◊ 2-Forelimb ◊
LAMENESS IN THE FORELIMB
1-Sweeny or atrophy of the supraspinatus and infraspinatus muscles, and suprascapular paralysis or shoulder slip: -
General term refers to atrophy of muscular group, but commonly applied to atrophy of supra and infraspinatus muscles as a result of paralysis of suprascapular nerve.
1-Muscular disuse due to lameness
2-Injury of suprascapular nerve as a result of
a-Direct trauma to the point of the shoulder
b-Stretching of the nerve during sudden backward thrust of the limb
2-Prominance of the shoulder joint and scapular spine with flattened shoulder area
3-Outward rotation of the shoulder during progression
4-Imperfect extension of the joint (slight flexion)
Diagnosis: The condition must be determined whether due to nerve paralysis or disuse of the limb (attitude during motion)
Treatment: There is no known treatment of the condition when it is due to injury of the nerve, but the following can be tried to stimulate circulation;
1-Application of antiphlogistic packs
4-Blistering and firing
5-Subcutaneous injection of irritants for cosmetic stimulation of scar formation and normal appearance of shoulder
6-Prophylactic surgical notching of the scapula under the nerve
*Guarded to unfavorable according to the extent of nerve regeneration (after 6 months)
2-Shoulder lameness, Bicipital bursitis, or Bursa intertubercularis: -
Acute or chronic inflammation of the bicipital bursa (between biceps brachii tendon and bicipital groove of the humerus), it is true bursitis.
1-Severe trauma to the shoulder point that may affect bones and suprascapular nerve
2-Infection of the bursa (open wound, injection, or septicemia)
1-Swelling at the point of the shoulder (bursa)
2-The foot is posterior to its normal position and the animal rests on toe (raised heel) in less severe cases
3-Dropped elbow if the inflammation is severe or if the radial nerve is involved too
At motion or examination
4-Pain on pulling the limb upward and backward
5-Fixation of the shoulder joint during progression
6-Lifting the head during advancing, to make minimal flexion of the shoulder joint
7-Low arc of foot in flight (imperfect flexion of the limb) and short anterior phase of stride
8-Stumbling as a result of low arc of foot in flight, short anterior phase of stride, and too soon landing on the toe
9-Mild cases have signs like navicular disease
10-In severe cases, the limb is used only during backing
11-Circumduction of the limb to over come the difficulty of advancing the limb
12-Increased lameness on rough or uneven ground surface.
2-Differential diagnosis from
a-Navicular disease (posterior digital nerve block)
b-Fracture of lateral tuberosity of the humerus, tuber scapulae, or tuber spinae
c-Sweeny because it has relative large joing
2-Parenteral and local injection of the bursa with corticoid (5 times week interval) if it is noninfectious
3-Counter irritation by blistering, injection of irritants, or firing
*Guarded to unfavorable (especially when it is chronic case due to permanent changes)
3-Sprain and rupture of muscles and tendons of the shoulder: -
1-Over stretching due to accidents
2-Exagerated muscular effort
3-Gap of muscular ends with hematoma if the muscle ruptured
Rest, cold application, and astringents, followed by hot application and massage with linaments.
