Anatomy of Long Bones

• Concept of Long Bones

  • Discussed the anatomy of long bones, emphasizing their structure and functionality.

• Articular Cartilage

  • Located where joints come together, facilitating smooth movement between bones.

Types of Bone Cells

• Osteogenic Cells

  • Definition: Undifferentiated stem cells that serve as precursors to other bone cells.

• Osteoblasts

  • Definition: Immature bone cells responsible for bone formation.

• Osteocytes

  • Definition: Mature bone cells that maintain bone tissue.

• Osteoclasts

  • Definition: Cells that break down and resorb older bone cells, playing a crucial role in bone remodeling.

Structure of Bone

• Types of Bone

  • Compact Bone
  • Location: Forms the external layer of all bones; comprises most of the diaphysis (the shaft) of long bones.
  • Spongy Bone
  • Location: Found on the inside of bones, typically at the tips of long bones.

• Osteon

  • Definition: The structural unit of compact bone, comprising a central canal surrounded by concentric rings (concentric lamellae).
  • Function: Provides strength and support to the bone structure.

• Central Canal (Haversian Canal)

  • Part of the osteon; contains blood vessels and nerves.

Blood Supply to Bone

• Various types of arteries supply blood to different regions of the bone:
  • Metaphysial Artery: Supplies blood to the metaphysis of the bone.
  • Epiphysial Artery: Supplies blood to the epiphysis of the bone.
  • Periosteal Artery and Vein: Supply blood to the outermost layer of the bone, known as the periosteum.

Growth of Bones

• Growth in Length and Width

  • Epiphyseal Plate: Responsible for bone growth in length.
  • Note: Once growth is complete, the epiphyseal plate becomes the epiphyseal line visible on X-rays.
  • Example provided of X-ray imaging to observe growth plates in younger individuals.

• Bone Remodeling

  • Process involves osteoblasts building new tissue while osteoclasts break down old tissue.
  • Significance: Crucial for healing injuries and adapting to stresses placed on bones.

Anatomy and Number of Bones

• Total Number of Bones: 206 bones in human body.
• Rib Pairs: 12 pairs (24 ribs total).
• Phalanges: 14 in each hand and foot, totaling 56.
• Infant vs. Adult Skeleton: Infants have more bones which fuse together as they grow (e.g., sacrum and coccyx).
• Coccyx: Made up of four fused bones.
  • Common Injury: Coccyx fracture from falls can be very painful, often treated with specialized seating (donuts).

Axial Skeleton Components

• Components:
  • Skull
  • Ribs
  • Sternum
  • Vertebral column
  • Ossicles (ear bones)
  • Hyoid bone (does not connect to any other bone, provides muscle attachment).

Appendicular Skeleton Components

• Components:
  • Pectoral girdle (shoulder)
  • Pelvic girdle (hip).

Cranial Bones

• Identification of Cranial Bones:
  • Frontal Bone: Forehead part (in blue).
  • Parietal Bones: Two bones on either side of the frontal bone.
  • Occipital Bone: Back part of the skull (purple).
  • Temporal Bones: Bones around the ears.
  • Zygomatic Bone: Cheekbone.
  • Sphenoid Bone: Located centrally behind the nose bridge.
  • Ethmoid Bone: Roof of the nasal cavity; contains cribriform plate for olfactory (smell).

Bone Markings

• Openings and Protrusions:
  • Foramina: Openings in bones, such as the foramen magnum (big hole).
  • Meatus: Tube-like opening (e.g., external auditory meatus).
  • Condyles: Rounded protuberances on bones, such as the femur’s medial and lateral condyles.
  • Processes: Projections from bones for muscle attachment (e.g., styloid process).

Function of Skull Bones

• Functions:

  • Protects the brain and sensory organs (smell, taste, hearing).
  • Provides muscle attachments.
  • Supports openings to digestive and respiratory tracts.

• Cranial Bones:

  • Form sutures and fontanels at birth, later fuse to joints.
  • Skeletal movements (e.g., cranial bones moving for cerebrospinal fluid flow).

Other Facial Bones

• Cheekbone: Zygomatic bone.

• Maxilla: Upper jaw; supports upper teeth.

• Mandible: Lower jaw; freely movable.

• Lacrimal and Nasal Bones: Small bones of the facial structure.

• Orbit Structure: Made up of three bones (maxilla, frontal, zygomatic).

Practical Tips on Pulse Rate Measurement

• To Measure Pulse:
  • Use at least three fingers on the radial artery without using the thumb.
  • Count for 15 seconds and multiply by 4 to get beats per minute (bpm).
  • Normal bpm: 80 to 100.
• Breath Rate Measurement:
  • Observe breathing visually to avoid alarming the subject while taking pulse rate.