The Skeleton The Human Skeleton Learn major bones
The Skeleton
The Human Skeleton • Learn major bones and markings on handout. • 206 bones of human skeleton divided into: axial skeleton appendicular skeleton
Axial Skeleton • skull and trunk • vertebral column and rib cage
Appendicular Skeleton • arms and legs • includes pectoral and pelvic girdles
Bone Markings • sites of muscle, ligament, and tendon attachment • points of articulation • pathways for blood vessels and nerves – Projections • grow outward – Depressions and Openings • for blood and nerve supply
Projections • Crest - narrow ridge ilium • Head - bony expansion humerus, ribs • Condyle – rounded lower humerus, mandible • Process - lump elbow- olecranon process • Spine - sharp, slender vertebra articular projection pointed
Depressions and Openings • Meatus - canal-like auditory • Sinus - air filled cavity paranasal • Fossa - shallow depression iliac • Foramen – round/ oval opening vertebrae • Fissure - slit-like, cleft eye socket
How to Identify the Sex of a Skeleton
Male and Female Pelvis • female modified for childbearing • wider, shallower, lighter, rounder, tilted forward
Developmental Aspects of the Skeleton
Fontanels • At birth fontanels (still fibrous areas of cranium) accommodate future brain growth. - “soft spot” - by age 2 skull is 3/4 adult size - by age 11 skull is full size and face is starting to grow out
Spinal Curvatures • 6 months • Lift head • Cervical curvature develops • Spinal curve at birth • No curvature • 9 months • Walking • Wight over center of gravity • Develops lumbar curvature
Natural Spinal Curvatures
Disorders: normal curves become exaggerated Scoliosis • lateral bend in thoracic region • one leg shorter, congenital, poor posture, muscle paralysis on one side
Kyphosis • hunch back, “rounded shoulder” • exaggeration of thoracic curve • poor posture, degeneration of discs, rickets
Lordosis • sway back • exaggeration of lumbar curve • increase wt. in abdomen, pregnancy, poor posture
• After birth, legs grow more rapidly than trunk. • With age, all bones lose some mass.
- Slides: 20