A1 - skeletal system Flashcards
Cranium
- box like cavity (space)
- interlinking bones (these are not fused when born)
- contains and protects the brain
Ribs
- 12 pairs of ribs (forming the ‘thoracic cage’)
- first 7 are attached to the sternum
- bottom 5 are not attached to the sternum
Carpals
- 8 small bones that make up the wrist
- arranged in 2 rows of 4
- held in place by ligaments
Metacarpals
- 5 long bones in the palm of the hand (one corresponding to each finger)
Pelvis
- made up of 2 hip bones
- each hip bones has 3 sections (illium, ischium and pubis)
- these fuse together during puberty
Femur
- longest and strongest bone in the body
Vertebral column
- made up of 5 different sections
- cervical, thoracic, lumbar, sacral and coccygeal
What are the 5 classifications?
- short bones
- irregular bones
- long bones
- flat bones
- seasamoid bones
Long bones
- bones found in the limbs
- used in movement
- they have two distinct parts ( diaphysis and epiphysis )
- femur, clavical, carpals, metatarsals
Short bones
- small, light, strong and cube shaped
- they are a ‘cancellous bone’ = light and porous bone material that has a honeycomb or spongy appearance
- used for weight bearing
- tarsals and carpals
Flat bones
- used for protection
- thin, flattened and slightly curved bones
- large surface area
- sternum, scapulae and cranium
Irregular bones
- complex shapes (that fit into no other bone categories)
- vertebrae
- used for protection and movement
Sesamoid bones
- these have a specialised function (usually found within a tendon)
- these provide a ‘smooth’ surface for the tendon to slide over
- used to reduce friction and protect inner parts of a joint
- patella
Appendicular skeleton
- consists of the bones attached to the axial skeleton
- there are 4 main sections of the appendicular skeleton (upper limbs, lower limbs, shoulder girdle and pelvis girdle)
What are the two parts of the skeleton?
Axial skeleton - 80 bones forming the ‘long’ axis of the body (middle-midriff-spine-main bit)
Appendicular skeleton - 126 bones forming the bones attached to the axial skeleton (extremities/appendages-arms-legs)
Upper limbs (appendicular skeleton)
- consists of 60 bones (30 in each arm)
- humerus-radius-ulna-carpels-metacarpals-phalanges
Lower limbs (appendicular skeleton)
- consists of 60 bones (30 in each leg)
- femur-patella-tibia-fibula-tarsals-metatarsals-phalanges
Shoulder girdle (appendicular skeleton)
- consists of 4 bones
- clavical-scapula-ribs-humerus
Pelvic girdle (appendicular skeleton)
- consists of 3 bones
- illium, ischium and pubis
- vertebrae-femur-coccyx
Axial skeleton
The axial skeleton (main core) of the body consists of …
- the skull (including cranium and facial bones)
- the thoracic cage (sternum and facial bones)
- the vertebral column (cervical, thoracic, lumbar, sacrum, coccyx)
vertebral column/ spine (axial skeleton)
- between each vertebrae is an ‘inter vertebral disc’ and they act as shock absorbers, spongy tissue material
- main roles are to protect the spinal cord and support the rib-cage
- made of 33 irregular bones called vertebrae
- the vertebral column accounts for around 40% of a persons height
- the vertebrae held together by powerful ligaments, theses allow a little movement between the vertebrae, but a considerable amount of flexibility along the spine
What the 5 classified sections of the vertebral column and how many vertebrae do they have?
- cervical vertebrae (7)
- thoracic vertebrae (12)
- lumbar vertebrae (5)
- sacral vertebrae (fused 5)
- coccygeal vertebrae (fused 4)
Cervical vertebrae
- 7 vertebrae of the neck (C1 known as the ‘atlas’ and C2 known as the ‘axis’
- theses form a pivot joint that allows the head and neck to move freely
- these are the most vulnerable vertebrae of the column
Thoracic vertebrae
- the ‘mid spine’ made of 12 vertebrae
- these articulate (connect) with the ribs
- they lie in the ‘thorax’ a dome shaped structure that protects the heart and lungs
Lumbar vertebrae
- the 5 largest (and most vulnerable) vertebrae
- situated into the lower back
- they support more weight than any other vertebrae, and provide a base for muscle attachment
- these create a ‘concave’ curve in the back
Sacral vertebrae
- made of 5 vertebrae fused together to form the ‘sacrum’
- this forms the back wall of the pelvic girdle, sitting between two hip bones
- the upper of the 5 bones connects to the bottom lumbar vertebrae, and the bottom of the 5 connects to the coccyx
- needed for protection
Coccygeal vertebrae
- found at the very bottom of the vertebral column
- made of 4 coccygeal vertebrae which are fused together to form the coccyx (tail bone)
What are the effects of a pelvic tilt and hip/knee hyper-extension on the lower posture?
- anterior pelvic tilt (lordotic back)
- posterior pelvic tilt (flat back)
- forward shifted pelvis (sway back)
- neutral pelvic tilt (balanced posture)
What are postural deviations?
- these are disorders which can cause the natural curves of the spine to deviate
Kyphosis
- excessive outward curve of the thoracic region of the spine, resulting in a ‘hunchback’ appearance
- often caused by poor posture or deformities in the vertebrae
Scoliosis
- abnormal curvature to the left or right (lateral curvature)
- most likely in the thoracic region and mostly in children
- not caused by posture, actual cause unknown, but it is inherited
What is bone?
- a living organism that is constantly being replaced/ strengthened/ replenished
- it is constantly being reshaped through a process called ‘remodelling’
What is ossification?
- the process in which bones are formed
- throughout the process parts of the bone are reabsorbed so that unnecessary calcium is removed (via cells called osteoclasts) while new layers of bone are created
How is calcium used in cells?
- osteoclasts = take away/ remove calcium
- osteoblats = bring calcium and create bone matter
- osteoblats activity increases after exercise (therefore PA makes bones denser and stronger)
- calcium stores are increased so that there is less chance of developing osteoporosis in later life (covered in depth layer)
What happens in osteoporosis?
- bone mineral density and bone mass decrease
What is bone growth and how does it work?
- the ends of each long bone contain ‘growth plates’ which allow the bone to grow longer
- this continues throughout childhood until they reach full maturity
- these are specifically known as ‘epiphyseal plates’
- once the bone has finished growing the plates fuse to the main shaft (diaphysis) to create the ‘epiphyseal line’