IB Syllabus focus: 'The human skeleton is divided into axial and appendicular components with different primary functions. Positional terminology describes relative body-part positions, including superior, inferior, proximal, distal, anterior and posterior.'
Understanding body structure begins with knowing which bones belong to each skeleton division and how anatomists describe locations. These ideas make descriptions of posture, injury, and movement clear and consistent.
Divisions of the skeleton
The human skeleton is commonly separated into axial and appendicular divisions.
Practice Questions
FAQ
The sacrum is classified as part of the vertebral column, so it belongs to the axial skeleton.
The hip bones form the pelvic girdle, whose main role is attaching the lower limbs to the trunk. Because of that attachment role, they are part of the appendicular skeleton.
Yes. Anatomical descriptions are based on the anatomical position, not on the person’s current posture.
That means the same relationships stay true during activity. For example, the sternum is still anterior to the heart whether a person is standing, lying down, or performing a handstand.
Using the subject’s right and left creates a fixed standard. Without that rule, two people facing each other could describe the same structure differently.
This matters in sport and medicine because accurate communication reduces mistakes when discussing injury location, side dominance, or treatment.
Yes. A structure can have several correct relationships, depending on what it is being compared with.
For example:
the hand is distal to the elbow
the hand is inferior to the shoulder in anatomical position
the palm is anterior to the back of the hand in anatomical position
The key is that each term must compare two specific structures correctly.
The trunk does not extend from a single attachment point in the same way that an arm or leg does. Because of that, proximal and distal are less precise there.
For the trunk, anatomists usually prefer:
superior/inferior
anterior/posterior
These terms describe location more clearly across the head, chest, abdomen, and back.