2-Reatment of persistent hematoma
4-Inflammation of tendon and bursa of infraspinatus muscle: -
Most commonly affect animals with base-narrow
1-Abduction of the entire limb (supporting leg lameness) to relief tension on the tendon
2-Local signs of inflammation
5-Dislocation of the shoulder: -
1-Sudden severe shoulder lameness
2-Difficult manual extension or flexion and easy manual abduction and adduction of the joint
3-Shortening of the leg
Reduction and rest
6-Arthritis of shoulder joint or Omarthritis: -
1-Fracture of lateral tuberosity of the humerus or tuber scapulae of the scapula. Usually it is small and stability of the joint can be retained but irritation by bone fragments causes persistent lameness
3-Unknown cause osteochondritis dissecans (aseptic necrosis) in young horses, s it causes damage and chronic osteoarthritis of the joint
Typical signs of shoulder lameness, and highly variable (severe in early stages and mild in chronic cases)
1-The foot is posterior to the opposite sound one during rest
2-Obvious swelling of the shoulder in some cases (it is difficult to detect that in most cases)
At motion or examination
3-Holding the head to the affected side when advancing the limb
4-Circumduction to avoid flexion of the shoulder
5-Fixation of the shoulder joint
3-Nerve block (median, ulnar, and musculocutaneous), and articular analgesia of the shoulder joint
1-Injection of the joint with corticoid for temporary relief
2-No treatment will be helpful, if osteoarthritis is due to joint trauma
3-Surgical removal of small chip fracture of the lateral tuberosity of the humerus
7-Rupture of pectorals muscle: -
1-Violent abduction of the limb
1-Lmeness with marked abduction of the limb and shoulder
2-Wide separation of the shoulder point from the thorax
8-Radial paralysis: -
Inactivation of extensors of elbow, carpal, and digital joints and lateral flexor of the carpus (ulnaris lateralis), as a result of injury to radial nerve. The condition is usually temporary and the greatest danger is the additional injury to the limb while it is not functioning
1-Trauma of the radial nerve as it crosses musculospiral groove
2-Fracture of the humerus
3-Prolonged lateral recumbency on hard surface
4-Myositis of triceps
Varies depending upon the degree of injury of the nerve but it is characteristic when the nerve supply of digit extensors is injured
1-The limb appears longer due to relaxation of elbow muscles and extensors of the digit
2-If the innervation of triceps is involved the elbow is extended and dropped with flexion of digit
At motion or examination
3-In mild cases, the horse moves with mild lameness but he may stumbles as the toe doesn’t land flat
4-Dragging of the leg may lead to wearing of the anterior surface of fetlock
5-The horse can’t advance the limb to put weight on foot but he can bear weight on foot with no difficulty if the limb is put under him. If the entire brachial plexus is injured, both flexors and extensors are involved and the animal can’t bear weight on the limb
3-Examination (presence of fracture)
1-In most cases treatment is of no value and light plaster cast (changed every 2-3 weeks) can be used to prevent further injury, contraction of flexors of the carpus and digit, and to protect the anterior surface of the fetlock. Generally 6 months should be allowed fore recovery
2-Manual massage of the muscles of the limb
3-Surgical correction in case of humeral fracture (no sooner than 8 weeks and no longer than12 weeks, post injury) either by dissection of the nerve from adhesion or by anastamosis.
4-Prophylactic prevention during recombency by proper padding under the shoulder region.
*Guarded in mild cases *Unfavorable in severe cases
9-Fracture of ulnar (Olecranon): -
Most cases show signs similar to radial paralysis in the form of acute disability of the limb
1-The animal is unable to flex the elbow and can’t bear weight on affected limb
2-The elbow joint appears to be dropped
3-Bone crepitation and pain on manual manipulation, and pain will be greater when the ulna is fractured near articulation than through the proximal end of the olecranon
1-Rest with sling for 6 weeks if there is no bone separation
2-Surgical reduction (if there is separation of the bone fragments), and it should be followed by rest for 6 weeks. The great force of triceps on olecranon can bend bone plate, pin, or screw
10-Rupture of the medial collateral ligament of the elbow joint: -
1-Severe adduction of the limb by the animal
2-Severe abduction of the limb by the owner
1-Acute pain in the limb that diminishes after 24 hours
2-Outward movement of the limb, from the elbow and downward, during progression
3-Pathognomonic sign is the opening of the medial side of the elbow joint that can be palpated on adduction of the foot and pushing in of the elbow joint
Rest and sling for 6 weeks
*Guarded to unfavorable
11-Bursitis of elbow point, Capped elbow, Olecranon bursitis, or Shoe boil: -
Acquired bursitis of the olecranon bursa due to repeat trauma by the shoe either during motion or lying down.
