The cerebral hemispheres are the largest part of the human brain: they consist of the telencephalon (cerebral cortex and underlying white matter), basal ganglia and diencephalon. Both hemispheres are interconnected by the corpus callosum and the anterior commissure. The cerebral…
The term basal ganglia is used to denote a number of subcortical nuclear masses that lie in the inferior part of the cerebral hemisphere, in close relationship with the internal capsule ( Fig. 31.1 ). The traditional definition of the…
The diencephalon is part of the prosencephalon (forebrain), which develops from the most rostral primary cerebral vesicle that differentiates into the caudal diencephalon and the rostral telencephalon. The cerebral hemispheres, containing the lateral ventricles, develop from the telencephalon. The sites…
The cerebellum is the largest part of the hindbrain, recognized as a distinct division of the brain from the time of Herophilus (335–280 BC) and Galen (AD 131–200). It is situated in the posterior cranial fossa, beneath the tentorium cerebelli,…
The brainstem is situated in the posterior cranial fossa, where it faces the clivus and dorsum sellae ventrally and the cisterna magna, fourth ventricle and cerebellum dorsally ( Fig. 28.1 ). It is approximately 6–7.5 cm in length and 3–4…
The spinal cord provides innervation for the trunk and limbs via spinal nerves and their peripheral ramifications. It receives primary afferent fibres from peripheral receptors located in widespread somatic and visceral structures, and sends motor axons to skeletal muscle. It…
The brain is a highly vascular organ, its profuse blood supply characterized by a densely branching arterial network ( ). It has a high metabolic rate that reflects the energy requirements of constant neural activity. It receives about 15% of…
The meninges consist of three concentric membranes that envelop the brain and spinal cord, supporting and protecting the delicate tissues they surround. The individual layers, from outside to inside, are the dura mater (pachymeninx), arachnoid mater and pia mater. The…
The human nervous system is the most complex product of evolution. The activity of its billions of neurones constitutes the physical basis of sensory experience, motor behaviour, consciousness and self-awareness. Research to elucidate the mechanisms that underlie these functions is…
Prenatal Stages Development of a human from fertilization to delivery at ‘full term’ averages 266 postfertilization days, or 9.5 lunar months (28 day units). It has long been customary to compute the length of a pregnancy, whether in a normal…