1.3 Introduction to Bones and Joints

Question 1

List the six functions of bones

Answer 1

1. Support: Are a framework for the body, provide attachment points for skeletal muscle, and provide support for soft tissues
2. Protection: Surround and protect internal organs
3. Movement: Attach to skeletal muscles, and produce movement as the muscles contract
4. Mineral Storage: Store minerals such as calcium and phosphorus, essential for muscle contraction and nervous system functioning
5. Haematopoiesis: Red bone marrow in some bones produces red blood cells, white blood cells, and platelets.
6. Energy Storage: Yellow bone marrow store lipids/fat

Question 2

Which type of bone structure…

• Has fewer and smaller spaces for blood vessels and marrow, less solid matter
• Forms the external/outer layer of all bones, and the diaphysis of long bones

Answer 2

Compact/Dense Bone

Question 3

Which type of bone…

• Has more and larger spaces for blood vessels and marrow, less solid matter
• Usually forms the central mass of short, flat, and irregular bones and the epiphyses of long bones
• Is composed of an irregular lattice of thing plates called trabeculae

Answer 3

Spong/Cancellous Bone

Question 4

List and define the five types of bone shapes and their roles, and give an example of each

Answer 4

1. Long Bone
   
   • Shape: Greater length than width
   • Composed of
     
     • One Diaphysis (middle) composed predominantly of compact/dense bone
     • Two epiphyses (ends) composed predominantly of spongy/cancellous bone, expanded fr articulation with other bones
   • Role: Bearing weight
   • E.g. Femur, tibia, ulna, phalanges
2. Short Bone
   
   • Shape: ~Equal length and width
   • Composition: Spongy bone covered by a thin layer of compact bone
   • E.g. Carpal bones
3. Flat Bone / Squamous Bone
   
   • Shape: Generally thin and wide
   • Composition: 2 nearly parallel plates of compact/dense bone enclosing a layer of spongy/cancellous bone
   • Role: Important in providing both protection and large surface area for skeletal muscle attachment
   • E.g. Cranial bones, ribs, scapula
4. Irregular Bones
   
   • Shape: Complex and variable shapes.
   • Composition: Varying amounts of compact/dense and spongy/cancellous bones
   • Role: Have large projections which articulate with surrounding bones for forming joints. Have large surface areas for attachment of tendons.
   • Cannot be classified into any other categories.
   • E.g. Vertebrae, facial bones
5. Sesamoid Bones
   
   • Shape: Small round bones which develop in some tendons
   • Role: Develop in some tendons to protect them from excessive wear, and to change the angle of the tendon as it passes to its distal attachment, providing greater mechanical advantage
   • E.g. Patella (within quadriceps tendon of thigh), thumb

Question 5

Define Fissure

Answer 5

• Fissure- Narrow crack/cleft-like opening between adjacent parts of bones.
  
  • Role: Passage of vessels and/or nerves
  • Looks more like a crack or a cleft whereas foramen is more of a round hole

Question 6

Define Foramen

Answer 6

• Foramen- A hole/opening
  
  • Role: Passage of blood vessels and/or nerves
  • Is a hole for-a-man
  • Looks more like a hole, whereas fissures look more like a crack or a cleft
  • E.g. Mandibular foramen in mandible, obturator foramen in os coxae, or infra-orbital foramen below the orbits on the maxilla

Question 7

Define Fossa

Answer 7

• Fossa- Flattened, broad, shallow depressions
  
  • E.g. cerebral fossa on the endocranial surface of the occipital bone

Question 8

Define Sulcus/Groove

Answer 8

• Sulcus/Groove- long narrow depression
  
  • Role: Accommodates blood vessels, nerves and tendons
  • E.g. Intertubecular Sulcus/groove (dip between two tubercles) on the humerus

Question 9

Define Meatus/Canal

Answer 9

• Meatus/Canal- Tube-like passageway within a bone
  
  • E.g. External auditory meatus forming the opening of the ear canal

Question 10

Define Sinus

Answer 10

• Sinus- Air-filled cavity or hollow space within a bone
  
  • E.g. maxillary sinus

Question 11

Define Notch

Answer 11

• Notch- Indentation at the edge of a bone
  
  • E.g. Mandibular Notch

Question 12

Define Condyle

Answer 12

• Condyle- Smooth, large, rounded articulating prominence
  
  • Forms joints
  • E.g. Lateral and medial condyles of the femur

Question 13

Define Facet

Answer 13

• Facet- A small, flat, shallow, smooth articulating surface
  
  • Forms joints
  • E.g. Superior articular facets on the sacrum which articulate with the most inferior lumbar vertebrae

Question 14

Define Head

Answer 14

• Head- A rounded articulating projection supported by a constricted portion (neck) of the bone
  
  • Forms joints
  • E.g. The femur head

Question 15

Define Crest

Answer 15

• Crest- Prominent sharp, often thin, ridgelike projection
  
  • Articulates to tendons, ligaments, and other connective tissues
  • E.g. Median crest on sacrum

Question 16

Define Linea/Line

Answer 16

• Linea/Line- A low ridge or border less prominent than a crest
  
  • Articulates to tendons, ligaments, and other connective tissues
  • E.g. Temporal Lines on the parietal (side of skull) bones

Question 17

Define Epicondyle

Answer 17

• Epicondyle- Projection above a condyle
  
  • Articulates to tendons, ligaments, and other connective tissues
  • E.g. Epicondyles on the humerus

Question 18

Define Tochanter

Answer 18

• Trochanter- Very large, prominent, but blunt projection, only found on the femur
  
  • Articulates to tendons, ligaments, and other connective tissues
  • E.g. Greater and lesser trochanters of the femur

Question 19

Define Tubercle

Answer 19

• Tubercle- Small, sometimes roughened, rounded process
  
  • Articulates to tendons, ligaments, and other connective tissues
  • E.g. Greater Tubercle of the humerus

Question 20

Define Tuberosity

Answer 20

• Tuberosity- Variably shaped, large and often roughened process
  
  • Articulates to tendons, ligaments, and other connective tissues
  • E.g. Ischial tuberosity on the ischium of the os coxae, and tibial tuberosity on the superior end of the tibia