1-Prominent swelling at the point of the olecranon process of the ulna
2-The swelling is serous in early stages and fibrous in chronic cases
3-Lameness is not present or very mild
Injection of the bursa and surrounding tissue with corticoid 2-3 times weekly
1-Blistering or firing (ineffective due to deposition of more fibrous tissue)
2-Surgical excision (incision line curved laterally over the bursa), preceded by injection with 3% Copper sulfate 4-5 days prior to surgery for easy dissection, and followed by cross tying for 10 days
12-Anterior deviation of the carpal joint, Bucked or Goat knees, or Knee sprung: -
Definition: Deformity of the carpal joint leading to alteration of articulations and consistent partial flexion of the carpus
2-Mineral and vitamin deficiency
3-Traumatic inactivity of extensors with contraction of flexors (ulnaris lateralis and flexor carpi ulnaris muscles, and superficial and deep flexor tendons)
4-Chronic injury to suspensory ligament, superficial or deep flexor tendons, or heel, predisposing the horse to rest the carpus forward and contraction of tendons
5-Chronic arthritis of the carpus with flexion of the carpus may predispose to contraction of flexor muscles and tendons
Vary according to severity
1-Unilateral or bilateral, forward deviation or flexion of the carpus to some degree
2-Shortening of the anterior phase of stride
3-The horse may fall to the carpal joint while standing or walking
4-The carpal joint may be unable to support its share of weight leading to damage of other areas
5-Knuckling of the fetlock in some cases when there is contraction of flexor tendons
1-If the condition is not severe, and the foal doesn’t knuckle over the carpus and able to put the foot flat on the ground, correction of nutrition will be enough (Most foals straighten up by the 6th month)
2-If lateral or medial deviation is present the foal should be subjected to corrective procedures
3-If the condition is severe or associated with lateral or medial deviation the animal should be treated by plaster cast for 2 weeks, removed for 2 weeks to allow the animal to over come the muscular disuse atrophy, and application of another cast for 2 weeks if it is necessary.
4-Surgical correction, by tenotomy of tendons of ulnaris lateralis and flexor carpi ulnaris, if the condition is severe and doesn’t response to plaster cast. This is followed by bandage for 10 days and rest of 2 months. If the limbs don’t straighten after the operation, plaster cast for 2 weeks. The success rate is low as a result of deformity of carpal bones, and contraction of superficial and deep flexor tendons, suspensory ligament, and tendons of ulnaris lateralis and flexor carpi ulnaris.
1-Correction of the original pathological changes if it is not chronic (flexor tendons, suspensory ligament, foot, or carpus)
2-Surgical correction by tenotomy as foals, and it has higher success rate than in foals.
*Guarded in all acquired cases
*Unfavorable in severe congenital type
*Favorable in mild congenital type if the nutrition is corrected
13-Medial (Knock knees) or lateral (bowed knees) deviation of the carpus, and medial and lateral deviation of tarsal joint: -
The animal should be treated in time to avoid damage of carpal or tarsal bones, and it is important to straighten the distal epiphyseal line
1-If the foal is young (up to 3 week-old) and deviation is severe or aseptic necrosis is present, plaster cast can be used for 2 weeks, removed for 2 weeks to over come muscular atrophy, then another cast applied for 2 weeks if the 1st cast doesn’t straighten the limb. After removal of the cast, the foal may has weakened flexor tendons and dropped fetlock, so he should be confined to box stall until the flexor tendons strengthen and the fetlock raise, then exercise can be started
2-Braces with hinge joints can be used for knock knees, and it cause less muscular atrophy than cast
3-If the condition is associated with damage to the epiphyseal growth center on the lateral side and the animal over two months age, epiphyseal staples can be used on the convex side, followed by pressure bandage for 2 weeks, removal of the staples as soon as the limb straighten, and pressure bandage for 3 weeks. The time at which staples are used differ according to epiphyseal closure time
4-Corrective trimming of the hoof wall every 2 weeks, with all of the mentioned above
From lateral deviation of the tarsus as a result of looseness of lateral collateral ligament (the limb can be pushed to normal position by hand) and it can be treated by cast for month
*Guarded in all cases
14-Hygroma of the carpus: -
Evenly distributed synovial swelling over the anterior aspect of the carpus due to acquired bursitis. The tendon sheath of extensor carpi radials and common digital extensor may be involved
Evenly distributed synovial swelling over the anterior aspect of the carpus
1-Synovial hernia of the radiocarpal or intercarpal joint capsule (irregular outline and doesn’t uniformly cover the carpus)
2-Distention of common or lateral digital extensor tendon sheaths
1-Local injection with corticoid 3-5 times weekly interval, followed by counter pressure (elastic bandage) to promote adhesion between skin and underlying tissue
2-Incision, drain, and daily swap with tincture of iodine
3-Blistering and firing, or injection with Lugol’s iodine (of low value)
4-Surgical removal of the longstanding thick synovial lining of the bursa, followed by pressure bandage for month
*Guarded to favorable.
