Compressive lesions at the optic chiasm most commonly cause a quadrantanopic field defect. Occasionally asymmetrical compression of the chiasm may cause a homonymous defect and, most infrequently, is the only site along the visual pathway to produce a bitemporal hemianopia. Muscle atrophy is a prominent feature of lower motor neurone syndromes. Cervical spondylosis can cause focal muscle atrophy in the distribution of the compressed nerve root, although the usual symptoms are those of dysaethesiae. A basic knowledge of the components of the innate immune system and the clinical effects that result from inherited and acquired deficiencies is required. Patients with recurrent syncope associated with synchronous arrhythmia are likely to benefit most from a pacemaker. There are a number of infectious diseases that overlap between childhood and adulthood, and as such may appear in the adult exam.