Canis ISSN: 2398-2942

Lameness: forelimb - investigation

Contributor(s): Gareth Arthurs, Toby J Gemmill

Orthopedic examination of the thoracic limb

  • Start with the dog standing or sitting and assess forelimb muscle bulk / atrophy. Compare the size of supraspinatus and infraspinatus muscles between left and right sides - this is relatively straightforward to do except in obese patients. The spine of the scapula is an easy to palpate landmark; supraspinatus lies cranial to it, and infraspinatus lies caudal to it. The affected forelimb will likely have palpable muscle atrophy.
  • The rest of the thoracic limb examination can be performed with the dog standing, sitting or lying down. If the dog is sitting or standing, the left and right sides can be compared simultaneously - if a subtle abnormality is found, comparing left and right can help determine whether the finding is significant or not. If bilateral disease is present, comparing left to right sides means bilateral disease should not be missed. Similarly if the patient shows a subtle or unconvincing response to manipulation, repeat the manipulation at least once to check the reliability of the response. If the dog is clearly in pain, such repetition is not advisable.
  • Be methodical and thorough, take your time and carefully identify, palpate and manipulate all structures indicated below. Start distally and work proximally or vice versa. This should ensure that lesions are not missed.
Follow the diagnostic trees for Forelimb lameness and elbow pain and Shoulder pain/lameness.

The Pes (foot)

  • Examine the digits carefully, methodically and systematically. The digits have a large range of movement in flexion and extension with a reasonable amount of medial and lateral movement:
    • Check the interdigital skin for signs of dermatitis, wounds or lacerations.
    • Check the interdigital hair for signs of saliva staining.
    • Check the pads (individual digits and large stopper pads) for wounds or embedded foreign bodies.
    • Check the claws and nail-beds for signs of disease / abnormalities.
    • Check each of the inter-phalangeal and metacarpo-phalangeal joints individually for normal, pain-free range of movement in extension and flexion, and for instability medially and laterally. If unsure, compare any suspicious digit to the adjacent digit
    • Check each of the proximal and distal inter-phalangeal joints and the metacarpo-phalangeal joints individually for swelling, pain, heat or crepitus.
    • Check the metacarpo-phalangeal joints specifically for pain on deep palpation in the region of the palmar sesamoid bones (particularly sesamoid bones 2 and 7 in affected breeds such as the Rottweiler Sesamoid: disease ).
    • Moving proximally, palpate each of the metacarpal bones individually checking for swelling, thickening, pain, heat or overlying soft tissue (extensor / flexor tendon) abnormalities.

Carpus

  • The carpus functions as a hinge joint; the joint has a large range of movement through full extension to full flexion. A small degree of carpal valgus and varus movement is also possible. A minor degree of standing carpal valgus is normal for most dogs. Working distally to proximally, check:
    • Carpal range of movement; the normal carpus should move from approx 30 degrees of flexion (where the nails / pads touch the antebrachium) to approx 200 degrees of extension.
    • Medial and lateral carpal stability.
    • Carpal swelling / effusion (most easily palpable dorsally)
    • Pain, crepitus or limited range of movement with any of these manoeuvres.

Antebrachium

  • Gently palpate the antebrachium, working distally from the carpus proximally towards the elbow. Palpate the radius distomedial and proximolateral, the ulnar styloid distolaterally and the caudal ulna and olecranon caudoproximally. The extensor muscles of the carpus and digits are palpable on the proximolateral antebrachium; the flexor muscles of the carpus and digits are palpable on the caudomedial antebrachium.
  • Gently palpate all these structures, checking for areas of heat, swelling, discomfort or abnormal and irregular texture. The antebrachium of dogs has some but limited ability to supinate and pronate. Pain associated with simultaneous antebrachial supination and elbow flexion can be observed with some elbow pathology.

Elbow

  • Palpate the elbow carefully and check:
    • Range of movement; the normal range of movement is approx. 40 degrees of flexion (antebrachium nearly contacting the humerus) to approx. 170 degrees of extension.
    • During manipulation: for signs of pain or reluctance to allow full movement or crepitus. Stoic dogs with elbow disease may show only subtle signs of pain, eg they will gently pull the elbow up towards the body during examination, or they may not allow elbow flexion or extension beyond a particular point.
    • Presence of an effusion; this is best palpated laterally, caudal and distal to the palpable lateral aspect of the humeral condyle in the region of the anconeus muscle. A dog that has an elbow effusion will have a soft swelling of variable size in this location. In lean, well-muscled dogs, the anconeal muscle can easily be mistaken for a subtle effusion; conversely in obese dogs, an effusion could be over-looked.

