Axial and Appendicular Skeleton

Overview of the Human Skeleton

The human skeleton is divided into two main parts: the axial skeleton and the appendicular skeleton. Understanding the location and function of major bones is essential for the study of anatomy and physiology.

• Axial Skeleton: Includes the skull, vertebral column, and thoracic cage (ribs and sternum).

• Appendicular Skeleton: Includes the bones of the limbs and girdles (shoulder and pelvic girdles).

Major Bones of the Human Body

The following are key bones commonly labeled in anatomical diagrams:

• Clavicle: Also known as the collarbone; connects the sternum to the scapula.

• Femur: The thigh bone; the longest and strongest bone in the body.

• Fibula: The lateral and smaller bone of the lower leg.

• Humerus: The upper arm bone, running from shoulder to elbow.

• Ilium: The broad, upper part of the pelvic bone.

• Metacarpals: The five bones forming the palm of the hand.

• Phalanges: The bones of the fingers and toes.

• Radius: The lateral bone of the forearm (thumb side).

• Sternum: The breastbone, located in the center of the chest.

• Tarsals: The group of seven bones forming the ankle and proximal foot.

• Tibia: The medial and larger bone of the lower leg (shinbone).

• Ulna: The medial bone of the forearm (pinky side).

Example: Application in Clinical Practice

• Fractures of the femur are serious due to the bone's size and the force required to break it.

• Knowledge of the radius and ulna is essential for understanding forearm rotation (pronation and supination).

Skull Anatomy

Major Bones of the Skull

The skull is composed of several bones that protect the brain and form the structure of the face. These bones are often identified in anatomical diagrams from different views (anterior, lateral, midsagittal).

• Frontal Bone: Forms the forehead and the upper part of the eye sockets.

• Parietal Bone: Paired bones forming the sides and roof of the cranium.

• Occipital Bone: Forms the back and base of the skull.

• Temporal Bone: Paired bones located at the sides and base of the skull.

• Sphenoid Bone: A butterfly-shaped bone at the base of the skull, visible from the side and inside.

• Ethmoid Bone: A light, spongy bone located between the eyes, forming part of the nasal cavity.

• Maxilla: The upper jawbone, forming part of the orbit and nasal cavity.

• Mandible: The lower jawbone; the only movable bone of the skull.

• Nasal Bone: Small bones forming the bridge of the nose.

• Zygomatic Bone: The cheekbone, forming part of the orbit.

Table: Major Skull Bones and Their Locations

Example: Clinical Relevance

• Fractures of the zygomatic bone can affect the shape of the face and the function of the orbit.

• Injury to the temporal bone can impact hearing due to its proximity to the ear structures.

Summary Table: Selected Major Bones of the Body

Additional info: The diagrams referenced in the materials are standard for introductory anatomy courses and are used to test students' ability to identify and label major bones. Mastery of this content is foundational for further study in anatomy and physiology.