Structure of the human skeleton

The human skeleton is composed of 206 bones that provide support, protection, and movement for the body. The skeleton is divided into two main parts: the axial skeleton and the appendicular skeleton.

1. Axial skeleton:
- The axial skeleton consists of the skull, vertebral column, and rib cage.
- The skull is made up of 22 bones, including the cranium (skullcap) and the facial bones.
- The vertebral column, also known as the spine, is made up of 33 vertebrae that are divided into five regions: cervical (neck), thoracic (chest), lumbar (lower back), sacrum, and coccyx.
- The rib cage consists of 12 pairs of ribs that protect the organs of the chest cavity.

2. Appendicular skeleton:
- The appendicular skeleton consists of the bones of the upper and lower limbs, as well as the girdles that attach the limbs to the axial skeleton.
- The upper limb includes the humerus (upper arm bone), radius and ulna (forearm bones), carpals (wrist bones), metacarpals (hand bones), and phalanges (finger bones).
- The lower limb includes the femur (thigh bone), tibia and fibula (leg bones), tarsals (ankle bones), metatarsals (foot bones), and phalanges (toe bones).
- The pectoral girdle attaches the upper limbs to the axial skeleton and consists of the clavicle (collarbone) and scapula (shoulder blade).
- The pelvic girdle attaches the lower limbs to the axial skeleton and consists of the hip bones (ilium, ischium, and pubis).

Overall, the human skeleton provides structure and support for the body, protects vital organs, and allows for movement and flexibility.

Axial Skeleton (80 bones)

- Skull (22 bones):
- Cranium (8 bones): Temporal (2), Parietal (2), Frontal, Occipital, Sphenoid, Ethmoid
- Facial bones (14 bones): Mandible, Maxilla (2), Nasal (2), Lacrimal (2), Zygomatic (2), Palatine (2), Inferior nasal concha (2)
- Vertebral Column (33 bones):
- Cervical vertebrae (7): C1-C7 (atlas, axis, and 5 cervical vertebrae)
- Thoracic vertebrae (12): T1-T12
- Lumbar vertebrae (5): L1-L5
- Sacrum (5 fused vertebrae)
- Coccyx (4 fused vertebrae)
- Thoracic Cage (25 bones):
- Ribs (12 pairs): True ribs (7 pairs), False ribs (5 pairs), Floating ribs (2 pairs)
- Sternum (3 bones): Manubrium, Body, Xiphoid process

Appendicular Skeleton (126 bones)

- Upper Limbs (60 bones):
- Pectoral Girdle (4 bones): Clavicle (2), Scapula (2)
- Arm (12 bones): Humerus (2)
- Forearm (12 bones): Radius (2), Ulna (2)
- Wrist (8 bones): Carpals (8)
- Hand (24 bones): Metacarpals (10), Phalanges (14)
- Lower Limbs (66 bones):
- Pelvic Girdle (2 bones): Hip bones (2), formed by ilium, ischium, and pubis
- Thigh (12 bones): Femur (2)
- Leg (12 bones): Tibia (2), Fibula (2)
- Ankle (10 bones): Tarsals (10)
- Foot (26 bones): Metatarsals (10), Phalanges (16)