axial skeleton

Question 1

describe the structure and function of the vertebral column

Answer 1

• flexible curved structure containing ~26 irregular bones
• transmits weight of trunk to lower limbs, surrounds and protects spinal cord, supports head, point of attachment for ribs, pelvic girdle and muscles
• cervical (7), thoracic (12), lumbar (5), sacrum and coccyx

Question 2

what are the curvatures of the spine / their purpose

Answer 2

• increase resilience and flexibility
• allow lateral rotation, bending and movement
• thoracic and sacral: two posteriorly convex curvatures (primary - birth)
• cervical and lumbar: two posteriorly concave curvatures (secondary - develop in childhood)

Question 3

abnormal curvatures of the spine

Answer 3

• kyphosis: abnormal thoracic curvature, old people / those with osteoporosis
• lordosis: abnormal lumbar curvature, obese / last period of pregnancy
• scoliosis: abnormal lateral bend of spine (semi-vertebra / half vertebra), impaired breathing, surgery (steel rod / straightening), kids / female

Question 4

what are the intervertebral discs

Answer 4

• fusion like pad composed of two parts, pillow, soft, absorb stress
• nucleus pulposus: inner gelatinous nucleus, gives disc elasticity and compressibility
• annulus fibrosus: outer collar, collagen and fibrocartilage
• spinal hernia: pain, movement impairment, paralysis, damage to annulus fibrosus

Question 5

general structure of the vertebrae

Answer 5

• body / centrum: anterior weight bearing region
• vertebral arch: pedicles / laminae, enclose vertebral foramen
• vertebral foramine: make up vertebral canal for spinal cord
• intervertebral foramina: lateral opening between adjacent vertebrae for spinal nerves

Question 6

describe the cervical vertebrae and C1 / C2

Answer 6

• C1-C7
• thin, small body (oval), spinous process (short and bifid), vertebral foramen (triangular), transverse process (contain foramina), bear weight of skull
• C1: no body or spinous process, anterior / posterior arches, two lateral masses (superior articular facet), superior surface of masses articulate with occipital condyles (nodding yes)
• C2: dens projects superiorly into anterior arch, pivot joint (atlantoaxis) lateral rotation of head (shaking no)

Question 7

describe the thoracic vertebrae

Answer 7

• T1-T12
• articulates with ribs at facets and Demi facets
• long spinous process
• articular facets allow lateral rotation of spine (joining of vertebrae)
• heart shaped body, circular vertebral foramen, spinous process (long sharp, projects inferiorly)

Question 8

describe the lumbar vertebrae

Answer 8

• L1-L5
• short, thick pedicles and laminae (weight bearing)
• flat hatchet shaped spinous processes
• orientation of articular facets locks vertebrae together (prevent rotating and allows bending)
• massive body (kidney shaped), triangular vertebral foramen,

Question 9

describe the sacrum / coccyx

Answer 9

• S: 5 fused vertebra (S1-S5), forms posterior wall of pelvis
• C: tailbone, 3-5 fused vertebrae

Question 10

what is the thoracic cage / its function

Answer 10

• formed by sternum, ribs, costal cartilage and thoracic vertebrae
• enclose and protect organs in thoracic and abdominal cavities, provide support for bones of upper limb
• play a role in breathing

Question 11

describe the ribs and their attachment

Answer 11

• true: 1-7, attach directly to the manubrium / sternum by individual costal cartilages
• false: 8-12, attach to sternum indirectly, join costal cartilage immediately above
• floating: 11-12, lack a sternal attachment, costal cartilages lie embedded in muscles of lateral body wall

Question 12

what is the typical rib attachment and rib injuries

Answer 12

• head of rib (head and lateral tubercle)
• neck, tubercle and shaft
• injuries: fractures from sports, severe coughing, severe force / stress
• costochondral separation: bone of rib and cartilaginous portion of rib

Question 13

describe number of bones, evolution and function of the skull

Answer 13

• 22 bones (8 = cranium, 14 = facial)
• reduced supra-orbital ridge, zygomatic arch, changes in teeth / weaker jaw muscles, reduction in thickness of bone
• F: framework of face, cavities for special sense organs, main openings to external environment, secure teeth, anchor facial muscles, protection of brain

Question 14

what is the cranium

Answer 14

• vault ‘cavaria’ = skullcap
• superior lateral and posterior aspects of skull / forehead
• base: inferior, prominent bony ridges, 3 fossa (anterior, middle and posterior)
• bones: frontal, parietal (2), occipital, temporal (2), sphenoid, ethmoid (sensory / nasal)
• sutures: coronal (frontal), sagittal (parietal), lambdoid (occipital), squamous (temporal)

Question 15

what are the skull facial bones

Answer 15

• 14 bones
• mandible, lower jaw, largest strongest bone of face, temporo-mandibular (modified hinge, lateral and vertical movement)
• vomer (divides nasal cavity into two)
• maxilla (2), upper jaw, hard palate, articulates with facial bones
• zygomatic (2), cheekbones, prominences of cheek
• nasal (2)
• lacrimal (2)
• palatine (2)
• inferior nasal conchae (2), bridge of nose, frame, anterior = cartilage