Major Bones of the Human Skeleton

The human skeleton consists of major bones that provide structure, protect vital organs, and enable movement. Understanding these bones is essential in Honors Anatomy and Physiology, as they play a crucial role in our overall health and function.

1. Skull (Cranium)

   • Composed of 8 bones that protect the brain.
   • Contains facial bones that form the structure of the face.
   • Houses the cavities for the eyes, ears, and nasal passages.

2. Mandible

   • The only movable bone of the skull.
   • Supports the lower teeth and is involved in chewing.
   • Articulates with the temporal bone at the temporomandibular joint (TMJ).

3. Vertebrae (Cervical, Thoracic, Lumbar, Sacrum, Coccyx)

   • Composed of 33 individual vertebrae that protect the spinal cord.
   • Cervical (7) supports the neck; Thoracic (12) supports the ribs; Lumbar (5) supports the lower back.
   • Sacrum (5 fused) and Coccyx (4 fused) form the base of the spine.

4. Ribs

   • 12 pairs of ribs that protect the thoracic cavity and organs.
   • True ribs (1-7) attach directly to the sternum; false ribs (8-10) attach indirectly; floating ribs (11-12) do not attach to the sternum.
   • Play a role in respiration by expanding and contracting during breathing.

5. Sternum

   • Also known as the breastbone, it consists of three parts: manubrium, body, and xiphoid process.
   • Serves as the attachment point for the ribs via costal cartilage.
   • Protects the heart and lungs.

6. Clavicle (Collarbone)

   • Connects the arm to the body and acts as a strut to stabilize the shoulder.
   • S-shaped bone that articulates with the sternum and scapula.
   • Commonly fractured due to its superficial position.

7. Scapula (Shoulder blade)

   • Flat, triangular bone that connects the humerus to the clavicle.
   • Provides attachment points for muscles that move the shoulder and arm.
   • Contains the glenoid cavity, which forms the shoulder joint with the humerus.

8. Humerus

   • The long bone of the upper arm, extending from the shoulder to the elbow.
   • Articulates with the scapula at the shoulder and the radius and ulna at the elbow.
   • Contains the greater and lesser tubercles for muscle attachment.

9. Radius

   • One of the two bones of the forearm, located on the thumb side.
   • Plays a key role in wrist movement and forearm rotation.
   • Articulates with the humerus at the elbow and the carpal bones at the wrist.

10. Ulna

    • The second bone of the forearm, located on the side opposite the thumb.
    • Forms the elbow joint with the humerus and provides stability to the forearm.
    • Has a prominent olecranon process that forms the elbow's bony tip.

11. Carpals (Wrist bones)

    • Composed of 8 small bones arranged in two rows.
    • Allow for a wide range of wrist movements and flexibility.
    • Form the base of the hand and articulate with the metacarpals.

12. Metacarpals

    • Five long bones that form the middle part of the hand.
    • Each metacarpal corresponds to a finger and supports the palm.
    • Important for grip and hand function.

13. Phalanges (Fingers and toes)

    • Each finger has three phalanges (proximal, middle, distal), while the thumb has two.
    • Toes also consist of three phalanges (except the big toe, which has two).
    • Essential for dexterity and balance.

14. Pelvis (Hip bones)

    • Composed of the ilium, ischium, and pubis, fused to form the pelvic girdle.
    • Supports the weight of the upper body and protects pelvic organs.
    • Provides attachment points for lower limb muscles.

15. Femur

    • The longest and strongest bone in the body, located in the thigh.
    • Articulates with the pelvis at the hip joint and the tibia at the knee joint.
    • Critical for weight-bearing and movement.

16. Patella (Kneecap)

    • A small, triangular bone that protects the knee joint.
    • Increases the leverage of the quadriceps muscle during knee extension.
    • Articulates with the femur and is embedded in the tendon of the quadriceps.

17. Tibia

    • The larger and stronger of the two bones in the lower leg, also known as the shinbone.
    • Supports the majority of body weight and articulates with the femur at the knee and the talus at the ankle.
    • Contains a prominent anterior crest that is easily felt under the skin.

18. Fibula

    • The thinner bone of the lower leg, located alongside the tibia.
    • Provides stability to the ankle and serves as an attachment point for muscles.
    • Does not bear significant weight but is important for balance.

19. Tarsals (Ankle bones)

    • Composed of 7 bones that form the ankle and the back part of the foot.
    • Includes the talus and calcaneus, which are crucial for weight-bearing and movement.
    • Allow for flexibility and stability during walking and running.

20. Metatarsals

    • Five long bones that form the middle part of the foot.
    • Each metatarsal corresponds to a toe and supports the weight of the body.
    • Important for balance and propulsion during movement.