Gary M. Baxter, VMD, MS, DACVS, is Associate Dean for Clinical Services at the University of Georgia College of Veterinary Medicine in Athens, Georgia, USA.

List of Contributors xv Preface to the Seventh Edition xix Preface to the Sixth Edition xxi Preface to the Fifth Edition xxiii Preface to the Fourth Edition xxv Acknowledgments xxvii Common Terminologies and Abbreviations xxix About the Companion Website xxxi 1 Functional Anatomy of the Equine Musculoskeletal System 1Anna Dee Fails Anatomic Nomenclature and Usage 1 Thoracic Limb 1 Hindlimb 34 Axial Components 60 Acknowledgment 64 2 Examination for Lameness 67 History, Visual Exam, and Conformation 67Gary M. Baxter and Ted S. Stashak Introduction 67 Adaptive Strategies of Lame Horses 67 Classification of Lameness 68 Signalment and Use 71 History (Anamnesis) 71 Visual Examination at Rest 71 Conformation 72 Conformation Components and Traits 74 Acknowledgment 91 Palpation and Manipulation 93Gary M. Baxter and Ted S. Stashak Foot 93 Pastern 96 Fetlock 97 Metacarpus/Metatarsus (MC/MT) 97 Suspensory Ligament 99 Flexor Tendons 100 Carpus 100 Forearm (Antebrachium) and Elbow 101 Shoulder and Scapula 102 Tarsus (Hock) 105 Tibia 107 Stifle 109 Femur 112 Hip 112 Pelvis 113 Back 113 Neck 115 Flexion Tests/Manipulation 115 Distal Limb/Phalangeal/Fetlock Flexion 115 Carpal Flexion 117 Elbow Flexion 117 Shoulder/Upper Forelimb Flexion 117 Tarsal/Hock Flexion 117 Stifle Flexion 119 Full¿Limb Forelimb and Hindlimb Flexion 119 Navicular Wedge Test 119 Direct or Local Pressure plus Movement 120 Subjective Assessment of Lameness 123Kevin G. Keegan Evaluation of the Horse for Lameness at the Walk 124 Evaluation of the Horse at the Trot 126 Evaluation of Vertical Movement of the Head for Forelimb Lameness 126 Withers Movement 129 Evaluation of Vertical Movement of the Pelvis for Hindlimb Lameness (the Vertical Pelvic Movement [VPM] Method) 129 Evaluation of Pelvic Rotation for Hindlimb Lameness (The Pelvic Rotation Method [PRM]) 131 Bilateral Lameness 132 Observing Movement of the Limbs 134 Joint Angle Measurements Associated with Lameness 134 Stride Timing and Length Variables Associated with Lameness 134 Hoof Trajectory Associated with Lameness 135 Lameness Evaluation During Ipsilateral Gaits 135 Evaluation of Lameness at the Lunge 136 Evaluation of Lameness Under Saddle 136 Subjective Scoring Methods 137 Objective Assessment of Lameness 139Kevin G. Keegan Measurement of Ground Reaction Forces (Kinetics) 139 Measurement of Movement (Kinematics) 140 Perineural and Intrasynovial Anesthesia 157Gary M. Baxter Types of Local Anesthetics 157 Skin Preparation and Restraint 157 Perineural Anesthesia 157 Intrasynovial Anesthesia 167 Acknowledgment 187 3 Diagnostic Imaging 189 Radiography 189Myra Barrett and Elizabeth Acutt Equipment 189 Digital Radiography Systems 191 Radiation Safety 194 Contrast Examinations 195 Principles of Radiographic Interpretation 198 Limitations of Radiography 210 Normal Radiographic Anatomy 211 Acknowledgments 299 Ultrasound 301W. Rich Redding Introduction 301 Ultrasound to Evaluate Tendons and Ligaments 302 Patient Preparation and Scan Protocol 303 Ultrasonographic Assessment of Tendon/Ligament Pathology 316 Limitations of Ultrasonography 321 Ultrasound to Evaluate Joint Injury 323 Indications for Ultrasonography of Joints 324 Equipment and Technique 324 Ultrasonographic