Human Skeletal System: All 206 Bones
The adult human skeleton has 206 bones organized into two major divisions: the axial skeleton (80 bones) and the appendicular skeleton (126 bones). The axial skeleton forms the central axis and includes the skull, vertebral column and thoracic cage, protecting the brain and vital organs. The appendicular skeleton comprises the limbs and girdles (shoulder and pelvic) that anchor them, facilitating movement. In an adult, the skull contains 22 bones (8 cranial + 14 facial) plus 7 accessory bones (6 auditory ossicles + 1 hyoid) for a total of 29 bones in the head. The vertebral column has 26 bones (7 cervical + 12 thoracic + 5 lumbar vertebrae, plus the sacrum and coccyx). The thoracic cage has 25 bones (24 ribs + 1 sternum). Each upper limb has 32 bones (64 total) and each lower limb 31 bones (62 total). In the lists below, each bone or group is identified with its Name – Count – Type – Key function/anatomical role, with authoritative sources cited.
Figure: Lateral view of the human skull bones. Cranial bones (frontal, parietals, occipital, temporals, sphenoid, ethmoid) form a protective case for the brain, while facial bones form the jaw and face.
Axial Skeleton (80 bones)
Skull (29 bones including ear and hyoid)
Cranial bones (8 total): flat bones protecting the brain.
Frontal bone – 1, flat. Forms the forehead; protects the frontal lobes.
Parietal bones – 2, flat. Form the superior sides of the cranium; protect the parietal lobes.
Occipital bone – 1, flat. Forms the posterior skull; contains the foramen magnum for spinal cord.
Temporal bones – 2, irregular (complex shape). House the middle/inner ear and zygomatic arches.
Sphenoid bone – 1, irregular. Wedged at the skull base; contributes to floor of the cranium and orbits.
Ethmoid bone – 1, irregular. Forms part of the nasal cavity and medial wall of orbits.
Facial bones (14 total): primarily irregular bones forming the facial skeleton.
Nasal bones – 2, flat. Bridge of the nose.
Lacrimal bones – 2, irregular. Medial walls of the orbits, contain tear ducts.
Zygomatic bones – 2, irregular. Cheekbones; form lateral rims of orbits.
Maxillae – 2, irregular. Upper jaw bones; hold upper teeth and form part of orbits.
Palatine bones – 2, irregular. Form posterior hard palate and floor of the nasal cavity.
Inferior nasal conchae – 2, irregular. Scroll-like bones on lateral nasal cavity walls.
Vomer – 1, flat/irregular. Forms the inferior part of the nasal septum.
Mandible – 1, irregular. Lower jaw; the only movable skull bone.
Auditory ossicles (6 total): 3 in each ear, very small irregular bones transmitting sound.
Malleus – 2; Incus – 2; Stapes – 2 (smallest bone in body).
Hyoid bone (1): irregular. A U-shaped bone in the neck that supports the tongue and larynx.
Classification: Most cranial vault bones (frontal, parietals, occipital) are flat bones for protection. The sphenoid, ethmoid and many facial bones are irregular bones (complex shapes).
Vertebral Column (26 bones)
Figure: Vertebral column with cervical, thoracic, and lumbar regions, sacrum and coccyx. The irregular vertebrae protect the spinal cord and bear the weight of the body.
Cervical vertebrae – 7 irregular bones (C1–C7). C1 (atlas) and C2 (axis) allow head movement (nodding, rotation). Protect the spinal cord in the neck.
Thoracic vertebrae – 12 irregular bones (T1–T12). Articulate with ribs; protect the spinal cord and support the rib cage.
Lumbar vertebrae – 5 irregular bones (L1–L5). Large, weight-bearing bones of the lower back. Protect the spinal cord and support torso weight.
Sacrum – 1 bone (fusion of 5). Irregular; connects spine to pelvis, forming back of pelvic cavity.
Coccyx – 1 bone (fusion of 4). Irregular; tailbone, supports pelvic floor ligaments and muscles.
Each vertebra is an irregular bone (complex shape) that protects the spinal cord. The vertebral column as a whole provides structural support, bears body weight, and enables flexibility. (Total in adults: 26 bones, since sacrum and coccyx are each counted as one fused bone.)
Thoracic Cage (25 bones)
Sternum – 1, flat (fusion of manubrium, body, xiphoid). Anterior midline chest bone; connects to ribs via costal cartilages. Protects the heart and major vessels.
Ribs – 24 (12 pairs), flat bones. Each rib is a curved flat bone (pairs 1–7 true ribs attach to sternum; 8–10 false ribs attach via cartilage; 11–12 floating ribs). They enclose the chest cavity to protect the lungs and heart. .
The thoracic cage (rib cage) forms a protective enclosure for the thoracic organs. Flat bones like the ribs and sternum shield internal organs. (Some people have an extra cervical rib, an anatomical variation.)
