Tabloncillo Perla (Tomakuixtic ó Tepite)
2.1.2.4. Nuevos tipos de maíz en Michoacán de Ocampo
5
C. Congenital
1. Polydactyly: One or more extra digits
2. Syndactyly: Bony fusion of one or more digits 3. Many types of dwarfi sms and skeletal dyspla- sia occur but are uncommon. These usually re- sult in abnormal ossifi cation and shape/length of the skeleton
D. Developmental
1. Panosteitis: Disease of young, large to giant breed dogs (Figure 5-1)
a. Radiographs: Increased intramedullary opacity of long bones
b. Most common in the German shepherd (can be seen in older shepherds) and basset hound
2. Hypertrophic osteodystrophy (HOD): Disease of young large to giant breed dogs. Radiographs - abnormal lucent lines (double physeal line) in the metaphysis (most commonly the distal an- tebrachium) (Figure 5-2)
E. Hypertrophic osteopathy (HO) generally affects older dogs secondary to a thoracic (and less commonly abdominal) mass
1. Radiographs: Palisading periosteal reaction and soft tissue swelling of multiple long bones; bilaterally symmetrical
2. The periosteal reaction starts distally and eventually progresses up the limb
3. Always take thoracic radiographs to check for a mass
III. Axial skeleton: Spine A. Atlantoaxial subluxation
1. Congenital malformation or hypoplasia of the dens
2. Young small and toy breeds
3. Be careful to avoid excessive fl exion of the neck in these patients during radiography 4. Radiographic fi ndings
a. Widening of the space between the atlas and spinous process of the axis
b. Abnormal or absent dens
B. Cervical spondylopathy (wobbler syndrome, cervical vertebral instability)
1. Young Great Danes and older Doberman pinschers
2. Radiographic fi ndings:
a. Malformation of the vertebral bodies (C5-C7)
b. Malalignment of the vertebral bodies c. Intervertebral disk space narrowing d. Spondylosis deformans
e. Sclerosis of the vertebral end plates f. Degenerative changes of the articular
facets
3. Often need myelography for a defi nitive diagnosis
C. Lumbosacral instability
1. Radiographic fi ndings (note these same fi nd- ings are found in dogs with degenerative disease that do not have signs of neurologic disease)
a. Narrowing of intervertebral disk space at L7-S1
b. Spondylosis deformans at L7-S1 c. Sclerosis of the end plates at L7-S1 d. Malalignment of the sacrum and L7 2. Often need computed tomography (CT) or
magnetic resonance imaging (MRI) to confi rm
Figure 5-1 Stages of panosteitis. A, Early stage in a femur. Circumscribed increased opacity is visible in the mid-diaphysis and the proximal diaphysis. B, Middle stage in a humerus. Diffuse increased opacity of the entire diaphysis and a continuous periosteal new bone formation on the diaphysis are present. C, Later stage in radius and ulna. Less intense but still apparent increased opacity is visible, primarily in the proximal radius and ulna. Mild periosteal new
bone formation is present on the cranial radius (arrow). (From Thrall DE. Textbook of Veterinary Diagnostic Radiology, 5th ed. St Louis, 2007, Saunders.)
42 SECTION I GENERAL DISCIPLINES IN VETERINARY MEDICINE
D. Intervertebral disk disease
1. Most common in chondrodystrophic breeds (dachshund)
2. Radiographic fi ndings
a. Narrowing or wedging of the intervertebral disk space
b. Narrowing of the intervertebral foramina c. Increased opacity in the spinal canal d. Narrowing of the joint space at the articular
facets
3. Myelography is performed to confi rm a lesion prior to surgery
E. Spondylosis deformans
1. Degenerative change of the spine
2. Radiographic fi ndings. Smooth new bone for- mation that may be bridging at the ventral (and sometimes lateral) vertebral endplates F. Neoplasia
1. Primary bone tumors generally affect one vertebra
2. Spinal cord tumors usually cannot be detected without myelography
3. Extension of neoplastic disease from the cau- dal abdomen and perineal tissues can result in osteolytic and osteoproductive changes at L5 through the sacrum and caudal vertebrae G. Diskospondylitis
1. Infection of the intervertebral disk space and adjacent vertebral endplates
2. Radiographic fi ndings
a. Osteolysis of the vertebral endplates b. Multiple sites may be affected
c. Widening or collapse of the intervertebral disk space
H. Trauma
1. Compression fractures 2. Subluxation and luxation IV. Axial skeleton-skull
A. Ear disease
1. Otitis externa: Thickening and mineralization of the external ear canals, with partial to complete occlusion of the normally air fi lled canals
2. Otitis media: Soft tissue or fl uid opacity of the tympanic bulla with occasional changes in the bulla wall in severe cases
3. Nasopharyngeal polyps: May see increased soft tissue opacity of tympanic bulla and nasopharynx
B. Nasal disease: Usually divided into destructive or nondestructive rhinitis
1. Destructive rhinitis a. Causes
