The equine scapula is characterised by an un-ossified portion that extends dorsally, the scapular cartilage, enlarging the area for muscular attachment (Dyce et al., 2010).  The lateral surface is divided by a spine, with a palpable tuber, into supraspinous and infraspinous fossae, the spine extends from the dorsal border to the neck without producing an acromion (Budras et al., 2003). The supraspinatus arises from and fills the supraspinous fossa, functioning mainly to stabilise the shoulder joint (Dyce et al., 2010). The infraspinatus arises from and fills the infraspinous fossa, it has a deep tendon that inserts onto the greater tubercle of the humerus and a superficial tendon that attaches more distally, it functions as a fixator of the shoulder and also as an abductor (Dyce et al., 2010). The suprascapular nerve is angled around the cranial border of the scapula, ending in the infraspinatus and supraspinatus muscles [Figure 1]. As the border of the scapula is sharp, and there is no acromion, the nerve is in danger of mechanical trauma (Budras et al., 2003).  If the suprascapular nerve that innervates the infraspinatus and supraspinatus muscles is damaged, the result is atrophy of these muscles. As the nerve crosses the cranial aspect of the neck of the scapular it is vulnerable to pressure from either direct trauma (commonly running into a wall/solid object or a kick from another horse (Parker, 2013)) or collars as used with draught horses. Sweeney may also be a result of injury to the brachial plexus, more muscles such as the triceps may show atrophy in this case, and caudal cervical arthropathy (Mair et al., 2013), a syndrome of sensorimotor deficits and/or pain due to compression of the root of a cervical nerve (Caridi et al., 2011), also resulting in atrophy of more muscles.