*Unfavorable in old cases as a result of fibrous tissue formation, doesn’t response to corticoid therapy, require surgical drainage or removal.
15-Carpitis, Popped knee, or traumatic arthritis of the carpus: -
Acute or chronic inflammation of the carpal joint including joint capsule, associated carpal ligaments, and carpal bones. Early stages are serous but later on severe osteoarthritis may involve the joint (if it is not treated properly, the injury is severe, or the trauma is repeated) and new bone growth may ensue on the non-articular surface as a result of injury to the insertions of the ligaments or the capsule.
1-Bad conformation like calf knees or bench knees
2-Repeat concussion like racing
3-Repeat trauma to hard objects leading to formation new bone growth
New bone growth on the anterior surface of the carpus including distal end of the radius, proximal and distal rows of carpal bones, and proximal end of cannon, as a result of periostitis either due to pulling of the joint capsule attachment or intercarpal ligaments. This may be associated with irreversible changes in the cartilage if osteoarthritis is present.
1-Evidence of supporting and swinging-leg lameness
2-Slight flexion and swelling of the carpus during rest (due to distension of joint capsule and periarticular structures)
3-Short anterior phase of stride during motion due to reduced carpal flexion
1-Lameness may be not evident in walk but appears on trotting.
2-Enlargement of the anterior surface of radial, intermediate, and 3rd carpal bones as a result of fibrous or bony inflammatory tissue.
3-Crepitation can be detected by thumb pressure.
2-Examination (flexed carpus)
3-Radiographs for determination of presence of new bone growth, extent of the lesion, and for differential diagnosis from fracture of radial and 3d carpal bones
4-Differential diagnosis from fractures of radial or 3rd carpal bones.
Treatment of selected cases is based on radiographic picture. It is not successful if bone growth is present on articular surface.
1-Three corticoid injection, weekly interval, followed by bandage for 2 weeks, and rest for 4 months can be used for treatment of acute or serous arthritis with no bony growth. If there is bony growth, temporary relief can be achieved.
2-Blistering and firing of new bone growths, after subsidence of acute signs, if it does not involve articular surface. Firing should be followed leg paint for 3 weeks and 6 months rest.
3-Treatment by firing is not often successful if new bone growths encroach the articular surface. These cases can be treated by surgical removal of the new bone growth with smoothing the bone surface, followed by cast for a week, pressure bandage for a month, and rest for 6 months.
*Guarded to favorable in early cases with good conformation
*Guarded if new bone growth doesn’t encroach articular surface
*Unfavorable if the new bone growth encroaches articular surface or the condition is due to bad conformation
16-Fracture of carpal bones: -
Fracture commonly affects the radial or 3rd carpal bones, and rarely the intermediate carpal bone. The radial and intermediate carpal bones usually show chip fracture of the anterior proximal or distal ends. Chip fractures of the distal end of the radius or the proximal end of the cannon bone may occur too.
2-Bad conformation like calf knee
3-Over extension of the joint.
Similar to those of carpitis
1- Heat, pain, and swelling of the carpal joint, and lameness.
2-Hard prominent swelling over the anterior-medial aspect of the joint in old cases
3-No improvement with firing
1-Signs and examination
1-Surgical removal of small fragments.
2-Surgical fixation of large fragments with bone screw.
Both are made as soon as 2 weeks after injury, and should be followed by bandage for a week, elastic bandage for a month, and rest for 6 months.
