General structure and working of the body
The body is composed of the bones, which together form the skeleton, and the soft parts, namely the skin, fat, muscles, blood vessels, et cetera, which cover and surround the bones. The internal organs of the body are also soft parts. The body is subdivided into the head and neck, the trunk, the two upper limbs, and the two lower limbs. It is usual to include with the bones of the upper limb also the shoulder blade and the collar bone, which attach the arm to the trunk, and with the bones of the lower limb the hip bone by which each thigh is attached to the trunk. The vertical middle line of the body is an imaginary line which, with the body in the erect position and the palms of the hands facing forwards, runs from the middle of the crown of the head to between the feet.