Humerus

  • The distal humerus is readily palpated; the condyle, and particularly the medial and lateral epicondyles are easy to palpate as is the characteristic caudal ridge of the medial aspect of the condyle; the supracondylar bone and distal diaphysis is also relatively easy to palpate. Palpate for pain, swelling, discomfort, irregular or abnormal texture.
  • Working proximally, the mid humeral diaphysis is not easily palpated but the large biceps brachhii muscle is palpable cranial to the mid humeral diaphysis and the triceps muscle group is palpable caudal to the humerus. Palpate these muscles and check for pain, discomfort, swelling, atrophy, or abnormal surface texture.
  • Working further proximally, the proximal third of the humerus is palpable; the greater tubercle is the most prominent aspect. Palpate the bone for swelling, pain, and check that the shape and texture is normal.

Shoulder joint

  • The shoulder joint lies relatively deep to the palpable superficial anatomy. The shoulder joint itself cannot be directly palpated and the joint is too deep for an effusion to be appreciated. The position of the joint is inferred from the positions of the acromium (distal end of the scapular spine) and the greater tubercle of the humerus. The shoulder is a complex joint; most movement occurs in the cranio-caudal plane, ie extension and flexion but internal / external rotation and abduction /adduction are also possible. It has been claimed (Cook, Renfro et al 2005) that excessive abduction / adduction is pathological but this is not universally accepted (Devitt, Neely et al 2007). When palpating the shoulder, check:
    • Shoulder joint range of movement; normal is approximately 60 degrees of flexion to 160 degrees of extension. The dog should tolerate full range of movement without signs of pain.
    • The biceps tendon; the biceps tendon lies in the intertubercular groove, just medial to the medial aspect of the greater tubercle. It is difficult to palpate directly but if the shoulder joint is fully flexed, the elbow joint is extended, and digital pressure is applied directly to the biceps tendon in the region of the intertubercular groove; a pain response suggests biceps tendon pathology Bicipital tenosynovitis Shoulder: medial displacement of the biceps brachii tendon Rupture / avulsion of the biceps brachii tendon.
  • Shoulder pain can be difficult to differentiate from elbow pain as it is not possible to fully extend and flex the shoulder without extending and flexing the elbow. However, the elbow joint can be manipulated through a full range of movement without full shoulder movement.

Scapula

  • The acromium, scapular spine, dorsal aspect of the scapula, supraspinatus and infraspinatus muscles are easily palpated in all but the most obese patients Suprascapular neuropathy. Palpate each of these structures, checking for discomfort, swelling, and change in texture/shape.

Further diagnostic tests

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Thoracic limb lameness common differential diagnoses

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Devitt C M, Neely, M R et al (2007) Relationship of physical examination test of shoulder instability to arthroscopic findings in dogs. Vet Surg 36(7), 661-668 PubMed.
  • Cook J L, Renfro D C et al (2005) Measurement of angles of abduction for diagnosis of shoulder instability in dogs using goniometry and digital image analysis. Vet Surg 34(5), 463-468 PubMed.
  • Jaegger G, Marcellin-Little D J et al (2002) Reliability of goniometry in Labrador Retrievers. Am J Vet Res 63(7), 979-86 PubMed.

Other sources of information

  • Arthurs G I (2011) Orthopaedic Examination of the Dog 1.Thoracic Limb. In Practice 33, 126-133
  • Scott H & Whitte P (2011) Investigationof lameness in dogs: 1. Forelimb. In Practice 33, 20-27.
  • Piermattei D L, Flo G L, DeCamp C E, (2006) Orthopaedic Examination and Diagnostic Tools. In: Brinker, Piermattei and Flo's Handbook of Small Animal Orthopaedics and Fracture Repair. 4th ed. Missouri, Saunders Elsevier. pp 3-24.
  • Jeffery N (2001) Neurological examination of dogs 1. techniques. In Practice 23(3), 118-130.
  • Houlton J E F (1994) A problem orientated approach to the diagnosis of joint disease. In: BSAVA Manual of Small Animal Arthrology. Eds Houlton J E F & Collinson R W. BSAVA publications, pp 8-21.

Other sources of information


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