Articulations and the Axial Skeleton

Question 1

Articulations

Answer 1

wherever two bones meet

Question 2

movement occurs at

Answer 2

articulations

Question 3

How are articulations classified

Answer 3

structurally, by the tissue joining the articulating bones OR functionally, by the range of movement permitted

Question 4

Types of articulations

Answer 4

• Synarthroses
• Amphiarthroses
• Diarthroses

Question 5

Synarthroses

Answer 5

syn meaning together, this type is immoveable

Question 6

Fibrous synarthroses

Answer 6

bones joined by dense irregular CT

ex. suture between bones of the skull
ex. gomphosis between each tooth and bony socket

Question 7

Cartilagenous synarthroses

Answer 7

bones joined by cartilage

ex. synchondrosis, ex. epiphyseal plate of a growing bone, first costosternal joint

Question 8

Bony fusion

Answer 8

exactly what it sounds like, type of synarthroses where two bones become one
synostosis ex. skull, sacrum, hip bones, sternum, vertebrae, mature long bones

Question 9

Amphiarthroses

Answer 9

Permit slight movement

Question 10

Fibrous amphiarthrosis

Answer 10

bones joined by a ligament or a band of CT

syndesmosis ex. distal tibiofibular joint

Question 11

Cartilaginous amphiarthrosis

Answer 11

bones joined by a wedge of cartilage (high water content)

symphysis ex. intervertebral discs, symphysis pubis

Question 12

Diarthroses

Answer 12

Also called synovial joints . All diarthroses have:

• fibrous joint capsule encloses the joint space (fuses bone on either side)
• articular cartilage covers articular surfaces
• synovial membrane covers all internal, non articulating surfaces and secretes synovial fluid

Question 13

synovial fluid

Answer 13

• lubricant
• shock absorber
• medium for solute transfer between blood and cartilages

Question 14

Articular cartilage

Answer 14

avascular and not innervated so the synovial membrane lamina propria provides blood vessels for the cartilage (nutrients)

Question 15

Articular discs

Answer 15

also called menisci, ex. medial and lateral menisci of the knee joint
- improve the articulation between bones (make them fit together better)

Question 16

Accessory structures of Synovial Joints

Answer 16

• articular discs or menisci
• fat pads
• tendons
• bursae
• intrinsic and extrinsic ligaments

Question 17

Bursae

Answer 17

sacks of synovial membrane containing synovial fluid

• facilitate relative movement between structures
• may be subcutaneous or subtendinous
• when inflamed, results in bursitis

Question 18

ligament

Answer 18

connects bone to bone to hold structures together

Question 19

Stability is inversely proportional to

Answer 19

mobility

Question 20

Stability and mobility are influenced by

Answer 20

• the shape of articulating surfaces (do they fit together)
• the capsule
• ligaments
• tone of surrounding muscles (stronger muscles stabilize the joint)
• other tissues surrounding the joint

Question 21

linear motion

Answer 21

gliding motion - on a plane

Question 22

Angular motion

Answer 22

uniaxial - elbow
biaxial - wrist
triaxial - shoulder or hip

Question 23

Circumduction

Answer 23

a combination of angular motion around 2 axes

- kind of a reinvention of biaxial movement

Question 24

Rotation

Answer 24

Angular motion around the long axis (ex. pronation and supination of the forearm)

Question 25

Functional classification of synovial joints

Answer 25

by the type of movement: linear, angular, circumduction, rotation

Question 26

Structural classification of Synovial joints

Answer 26

gliding joint - ex. intercarpal joints (linear motion) hinge joint - ex. elbow joint (uniaxial) Pivot Joint - ex. first cervical vertebrae can rotate around a peg of bone (uniaxial) ellipsoidal joint - radiocarpal joint (biaxial) Saddle joint - ex. metacarpal of thumb Ball-and-socket joint - ex. shoulder

Question 27

Axial Skeleton

Answer 27

consists of: - the skull - vertebral column (24 vert, sacrum, coccyx) - the thoracic cage (24 ribs - 12 pairs, 1 sternum)

Question 28

Appendicular Skeleton

Answer 28

consists of: - the pectoral girdles and upper limbs - the pelvic girdles and lower limbs

Question 29

Number of bones in the skull

Answer 29

8 that form the cranium and 14 facial bones

Question 30

Bones of the face (14)

Answer 30

- maxillae (2) - palatine bones (2) - Nasal bones (2) - Inferior nasal conchae (2) - zygomatic bones (2) - lacrimal bones (2) - vomer (middle plate part of septum and other bit extends to above teeth) - mandible MPNIZLVM (ma'am pls never imply zat love vill manifest)

Question 31

Bones of the cranium

Answer 31

- occipital bone - parietal bone (2) - frontal bone - temporal bone (2) - sphenoid (tiny one between frontal and temporal bone) - ethmoid

Question 32

Bones that form the orbits of the eyes

Answer 32

- frontal bone - zygomatic bones - the maxillae

Question 33

Coronal suture

Answer 33

joining of frontal and temporal bones | - like a headband (crown = corona)

Question 34

Saggital suture

Answer 34

ruby head. runs between temporal bones.

Question 35

Lambdoid suture

Answer 35

joins the temporal bones and the occipital bone

Question 36

Ethmoid bone

Answer 36

shaped kind of like a tie fighter - the lateral masses contain the ethmoid air cells - the perpendicular plate contributes to the nasal septum

Question 37

Vertebral Regions

Answer 37

``` Cervical - 7 cerv vert, C1-C7 Thoracic- 12, T1-T12 Lumbar - 5, L1-L5 Sacral - S1-S5, fused in maturity coccygeal region - Co1- Co5 (3-5 vertebrae, fusion is variable) ```

Question 38

Spinal Curves

Answer 38

primary curves - thoracic and sacral develop prenatally secondary curves - cervical and lumbar develop postnatally - cervical curve holds head up, lumbar for upright posture (critical for balance)

Question 39

Anatomy of a typical vertebra

Answer 39

- vertebral body - vertebral arch - vertebral foramen - 1 spinous process - 2 transverse processes - 2 superior articular processes - 2 inferior articular processes

Question 40

Regional variations in vertebrae

Answer 40

in rostrocaudal direction, - the size of the vertebral body increases because the load increases (cervical, we only hold up head) - diameter of the vert. canal decreases - regional differences in processes ex. transverse foramina in cervical region, costal facts in thoracic

Question 41

Atlas

Answer 41

atlas holding up the world- C1 vertebrae, has two superior articular facets that articulate with the occipital condyles, allows you to nod yes, has transverse foramina to accommodate the vertebral arteries

Question 42

Axis

Answer 42

Axis - C2, does not have a body, does have superior articular facets, also has a little bony tooth that articulates with atlas that allows us to shake our head no (rotation)

Question 43

the median sacral crest of the sacrum is where...

Answer 43

the spinous processes of the sacral vertebrae fused