(1) Neoplasia: Adenocarcinomas most common
(2) Fungal rhinitis
(3) Chronic foreign bodies (4) Chronic infl ammatory disease b. Radiographic fi ndings
(1) Increased soft tissue opacity in the na- sal passages and frontal sinuses (2) Destruction of the nasal turbinates (3) Destruction of the bones surrounding
the nasal passages, usually most severe with neoplasia
2. Nondestructive causes a. Infl ammatory disease b. Bacterial rhinitis c. Foreign bodies
C. Dental disease: Peridontal disease is most com- mon. Radiographic fi ndings include the fi nding: 1. Widening of the periodontal space
2. Loss of the radiopaque lamina dura 3. Root resorption
4. Tooth loss D. Other
1. Cranial mandibular osteopathy (CMO) a. Affects terrier breeds
b. Radiographic fi ndings:
(1) Irregular new bone involving the mandi- bles and occasionally parietal, frontal, and maxillary bones
(2) Can result in temporomandibular joint (TMJ) ankylosis
2. Neoplasia: Can occur anywhere on the skull. Osteosarcoma is most common, with a vari- able degree of osteolysis and osteoproduction V. Joint disease
A. Traumatic
1. Luxations and fractures
2. Stress radiographs may be helpful to demon- strate instability
B. Degenerative
1. Commonly stifl e secondary to cranial cruciate rupture, coxofemoral joints secondary to hip dysplasia, and elbow and shoulder joints 2. Radiographic fi ndings
Figure 5-2 Hypertrophic osteodystrophy. A, Acute phase. Irregular radio-
lucent regions are evident in the distal radial and ulnar metaphyses, proxi- mal to the physis. B, Chronic phase. An irregular, pallisading periosteal pro-
ductive response surrounds the radial and ulnar metaphyses. The physes are relatively unaffected. (From Thrall DE. Textbook of Veterinary Diagnostic
Radiology, 5th ed. St Louis, 2007, Saunders.)
a. Increased synovial mass/intraarticular swelling
b. Decreased joint space width c. Periarticular osteophyte formation d. Enthesopathy: New bone at soft tissue at-
tachment sites
e. Subchondral bone sclerosis
f. Subchondral cystic changes in severe cases
g. Mineralization of soft tissues: Intra articular or periarticular
C. Neoplastic. Synovial cell sarcoma is most common
1. Destruction of subchondral bone 2. Soft tissue swelling
D. Infl ammatory 1. Infectious
a. Hematogenous
b. Direct: Wounds, surgery, injections c. Radiographic fi ndings
(1) Subchondral bone lysis
(2) Intraarticular soft tissue swelling 2. Noninfectious: Immune mediated
a. Erosive
(1) Rheumatoid arthritis (2) Greyhound polyarthritis (3) Feline polyarthritis (4) Radiographic fi ndings
(a) Joint effusion
(b) Variable degree of subchondral bone lysis
(c) Decreased joint space width (d) Variable degree of periarticular
new bone
b. Nonerosive: Radiographs usually normal or show joint effusion
(1) Systemic lupus erythematosus (SLE) (2) Idiopathic
E. Developmental
1. Osteochondrosis (OC) or osteochondritis dessicans (OCD)
a. Large and giant breed, young dogs b. Failure of endochondral ossifi cation c. Common sites: Caudal humeral head, hu-
meral condyle (medial aspect), stifl e, tarsus (medial or lateral trochlear ridges)
d. OC has no fl ap; OCD has a mineralized fl ap or joint mouse
e. Radiographic fi ndings
(1) Concave or fl attened defect of the subchondral bone with adjacent bone sclerosis
(2) With or without bone fl ap at the site or within the joint
(3) Joint effusion
(4) Secondary degenerative joint disease 2. Hip dysplasia
a. All breeds of dogs and cats are affected, but it is most common in large- and giant- breed dogs
b. Radiographic fi ndings:
(1) Incongruency or subluxation of the cox- ofemoral joints
(2) Poor coverage (less than 60%) of the fem- oral head by the dorsal acetabular rim (3) Signs of degenerative joint disease
(osteoarthrosis):
(a) Osteophytes at the cranial acetabulum
(b) Shallow acetabulum
(c) Remodeling of the femoral head and neck
(d) Enthesopathy at the joint capsule attachment
c. OFA (Orthopedic Foundation for Animals) and PennHIP are the two most commonly used regeristries
3. Elbow dysplasia
a. Ununited anconeal process: Anconeal pro- cess should fuse by 20 weeks (5 months) b. Fragmented medial coronoid process: Often
see the degenerative changes rather than the actual fragment
c. OC at the medial aspect of the humeral condyle
4. Avascular necrosis of the femoral head (Legg-Calves Perth disease)
a. Small and toy breed, young dogs affected b. Radiographic fi ndings
(1) Flattening/misshapen femoral head (2) Increased and decreased opacity of the
femoral head and neck (3) Increased joint space width
(4) Fractures of the femoral head can occur 5. Patellar luxation
a. Most common in small and toy breeds b. Medial luxation is more common than lateral c. Lateral luxations usually occur in larger
breeds
d. The luxation may be intermittent so may not always see on radiographs