SPPC: Musculoskeletal Ultrasound
A basic shoulder exam consists of _____ images.
11
What should the AP measurement of the Achilles tendon be?
5-6 mm
Where is the carpal tunnel located?
Between the carpal bones and the flexor retinaculum on the palmar side of the wrist
What MSK structures are typically included in a shoulder ultrasound?
Biceps tendon Subscapularis Supraspinatus Intraspinatus Teres minor
What is the sac-like structure that surrounds the joints and tendons, containing a viscous fluid?
Bursa
Where do you scan for the Achilles tendon?
From the gastroc/soleal muscles all the way down to the calcaneus
The Achilles tendon connects the ________________ and ________________ muscles to the ______________.
Gastrocnemius and soleal muscles to the calcaneus (2/3 from gastroc, 1/3 from soleal)
What is the tunnel on the ulnar side of the wrist that often compresses the ulnar nerve?
Guyons canal
How is the patient positioned for a carpal tunnel exam?
Hand palm side up; sometimes helpful to roll up a towel to place under the wrist to place joint in a neutral position
What must we do to try and correct for anisotrophy?
Heel/toe probe to create a 90 degree angle as best we can
What type of transducer is used to scan MSK?
High frequency linear
In transverse, how do the nerve fibers appear sonographically?
Hypoechoic with a hyperechoic perineurium surrounding each fiber; the collagenous epineurium (outer layer of nerve) appears as a hyperechoic layer.
How do we want the patient positioned for an MSK ultrasound?
In a comfortable position where the joint is positioned properly for dynamic examination
When is comet tail artifact often seen in MSK?
In post-op patients who have metal pins or hardware that is placed close together
What would the abnormal appearance of the nerves be in a patient with carpal tunnel/carpal tunnel syndrome?
Large, flattened nerves
___________________ are short bands of tough fibers that connect bones to other bones.
Ligaments
Which MSK structures have the most pronounced problem with anisotrophy?
Tendons
Are tendons vascular or avascular?
Relatively avascular
If a tendon does not have a synovial sheath, what surrounds them?
The paratenon and the epitendineum
The ___________ plays an important role in imaging tendons with sonography.
Sheath
What are some common MSK exams?
Shoulder for rotator cuff Wrist for carpal tunnel Achilles tendon for tear Tendinitis (multiple sites) Biceps tendon
Where do synovial sheaths usually occur?
Shoulder, hand, wrist and ankle
Tendons are a tough bundle of _____________ tissue.
Fibrous
What are the three shapes that muscles can have?
1. Fibers that run parallel to the bone 2. Fan shape 3. Pennate pattern
What is the epitendineum?
A layer of dense connective tissue that surrounds the paratenon of the tendon without a sheath
What is the paratenon?
A layer of fat and loose connective tissue that surrounds a tendon absent of the sheath
What does anisotrophy create?
A loss of definition
What is the synovial sheath?
A tubular sac-like structure that has two layers separated by fluid
What is the largest tendon in the body?
Achilles
What does the bursa do?
Aids in reduction of friction between two musculoskeletal structures
What is Phalen's sign?
An increase in wrist compression due to hyperflexion of the wrist. Place hands top sides together, fingers toward floor and compress for 60 seconds. A positive test produces numbness, tingling, or other change of sensation in the hands.
The angle and direction of the reflected beam depend on the __________________________________.
Angle of incidence
What artifact occurs when the sound beam misses the transducer on the return because of the curve of the structure?
Anisotrophy
Tendons are either cordlike, or flat sheets called __________________.
Aponeuroses
Attachment of muscles occurs where?
At the proximal and distal portions of the bundle
What is another term to describe refractile shadowing?
Edge artifact
True or False: Tendons have to have a synovial sheath.
False; Tendons can be present with or without a synovial sheath
Nerve fibers are arranged into bundles called _______________.
Fasciculi
What does the carpal tunnel contain?
Median nerve Flexor policis ongis 8 flexor digitorum tendons
Tendons connect _____________ to ________________.
Muscle to bone
Time of flight artifact happens commonly in MSK when imaging patients with a __________________ interface.
Muscle/fat
Elements of the nerve include what?
Nerve fibers surrounded by sheets of myelin
Does the Achilles tendon have a synovial sheath?
No; it is surrounded by paratenon and epitendineum
What is Tinel's sign?
Pins and needles type tingling felt distal to a percussion site
What is Thompson's test and what is it assessing?
Plantar flexion with squeezing of the calf; tests integrity of Achilles tendon
Does the Achilles tendon have a good or poor blood supply?
Poor; heals slowly
How should a patient be positioned for an Achilles tendon exam?
Prone with foot hanging over edge of bed; if they can't lie prone, put them on their side
What artifact occurs when returning sound waves have traveled between two tissues with markedly different speeds?
Time of flight artifact
What is the purpose of the sheets of myelin surrounding nerve fibers?
To insulate and protect
True or False: For many exams, you will be moving the joint to confirm structures or injuries
True
The lack of ________________ in tendons lends itself to slow healing.
Vascularity