3.1 MSK Normal anatomy Flashcards
Why is ultrasounds beneficial for MSK
Can see tendons in motion
Is MSK better than MRI and CT?
It can be. Very operator dependent, can exceed MRI and CT
What are Tendons? (4)
- Bundles of collagen fibers
- Attach muscle to bone
- Facilitate flexion and extension
- Poor /Weak blood supply = poor healing. must be surgically repaired.
What is the point of attachments that are raised ridges on the bones?
tuberosities
Tendons in Long Axis appearance
Fibrillar pattern
hyperechoic strands interspersed with hypoechoic CT
Tendons in Short Axis appearance
Hyperechoic finely punctate foci
hypoechoic CT
round, oval or flattened shape.
Tendon echogenicity is highly dependent on?
Angle of insonation
Angles >__degrees off perpendicular may demonstrate a loss of ____?
> 10; echogenicity
What is the off angle artifact called?
ANISOTROPY
Maybe mistaken for pathology or tears
It is vital when scanning a tendon that the beam be?
PERPENDICULAR TO TENDON
The tendon has a ____ shape so you may need to change the probe position/or have pt move to straighten tendon to avoid this artifact.
Curved
What are 2 types of fibrous sheaths?
- Synovial
2. Paratenon/Peritenon
What does a Synovial sheath do?
wrap around tendon to decrease friction
and secrete fluid for motion
What does Paratenon/Peritenon do?
loose CT that surrounds Achilles and patellar tendon
What are flattened synovial lined pouch /sacs called?
Bursa
What does the Bursa produce?
Synovial fluid
Where are the Bursa located?
High friction points
What does the Bursa look like sonographically?
Hypoechoic flattened structure
Normal Bursa are Difficult to see on US.
(often only see if inflamed or excess fluid collection)
Nerves in LONG axis have what appearance?
“Railroad” hypoechoic nerve fibers divided by hyperechoic CT
Nerves in SHORT axis have what appearance?
“Honeycomb” circular nerve fibers (holes) surrounded by hyperechoic CT (web)
many nerves are too small to see. wrist you can see some
What do ligament attach?
bone to bone
remember tendons attach Muscle to bone
What is the purpose of ligaments and what are they composed of?
Stability and strength of joints
Collagen
What is the sonographic appearance of ligamnets?
similar to tendon but HARDER to visualize due to smaller size and location
What does bone look like sonographically?
Hyperechoic line with alot of shadowing
US is not good to assess bone we see more of the ______ of the bone
Cortical (superficial) surface
Cartilage is a____ ____ in the body?
Shock absorber
____Cartilage lies at the terminal ends of bones
Hyaline
On US the Cartilage appears as (4)
Hypoechoic
well defined
smooth
Non-compressible (with Transducer pressure)
The muscle we see when performing MSK US is ?
Skeletal striated muscle
Skeletal striated muscle can?
Extract and extend
Skeletal striated muscle sonographically
Hypoechoic tissue (muscle) with hyperechoic fibers (striations)
what is the most common joint evaluated by US?
The shoulder joint
The shoulder is scanned with a??? and how is pt positioned?
high resolution linear array transducer
pt sitting on rotating stool
What is the upper arm bone in the shoulder?
Humerus
The shoulder blade is called the?
Scapula
The 2 shoulder extension off of the scapula are called?
the coracoid process
and the Acromion
The rotator cuff is what we visualize with US and has 4 tendons, which are?
- Subscapularis
- Supraspinatus
- Infraspinatus
- Teres minor
The Biceps tendon is a ?
Flexor and Extendor
where does the biceps tendon sit and location?
In the bicipital groove between the greater and lesser tuberosity
located anterior to humerus
Patient position of biceps tendon
Arm nutral, eblow bent 90 degree
The biceps tendon in SAX protocol?
Document proximal tendon, check position in bicipital groove
(we are checking to R/O subluxation (if tendon is displaced outside of groove. medial or laterally, medial being more common)
The biceps tendon in LAX protocol?
Document proximally and more distally
The subscapularis originates from?
the underside of scapula
attached to the lesser tuberosity of the humeral head.
