Human Skeleton Flashcards
Function of the skeleton
- support, protection, locomotion, mineral reserve, haematopoiesis
Composition of bone
- Osteons ( Haversian System- layers in bones)
3 types of osteons: organic (~30%, type 1 collagen) gives bones flexibility, tensile strength, inorganic (~70%, calcium and phosphate salts) makes the bone sturdy, compressive strength
Composition of bones (blood and nerve)
- blood vessels: provide nutrients to the bone
- nerves
Remodelling of bone
- a dynamic living tissue, ableto respond to changes in the environment
- always been remodelled, the new bone is layedd down (osteoblasts cells) and old bone breaks down (osteoclasts cells)
- reason why bone is able to heal after a fracture
Rickets
- vitamin d deficiency
- required for calcium absorption
- bones overly flexible- lack mineral content
Osteogenesis imperfecta (OI)
-congenital: generic disorder
-affects collagen production
-bones brittle- fracture easily (brittle bone disease)
Shape of bones: long bones
- longer than wider
- long diaphysis- shaft
- bones of the limbs eg femur
Shapes of bones: short bones
- width~length
- similar to long bones
- bones of the wrist and ankle
Shape of bones: flat bones
-thin, flat, usually curved
- skull, sternum, scapula, ribs
Shape of bones: irregular bones
- don’t fit in other categories
- vertebrae, sacrum, facial bones
Shakes of bones: sesamoid bones
-small, round bones embedded in tendons
- protect tendon and increase movement
- patella (knee cap)
Structure of bones
Diaphysis (long tube like)
- strong but some flexibility
-most compact bone
Epiphyses (on ends of bone)
- articulate surfaces for joints
- mostly spongy bone but compact on surface
Epiphyseal (growth plate)
- separates diaphysis and epiphysis
- site of growth
-once growth complete, plate ossifies
Structure of bone: periosteum and endosteum
Periosteum: covers outer surface of bone and site of attachment for tendons
Endosteum: lines internal surfaces of cavities within bones
Structure of flat bone
- two sheets of compact bone with spongy bone in the middle (cancellous bone (diploe))
How do bones grow
- growth plates in between the surface of dialysis and surface of epiphysials
-endochondral ossification: happens mainly in growth plates - in children, bones are made of soft, flexible tissue (cartilage). The cells in the growth plate start to grow and divide, making the bone longer. As new cartilage is made , the old cartilage is slowly replaced by bone tissue
- osteoblasts help turn cartilage into bone
- late teens to early 20s the growth plate fuses with the dialysis, preventing u from growing
Joints in the skeleton
- fibrous: do not allow movement (bones between skull)
- cartilaginous: have a layer of cartilage between the stow connecting bone
- synovial “true joints”: have a gap between the twos surfaces of the bones that articulate with each other, allow a greater range of movement that fibrous
Organisation of the skeleton
- Axial Skeleton
• skull (22)
•vertebral column (33)
• ribs (12 pairs)
• sternum - Appendicular Skeleton
~ upper limb
• pectoral girdle
• bones of the arm/hands
~lower limb
•pelvic girdle
•bones of legs and feet
Skull
- most complex area of Skelton
- houses brain and special sense organs (protective function)
- viscerocranium: facial skeleton 14
- neurocranium: surround brain 8
Vertebral column
- cervical (7)
• small, relatively mobile
• most susceptible to dislocation - thoracic (12)
• articulate with ribs
• long processes for muscle attachment
-lumbar (5)
• largest body
• susceptible to herniated IVDs
- sacrum (5 fused)
• vertebrae fused
•articulates with hip bones - coccyx (~4 fused?)
• tailbone ( can fracture if land on it)
The pectoral girdle
- clavicle and scapula
-clavicle only bone connecting upper limb to axial skeleton - facilitate movement
The pelvic girdle
- locomotion (walking, supporting body weight)
- innominates (hip bones) illium at the top, pubis and ischium (posterior)
- protect pelvic organs
- different shape in males and females
Limbs
- upper limb
• arm= humerus
•forearm= radius and ulna
• wrist= carpals (8)
• hand= metacarpals (5), phalanges (14)
-lower limb
• thigh= femur
• leg= tibia and fibula
• ankle= tarsals (7)
•foot= metatarsals (5) and phalanges (14)
Sternum and ribs
- surrounding and protect thoracic organs (thoracic cage)
Important role in respiration
-flexibility provided by costal cartilages anteriorly - sternum angle- important anatomical landmark
- at level of T4/T5 IVD posteriorly
-2nd ribs articulate anteriorly
Importance of sternum angle
- horizontal plane at level of sternum angle passes through several important structure
-allows us to palpate and locate 2nd ribs
Clinical relevance: - sternum angle forms boundary of mediastinum
- location of important structures like aorta, trachea
