2.7.1. Ultrasound

Question 1

Rotator cuff tears commonly involve the “____” tendon.

Answer 1

supraspinatus

*most are anterior and distal (within 1cm of its insertion on the lesser tuberosity of humerus)

Question 2

Define:
Full thickness rotator cuff tear
…and its appearance on ultrasound

Answer 2

well-defined hypoechoic or anechoic abnormality that disrupts the hyperechoic tendon fibers and extends from the articular to bursal surfaces of the tendon.

Question 3

Define:
Partial Thickness rotator cuff tear
…and its appearance on ultrasound

Answer 3

• Characterized by a well-defined, hypoechoic or anechoic abnormality that disrupts tendon fibers.
  – They may either be articular-side or
  bursal-side partial thickness tears.

Question 4

What position should the patient be in to view the rotator cuff interval short axis?

Where should the probe be?

Answer 4

Place the patient with hand on their hip (with thumb dorsal) with chest thrust out and shoulder pulled back.

Place the probe to view the Long Head Biceps (LHB) tendon in Short Axis, and short axis slide towards the shoulder, adjusting
the probe as needed to follow the LHB tendon to the rotator cuff interval (where the LHB enters the shoulder capsule between the
subscapularis and the supraspinatus.)

Question 5

Describe the Biceps short axis view.

Answer 5

• key view for orientation to the shoulder
• Patient: sitting up with elbow flexed to 90, palm up with hand resting on thigh
  
  • assess for effusion (may be associated with RT tear)
• this space (proximal bicipital groove) communicates with the gleno-humeral joint

Question 6

describe viewing the subscapularis long axis.

Answer 6

• assess muscle at the level of the corocoid process from its insertion on the lesser tuberosity towards its origin by having the patient externally rotate their arm while scanning

Question 7

describe viewing the subscapularis short axis

Answer 7

• probe in long axis
• over the biceps tendon, short axis slide medially to assess the subscapularis insertion at the lesser tuberosity.
• Observe the superior, middle and inferior bundles of the subscapularis muscle.

Question 8

describe viewing the subacromial space with the arm in neutral position.

Answer 8

• From the AC joint, long axis slide laterally over the acromion.
-Freeze the image and use calipers to measure the distance from the caudal portion of the acromion to the humeral head.
• Note the subacromial-subdeltoid (SA-SD) bursa.

Question 9

describe viewing the subacromial space with arm abducted.

Answer 9

Conduct the same as viewing the subacromial space with arm in neutral, then internally rotate and abducted to 60 degrees, compare the measured distance to the arm in neutral posi1on. 10 mm is normal.
• Observe for “bunching” or effusion of the subacromial bursa as the arm is abducted.
• More importantly, the supraspinatus tendon should move smoothly under the acromion during abduction.
Abducting the arm with slight forward
flexion may make the impingement more noticeable.

Question 10

describe viewing the supra/infraspinatus long axis.

Answer 10

• have patient place hand behind back, palm out, in his contralateral “back pocket”
• orient the long axis of the probe toward the patient’s umbilicus (note bird’s beak appearance of the insertion of the supraspinatus to the greater tuberosity)
  
  • a short slide laterally will show a slight flattening of the humeral head contour which indicates the infraspinatus is in view

Question 11

describe viewing the supra/infraspinatus short axis

Answer 11

patient in “hand in back pocket” position
orient the probe towards the patients ear
- observe separated appearance of the tendon