Skeletal System and Articulations: Study Guide for Anatomy & Physiology

Exercise 8: Skeletal Overview

Functions and Structure of the Skeleton

• Functions of the Skeleton: The skeleton provides support, protection for internal organs, facilitates movement, stores minerals (such as calcium and phosphorus), and houses bone marrow for blood cell production.

• Major Types of Skeletal Cartilages: There are three main types:

  • Hyaline cartilage: Most abundant; found in articular surfaces, costal cartilages, nose, trachea, and larynx.

  • Elastic cartilage: Contains more elastic fibers; found in the ear and epiglottis.

  • Fibrocartilage: Highly compressible; found in intervertebral discs, pubic symphysis, and menisci.

• Characteristics of Cartilage Types: Hyaline is glassy and smooth, elastic is flexible, fibrocartilage is tough and dense.

• Bone Classification: Bones are classified by shape:

  • Long bones (e.g., femur, humerus)

  • Short bones (e.g., carpals, tarsals)

  • Flat bones (e.g., sternum, skull bones)

  • Irregular bones (e.g., vertebrae, hip bones)

• Structure of a Long Bone: Includes diaphysis (shaft), epiphyses (ends), metaphysis, medullary cavity, periosteum, and endosteum. Figure 8.3 illustrates these parts.

• Microscopic Structure of Compact Bone: Compact bone is organized into osteons (Haversian systems), which consist of concentric lamellae surrounding a central canal. Figure 8.4 shows this structure.

• Inorganic and Organic Components of Bone Matrix:

  • Inorganic: Mainly hydroxyapatite (calcium phosphate crystals) providing hardness.

  • Organic: Collagen fibers and ground substance, providing flexibility and tensile strength.

• Bone Markings: Table 8.1 lists terms such as foramen, process, tubercle, etc., which describe features on bones for attachment or passage of structures.

• Epiphyseal Plate Zones: The epiphyseal plate (growth plate) has zones: resting, proliferating, hypertrophic, calcification, and ossification. These zones are involved in bone growth.

Exercise 9: Axial Skeleton

Overview and Identification

• Axial Skeleton: Consists of the skull, vertebral column, and thoracic cage (ribs and sternum).

• Study Approach: Focus on names and locations of bones, major features (foramen, fossae, sutures, processes), and their functions.

• Skull Bones: Know the sphenoid and ethmoid bones, and their unique features.

• Paranasal Sinuses: Air-filled spaces in the skull that lighten the bone and enhance voice resonance.

• Vertebral Column:

  • Composed of cervical (7), thoracic (12), lumbar (5), sacral (5 fused), and coccygeal (4 fused) vertebrae.

  • Be able to identify vertebrae by region and specific features (e.g., C1 = atlas, C2 = axis).

  • Know the major structures of the sacrum and coccyx.

• Thoracic Cage: Includes the ribs, sternum, and costal cartilages. Be able to identify individual ribs and their features.

• Bone Marrow Harvesting: The iliac crest of the pelvis is a common site for bone marrow extraction.

• Fetal vs. Adult Skull: The fetal skull has fontanelles (soft spots) and different proportions compared to the adult skull.

Exercise 10: Appendicular Skeleton

Identification and Functional Aspects

• Appendicular Skeleton: Includes the pectoral girdle (clavicle and scapula), upper limbs, pelvic girdle, and lower limbs.

• Bone Sides: Be able to identify left vs. right bones (e.g., femur, humerus, scapula) based on anatomical features.

• Pelvis: Know the differences between male and female pelvises (female pelvis is wider and shallower for childbirth).

• Carpals and Tarsals: Know the names and arrangement of wrist (carpal) and ankle (tarsal) bones.

• Urals: Additional info: Possibly refers to 'urals' as a typo for 'tarsals' or 'carpals'.

• Metacarpals, Metatarsals, Phalanges: No need to identify individual bones for the exam.

Exercise 11: Articulations and Body Movements

Joint Classification and Movements

• Functional Categories of Joints:

  • Synarthroses: Immovable joints (e.g., sutures of the skull).

  • Amphiarthroses: Slightly movable joints (e.g., intervertebral discs).

  • Diarthroses: Freely movable joints (e.g., shoulder, knee).

• Structural Categories of Joints:

  • Fibrous: Bones joined by dense connective tissue (e.g., sutures).

  • Cartilaginous: Bones joined by cartilage (e.g., symphysis, synchondrosis).

  • Synovial: Bones separated by a fluid-filled joint cavity (e.g., most limb joints).

• Synovial Joints: Characterized by articular cartilage, joint cavity, synovial fluid, articular capsule, reinforcing ligaments, and nerves/blood vessels.

• Examples of Synovial Joints: Shoulder, elbow, hip, knee.

• Figures 11.1 and 11.2: Illustrate synovial joint structure and types of movement.

• Movements of Joints: Flexion, extension, abduction, adduction, rotation, circumduction, etc. (see Table 11.5).

• Major Joints: Table 11.3 covers major joints such as the hip, shoulder, elbow, and knee, including bones, muscles, cartilage, ligaments, and tendons involved.

• Specific Ligaments: Know the main ligaments for major joints discussed in class.

Sample Table: Comparison of Joint Types

Joint Type	Structural Category	Functional Category	Example
Suture	Fibrous	Synarthrosis	Skull sutures
Symphysis	Cartilaginous	Amphiarthrosis	Pubic symphysis
Ball-and-socket	Synovial	Diarthrosis	Shoulder, hip

Additional Study Tips

• Use pre-lab quizzes and post-lab review sheets for practice.

• Practice Anatomy Lab resources (such as myA&P website) are recommended for further study.