Appearance of Periarticular Structures 326 Ultrasonic Appearance of the Joint 327 Conclusions 331 Other Indications for Ultrasonography of the Musculoskeletal System 332 New Directions in the Use of Ultrasound 335 Nuclear Medicine/Scintigraphy 342Kurt Selberg, Elizabeth Acutt, and Alejandro Valdés¿Martínez Principles of Nuclear Medicine 342 Radiation Safety and Protection 343 Imaging Equipment 343 Method for a Scintigraphic Exam of the Musculoskeletal System 344 Indications for Nuclear Scintigraphy of the Musculoskeletal System in Horses 347 Normal Bone Scan 348 Scintigraphic Signs of Disease 356 Abnormal Conditions for Specific Anatomical Regions 361 Limitations of Nuclear Medicine 373 Computed Tomography 376Mathieu Spriet Introduction 376 Equipment and Principles of CT 376 Clinical Use of CT in Equine Orthopedic Imaging 378 Contrast¿Enhanced CT 380 Positron Emission Tomography 383 Conclusion 383 Magnetic Resonance Imaging 387Michael Schramme and Emilie Segard¿Weisse Introduction 387 General Principles and Physics of MRI 387 Equipment, High¿ and Low¿Field Magnets, and RF Coils 387 Sequences and Protocols for Equine MRI 389 Artifacts of MRI 390 Interpretation of Musculoskeletal MR Images 393 Contrast MRI Techniques 396 How to Read an Equine MRI Study 397 Indications, Case Selection, Advantages, and Disadvantages of MRI 397 Magnetic Resonance Imaging of the Foot and Pastern 397 Magnetic Resonance Imaging of the Fetlock Region 409 Magnetic Resonance Imaging of the Metacarpal and Metatarsal Regions 416 Magnetic Resonance Imaging of the Carpal Region 420 Magnetic Resonance Imaging of the Tarsal Region 421 Magnetic Resonance Imaging of the Stifle Region 424 Thermography 431Tracy A. Turner Thermographic Instrumentation 431 Principles of Use 431 Specific Applications for Lameness Diagnostics 433 4 Lameness of the Distal Limb 439 Navicular Region/Palmar Foot 439Randy B. Eggleston and Gary M. Baxter Navicular Syndrome/Disease 439 Fractures of the Navicular (Distal Sesamoid) Bone 454 Soft Tissue Injuries in the Foot (DDFT and Podotrochlear Apparatus) 456 Acknowledgments 459 Coffin Joint and Distal Phalanx 463Gary M. Baxter Osteoarthritis (OA) of the Distal Interphalangeal (DIP) Joint 463 Fractures of the Distal Phalanx (P3, Coffin Bone) 465 Subchondral Cystic Lesions of the Distal Phalanx (P3) 471 Collateral Ligament Injuries of the Distal Phalanx 472 Ossification of the Collateral Cartilages of the Distal Phalanx (Sidebone) 474 Miscellaneous Conditions of the Foot 477Gary M. Baxter Sole Bruises, Corns, and Subsolar Abscesses 477 Septic Pedal Osteitis 479 Penetrating Injuries of the Foot 481 Keratoma 483 Avulsion Injuries of the Hoof 485 Acknowledgments 489 Laminitis 490James Belknap, Andy Parks, and Katy Dern Overview 490 Relevant Anatomy 490 Pathogenesis: Pathophysiologic Considerations 491 Pathogenesis: Structural Considerations of the Equine Digit 492 The Clinical Presentation: The Horse at Risk of Laminitis 494 Clinical Signs: The Acute Onset of Laminitis 496 Hoof Wall Resections 509 Coronary Band Grooving and Resection 509 The Pastern 512Ashlee E. Watts and Gary M. Baxter Osteoarthritis (OA) of the PIP Joint (High Ringbone) 512 Osteochondrosis (OC) of the PIP Joint 517 Luxation/Subluxation of the Proximal Interphalangeal (PIP) Joint 518 Fractures of the Middle (Second) Phalanx (P2) 522 Fractures of the Proximal (First) Phalanx (P1) 525 Desmitis of the Distal Sesamoidean Ligaments (DSLs) 532 Desmitis of Digital Annular Ligaments 535 SDFT and DDFT Abnormalities 536 The Fetlock 541Matt Brokken and Alicia Bertone Osteochondral Fractures and Fragmentation of the Proximal Phalanx 541 Fractures of the Proximal Sesamoid Bones 543 Sesamoiditis 548 Axial Osteitis/Osteomyelitis of the Proximal Sesamoid Bones 549 Osteoarthritis of the Metacarpophalangeal/ Metatarsophalangeal Joint 550 Palmar/Plantar Osteochondral Disease 552 Fetlock Subchondral Cystic Lesions (SCLs) 553 Traumatic Rupture of the Suspensory Apparatus 554 Luxation of the Metacarpophalangeal/ Metatarsophalangeal Joint (Fetlock Luxation) 556 Constriction of or by the Fetlock Palmar/Plantar Annular Ligament 558 Acknowledgments 560 The Metacarpus and Metatarsus 563Kyla F. Ortved and Alicia L. Bertone Bucked Shin Complex and Stress Fractures of the Dorsal Third Metacarpus 563 Fractures of the Condyles of the Third Metacarpal/ Metatarsal Bones (Condylar Fractures, Longitudinal Articular Fractures) 567 Fractures of the Third Metacarpal/Metatarsal (Cannon) Bone 571 Metacarpal/Metatarsal Exostosis (Splints) 572 Fractures of the Small Metacarpal and Metatarsal (Splint) Bones 576 Enostosis¿Like Lesions 580 Suspensory Ligament Desmitis 580 Superficial Digital Flexor (SDF) Tendinitis (Bowed Tendon) 585 Deep Digital Flexor Tendinitis 590 Desmitis of the Accessory Ligament of the Deep Digital Flexor Tendon (Distal Check Ligament) 591 5 Lameness of the Proximal Limb 597 The Carpus 597Chris Kawcak Developmental Abnormalities of the Carpus 598 Miscellaneous Carpal Swellings 604 Dorsal Carpal Swelling 605 Inträarticular Fractures 607 Accessory Carpal Bone Fracture 612 Carpal Luxations 613 Soft Tissue Damage to the Carpus 614 Osteoarthritis 615 Carpometacarpal Osteoarthritis 616 Osteochondrosis of the Carpus 617 Osteochondroma of the Distal Radius 617 Desmitis of the Accessory Ligament (Radial or Superior Check Ligament) of the Superficial Digital Flexor Tendon 619 The Antebrachium, Elbow, and Humerus 623Jeremy Hubert Fractures of the Radius 623 The Elbow 627 Fractures of the Humerus 633 Neoplastic Lesions of the Humerus 637 Paralysis of the Radial Nerve 637 Acknowledgment 638 The Shoulder and Scapula 641Jeremy Hubert Inflammation of the Intertubercular Bursa (Bicipital Bursitis) 641 Inflammation of the Infraspinatus Bursa 643 Osteochondrosis (OC) of the Scapulohumeral (SH) Joint or Shoulder 644 Osteoarthritis (OA) of the Scapulohumeral Joint 646 Luxation of the Scapulohumeral (Shoulder) Joint 648 Suprascapular Nerve Injury (Sweeny) 650 Fractures of the Scapula 652 Fractures of the Supraglenoid Tubercle (Tuberosity) 653 Acknowledgment 655 The Tarsus 657W. Rich Redding Introduction 657 Diagnosis of Tarsal Lameness 657 Articular Diseases of the Tarsus 662 Cunean Tenectomy 672 Fractures and Luxations of the Tarsus 680 Soft Tissue Injuries of the Tarsus 687 Periarticular Tarsal Cellulitis 697 Tibia and Crus 701W. Rich Redding Introduction 701 Diagnostic Analgesia of the Crus 701 Imaging the Tibia/Crus 701 Clinical Conditions 701 Enostosis¿Like Lesions 702 Fractures of the Tibia 703 Incomplete Fractures 704 Proximal Physeal Fractures 705 Diaphyseal Fractures 706 Tibial Tuberosity Fractures 706 Gastrocnemius Disruption in Foals and Adults 707 The Stifle: Femoropatellar Region 709Gary M. Baxter and Ken E. Sullins...