Lab #7 TTK (Appendicular Bony Landmarks)

Overview of the Human Skeleton and Appendicular Skeleton

Introduction

The human skeleton is a dynamic structure that provides support, protection, and facilitates movement. The appendicular skeleton includes the bones of the limbs and girdles, enabling mobility and interaction with the environment. Understanding joint classification and bony landmarks is essential for anatomical orientation and clinical applications.

Classification of Joints

Functional Classification of Joints

Joints are classified functionally based on the degree of movement they allow:

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

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

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

Structural Classification of Joints

Joints are also classified structurally according to the material binding the bones and the presence of a joint cavity:

• Synovial Joints:

  • Have a joint cavity filled with synovial fluid.

  • Components include:

    • Articular capsule (fibrous capsule and synovial membrane)

    • Articular cartilage

    • Reinforcing ligaments

• Fibrous Joints: Bones joined by dense connective tissue; no joint cavity (e.g., sutures).

• Cartilaginous Joints: Bones joined by cartilage; no joint cavity (e.g., symphysis).

Major Joints and Their Structures

Knee Joint (Femoro-tibial Joint)

The knee is a complex synovial joint, stabilized by several ligaments and menisci:

• Lateral (fibular) collateral ligament

• Medial (tibial) collateral ligament

• Anterior cruciate ligament (ACL)

• Posterior cruciate ligament (PCL)

• Lateral meniscus

• Medial meniscus

Example: The ACL prevents anterior displacement of the tibia relative to the femur.

Bony Landmarks of the Upper Limb

Shoulder (Pectoral) Girdle

• Clavicle

  • Sternal (medial) end

  • Acromial (lateral) end

  • Conoid tubercle

• Scapula

  • Glenoid fossa

  • Supraspinous fossa

  • Infraspinous fossa

  • Subscapular fossa

  • Coracoid process

  • Acromion process

  • Spine

  • Superior angle

  • Inferior angle

  • Medial border (vertebral border)

  • Lateral border

  • Supraglenoid tubercle

Arm and Forearm Bones

• Humerus

  • Head

  • Greater tubercle

  • Lesser tubercle

  • Intertubercular sulcus (bicipital groove)

  • Deltoid tuberosity

  • Medial epicondyle

  • Lateral epicondyle

  • Trochlea

  • Capitulum

  • Lateral supracondylar ridge

  • Olecranon fossa

• Radius

  • Head

  • Radial tuberosity

  • Styloid process

• Ulna

  • Olecranon process

  • Coronoid process

  • Trochlear notch

  • Radial notch

  • Styloid process

Hand Bones

• Metacarpals (1–5)

• Carpals

  • Scaphoid

  • Lunate

  • Triquetrum (Triquetral bone)

  • Pisiform

  • Hamate

  • Capitate

  • Trapezoid

  • Trapezium

• Phalanges (1–5)

  • Proximal

Bony Landmarks of the Lower Limb

Pelvic Girdle

• Coxal Bone

  • Ilium (regional division)

    • Iliac crest

    • Iliac fossa

    • Greater sciatic notch

    • Anterior superior iliac spine

    • Anterior inferior iliac spine

    • Posterior superior iliac spine

    • Posterior inferior iliac spine

    • Articular surface for sacrum

  • Ischium (regional division)

    • Ramus

    • Ischial tuberosity

    • Lesser sciatic notch

    • Ischial spine

  • Pubis (regional division)

    • Rami (superior & inferior)

    • Articular surface for pubic symphysis

• Acetabulum

• Obturator foramen

Femur

• Head

• Greater trochanter

• Lesser trochanter

• Gluteal tuberosity

• Linea aspera

• Lateral epicondyle

• Medial epicondyle

• Lateral condyle

• Medial condyle

Other Lower Limb Bones

• Tibia

  • Plateau

  • Lateral condyle

  • Medial condyle

  • Intercondylar eminence

  • Tuberosity

  • Medial malleolus

  • Soleal line

• Fibula

  • Head

  • Lateral malleolus

• Patella (a sesamoid type bone)

• Metatarsals (1–5) Bases & heads

• Tarsals

  • Calcaneus

  • Talus

  • Navicular

  • Cuboid

  • Cuneiforms – Medial, Intermediate, Lateral

• Phalanges (1–5)

  • Proximal

  • Middle (except for hallux)

  • Distal

Comparative Anatomy: Pelvis Male vs. Female

Pelvic Differences

The male and female pelvis differ in structure to accommodate childbirth in females:

• Female pelvis: Wider, shallower, larger pelvic inlet and outlet.

• Male pelvis: Narrower, deeper, more robust.

Example: The subpubic angle is greater in females (>80°) than in males (<70°).

Summary Table: Joint Classifications

Classification	Type	Movement	Example
Functional	Diarthrosis	Freely movable	Shoulder, knee
Functional	Amphiarthrosis	Slightly movable	Intervertebral discs
Functional	Synarthrosis	Immovable	Skull sutures
Structural	Synovial	Freely movable	Elbow, hip
Structural	Fibrous	Immovable	Sutures
Structural	Cartilaginous	Slightly movable	Pubic symphysis

Key Terms and Definitions

• Articular cartilage: Smooth, white tissue covering the ends of bones in synovial joints.

• Ligament: Dense connective tissue connecting bone to bone, providing joint stability.

• Meniscus: Crescent-shaped fibrocartilage in the knee, improving fit and shock absorption.

• Synovial fluid: Lubricating fluid within synovial joints, reducing friction.

• Sesamoid bone: A bone embedded within a tendon (e.g., patella).

Applications and Clinical Relevance

• Understanding joint structure aids in diagnosing injuries (e.g., ligament tears, dislocations).

• Bony landmarks are essential for physical examination, surgical approaches, and imaging interpretation.

Additional info: Academic context and definitions have been expanded for clarity and completeness.