamate bone (2)
  • The metacarpals (5 × 2=10)
  • The phalanges of the hand
    • proximal phalanges (5 × 2=10)
    • intermediate phalanges (4 × 2=8)
    • distal phalanges (5 × 2=10)

Leg

• The coxal bone, or hip bones, has three regions: ilium, ischium, and pubis (2)
  • The sacrum and the coccyx attach to the two hip bones to form the pelvis
• The femur
• The patella or knee cap
• The tibia
• The fibula
• The foot (52 bones in total, 26 per foot)
  • The tarsus
    • calcaneus or heel bone (2)
    • talus (2)
    • navicular bone (2)
    • medial cuneiform bone (2)
    • intermediate cuneiform bone (2)
    • lateral cuneiform bone (2)
    • cuboid bone (2)
  • The metatarsals (10)
  • The phalanges of the foot
    • proximal phalanges (5 × 2=10)
    • intermediate phalanges (4 x 2= 8)
    • distal phalanges (5 x 2=10)
    • The sesamoid bones

References

• The 206 Bones of the Human Body