Page 675 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness of the Proximal Limb 641

THE SHOULDER AND SCAPULA

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INFLAMMATION OF THE INTERTUBERCULAR with the swing and stance phases being altered. The
BURSA (BICIPITAL BURSITIS) lameness is often characterized by a shortened cranial
phase of the stride, a decrease in the height of the foot
Inflammation of the intertubercular (bicipital) bursa flight arc, reduced carpal flexion, and a fixed shoulder
as a primary cause of lameness is uncommon, even appearance during movement. The horse is often reluc-
though the condition can occur in horses of any age, tant to bear full weight on the affected limb while
breed, or sex. 11,42,48 In 2 reports the condition was standing. 48
responsible for lameness in 1 of 54 and 1 of 41 horses
suspected of having shoulder lameness. 40,64
The bicipital bursa is located between the bilobed ten- Diagnosis
don of the origin of biceps brachii muscle and the tubercles Radiographs of the shoulder and ultrasound exami-
at the cranioproximal aspect of the humerus. The synovial nation are performed if the physical examination local-
membrane of the bursa extends around the axial and abax- izes the pain causing lameness to the bursal region.
ial limits of the tendon and onto the margins of its cranial Manipulation of the elbow into hyperextension may
surface. Although uncommon, communication can exist stress the biceps brachii tendon, helping to localize the
between the shoulder joint and the bicipital bursa. lesion. However, if the localizing signs are not obvious,
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bursitis is confirmed by centesis and local anesthesia of
the bursa. A proximal approach to the bursa is consid-
Etiology ered to be the most successful for bursal centesis. This
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Trauma to the cranial surface of the shoulder region technique is further improved by extending the scapulo-
is believed to be the most common cause of a primary humeral joint. The radius is held in a plane parallel to
bursitis. 11,40,48,97 Other suggested causes include stretch- the bearing surface, and a 9‐cm 18‐g spinal needle
ing or tearing of the bursa or biceps tendon during the inserted parallel to the ground into the lateral portion
cranial phase of the stride with the limb in full extension of the intertubercular groove. This procedure was
or by a fall or slip that results in flexion of the shoulder more likely to access the bursa in the standing horse
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with extension of the elbow. 80,95 Inflammation of this (Figure 5.45). However, ultrasound‐guided centesis
bursa can also be caused by dislocation of the biceps has been demonstrated to be superior for reliably access-
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brachii tendon that may be associated with congenital ing the bursa.
hypoplasia of the minor tubercle. 25,51,66 Proximal humeral Radiographs of the shoulder region are taken to
subchondral bone cysts adjacent to the intertubercular identify any osseous changes in the tubercles or
groove of the bicipital bursa may cause local inflamma- bicipital groove or bursa and to rule out the possibil-
tion, and such cysts have been reported to be infected. 45 ity of fractures of the supraglenoid tuberosity or prox-
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Infection either from an open or penetrating wound imal humerus or ossification of the biceps tendon
or from hematogenous spread to the bursa has also been
reported. 40,79,97 Cases of septic bursitis concurrent with
septic tendinitis and arthritis of the scapulohumeral
joint or bursitis with associated tendinitis and humeral
osteitis have been reported. 43,44

Clinical Signs
A history of trauma to the shoulder region is the most
common factor; the signs of lameness usually have an
acute onset that is most obvious during the stance and
swing phases of the stride. On physical examination
swelling over the cranial aspect of the shoulder region
may be evident with or without a wound being present.
Generalized shoulder and pectoral muscle atrophy may
be seen in more chronic cases. 40,48,97 Pressure applied
over the biceps tendon and bursal region and manipula-
tion of the shoulder region in flexion and extension usu-
ally result in a prominent painful response (Figure 5.44).
The responses to pressure and limb manipulation should
be compared with those found on the contralateral
unaffected limb. 48 Figure 5.44. As the shoulder is flexed, tension is created in the
The lameness is often obvious. At exercise, a lame- tendon of the biceps brachii muscle. If the horse has bicipital bursitis
ness of 3–4 out of 5 is generally seen (greater if septic), or ossification of the tendon, a painful response is elicited.