Bones Flashcards
What is the total number of bones in an average human body?
206 bones = we start off with around 300 bones at birth
What are the two types of skeleton?
Axial and Appendicular
What are the two types of appendicular skeleton - include the bones that come under them?
- Upper Limb
Clavicle, Scapula, Humerus, Radius, Ulna, Carpals, Metacarpals and Phalanges - Lower Limb
Innominate Bones (Ilium, Pubis and Ischium) Pelvis, Sacrum, Femur, Patella, Fibula, Tibia, Tarsals, Calcaneus, Metatarsals and Phalanges
What bones come under axial?
Skull (cranial and facial bones), mandible, sternum, costal cartilage, vertebral column (cervical, thoracic and lumbar), sacrum and coccyx
Bones can be classified into?
- Long Bones
- Short Bones
- Flat Bones
- Irregular Bones
- Sesamoid Bones
Describe long bones and give the examples
- The length exceeds width
- shaft and two ends
- made of compact bone with spongy cancellous interior
Examples =
In the upper limb = clavicle, humerus, radius, ulna, metacarpals and phalanges
In the lower limb = femur, tibia, fibula, metatarsals and phalanges
Describe short bones and give the examples
- cube like shape
- made of spongy bone
Examples =
Carpals in the wrist = scaphoid, lunate, triquetral, hamate, pisiform, capitate, trapezoid and trapezium
Tarsals in the foot = calcaneus, talus, navicular, cuboid and cuneiform (lateral, intermediate and medial)
Describe flat bones and give the examples
- thin and flattened
- slight curvature
- compact bone surfaces with spongy layer
Examples =
In the skull = frontal, parietal, lacrimal, nasal, occipatal and vomer
In the arm = scapula
In the chest = sternum and ribs
In the pelvis = the innominate bone (ilium, pubis and ischium)
Describe irregular bones and give the examples
- complicated shape
- mostly composed of spongy bone
Examples =
Facial Bones = Ethmoid, temporal, sphenoid, inferior nasal concha, zygomatic, maxilla, mandible and
Neck = hyoid
Upper body = Vertebrae (cervical, thoracic and lumbar), sacrum and coccyx.
Describe sesamoid bones and give the examples
- short and round bones
- form within tendons
Examples =
Knee = patella
State the two internal structures of Long Bones
Cortical or compact bone
Cancellous or trabecular, spongy bone
What is a cortical (compact) bone
- dense, hard and strong outer layer of long bones
- composed of cylindrical osteons (or haversian systems)
What is a cancellous (trabecular, spongy) bone
- series of small plates of softer and thinner bone
- contains a vascular network, where the red bone marrow sits
- contained within ends of long bones and inside other irregular bones such as vertebral bodies
State the two bone tissues
Periosteum
Endosteum
What is the periosteum?
- outer membrane of dense connective tissue covering outer surface of bones except in areas where cartilage covers articular surface
- contains nerves, lymphatic and blood vessels, osteoblasts and osteoclasts
What is the endosteum?
- inner membrane that lines bone cavities, similar to periosteum.
- contains nerves, lymphatic and blood vessels, osteoblasts and osteoclasts
State the three bone cells
Osteoblasts
Osteoclasts
Osteocytes
Function of osteoblasts?
To make new bone
Function of osteoclasts?
To break down and reabsorb old bone
Function of osteocytes
To mature bone cells; responsible for maintaining a solid bone matrix by making sure they do not deteriorate and ensures any deficits are replaced
What is osteoporosis?
- a medical condition where there is low bone density due to increased bone absorption rather than bone formation; therefore the low bone density increases the risk of fractures
Describe haversian systems?
Haversian systems (or osteons) are what makes the compact bone hard and dense. They are cylindrical structures that composed of concentric bone layers called lamellae, which surround the haversian canal.
State the two types of bone marrow
Red and Yellow
Describe red bone marrow?
Red bone marrow is found in spongy bone at the ends of long bones and at the centre of other bones. They are responsible for manufacturing blood cells. At birth, all bone marrow is red.
