Musculoskeletal System Review

Musculoskeletal System Overview

• Focus on muscles and joints interaction and their anatomical aspects.

Lecture Objectives

• Anatomical Limb Segments:
  • Identify and describe muscle groups associated with each segment.
• Joint Movements:
  • Understand how movements occur at joints.
• Muscle Actions:
  • Define general actions of muscles.
• Functional Classifications of Joints:
  • Types and examples of each joint category.
• Structural Types of Joints:
  • Features of three structural joint types.
• Synovial Joint Classes:
  • Different types with examples.
• Shoulder vs. Hip Joints:
  • Compare similarities and differences.
• Anatomy of Key Joints:
  • Detailed study of knee and elbow joints.

Muscle Actions

• General Function:
  • Movement of bones via joint articulation.
• Exceptions to Typical Functionality:
  • Muscular hydrostats (e.g., tongue).
  • Muscles acting on skin or multiple joints.
• Uniarticular vs. Biarticular Muscles:
  • Defined by the number of joints crossed.

Anatomical Directions and Movements

• Directional Terms:

  • Superior: Above
  • Inferior: Below
  • Proximal: Closer to the trunk
  • Distal: Further from the trunk
  • Medial: Towards the midline
  • Lateral: Away from the midline.

• Joint Movements:

  • Flexion: Decrease angle (bending).
  • Extension: Increase angle (straightening).
  • Pronation: Rotate downwards (palms down).
  • Supination: Rotate upwards (palms up).
  • Internal Rotation: Rotate towards midline.
  • External Rotation: Rotate away from midline.
  • Abduction: Move away from midline.
  • Adduction: Move towards midline.
  • Elevation: Move superiorly.
  • Depression: Move inferiorly.

Limb Segments and Joints

• Limb Composition:
  • Shoulder, Arm, Elbow, Forearm, Hip, Wrist, Hand, Thigh, Knee, Leg, Ankle, Foot.

Axial Muscles and Movements

• Posture and Muscle Groups:
  • Key muscles: Semispinalis, Splenius, Longissimus, Iliocostalis, Spinalis, Transverse Abdominis.
• Major Movements: Flexion, Extension, Lateral Rotation.

Forelimb and Hindlimb Muscle Groups

• Forelimb Muscles:
  • Rotator cuff, Elbow flexors/extensors, Wrist flexors/extensors.
• Hindlimb Muscles:
  • Quadriceps, Gluteals, Hamstrings, Calf muscles.

Muscle Action Dynamics

• Agonists: Prime movers responsible for the action.
• Antagonists: Oppose the action, relaxing when agonists contract.
• Synergists and Fixators: Aid the action and stabilize the joint.

Types of Joints

• Functional Classification of Joints:
  • Synarthrosis: No movement.
  • Amphiarthrosis: Little movement.
  • Diarthrosis: Freely moveable.
• Structural Classification of Joints:
  • Fibrous: Dense connective tissue, minimal movement.
  • Cartilaginous: Cartilage connection, minimal/slight movement.
  • Synovial: Freely movable joints with a synovial cavity.

Synovial Joint Structures

• Common Features:
  • Articular capsule, cartilage, ligaments, tendons, bursae, synovial fluid for lubrication, shock absorption, and nutrition.
• Joint Types by Movement:
  • Gliding (Plane), Pivot, Ellipsoidal (Condyloid), Hinge, Saddle, Ball and Socket.

Specific Joints

• Hip and Shoulder Similarities:

  • Both are ball and socket joints allowing for a wide range of motion but structured differently.

• Differences between Joints:

  • Hip: More robust, bearing weight, with a deep socket.
  • Shoulder: Greater range, shallow socket, higher dislocation risk.

• Knee and Elbow Joints:

  • Both synovial hinge joints, connecting long bones.
  • Key ligaments include collateral ligaments, cruciate ligaments, and menisci (for the knee).

Study Recommendations

• Review chapters on joints, appendicular skeleton, and muscular tissue from Tortora for detailed anatomy and physiology.
• Utilize visual aids and videos from resources like "Crash Course" to reinforce learning outcomes.

Summary

These notes outline the essential components of the musculoskeletal system, particularly focusing on muscle actions, the classification of joints, and the fundamental anatomy of key regions such as the hip, shoulder, knee, and elbow, preparing for deeper studies or practical examinations in this biological field.