Osteoarthritis and cervical pain can present with clinical. Almost all skeletal preparations of horses over 18 years old
have evidence of arthritic changes. The disease occurs with some frequency in horses at competitive event ages. Osteoarthritis
and other degenerative changes initiated via acute or chronic trauma, or osteochondrosis of articular process articulations
are common etiologies.
Figure 1 is a skeletal preparation of C4 and C5 and depicts the gross anatomy of the structures in question. The area of
synovial attachment has evidence of osteophyte formation (c). The caudal C4 facet (a) cranial C5 facet (b) and transverse
process of C4 (d) are evident and labeled.
Figure 1: A right lateral view of a skeletal preparation of cervical vertebrae C4 and C5. See text for legend.
The cervical articular facets form an identifiable ultrasonographic landmark that has the appearance of a hand with an outstretched
thumb and flexed 2 first digits (Figure 2).
Figure 2: A bone preparation and ultrasound image of the right vertebral articulation of C4 and C5. See text for legend.
In Figure 2, the image of the hand (right) represents the ultrasonographic image. The caudal facet of C4 (C) and its transverse
process (E), and the cranial facet of C5 (B) and its transverse process (D) are labeled. The ultrasound probe (A) is at the
approximate scanning position as the image in the center. The ultrasound image in the center shows the bone shadows of the
transverse process of C4 (E), the cranial facet of C5 (B) and caudal facet of C4 (C). The image of the hand is likewise labeled
with the caudal facet of C4 (C) and its transverse process (E), and the cranial facet of C5 (B).
Figure 3: A method of evaluating neck flexibility.