Appendicular Skeleton (126 bones)
Upper Limbs (64 bones total)
Shoulder (Pectoral) girdle (4):
Clavicle – 2 (left/right), long bone. Runs horizontally between sternum and scapula; braces the shoulder and transmits force from arm to axial skeleton.
Scapula – 2, flat bone. Shoulder blade; triangular flat bone on the back that provides attachments for arm muscles and forms the socket of the shoulder joint.
Arm (2 bones):
Humerus – 2, long bone. Upper arm bone from shoulder to elbow; supports arm muscles and forms elbow joint.
Forearm (4 bones):
Radius – 2, long bone. Lateral forearm bone (thumb side); rotates around the ulna (supination/pronation of hand).
Ulna – 2, long bone. Medial forearm bone (pinky side); forms elbow hinge with humerus.
Hand (54 bones total; 27 in each hand):
Carpal bones – 16 (8 per wrist), short bones. Names: Scaphoid, Lunate, Triquetral, Pisiform (proximal row); Trapezium, Trapezoid, Capitate, Hamate (distal row). Form the wrist joint and allow complex wrist movements.
Metacarpals – 10 (5 per hand), long bones. Palm bones numbered I–V from thumb to little finger; support the palm and articulate with phalanges.
Phalanges (hand) – 28 (14 per hand), long bones. Each finger has 3 phalanges (proximal, intermediate, distal), except the thumb (2 phalanges). Allow finger flexion/extension for grasping.
Classification: Most upper-limb long bones (humerus, radius, ulna, metacarpals, phalanges) facilitate leverage and movement. The short carpals provide wrist stability. The clavicle is categorized as a long bone (it is longer than wide), while the scapula is a flat bone.
Figure: Bones of the upper limb. The shoulder girdle (clavicle, scapula), arm (humerus), forearm (radius, ulna), and hand bones (carpals, metacarpals, phalanges) are shown.
Hand
Figure: Bones of the human hand. Carpals (purple) form the wrist, metacarpals (orange) the palm, and phalanges (green, blue, red) the fingers.
Carpals – 8 (per hand) – short bones named above.
Metacarpals – 5 (per hand) – long bones in the palm.
Phalanges (hand) – 14 (per hand) – long bones of the fingers (proximal, intermediate, distal phalanges for digits 2–5; thumb has only proximal and distal).
Total hand bones: 27 on each side (54 total). These bones allow fine manipulation and dexterity in the fingers.
Lower Limbs (62 bones total)
Pelvic girdle (2 bones):
Hip bone (coxal bone) – 2, irregular bones (each formed by fusion of ilium, ischium, pubis). Large, cup-shaped bones that attach lower limbs to the spine. Each hip bone connects at the sacrum and forms the acetabulum (hip socket).
Thigh (2 bones):
Femur – 2, long bone. Thigh bone; the largest and strongest bone in the body. It extends from hip to knee, bearing body weight and enabling hip/knee movement.
Knee (2 bones):
Patella – 2, sesamoid bone (embedded in a tendon). Kneecap; in the quadriceps tendon, protects the knee joint and improves leverage of the thigh muscles.
Leg (4 bones):
Tibia – 2, long bone. Shinbone; larger medial bone of the lower leg bearing most weight from the femur.
Fibula – 2, long bone. Thin lateral bone of the lower leg; stabilizes ankle and supports lower leg muscles.
Foot (52 bones total; 26 in each foot):
Tarsal bones – 14 (7 per foot), short bones. Names: Talus, Calcaneus (heel), Navicular, Cuboid, and three Cuneiforms (medial, intermediate, lateral). Form the ankle and heel structure.
Metatarsals – 10 (5 per foot), long bones. Bones of the instep, numbered I–V from big toe side.
Phalanges (foot) – 28 (14 per foot), long bones. Toe bones: each toe (digits 2–5) has 3 phalanges (proximal, intermediate, distal); the great toe has 2 (proximal and distal).
Classification: The lower limb is built for weight-bearing and stability. The femur, tibia, fibula and metatarsals are long bones that support body weight. The tarsals (like the carpals) are short bones providing ankle stability. The patella is a sesamoid bone that protects the knee joint and improves mechanical advantage of the quadriceps tendon.
Figure: Bones of the lower limb. Hip bone (ilium shown), femur, patella, tibia, fibula, and bones of the foot (tarsals, metatarsals, phalanges).
Foot
Figure: Bones of the human foot and ankle. Medial view of the right foot showing tarsals (calcaneus, talus, etc.), metatarsals and phalanges.
Tarsals – 7 per foot: Talus (ankle bone), Calcaneus (heel bone), Navicular, Cuboid, and three Cuneiform bones. These short bones create the ankle joint and heel, absorbing weight and enabling foot motion.
Metatarsals – 5 per foot, long bones of the arch. Transmit body weight from talus to toes and aid in balance during walking.
Phalanges (foot) – 14 per foot, long bones of the toes (3 each for toes 2–5, 2 for the big toe).
Total foot bones: 26 per side (52 total). The arches formed by the tarsals and metatarsals help support the body’s weight.
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