Hindlimb lameness associated with proximal suspensory desmopathy and injury of the accessory ligament of the suspensory ligament in five horses
Authors: Dyson S.
Journal: Equine Veterinary Education
Summary
# Editorial Summary Proximal suspensory ligament injuries in the hindlimb are well-recognised, but injury to the accessory ligament of the suspensory ligament (ALSL)—a structure originating from the calcaneus and blending with the suspensory ligament in the proximal metatarsal region—has received limited clinical attention. Dyson's ultrasonographic assessment of ALSL in sound horses established normal appearance as linear parallel echoes with consistent dorsal and plantar borders, providing essential baseline criteria against which pathology could be identified. In five lame horses, six of eight affected hindlimbs demonstrated ALSL injury characterised by marked loss of echogenicity and disruption of normal parallel fibre alignment, with all cases concurrent to proximal suspensory desmopathy. Notably, lameness was most apparent during ridden work, and whilst deep branch lateral plantar nerve analgesia resolved lameness in three horses, tibial nerve analgesia was required in two cases, indicating variable innervation patterns that may complicate diagnosis. For practitioners, this work highlights that hindlimb lameness with proximal suspensory involvement warrants careful ultrasonographic examination of the ALSL itself, and that standard perineural blocks may prove insufficient if ALSL pathology is present—potentially explaining some cases of apparent proximal suspensory desmopathy that respond poorly to conventional treatment protocols.
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Practical Takeaways
- •When investigating hindlimb lameness, specifically assess the accessory ligament of the suspensory ligament ultrasonographically, particularly when proximal suspensory desmopathy is present — this structure is commonly injured alongside it
- •Lameness associated with this injury may only be apparent during ridden work, so dynamic examination under saddle is essential for diagnosis
- •Perineural analgesia blocking the deep branch of the lateral plantar nerve may help localize the problem, but be prepared that some cases may require tibial nerve blocks for complete diagnostic confirmation
Key Findings
- •Injury to the accessory ligament of the hindlimb suspensory ligament was identified in 6 of 8 lame hindlimbs (75%), with concurrent proximal suspensory desmopathy in all cases
- •Ultrasonographic findings of accessory ligament injury include marked decrease in echogenicity and loss of parallel alignment of linear echoes
- •Lameness was best identified when horses were ridden, indicating dynamic loading is necessary for clinical detection
- •Deep branch of lateral plantar nerve analgesia abolished lameness in 3 horses, while tibial nerve analgesia was required in 2 horses, suggesting variable innervation patterns