Human Skeleton Overview

Skeleton Overview

• The human skeleton is comprised of approximately 206 bones in adults, and 270 in babies.
• Bones are categorized into two sections: axial and appendicular.

Axial Skeleton

• Contains 80 bones.
• Includes the skull, vertebral column, ribs, and sternum.
• The skull is divided into cranial (8 bones) and facial (14 bones)
• Auditory ossicles (malleus, incus, stapes) are 6 small bones within the ear.
• The hyoid is a single U-shaped bone located in the neck.
• The vertebral column (including sacrum and coccyx) comprises 26 bones.
• The sternum is a single flat bone.
• Ribs are 24 long, flat bones.

Appendicular Skeleton

• Contains 126 bones.
• Includes bones of the extremities (arms and legs), and girdles connecting the extremities to the axial skeleton.
• The shoulder girdle consists of the clavicle (2 bones) and scapula (2 bones).
• The upper extremities are formed by humerus (2), radius (2), ulna (2), carpals (16), metacarpals (10), and phalanges (28).
• The pelvic girdle consists of hip bones (2).
• The lower extremities are formed by femur (2), patella (2), fibula (2), tibia (2), tarsals (14), metatarsals (10), and phalanges (28).

Bone Classification by Shape

• Flat bones: These bones are thin and flat, like the skull cap, scapula, ribs, and sternum.
• Irregular bones: These bones have complex shapes, like vertebrae and hip bones
• Long bones: These bones have a shaft (long) and two ends. Examples are femur, humerus, tibia and fibula.
• Short bones: These bones are roughly cube-shaped. Examples are carpals and tarsals.
• Sesamoid bones: These bones develop in tendons where there is a lot of friction and stress, such as the patella.

Ossification (Bone Development)

• Membranous ossification: Flat bones of the skull develop from connective tissue.
• Cartilaginous ossification: Most other bones develop from cartilage and eventually become bone.

Bone Articulation (Joints)

• Bones articulate (connect) to form joints. These pages discuss skeletal structure and articulation of upper and lower limbs, including hip, knee, elbow and wrist joints.

This quiz covers the structure of the human skeleton, including the axial and appendicular sections, and the number of bones in adults and babies. It highlights key components like the skull, vertebral column, and extremities. Test your knowledge on bone classification and anatomy.