I. Axial Skeleton (80 bones)

1. Skull (Cranium and Facial Bones – 22 bones)

• Frontal bone (1) – Forms the forehead and upper eye sockets; protects the brain's frontal lobe.

• Parietal bones (2) – Form the sides and roof of the skull; protect the upper sides of the brain.

• Temporal bones (2) – House the inner ear structures and protect the brain’s temporal lobes.

• Occipital bone (1) – Forms the back and base of the skull; protects the cerebellum and occipital lobe.

• Sphenoid bone (1) – Forms part of the skull base and orbits; helps connect many other skull bones.

• Ethmoid bone (1) – Supports nasal cavity and part of the eye socket; allows olfactory nerves to pass.

• Nasal bones (2) – Form the bridge of the nose; give shape and support.

• Maxillae (2) – Upper jawbones; hold upper teeth and form part of the nose and eye sockets.

• Zygomatic bones (2) – Cheekbones; help form the eye sockets.

• Lacrimal bones (2) – Small bones forming part of the eye socket, near the tear ducts.

• Palatine bones (2) – Form the back part of the hard palate in the mouth.

• Inferior nasal conchae (2) – Curved bones inside the nasal cavity; help humidify and filter air.

• Vomer (1) – Forms the lower part of the nasal septum, dividing the nose in two.

• Mandible (1) – Lower jawbone; holds lower teeth, only movable skull bone.

2. Auditory Ossicles (6 bones)

• Malleus (2) – Transmits sound from eardrum to incus.

• Incus (2) – Transfers vibrations from malleus to stapes.

• Stapes (2) – Smallest bone; passes sound to the inner ear.

3. Hyoid Bone (1)

• Hyoid (1) – Located in the neck; supports tongue and aids in swallowing and speech.

4. Vertebral Column (26 bones)

• Cervical vertebrae (7) – Support the neck, protect the spinal cord, allow head movement.

• Thoracic vertebrae (12) – Attach to ribs; protect thoracic organs.

• Lumbar vertebrae (5) – Bear body weight and allow movement of the lower back.

• Sacrum (1) – Fused vertebrae forming the back of the pelvis; supports upper body.

• Coccyx (1) – Tailbone; supports sitting and attaches ligaments.

5. Thoracic Cage (25 bones)

• Sternum (1) – Breastbone; connects to ribs and protects the heart.

• Ribs (24) – Protect the lungs and heart, support breathing by moving during respiration.

  • True ribs (1–7) – Attach directly to the sternum.

  • False ribs (8–10) – Attach indirectly to the sternum.

  • Floating ribs (11–12) – Do not attach to the sternum.

II. Appendicular Skeleton (126 bones)

6. Shoulder Girdle (4 bones)

• Clavicles (2) – Collar bones; connect arms to the trunk and provide shoulder stability.

• Scapulae (2) – Shoulder blades; allow arm movement and muscle attachment.

7. Upper Limbs (60 bones)

• Humerus (2) – Upper arm bones; support lifting and arm rotation.

• Radius (2) – Forearm bones on thumb side; enable wrist rotation.

• Ulna (2) – Forearm bones on pinky side; forms elbow joint.

• Carpals (16) – Wrist bones; allow flexibility and movement.

  • Scaphoid (2), Lunate (2), Triquetrum (2), Pisiform (2)

  • Trapezium (2), Trapezoid (2), Capitate (2), Hamate (2)

• Metacarpals (10) – Palm bones; form the hand’s structure.

• Phalanges (28) – Finger bones; allow gripping and dexterity.

  • Each finger has 3 (proximal, middle, distal) except thumbs with 2.

8. Pelvic Girdle (2 bones)

• Hip bones (2) – Each formed by the fusion of ilium, ischium, and pubis; support body weight, protect pelvic organs, connect spine to legs.

9. Lower Limbs (60 bones)

• Femur (2) – Thigh bone; longest and strongest bone, supports body weight in walking and standing.

• Patella (2) – Kneecaps; protect the knee joint and improve leg movement efficiency.

• Tibia (2) – Shinbone; main weight-bearing bone in lower leg.

• Fibula (2) – Thin bone beside tibia; stabilizes ankle and supports leg muscles.

• Tarsals (14) – Ankle bones; support walking and balance.

  • Talus (2), Calcaneus (2), Navicular (2), Medial cuneiform (2), Intermediate cuneiform (2), Lateral cuneiform (2), Cuboid (2)

• Metatarsals (10) – Foot bones; help form the arch and support movement.

• Phalanges (28) – Toe bones; allow balance and walking.

  • Each toe has 3 phalanges except the big toe, which has 2.

Summary of Functions of Bone

• Support – Bones provide a rigid framework for the body’s structure.

• Protection – They shield delicate organs like the brain, heart, and lungs.

• Movement – Muscles attach to bones and move the skeleton at joints.

• Mineral storage – Bones store calcium and phosphorus.

• Blood cell formation – Bone marrow produces red and white blood cells.

• Fat storage – Yellow marrow stores fats in long bones.

• Hearing and speech – Special bones help transmit sound and support vocal function.