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Phalangeal Disorders 783.e1

Phalangeal Disorders Client Education
Sheet
VetBooks.ir Diseases and Disorders

BASIC INFORMATION
easily elicited with pressure over the firm
area. and melanoma are usually primary, although
multiple digits (and limbs) may be involved.
Definition • In cats, primary lung tumors have a tendency
• Bone, ligament, and tendon disorders that Etiology and Pathophysiology to metastasize to the digits (lung-digit
can cause lameness, swelling, or malposition- • DDF and SDF tendon rupture can be of syndrome).
ing of digits obvious traumatic origin. A degenerative • Digital pad corns may result from foreign
• Additional disorders affecting digits are process is possible in dogs with spontaneous body penetration or from abnormal
described in chapters on Footpad Disorders rupture of multiple tendons. mechanical forces; DDF tendon rupture,
(p. 350), Shearing/Degloving Wounds (p. • The two most common digital neoplasms in with resultant abnormal pad positioning,
909), Claw Disorders (p. 176), Squamous dogs are SCC and melanoma, although others is sometimes present concurrently.
Cell Carcinoma (p. 939), and Superficial (e.g., osteosarcoma, soft-tissue sarcomas, mast
Necrolytic Dermatitis (p. 952). cell tumor) occasionally occur. Digital SCC DIAGNOSIS
Epidemiology Diagnostic Overview
SPECIES, AGE, SEX Diagnosis is based on physical and radiographic
Dogs and cats of any age and both sexes findings. Histopathologic analysis of tissue is
necessary to finalize the diagnosis of neoplasia.
GENETICS, BREED PREDISPOSITION
• Squamous cell carcinoma (SCC): most Differential Diagnosis
common in rottweilers, giant schnauzers, • Pad/web lacerations
flat-coated retrievers, and black standard • Foreign bodies
poodles
• Melanoma: Scottish terriers Initial Database
• Digital pad corns: predominantly a sight- Physical examination:
hound problem • Palpate for crepitus, instability (note that col-
lateral ligament integrity should be checked
Clinical Presentation with the digit in extension).
DISEASE FORMS/SUBTYPES • Observe positioning of digits with the dog
• Phalangeal fractures standing.
• Sesamoid fractures and fragmentation • Apply firm, focal digital pressure on each
• Flexor tendon ruptures and lacerations digital pad to check elicited pain, suggesting
• Collateral/joint capsule injuries digital pad corns.
• Neoplasia (primary and metastatic) Radiography: orthogonal views; spreading the
• Ectrodactyly digits may be helpful:
• Pyogranulomatous infection • Lysis of a phalanx (especially P3) strongly
• Digital pad corns suggests neoplasia.
• Multipartite sesamoids are a common
HISTORY, CHIEF COMPLAINT incidental finding; check for swelling/pain
Depending on the problem, lameness, digital response.
swelling, or digital malpositioning may be PHALANGEAL DISORDERS Superficial digital
reported. flexor tendon disruption of digit 3. Note flattening Advanced or Confirmatory Testing
of this toe, with normal toepad and nail positioning. • Biopsy and histopathologic analysis when
PHYSICAL EXAM FINDINGS (Courtesy Dr. Kim Watson-McKenzie.) neoplasia is suspected
• Digital swelling: consider fractures, neoplasia,
and infection
• Firm swelling just proximal to the metacar-
pal/metatarsal pad on the volar side, digits
2 and 5: sesamoid abnormality
• Instability, mediolateral angulation: collateral/
joint capsule injuries, articular fractures
• Flat-footed appearance of one or more
digits: superficial digital flexor (SDF) tendon
laceration (look for a wound on the palmar/
plantar aspect of the digit[s] or metacarpus/
metatarsus), avulsion or rupture
• Upward (dorsal) rotation of claw and digital
pad when standing: deep digital flexor (DDF)
tendon laceration or rupture
• Missing, malformed or separated digits:
ectrodactyly
• Flat, firm hyperkeratotic area in center of a PHALANGEAL DISORDERS Superficial digital flexor and deep digital flexor tendon disruption secondary
digital pad (usually of third or fourth digit): to a laceration. Note the flattened appearance of the toes and the dorsal rotation of the toepads and nails.
typical of a digital pad corn. Pain can be (Courtesy Dr. Allison Uphill.)

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