Serratus anterior, along with other scapulothoracic muscles such as trapezius, stabilises the scapula upon the chest wall. It is innervated by the long thoracic nerve, a nerve that exclusively supplies this muscle. The long thoracic nerve is described as being purely motor (Bizzarri et al., 2001; Schultz & Leonard, 1992). However, given that this is its sole innervation, this is at odds with the observation that the muscle contains a normal complement of muscle spindles (Voss, 1971). The long thoracic nerve is superficial, which renders it vulnerable to injury and leads to dysfunctions of clinical significance. However, it also lends itself to electrophysiological studies. We have therefore taken advantage of this to investigate the reflexes evoked by the afferents of serratus anterior. With local ethical approval and informed consent of healthy subjects, reflexes of serratus anterior and trapezius were evoked using electrical stimuli of peripheral nerves. The effects of these stimuli were recorded electromyographically using surface electrodes placed over the ipsilateral and contralateral serratus anterior and trapezius muscle pairs. The long thoracic nerve can be located superficially at two points (i) at a proximal site, superior to the proximal end of the clavicle, and (ii) at a distal site, on the lateral surface of the chest wall along the mid-axillary line. Confirmation that the cathode was located on the long thoracic nerve was ascertained by the resulting contraction of the serratus anterior muscle. As the nerves to serratus anterior and trapezius are closely situated at the proximal site in the supra-clavicular fossa, it was also ensured that no trapezius H reflex or M response was present when stimulating at this site. Reflex activity evoked by electrical stimulation of the afferent nerve to trapezius was induced by electrical stimulation of the cervical nerve of C3/4 (see Alexander & Harrison, 2002). Electrical stimulation of the long thoracic nerve at both sites, evoked short latency, facilitatory reflexes in the ipsilateral serratus anterior. These would appear to be H reflexes. In contrast to the short latency reflexes evoked by trapezius (a close synergist of serratus anterior) in the contralateral trapezius, no short latency reflexes were evoked by serratus anterior in the contralateral serratus anterior. Also, no synergistic responses were evoked in trapezius from stimulation of the long thoracic nerve at the distal site. These results, indicating a very restrictive pattern of reflexes from serratus anterior, are similar to those observed in the cat by Caicoya et al (1999). In addition, the pattern of short latency reflexes evoked by serratus anterior differs from that evoked by trapezius afferents. This presumably reflects differences in independent control of these muscles bilaterally.