*Good prognosis in most cases
*Unfavorable if the joint has excessive periosteal bone growth (especially if it encroaches articular surface) or previously injected with corticoid.
17-Fracture of accessory carpal bone: -
Fracture of this bone usually shows separation as a result of pulling of the bone by flexor carpi ulnaris and ulnaris lateralis, while the articular portion of the bone is firmly attached by the accessory carpal ligaments.
2-Stress by tendinous attachments to the bone
Lameness is not acute
1-The animal can’t put full weight on the limb soon after injury
2-Distention of carpal sheath and pain on flexion
3-Crepitation before occurrence of swelling or separation of the bone fragments by pulling
1-Signs and examination
1-Injection of carpal sheath with corticoid, followed by 6 months rest
2-Plaster cast if the case is recent
3-Surgical removal of small fragment or fixation of large fragment by bone screw
4-Surgical relief of carpal canal constriction
*Guarded to unfavorable
18-Rupture of extensor carpi radials tendon: -
2-Over flexion of the carpal joint
1-Atrophy of the muscular portion of extensor carpi radials in old cases
2-Considerable flexion of the carpus of the affected limb than the sound one
3-Extension is accomplished by common and lateral digital extensors
4-Absence of extensor carpi radials tendon on the anterior surface of the carpus
Surgical suturing of the two ends of the tendon, followed by cast for 6 weeks
Extensor carpi obliqus tendon can be used for substitution of extensor carpi radials tendon
19-Contraction of digital flexor tendons: -
Congenital or acquired contraction of the superficial and/ or deep flexor tendons. Congenital form may be associated with contraction of suspensory ligament too.
3-Acquired after injury and disuse of the limb (unilateral)
A-Superficial flexor tendon alone
Knuckling of the fetlock and pastern areas forward (Cocked ankles, dorsal rotation of fetlock and pastern joints, or upright pastern)
B-Deep flexor tendon
It is rare alone, but it is characterized by inability to put the heel on the ground (lift the heal)
C-Deep flexor tendon and suspensory ligament
The animal may walk on the dorsal surface of fetlock joint and open the joint
1-Correction of diet if it is the cause
2-No need for treatment of mild congenital cases
3-No need for surgical treatment if the foot put flat on the ground, and the animals improves
4-Plaster cast for 2 weeks if it is difficult to put the foot flat on the ground, and there is severe knuckling of the fetlock and pastern. Cast weakens the tendons and it is helpful
5-Surgery can be performed later if the animal doesn’t response to cast
a-Tenotomy of the superficial tendon if the heel remains on the ground during standing
b-Tenotomy of both flexor tendons (two sites, one for each tendon to avoid adhesion) if the heel can’t be put to the ground or the animal walk on the fetlock joint.
Tenotomy should be followed by padding and application of plaster cast 2 weeks.
*Favorable in cases not require tenotomy
*Guarded for cases require tenotomy
*Unfavorable if the problem persists after tenotomy, as it indicates contraction of suspensory ligament too, but it shouldn’t be severed, or if the fetlock joint is opened and suppurative arthritis is present.
20-Tendosynovitis, bowed tendon, tendinitis, or tendovaginitis: -
Inflammation of the superficial (more common) and/ or deep flexor tendons and their tendon sheath. The lesion may ensue at the upper part of the tendon just below the carpus, at the middle 3rd of the metacarpal bone (no tendon sheath and the condition is just tendinitis), or at the lower 3rd of the metacarpal bone and may include the volar annular ligament (the deep flexor tendon may be injured below the fetlock joint along with insertions of superficial flexor tendon and distal sesamoidean ligaments). The injury may affect the upper or the lower areas alone but usually not in the middle area alone. When injured tissues are replaced with fibrous tissue, the tendons will never have their normal elasticity and strength again. The superficial tendon is more commonly affected than the deep one.
