axial skeleton Flashcards
name the 2 divisions of the skeletal system
axial
appendicular
how many bones is the axial skeleton composed of? and where?
80 bones around body axis
e.g. head, hyoid (found in neck), ribs, sternum, & vertebrae
appendicular skeleton is composed of how many bones? and where?
126 bones of upper & lower limbs plus girdles that connect them
pectoral and pelvic
name the areas of the axial skeleton (from superior to inferior)
Skull
- Cranial
- Facial
Hyoid
Thorax
- Sternum
- Ribs
Vertebral Column
the skull and hyoid bone include what areas of bones
cranial and facial
how many cranial bones are there and name them and their location
8 in total
Frontal, (a single bone at front of cranium)
2 parietal (to side or head),
2 temporal (just below the parietal bone), occipital (single bone at back of head), sphenoid, and ethmoid (nearer front of face)
what are cranial bones important for
protecting brain
how many facial bones are there and name them
14
2 nasal,
2 maxillae,
2 zygomatic,
mandible (jawbone, largest of facial bones),
2 lacrimal,
2 palatine,
2 inferior nasal conchae, &
the vomer (found in middle of nasal cavity)
Often 2 of each bone as one on either side of face
explain the growth of facial bones
Growth ceases at age 16
These bones grow lots after birth until age 16, where size and shape of cranium is achieved
what are sutures
immoveable joints between skull bones
name the 4 sutures, and there locations, including what bones they separate
Coronal, sagittal, lambdoidal, squamous
Sagittal suture
runs from front to back separating the (2 hemispheres of the head bone), so separates the parietal bones on one side of head from other
Coronal suture
separates the parietal and frontal bone
The parietal and temporal bones are separated by squamous suture
The lambdoid suture
is positioned at the back of the head and separates the occipital and parietal bones
explain Paranasal sinuses-cavities
Located in bones near nasal cavity
Mucous membranes – to assist mucus production
Resonating chambers – to help produce sounds when we speak. Explaining why when we get colds we sound different due to the excess mucus in these areas
name and locate the Paranasal sinuses-cavities
The frontal sinus – just above the eye
Ethmoidal cells – found deeper within the nasal cavity, behind the eyes
Sphenoidal sinus – further back in face, behind the ethmoidal cells
Maxillary sinus – largest cavity, and is closer to the maxilla
explain the fontanelle part of the foetal skull
Soft spot in foetal skull
Allow deformation at birth, as no sutures, only gaps the gaps will eventually Calcify to form sutures via – intramembranous ossification, so fontanelle can close up as child ages
cranium needs flexibly in babies, so cranium can be slightly squeezed during birthing process at the ‘soft spot’ so no damage to cranial bones. This also allows expansion as brain grows fast during this time.
what is most rapidly growing organ within the developing human
brain
explain the vertebral column
Encloses spinal cord
Supports head
Point of attachment for muscles of back, ribs and pelvic girdle
what are each of the bones in the vertebral column called
and how many are in adults and embryo
7 cervical vertebrae
12 thoracic
5 lumbar
1 sacral – which is 5 bones fused together
1 coccyx – which is 3 or 4 bones fused together
In adult – 26
In embryo – 33 vertebral bones
As these individual bones fuse together as we age into adulthood
explain the 4 normal curves in vertebral column (name and locate them and explain why we need them)
Relative to front: cervical & lumbar curves are convex (protrude to the anterior position)
Thoracic & sacral curves are concave (protrude towards posterior part of body)
Theyre important as increase strength, help in balance and absorb shocks
describe fetal compared to adult curves in the vertebral column
Curve shape differs from adult to growing foetus
each vertebra is separated into what 2 anatomical structures
Body- disc-shaped front part
Vertebral arch- extends back from body
- creates with the body a hole called vertebral foramen, through which the spine passes
Branching sections of the vertebral arch makes up what 7 processes and describe them
Transverse process extending laterally on each side =2
Spinous process extending dorsally =1
Two each of Superior and inferior articular processes - attach to neighbouring vertebrae =4
what does the thorax/chest comprise of
thoracic cage
sternum
ribs
explain the thoracic cage in the chest/thorax
Sternum, costal/rib cartilages & ribs and bodies of T1-T12 vertebrae
explain the sternum in the chest/thorax
formed from 3 bones that fuse by age
~at about 25yrs
= manubrium, body, xiphoid process
explain the ribs in the chest/thorax
12 pairs (numbered from top to bottom)
Ribs 1-7 articulate with sternum directly by costal cartilage = these are considered as true ribs
Ribs 8-12 – false ribs:
ribs 11-12 –floating ribs
