Classification of Bones Quiz

Bone Classifications

• Irregular Bones: Do not fit into conventional categories; examples include vertebrae and pelvic bones.
• Short Bones: Includes carpals (wrist) and tarsals (ankle).
• Flat Bones: Examples are the skull, sternum, and scapula.

Gross Anatomy of a Long Bone

• Epiphysis: Ends of long bones.
• Epiphyseal Plate: Flat plate of hyaline cartilage for growth.
• Diaphysis: Shaft, primarily made of compact bone, covered by periosteum.
• Periosteum: Fibrous connective tissue membrane covering bones.
• Medullary Cavity: Inner space containing bone marrow.
• Endosteum: Lining of the medullary cavity.
• Bone Markings: Indicate muscle, tendon, ligament attachment, and blood vessel/nerves passage.

Microscopic Anatomy of Bone

• Osteocytes: Mature bone cells found in lacunae.
• Haversian Canals: Central canals around which osteocytes are arranged in concentric circles (lamellae).
• Canaliculi: Tiny canals radiating from central canals to lacunae.
• Perforating (Volkmann’s) Canals: Channels connecting haversian canals.

Bone Formation and Remodeling

• Ossification: Process of bone formation from cartilage in young children.
• Osteoblasts: Bone-building cells involved in new bone formation.
• Osteoclasts: Giant cells that break down bone tissue.
• Remodeling Factors: Calcium ion levels in blood and gravitational/muscle pull.

Healing of Bone Fractures

• Bones undergo stages of healing post-fracture, involving remodeling to maintain strength.

Skeleton Division

• Axial Skeleton: Forms the body's longitudinal axis, consisting of skull, vertebral column, and thoracic cage.
• Appendicular Skeleton: Comprises the limbs and girdles.

Axial Skeleton Components

• Skull:
  • Cranium: Protects brain; includes frontal, parietal, occipital, and temporal bones.
  • Facial Bones: Include maxilla, palatine, zygomatic, lacrimal, nasal bones, and mandible.
• Vertebral Column: Comprised of 26 vertebrae forming four curves, provides weight support and flexibility.
• Thoracic Cage: Composed of ribs and sternum; protects thoracic organs.

Vertebral Column Structure

• Cervical Vertebrae (C1-C7): Form the neck; C1 (Atlas) supports skull, C2 (Axis) allows head rotation.
• Thoracic Vertebrae (T1-T12): Larger than cervical, articulate with ribs.
• Lumbar Vertebrae (L1-L5): Sturdy, kidney-bean shaped; support lower back.
• Sacrum & Coccyx: Sacrum formed by five fused vertebrae; coccyx is the tailbone.

Appendicular Skeleton Components

• Shoulder Girdle: Comprises the clavicle (prevents dislocation) and scapula (shoulder blade).
• Upper Limbs: Includes humerus (arm), radius and ulna (forearm), carpals, metacarpals, and phalanges (hand).
• Pelvic Girdle: Formed by two coxal bones; supports weight and protects organs.
• Lower Limbs: Include femur (thigh), tibia and fibula (leg), tarsals, metatarsals, and phalanges (foot).

Joints and Movements

• Definition of Joints: Sites where two or more bones meet, allowing movement.
• Types of Joints:
  • Synarthroses: Immovable joints, e.g., cranial sutures.
  • Amphiarthroses: Slightly movable, e.g., vertebrae.
  • Diarthroses: Freely movable joints, e.g., knee and elbow.
• Structural Classification:
  • Fibrous Joints: Bones united by fibrous tissue.
  • Cartilaginous Joints: Bones connected by cartilage.
  • Synovial Joints: Bone ends separated by a joint cavity with synovial fluid.

Types of Body Movements

• Flexion/Extension: Bending or straightening a limb.
• Abduction/Adduction: Moving a body part away from or towards the midline.
• Rotation: Moving a body part around a central axis.
• Dorsiflexion: Bending the foot upwards; plantar flexion is the opposite.
• Inversion/Eversion: Turning the sole of the foot inward or outward.

