4 – SA MSK Flashcards

1
Q

Why is proper collimation important?

A
  • Reduces amount of scatter radiation produced
    o Better radiation safety practice
    o Increased image quality
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2
Q

x-ray beams exit the sources as a fan

A
  • *place the centre beam with the joint(s) of interest
  • *mild distortion may be present at the edge of the field of view due to divergence of the beam
  • Axial skeleton: 4-5 collimate images of the spine, NOT 1 large image of the entire spine
    o Positioning devices needed to prop the sternum and spine in the SAME plane in lateral views
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3
Q

Cortex of bone *

A
  • Dense outer layer of compact bone
  • Periosteum: outer fibrous lining of cortical bone
    o serves as protective layer, also attachment surface for tendons, muscles, and ligaments
  • endosteum: layer that lines the medullary cavity
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4
Q

Medulla of bone *

A
  • porous cancellous/spongy bone deep to cortical bone
  • honeycomb cavities form by a lattice work of trabeculae
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5
Q

Subchondral bone *

A
  • bone immediately adjacent to the articular cartilage
  • changes often indicate problems with the cartilage (not visible radiographically)
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6
Q

Diaphysis of bone *

A
  • centre portion/shaft of long bones
  • can often see vascular canals in them (usually in the middle)
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7
Q

Metaphysis of bone *

A
  • transition from physis of diaphysis
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8
Q

Physis of bone *

A
  • Growth plate in immature animals
  • Physeal scar in mature animal
  • Some physes can look like fractures
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9
Q

Epiphysis of bone *

A
  • Between joint space and physis
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10
Q

Apophysis of bone *

A
  • Arise from a separate center of ossification, eventually fuses with the rest of bone
  • A site of tendon or ligament attachment
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11
Q

Sesamoid bones *

A
  • Small bone embedded with a tendon or muscle
  • Acts like a pulley, provides smooth surface for tendon to glide over
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12
Q

What are ‘cutback zones’ ? What animals are they seen in commonly?

A
  • In rapidly growing animals
  • *flaring of metaphysis adjacent to physis
  • Means there is a lot of bone turnover/growth
  • Common: large breed dogs and horses
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13
Q

Skull

A
  • DV preferred over VD (easier to get it straight)
  • *positioning device needed to elevate the nose
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14
Q

Skull DV/VD view

A
  • Equal spaces b/w the mandibular rami and zygomatic arches
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15
Q

Skull lateral view

A
  • Mandibles and tympanic bullae are superimposed
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16
Q

When do you do ‘nose up’ lateral oblique view?

A
  • To view temporomandibular joints
    o Eliminates superimposition of the 2 TMJ
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17
Q

When do you do open mouth/intraoral VD view ?

A
  • For nasal cavities
  • Eliminates superimposition of mandibles with nasal cavity
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18
Q

When do you do rostrocaudal view?

A
  • For frontal sinuses
19
Q

*What are some key anatomic features to see on a radiograph of a canine skull?

A
  • Nasal planum and cavity
  • Body of manible
  • Ramus
  • Tympanic bulla
  • Frontal sinus
  • Cranial vault
  • Zygomatic arch
  • Lateral aspect of ramus
  • TM joint
20
Q

*What are some key features you should look at in the pharynx/larynx?

A
  • Nasopharynx
  • Soft palate
  • Oropharynx
  • Pharynx
  • Larynx
  • *know general shape of hyoid apparatus
21
Q

Straight spinal radiographs: VD view

A
  • Dorsal spinous process completely end-on
  • Straight alignment of vertebral bodies
22
Q

Straight spinal radiographs: lateral view

A
  • Discrete margins of disc spaces
  • Well-defined and equal-size intervertebral foramina: “little horse heads”
  • Superimposed ribs and transverse processes (“Nike”)
23
Q

*What are some key anatomical landmarks of the spine on radiographs?

A
  • C6 has large transverse processes
  • T11 (sometimes T10) is the anticlinal vertebra (thoracic vertebra with a completely vertical spinous process)
24
Q

*What are some key radiographic features of the spine?

A
  • No disc between C1-C2
  • Diaphragmatic attachments at L3 and L4 ventral aspects
    o May cause indistinct ventral borders of the vertebral bodies
25
*What are some key breed variations and congenital anomalies with the spine?
- Transitional vertebrae o Asymmetric rib formation at C7/T1 or T13/L1 o Sacralization of L7, lumbarization of S1 - Hemivertebrae in brachycephalic breeds - Caudal vertebrae can vary in number and size (brachycephalic breeds, Manx cats)
26
*Transitional L7 with sacralization (of the right aspect)
- Enlarged right transverse process is articulating with the ilial wing and sacrum
27
*What view can you use to help see the dens of C2?
- 15 degree oblique lateral - Dens=between C1 and C2 to keep things stable
28
What are hemivertebrae commonly encountered in?
- Bulldogs - Boston terriers - Pugs
29
What are the most common locations of hemivertebrae?
- T7 - T8 - T12 - Occasional lumbar
30
*What is the result of hemivertebrae?
- Rib crowding, spinal kyphosis, scoliosis - NOT common to have associated neurological signs
31
*How do you interpret the spine?
- Evaluate positioning and technique - Number of vertebrae in each segment - Number and symmetry of ribs - Presence of anomalies and malformation - Symmetry and congruity of vertebral canal - Evaluate each vertebra, articular process joint, intervertebral disc space, intervertebral foramen - Paraspinal soft tissues
32
*What are some special views you can do with the shoulder?
- Supination and pronation o Can see different aspects of the humeral head (since rounded) - Cranioproximal-craniodistal oblique view o Skyline the intertubercular groove (bicipital groove) which contains the biceps tendon and sheath
33
What are some normal findings with the shoulder?
- Occasionally see incomplete fused ossification centers at distal part of acromion and caudal glenoid cavity - Might see axillobrachial vein and caudal circumflex humeral artery - *Clavicles: cats
34
Greater tubercule (shoulder)
- Supraspinatus attachement
35
Intertubercular groove and supraglenoid tubercule
- Where the biceps tendon runs and then attaches
36
What are some standard elbow views?
- Lateral - Craniocaudal - Flexed lateral o Visualize anconeal process without superimposition with the medial humeral condyle o Use it to look for fragmentation of anconeal process
37
What are some common findings in the elbow?
- Supracondylar foramen in CATS o Not dogs o Brachial artery and median nerve course within - Supratrochlear foramen in DOGS o Not cats - 30% animals have a supinator sesamoid bone on craniolateral aspect of radial head
38
*What are some standard views of the pelvis?
- Lateral - VD frog leg - VD with legs extended o Preferred, but proper leg extension may need deep sedation or GA
39
*How can you tell if you have a straight VD pelvis view?
- Symmetric obturator foramen - Symmetric coxofemoral joints - Parallel femurs
40
*Sacroiliac joint
- Partially a fibrous/cartilaginous joint that remains RADIOLUCENT in life
41
*What do you use open-leg lateral for?
- *to isolate one coxofemoral joint at a time
42
*What do you use a flexed DP view on a hind limb for?
- to see lateral talar trochlear ridge o if not flexed=then it is superimposed by the calcaneus
43
*What are stressed views of the carpus?
- Stress in all directions: flexed, extension, medial and lateral - Write ‘stress’ on the side you are challenging - If see more space or soft tissue=maybe a ligament is ruptured?
44
What are the principles of interpretation for the appendicular skeleton?
- Start to develop a systematic method of radiographic review - *ALWAYS correlate findings bac to the history and clinical signs - If finding does not add up to clinical signs: reevaluate, take additional views, consider another diagnostics