Anatomy and Physiology I: Articulations Midterm Review

Anatomy and Physiology I

Course Information

Course Code: BS 121
Instructor: Dr. Nancy Brandt
Subject: Articulations
Exam: Midterm Review (Chapter 14)

Course Outline

Cartilage Tissue
Classifications of Joints
- Fibrous
- Cartilaginous
- Synovial
Specific Joints
Types of Range of Motion (ROM)

Cartilage Tissue

Characteristics of Cartilage

Type: Avascular connective tissue
Structure: Fibers of cartilage are embedded in a firm gel that possesses flexibility akin to firm plastic.
Vascularity: No canal system or blood vessels present.
Nutrient Supply: Chondrocytes receive oxygen and nutrients by diffusion.
Perichondrium: A fibrous covering of cartilage.
Variability: Types of cartilage vary due to differences in matrix composition and the density of elastic and collagenous fibers.

Types of Cartilage

Hyaline Cartilage
- Commonality: Most prevalent type of cartilage.
- Locations: Covers articular surfaces of bones, forms costal cartilages, cartilage rings in the trachea and bronchi, and the tip of the nose.
- Formation: Forms from specialized cells in chondrification centers that secrete matrix material.
- Cell Structure: Chondrocytes are isolated into lacunae.
Elastic Cartilage
- Locations: Forms the external ear, epiglottis, and Eustachian tubes.
- Characteristics: Contains large numbers of elastic fibers, granting it elasticity and resiliency.
Fibrocartilage (Fibrous Cartilage)
- Locations: Occurs in the pubic symphysis and intervertebral disks.
- Characteristics: Contains small quantities of matrix with abundant fibrous elements, making it strong and rigid.

Functions of Cartilage

Support: Provides tough, rubberlike support, allowing it to sustain considerable weight and act as shock absorbers.
Flexibility: Offers a strong yet pliable structural support.
Growth Facilitation: Allows growth in length of long bones.

Growth of Cartilage

Types of Growth:
1. Interstitial (Endogenous) Growth
- Mechanism: Cartilage cells divide and secrete additional matrix, observed during childhood and early adolescence.
1. Appositional (Exogenous) Growth
- Mechanism: Chondrocytes within the deep layer of the perichondrium divide and secrete new matrix on the surface, increasing size; continues throughout life once initiated.

Articulations (Joints)

Definition

Articulation: Point of contact between two bones.
Movement: Most joints are movable, although some are immovable or only allow limited motion.
Functionality: Movable joints facilitate complex, highly coordinated, and purposeful movements.

Classification of Joints

Structural Classification

Based on the type of connective tissue that joins bones together:
- Fibrous Joints: Little to no movement.
- Cartilaginous Joints: Limited movement.
- Synovial Joints: Freely movable with a fluid-filled joint capsule.

Functional Classification

Based on the degree of movement allowed:
- Synarthroses: Immovable joints.
- Amphiarthroses: Slightly movable joints.
- Diarthroses: Freely movable joints.

Types of Joints

Fibrous Joints (Synarthroses):
- Types:
  - Syndesmoses: Ligaments connect two bones (e.g., tibia and fibula).
  - Sutures: Found only in the skull; interlocking teeth-like projections.
  - Gomphoses: Attachment between tooth roots and mandible/maxilla.
Cartilaginous Joints (Amphiarthroses):
- Types:
  - Synchondroses: Hyaline cartilage between articulating bones (e.g., ribs to sternum).
  - Symphyses: Fibrocartilage disc connects two bones (e.g., pubic symphysis).
Synovial Joints (Diarthroses):
- Structure: Freely movable joints characterized by:
  - Joint capsule enclosing the joint.
  - Synovial membrane lining the capsule and secreting synovial fluid.
  - Articular cartilage covering bone surfaces.
  - Joint cavity allowing free movement.
  - Menisci (articular disks) providing cushioning;
  - Ligaments stabilizing the joint.
  - Bursae reducing friction between structures.
- Types:
  - Uniaxial:
  1. Hinge Joints: Allow flexion and extension (e.g., elbow).
  2. Pivot Joints: Allow rotational movement (e.g., radius rotating against ulna).
  - Biaxial:
  1. Saddle Joints: Allow movement in two planes (e.g., thumb).
  2. Condyloid (Ellipsoidal) Joints: Oval condyle fits into an elliptical socket.
  - Multiaxial:
  1. Ball-and-Socket Joints: Most movable (e.g., shoulder, hip).
  2. Gliding Joints: Allow limited gliding movements (e.g., between vertebrae).

Range of Motion (ROM)

Measurement of ROM

Purpose: Assessment of joint injuries.
Types: Can be measured actively (with muscle engagement) or passively.
Instrument: Measured using a goniometer.

Types of ROM Movements

Angular Movements: Change the angle between articulating bones.
- Flexion & Extension: Flexion decreases the angle, while extension increases it; hyperextension stretches more than the anatomical position.
- Plantar Flexion & Dorsiflexion: Plantar flexion increases the angle between the foot and leg; dorsiflexion decreases it.
- Abduction & Adduction: Abduction moves a part away from the median plane; adduction moves it towards.
Circular Movements:
- Rotation & Circumduction: Rotation pivots a bone around its axis; circumduction moves a part in circular motion.
- Supination & Pronation: Supination turns palm upward; pronation turns palm downward.
Gliding Movements: Simplest movement involving one bone sliding over another.
Special Movements:
- Inversion & Eversion: Inversion turns the sole of the foot inward; eversion turns it outward.
- Protraction & Retraction: Protraction moves a part forward; retraction moves backward.
- Elevation & Depression: Elevation moves a part upward; depression lowers a part.

Study Preparation

Midterm II Preparation: Focus on main points from lectures, anatomy, and key definitions.
Exam Format: 20% questions, 80% fill-in structures.

Additional Notes

Review main points from quizzes and each lecture thoroughly.
Week 7: Midterm II (closed book) and begin reviewing muscle naming (Chapter 15).
Subsequent weeks will cover additional chapters and corresponding quizzes.