Anatomic Divisions and Terms

The 206 bones of the body divide into two major groups

  • Axial bones – comprise the vertical axis of the skeleton; 80 bones.
  • Appendicular bones – bones that append (aka attach) to the axial skeleton; 126 bones.

Anatomical position

  • The vertebral column is vertical, the arms are extended with palms facing anteriorly, and the legs are extended with toes pointing anteriorly (towards the front of the body).

Axial skeleton


  • Encloses and protects brain

Hyoid bone

  • U-shaped bone; muscles of speech and swallowing attach to the hyoid bone

Vertebral column

Bones of the spine, terminates in the sacrum

Thoracic cage

  • Sternum – breast bone
  • Ribs – form the lateral walls of the thoracic cage

Appendicular skeleton

Pectoral girdle

  • Comprises the scapula (aka shoulder blade), which articulates with the humerus; and, the clavicle, which articulates with the sternum and scapula


  • The humerus articulates with the scapula


  • The radius (laterally)
  • The ulna (medially)


  • Carpals (wrist)
  • Metacarpals (palm)
  • Phalanges (fingers)

Pelvic girdle

  • Bilateral os coxa bones (aka hip bone), articulate with the sacrum posteriorly


  • Femur (aka thigh bone) articulates with the lateral side of the coxal bone; it is the longest and strongest bone in the body


  • Fibula, laterally; very slim, attachment site for muscles
  • Tibia, medially (“shin” bone); thick, weight-bearing bone of the leg


  • Patella; encased within tendons that pass over the knee, so is a sesamoid bone


  • Tarsals (ankle)
  • Metatarsals (foot base)
  • Phalanges (toes)

Directional nomenclature


  • Closer to the center of the body or limb attachment


  • Further from the center of the body or limb attachment


  • On opposite sides of the body


  • On same side of the body


  • A structure between two others


  • Towards the top of the head


  • Towards the feet


  • Towards the midline of the body


  • Away from the midline of the body

Sagittal plane

  • Divides body into right and left sides

Transverse plane

  • Divides body into superior and inferior divisions


  • Structure that is close to the surface of the body


  • A structure that is near the center of the body

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