Chapter 7: The Skeletal System – The Axial Skeleton

Skeletal System

Includes bones, muscles, and joints.

Orthopedics

Medical science for musculoskeletal system.

Human Skeleton

Comprises 206 bones.

Axial Skeleton

80 bones including skull and vertebrae.

Appendicular Skeleton

126 bones including limbs and girdles.

Long Bones

Weight-bearing, slightly curved bones like femur.

Short Bones

Cube-shaped bones, e.g., wrist bones.

Flat Bones

Thin, protective bones like skull and ribs.

Irregular Bones

Bones with complex shapes, e.g., vertebrae.

Sesamoid Bones

Small bones in tendons, e.g., patella.

Sutural Bones

Extra bones in cranial sutures.

Bone Markings

Surface features for attachment or passage.

Fissure

Narrow slit for blood vessels/nerves.

Foramen

Hole for passage of nerves/blood vessels.

Fossa

Shallow depression in bone.

Meatus

Tubelike opening in bone.

Condyle

Rounded surface for joint articulation.

Crest

Prominent ridge on bone surface.

Trochanter

Large projection on femur.

Spinous Process

Sharp projection on vertebrae.

Tubercle

Small rounded projection on bone.

Tuberosity

Large rounded projection for muscle attachment.

Cranial Bones

8 bones forming the skull.

Facial Bones

14 bones forming the face.

Paranasal Sinuses

Air-filled spaces in skull bones.

Fontanels

Soft spots in infant skulls.

Hyoid Bone

U-shaped bone supporting the tongue.

Vertebral Column

Composed of 26 vertebrae.

Intervertebral Discs

Shock-absorbing fibrocartilage between vertebrae.

True Ribs

First 7 ribs, attach directly to sternum.

False Ribs

Ribs 8-10, attach indirectly to sternum.

Floating Ribs

Ribs 11-12, no attachment to sternum.

Herniated Disc

Nucleus pulposus leaks due to tear.

Scoliosis

Lateral curvature of the spine.

Kyphosis

Exaggerated thoracic curvature.

Lordosis

Exaggerated lumbar curvature.

Spina Bifida

Incomplete closure of vertebrae.