Page 69 - Clinical Manual of Small Animal Endosurgery

Diagnostic Arthroscopy 57

Fig. 2.23 Left shoulder, medial aspect. The cranial arm of the medial
glenohumeral ligament is visible, with the subscapularis tendon of
insertion in the background.

scapularis tendon of insertion; the medial aspect of the joint capsule
occupies the background. The articular surface of the glenoid cavity is
inspected by rotation of the light post ventrally and tilting of the arthro-
scope ventrally, with gentle retraction of the arthroscope, if necessary.
Further rotation of the light post cranioventrally and tilting of the arthro-
scope cranioventrally brings the caudal glenoid cavity into view and
reversal of this manoeuvre reveals the cranial glenoid cavity and the
tendon of origin of the biceps brachii. Rotation of the light post further
dorsally brings the tendon into view and the tendon can be followed as
it enters the bicipital groove. Further caudal tilting of the arthroscope
brings the arthroscope tip past the biceps tendon, allowing inspection of
the cranial compartment of the shoulder joint as it surrounds this struc-
ture. Reversal of these manipulations enables a survey of the articular
surface of the humeral head and brings the arthroscope back to the posi-
tion of insertion.
Inspection of the caudomedial compartment of the joint is possible by
cranioventral tilting of the arthroscope with rotation of the light post to
view the caudal component of the medial collateral ligament. The integ-
rity of the medial collateral ligament, the subscapularis tendon and the
medial joint capsule can be further assessed by abduction of the limb.
Only a small degree of abduction is normally possible and abduction is
seen to tension the structures of the medial aspect of the joint. Insertion
of the arthroscope over the humeral head with additional cranial tilting
of the arthroscope reveals the caudal shoulder joint pouch and the caudal
recess of the joint is viewed by judicious rotation of the light post.
The appearance of the articular cartilage should be evaluated using
the modified Outerbridge scale (see Table 2.2), and where there are car-
tilage lesions it is helpful to catalogue these using a chart representing
the joint surfaces (Table 2.3). Thickened cartilage or fissured cartilage