General Osteology, Arthrology and Myology

General Osteology

Definition

• Osteology: The branch of anatomy that deals with the study of bones, their structure, function, and development.

Properties and Structure of Bone

• Bone Composition:
  • Organic Components: Collagen fibers and ground substance, providing flexibility and tensile strength.
  • Inorganic Components: Primarily hydroxyapatite (calcium phosphate), giving bones rigidity and strength.
• Bone Types:
  • Compact Bone: Dense outer layer providing strength.
  • Cancellous (Spongy) Bone: Inner layer with a porous structure, housing bone marrow.

Classification of Skeletons

• Axial Skeleton:
  • Components: Skull, vertebral column, ribs, and sternum.
  • Function: Protects vital organs (e.g., brain, spinal cord) and supports the body.
• Appendicular Skeleton:
  • Components: Limbs (forelimbs and hindlimbs) and their girdles (pectoral and pelvic).
  • Function: Facilitates movement and locomotion.

Classification of Bones

• Long Bones:
  • Examples: Femur, humerus, tibia.
  • Function: Support weight and facilitate movement.
• Short Bones:
  • Examples: Carpals (wrist) and tarsals (ankle).
  • Function: Provide stability and support with limited movement.
• Flat Bones:
  • Examples: Scapula, skull bones, pelvic bones.
  • Function: Protect internal organs and provide surface area for muscle attachment.
• Irregular Bones:
  • Examples: Vertebrae, certain skull bones.
  • Function: Complex shapes for various functions (e.g., support, protection).
• Sesamoid Bones:
  • Examples: Patella (kneecap).
  • Function: Protect tendons from stress and wear.

Terminology in Osteology

• Diaphysis: The long shaft of a long bone.
• Epiphysis: The rounded ends of long bones, involved in joint formation.
• Metaphysis: The region between the diaphysis and epiphysis, where growth occurs in young animals.
• Articulation: The point where two bones meet, forming a joint.

Introduction to Arthrology

Definition

• Arthrology: The study of joints, their structure, function, and the movements they permit.

Classification of Joints

• Fibrous Joints:
  • Characteristics: Connected by dense connective tissue; generally immovable.
  • Examples: Sutures in the skull, syndesmoses between certain long bones.
• Cartilaginous Joints:
  • Characteristics: Connected by cartilage; allow slight movement.
  • Examples: Intervertebral discs, pubic symphysis.
• Synovial Joints:
  • Characteristics: Freely movable joints with a synovial cavity.
  • Examples: Shoulder, hip, knee, and elbow joints.

Diarthrodial Joints

• Structure:
  • Articular Cartilage: Smooth cartilage covering the ends of bones, reducing friction.
  • Joint Capsule: A fibrous envelope surrounding the joint, providing stability.
  • Synovial Fluid: Lubricating fluid produced by the synovial membrane, nourishing articular cartilage.
  • Ligaments: Connective tissue that reinforces the joint.

• Movements Permitted:
  • Flexion/Extension: Decreasing/increasing the angle between body parts.
  • Abduction/Adduction: Moving away from/towards the midline of the body.
  • Rotation: Twisting movement around an axis.
  • Circumduction: Circular movement combining flexion, extension, abduction, and adduction.

Introduction to Myology

Definition

• Myology: The study of muscles, their structure, function, and mechanics.

Classification of Muscles

• Skeletal Muscle:
  • Characteristics: Voluntary, striated, and multi-nucleated.
  • Function: Facilitates movement and posture; attached to bones via tendons.
• Cardiac Muscle:
  • Characteristics: Involuntary, striated, and branched; contains intercalated discs.
  • Function: Pumps blood throughout the body; found exclusively in the heart.
• Smooth Muscle:
  • Characteristics: Involuntary, non-striated, and spindle-shaped.
  • Function: Controls movements within internal organs (e.g., intestines, blood vessels).

Etymology of Muscles

• Muscle Names: Often derived from Latin or Greek, indicating location, shape, or function (e.g., “deltoid” means triangular).

Description of Related Structures

• Tendons:
  • Definition: Tough, fibrous connective tissue that connects muscles to bones.
  • Function: Transmits the force generated by muscles to bones, facilitating movement.
• Ligaments:
  • Definition: Fibrous connective tissue that connects bones to other bones at joints.
  • Function: Provides stability and support to joints, preventing excessive movement.
• Aponeurosis:
  • Definition: A flat, sheet-like structure of connective tissue that connects muscles to the parts they move.
  • Function: Distributes muscular force over a wider area.
• Synovial Bursa:
  • Definition: Fluid-filled sacs located between bones and soft tissues (muscles, tendons).
  • Function: Reduces friction and cushions pressure points during movement.
• Synovial Sheath:
  • Definition: A protective covering around tendons, particularly in areas where tendons pass through narrow spaces.
  • Function: Facilitates smooth gliding of tendons and reduces friction.
• Point wise shorts notes

General Osteology

Bone Composition

• Organic components: collagen, ground substance
• Inorganic components: hydroxyapatite

Bone Types

• Compact bone: dense outer layer
• Cancellous (spongy) bone: porous inner layer

Classification of Skeletons

• Axial skeleton: skull, vertebral column, ribs, sternum
• Appendicular skeleton: limbs and girdles

Classification of Bones

• Long bones: femur, humerus, tibia
• Short bones: carpals, tarsals
• Flat bones: scapula, skull, pelvis
• Irregular bones: vertebrae
• Sesamoid bones: patella

Osteology Terminology

• Diaphysis: shaft of long bone
• Epiphysis: ends of long bones
• Metaphysis: region between diaphysis and epiphysis
• Articulation: joint between bones

Introduction to Arthrology

Classification of Joints

• Fibrous joints: immovable (e.g., skull sutures)
• Cartilaginous joints: slightly movable (e.g., intervertebral discs)
• Synovial joints: freely movable (e.g., knee, elbow)

Diarthrodial Joints

• Components: articular cartilage, synovial fluid, joint capsule, ligaments
• Movements: flexion/extension, abduction/adduction, rotation

Introduction to Myology

Classification of Muscles

• Skeletal muscle: voluntary, striated, attached to bones
• Cardiac muscle: involuntary, striated, found in the heart
• Smooth muscle: involuntary, non-striated, found in organs

Muscle Etymology

• Names derived from Latin/Greek indicating location or function

Related Structures

• Tendons: connect muscles to bones
• Ligaments: connect bones to other bones
• Aponeurosis: flat sheet of connective tissue
• Synovial bursa: fluid-filled sacs reducing friction
• Synovial sheath: protective covering around tendons