Chapter 37The Metacarpal Region
Anatomy
This chapter discusses the examination and diagnosis of injuries to the metacarpal region of the horse. The detailed anatomy of the deep digital flexor tendon (DDFT) (see Chapter 70), the accessory ligament of the deep digital flexor tendon (ALDDFT) (see Chapter 71), the superficial digital flexor tendon (SDFT) (see Chapter 69), and the third interosseous muscle or suspensory ligament (SL) (see Chapter 72) is discussed elsewhere.
Imaging
Ultrasonography
Ultrasonographic examination of the metacarpal region is discussed in detail elsewhere (see Chapters 16 and 69 to 72). In large, cob-type horses, the skin and underlying subcutaneous tissues in the metacarpal region may be thick, making it difficult to obtain high-resolution images. Dense stubble may persist after fine clipping of the hair coat, making it difficult to maintain good contact. Deep skin folds may further complicate the issue. For these horses it may be necessary to amplify the power and gain controls of the ultrasound machine and increase the focal depth of the transducer. Image quality may be enhanced by application of copious amounts of the ultrasound coupling gel to the skin for at least 15 minutes before imaging.
Differential Diagnosis
Medial and Lateral Condylar Fractures of the Third Metacarpal Bone
See Chapter 36 for a discussion of medial and lateral condylar fractures of the McIII (see page 408).
Incomplete, Longitudinal Palmar Cortical Fatigue Fractures of the Third Metacarpal Bone and Stress Reactions
Midshaft Fractures of the Third Metacarpal Bone
See page 502 for a discussion of midshaft fractures of the McIII.