4: Skeletal System
- Page ID
- 90510
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 4.1: Connective Tissues of the Skeletal System
- The major connective tissues of the skeletal system provide support, protection, and structural strength, while also allowing movement and shock absorption. Differences in tissue structure give rise to compact and spongy bone, cartilage, and dense regular connective tissue, each adapted for specific roles in bones, joints, tendons, and ligaments.
- 4.2: Gross Anatomy of The Skeletal System
- Bone structure reflects function: weight-bearing bones are thick and strong, and surface features such as ridges and bumps develop where powerful muscles attach. The skeleton is a living, adaptable system that remodels in response to use, load, and lifestyle. It is organized into axial and appendicular divisions with bones classified by shape into 5 different groups.
- 4.3: Long Bones — Anatomy, Blood Supply, and Innervation
- Long bones are specialized for support and movement, with distinct regions that contribute to strength, growth, and joint function. Differences in structure between the diaphysis, epiphyses, metaphysis, and internal cavities allow long bones to support body weight, enable lengthwise growth during development, and house marrow, blood vessels, and nerves essential for bone health.
- 4.4: Bone Formation and Remodeling
- Bone formation, growth, and remodeling allow the skeleton to develop, adapt, and remain strong throughout life. Endochondral ossification replaces cartilage with bone during development, longitudinal growth occurs at the epiphyseal plates, and appositional growth and remodeling adjust bone thickness and strength in response to mechanical stress and physical activity.
- 4.5: Fractures and Bone Repair
- Bone fractures occur when forces exceed the strength of bone, resulting in distinct fracture patterns that vary in severity and cause. Differences in fracture type influence how bones heal, progressing through predictable stages of repair, and determine whether treatment involves simple immobilization or more complex reduction and surgical intervention.
- 4.6: The Functions of the Skeletal System
- Bones serve multiple essential roles that extend beyond structural support. Together, their protective, supportive, mechanical, metabolic, and blood-forming functions allow the skeletal system to safeguard vital organs, enable movement, regulate mineral balance, and produce the cells needed for life.
- 4.7: The Vertebral Column
- The vertebral column is a flexible column of irregular bones called vertebrae that extends from the neck to the tail region. It supports the body, protects the spinal cord, and allows for movement and flexibility. The vertebrae are organized into three regions — cervical, thoracic, and lumbar vertebrae — and natural curves that increase strength, stability, and shock absorption.
- 4.8: Disorders of the Vertebral Column
- Abnormal curvatures of the spine occur when the normal spinal curves become exaggerated or misaligned. The three main types are kyphosis, lordosis, and scoliosis, which can affect posture, balance, and movement. These conditions may be identified through observation and are often managed with conservative treatments, although severe cases may require surgical intervention.
- 4.9: Structural and Functional Classification of Joints
- Joints, also called articulations, are the locations where two bones meet and allow for movement in the skeletal system. Joints are classified structurally as fibrous, cartilaginous, or synovial based on the tissues that bind the bones together, and functionally as synarthroses, amphiarthroses, or diarthroses based on the amount of movement permitted.
- 4.10: Synovial Joints
- Synovial joints are the most common and most freely movable joints in the body and are defined by the presence of a fluid-filled joint cavity. Their specialized structures, including articular cartilage, synovial fluid, ligaments, and supporting muscles, allow smooth movement while maintaining joint stability. Based on the shapes of their articulating surfaces, synovial joints are classified into several types that permit different kinds and ranges of motion.
- 4.11: Types of Body Movements
- Synovial joints allow a wide variety of movements that result from muscle contractions acting across joints. These movements are described relative to the anatomical position and are organized by the body planes in which they occur, including flexion and extension, abduction and adduction, and rotation. In addition, several special movements such as pronation, supination, dorsiflexion, and opposition provide the body with its remarkable flexibility and mobility.
- 4.12: Diseases and Injuries of Joints
- Diseases of joints commonly involve inflammation, injury, or degeneration of the tissues that support movement. Conditions such as bursitis, sprains, strains, and arthritis can cause pain, swelling, stiffness, and reduced mobility, with causes ranging from overuse and trauma to autoimmune disease and metabolic disorders. While some joint diseases are temporary and heal with rest and treatment, others are chronic and require long-term management to preserve joint function and quality of life.