1-Speed and exertion
2-Long weak pasterns
3-Forced training procedures
4-Muscular fatigue near the end of long race
6-Too long toes
Severe strain to the flexor tendon
It may occur in conjunction with injury to suspensory ligament, and characterized by;
1-Forward position of the carpal joint with elevated heel during rest
2-Severe lameness, diffuse swelling over the affected area, and heat and pain on palpation (even months after injury)
3-The animal doesn’t allow the fetlock to drop during motion but if the tendon fibers are torn, the fetlock will drop abnormally
1-Fibrosis (firm prominent swelling), and various degrees of heat, pain, and lameness according to the extent of healing.
2-No lameness in walking or trotting but it is evident during hard work
3-If the volar annular ligament is involved, it will contract leading to persistent lameness and chronic swelling of the tendon sheath above the sesamoid bones (notching)
1-Injury of suspensory ligament (palpation)
2-Fractures of proximal sesamoidean bones (radiographs)
Rest (1 year), parenteral corticoid (10 days), plaster cast (14 days), and supporting bandage with antiphlogistic packs (30 days)
B-Chronic form When fibrosis ensues, little can be done
1-Blistering and firing (low value)
2-Local injection with irritants like iodine preparations or promazine and 50% dextrose
3-Corrective shoeing with raised heel (not longer than 10 weeks to avoid contraction of the tendon)
a-Cutting of the volar annular ligament to relieve pressure if the ligament is constricted
b-If only the superficial or deep flexor tendons are affected, the center of the lesion is incised longitudinally through the depth of the tendon and sutured, this is followed by cast (2 weeks), then another cast (6 weeks), and rest (8 months).
*Unfavorable generally as a result of possibility of recurrence, strictly if scar tissue is present like chronic cases, or if the condition is accompanied by tearing of suspensory ligament or fracture of sesamoidean bones
*Better if the case is recent and treated by corticoid and cast
21-Metacarpal periostitis, bucked shins, or sore shins: -
Definition: Periostitis of the dorsal surface of the 3rd metacarpal bone
1-Concussion in young horses (bilateral)
1-Shifting weight between the two forelimbs (when it is bilateral), or resting the affected limb (if it is unilateral)
2-Painful warm swelling on the dorsal surface of cannon bone, with subcutaneous edema
3-Short anterior phase of stride
4-Lameness increases with exercise
1-Signs and examination
2-Radiographs for detection of fracture
1-Rest for a month
2-Corticoid injection with bandage
3-Antiphlogistic packs and cold applications during 1st or 2nd day
4-Firing in old cases (after 10 days)
*Favorable if it is recent and the animal treated in proper manner
Disease of young horses most commonly on the medial aspect between the 2nd and 3rd metacarpal bones, 3 inches below the carpal joint, in the form of one large or number of smaller hard swellings
1-Irritation or disturbance to the interosseous ligament between 2nd and 3rd or 3rd and 4th metacarpal bones in young horses as a result of hard training, poor conformation (off-set knee or base narrow toe-out), or malnutrition.
2-It may ensue as a result of direct trauma like blows or interference.
1-Lameness (may be not evident in walk) that is clear on trotting or on hard ground
2-Heat, pain, and swelling over the affected area
3-If the new bone growth encroaches the carpal joint, it will lead to arthritis, and if it encroaches suspensory ligament, it will lead to chronic lameness.
1-Signs and examination
2-Radiographs, for differentiation from fractured splint bone, and to determine if new bone growth encroaches the carpal joint or the suspensory ligament
1-Rest for a month
2-Hot and cold applications followed by antiphlogistic packs with bandaging
3-Injection with corticoid with bandaging
4-Blistering and firing within two weeks of occurrence
5-Surgical removal of the bone if it affects suspensory ligament or carpal joint (50% success rate)
6-Correction of nutritional deficiency
*Favorable unless the exostosis affect the carpal joint or suspensory ligament, or it is due to interference
23-Fracture of splint bone: -
Fracture of either the 2nd (interference) or the 4th metacarpal bones (less common and occurs due to kicking), and it confuses with splint lameness. Fracture usually involves the distal 3rd of the bone.
1-Typical splints lameness that increases on exercise or trotting
2-Heat, pain, and swelling over the affected area (more diffuse than splint and may extend over the entire length of splint bone)