Skeletal Disorders

• Arthritis: Inflammation of joints.
  • Osteoarthritis: Common chronic degenerative condition, usually in the aged.
  • Rheumatoid Arthritis: Chronic inflammatory autoimmune disorder.
  • Gouty Arthritis: Uric acid accumulation leads to crystal deposits in joints.

Intervertebral Discs and Vertebral Column

• Intervertebral discs cushion vertebrae and absorb shocks, enhancing flexibility of the spine.
• The spinal cord runs through the central cavity of the vertebral column.
• Cervical curve consists of 7 vertebrae (C₁-C₇), the thoracic curve has 12 (T₁-T₁₂), and the lumbar curve contains 5 (L₁-L₅).
• The sacral curve comprises the sacrum and coccyx, not individual vertebrae.

Cervical Vertebrae

• C₁, the Atlas, supports the skull's occipital condyles.
• C₂, the Axis, allows for pivoting movement of the atlas and skull.

Thoracic Vertebrae

• T₁-T₁₂ are larger and uniquely articulate with the ribs.

Lumbar Vertebrae

• L₁-L₅ are kidney-shaped and are the sturdiest vertebrae, supporting the lower back.

Sacrum and Coccyx

• Sacrum formed from five fused vertebrae, creating the pelvis' posterior wall.
• Coccyx, or tailbone, consists of three to five fused irregular vertebrae.

Thoracic Cage

• Composed of bones and cartilage protecting thoracic cavity organs.
• Sternum formed by fusion of manubrium, body, and xiphoid process.
• Has 12 pairs of ribs: True ribs (7 pairs), False ribs (5 pairs), Floating ribs (2 pairs).
• Intercostal spaces are located between rib pairs.

Appendicular Skeleton

Shoulder/Pectoral Girdle

• Comprised of clavicle (collarbone) and scapula (shoulder blade).
• Clavicle prevents shoulder dislocation; scapula known as "wings".

Upper Limbs

• Bones of the arm include the humerus; forearm bones are the radius and ulna.
• The hand consists of carpals, metacarpals, and phalanges.

Pelvic Girdle

• Formed by two coxal (hip) bones, crucial for weight-bearing and protection of internal organs.
• Each coxal bone forms from three fused bones: ilium, ischium, and pubis.

Bone Classifications by Shape

• Short bones: carpals and tarsals.
• Flat bones: skull, sternum, scapula.
• Irregular bones: vertebrae and pelvic bones.

Gross Anatomy of Long Bones

• Epiphysis: ends of long bones.
• Diaphysis: shaft; mostly compact bone.
• Periosteum: fibrous connective tissue covering.
• Medullary cavity: contains bone marrow (red and yellow marrow).

Bone Markings

• Projections or processes indicate muscle and ligament attachment.
• Depressions or cavities refer to indentations in bone.

Microscopic Anatomy of Bone

• Osteocytes: mature bone cells located in lacunae, arranged in lamellae around central canals, forming osteons.
• Canaliculi: tiny canals extending from central canals to lacunae.
• Perforating canals (Volkmann's canals) allow for communication and nutrient transfer.

Bone Formation and Remodeling

• Ossification is the process of bone formation.
• Osteoblasts build bone; osteoclasts break it down.
• Bone is continuously remodeled based on calcium levels and gravitational/muscle strain.

Skeleton Overview

• Divided into axial skeleton (skull, vertebral column, thoracic cage) and appendicular skeleton (limbs and girdles).

Skull Structure

• Cranium protects the brain; facial bones form the structure of the face.
• Major cranial bones: frontal, parietal, occipital, temporal; each has specific anatomical functions.

Hyoid Bone

• Unique bone that does not articulate with others; serves as attachment for tongue and larynx muscles.

Vertebral Column

• Composed of 26 irregular bones forming four spinal curves for strength and balance.
• Transmits body weight to lower limbs.

Test your knowledge on the various classifications of bones based on their shapes, including irregular, short, and flat bones. This quiz covers the basic anatomy and functions of these bone types in the human body. Perfect for students exploring the subject of human anatomy.