The subscapularis is scanned with the arm in a ______ rotation
external
rotate in towards abdomen and then back out watching if the tendon will “catch” if impingement.. should be smooth
When scanning the subscapularis the probe will be _____ on pt but _____ on tendon
Transvere; LAX
What 2 pictures are taken of the subscapularis ?
1 at the Coracoid process (more medial)
1 at the insertion on the lesser tuberosity. (more lateral)
Performing a dynamic assessment to R/O impingement
What does the SUPRASPINATUS assist in?
abduction of humerus and stabilizes the humerus head
SUPRASPINATUS postion?
superior to the humeral head and attaches to the greater tuberosity
WHAT IS THE MOST COMMON TORN TENDON OF THE ROTATOR CUFF
SUPRASPINATUS tendon
How do you scan the SUPRASPINATUS?
Arm Hyperextended and internally rotated
Image the LAX (sharp beak like appearance)and SAX (symmetrical arch or “rainbow”)
(arm behind back and palm outwards, if sore, then “slip hand into back pocket”
The INFRASPINATUS is?
The External rotator of the humeral head.
It is the abductor of the humerus
The INFRASPINATUS postiion
lateral and posterior to shoulder and extends from the scapula to the greater tuberosity.
what is related closely to the The INFRASPINATUS?
Teres minor (below) white line separating the 2
Patient position of the The INFRASPINATUS and TERES MINOR
arm across chest (pledge position, hand over heart)
what is the only axis the The INFRASPINATUS and TERES MINOR taken in?
LAX ( INFRASPINATUS has beak like appearance)
The INFRASPINATUS is the abductor of the humerus. What is the ADDuctor of the humerus?
Teres minor
what 2 tendons does US examine with The knee?
Quadricep and patellar tendon
The quadriceps tendon is formed by __ quad muscles
4
The tendon is _____ when leg is extended so patient needs to flex leg to scan (over coming anisotropy)
Concave
quadriceps tendon inserts on to the base of the ?
patella
(inverted pyramid shaped bone, so base of patella is the more superior aspect of bone)
quadriceps tendon is scanned in both planes and appears as what shape in SAX?
oval
The patellar tendon extends from?
apex of patella (inferior pointed aspect) to tibial tuberosity (raised ridge of bone anterior prox portion on tiba)
The patellar tendon Length, width, AP?
scanned in both LAX and SAX
5-6cm L
2-2.5 cm W
4-5 mm AP (note mm)
The petellar tendon is technically a ligament why?
because it connects bone to bone.
The most COMMONLY imaged tendon of the ankle?
Achilles Tendon
The achilles tendon is the fusion of what 2 muscles?
Aponeuroses of the soleus and the gastronemius
The achilles tendon inserts on the posterior surface of the
calcaneus (heel)
The achilles tendon is examined this way…
pt in prone, foot hanging off table and dorsiflexed (toe towards shin) to straighten tendon (as it is concaved, over come anisotropy)
The achilles tendon is this wide and AP is?
- 2-1.5 cm wide
0. 5-0.7 cm AP
What is the area of variable echogenictiy anterior to distal half of tendon?
Kager’s fatty triangle
Besides trauma what is the most common cause of pathology in the hand and wrist?
Overuse/compression
What is the most common Hand/wrist entrapment syndrome involving the median nerve?
CARPAL Tunnel syndrome
What is the carpal tunnel?
Space between carpal bones (tiny bones of wrist) and the ligament (flexor retinaculum)
Tendons, the median nerve, muscles, vessels ….
all must pass through this tunnel any pathological process that decreases the size of this tunnel can result in an entrapment syndrome
The median nervecourses ____ to the flexor tendon of the _____ finger
Anterior; second
How is the median nerve scanned? and what is used as a landmark?
TRV; forearm resting on flat surface, wrist up (supination)
and ulnar artery used as a medial landmark (pulsing)
The sonographic appearance of the median nerve TRV?
Nerve Hypoechoic
Tendons echogenic
“honeycomb appearance”
