Preface

Clinical Neuroanatomy Made Ridiculously Simple is a book intended to help medical students rapidly master that part of neuroanatomy that is essential to clinical care. It is also of practical value to nurses and paramedical personnel who are confronted with neurological problems. This book was written to fulfill the need for a brief, but readable, summary of clinically relevant neuroanatomy, with examples of medical cases. It is common for neuroanatomy texts to be too greatly oriented toward...

Accommodation

Pathways Conjugate Eye Movement

Accommodation Fig. 36 involves a neural circuit to the visual cortex and back, which makes sense, for we need our cerebral cortex to determine that something is out of focus before we can send directions to correct the focus. Focusing occurs by stimulating the smooth muscle of the ciliary body in the eye to contract, thereby enabling the lens to change its shape accommodation . During accommodation not only does the lens focus but the pupil constricts, both smooth muscle actions mediated by...

Questions

Clinical Neuroanatomy Organization

7-1 In the Romberg test the patient is asked to close his eyes while standing. If he sways back and forth with his eyes closed, but does not sway with them open, then the Romberg test is called positive. Normally there should be no swaying even with the eyes closed. In what clinical conditions would you expect a positive Romberg Ans. In proprioceptive or vestibular defects, for the following reason. To keep one's balance requires at least two out of the three senses that help maintain balance...

Cerebral Cortex

Motor Speach Area

Lesions to the nervous system may lead to simple or complex levels of dysfunction depending upon the area involved. For instance, if one asks a patient to put on a polo shirt and his left brachial plexus is severed, he will only use his right arm, as his left arm is paralyzed.The cerebellum and basal ganglia represent a step further in levels of functioning. With a cerebellar lesion, the patient may perform the act awkwardly, e.g. overshooting the mark, or with tremor. With basal ganglia...

Basal Ganglia Disorders

Parkinsonism rigidity slowness resting tremor mask-like fecies shuffling gait, associated with degeneration in the basal ganglia and substantia nigra. 2. Chorea sudden jerky and purposeless movements e.g. Sydenham's chorea found in rheumatic fever Huntington's chorea, an inherited disorder . 3. Athetosis slow writhing, snake-like movements, especially of the fingers and wrists. 4. Hemiballismus a sudden wild flail-like movement of one arm.

Clinical Review

Wrist Flexor Reflex

9-1 What general principles are useful in determining whether a lesion lies at the level of the cerebral cortex, internal capsule, cerebellum,basal ganglia, brain stem, spinal cord or peripheral nerve Ans. Cerebellar and basal ganglia lesions result in motor problems, specifically in aberrations in the quality of coordinated movements, as opposed to paralysis. Cerebellar dysfunction is characterized by awkwardness of intentional movements. Basal ganglia disorders are more characterized by...

Autonomic System And Hypothalamus

Sympathetic Nerve Routes

The autonomic system regulates glands, smooth muscle and cardiac muscle. It contains sympathetic and parasympathetic components. The sympathetic system as a whole is a catabolic system, expending energy, as in the flight or fight response to danger, e.g. increasing the heart rate and contractility and shunting blood to the muscles and heart. The parasympathetic system is an anabolic system, conserving energy, e.g. in slowing the heart rate and in promoting the digestion and absorption of food....

Cranial Nerve

Otic Ganglion

Note in Figure 29 the appropriate positions of the nuclei of CN9, as well as the functions of this nerve. CNs 9 and 10 each have their own superior and inferior ganglia. -SOMATIC SOeOKYiooitongu, r VISCERAL SENSORY pottwior 1 9 Of M-twtii ptojra carotid body and sinus Otic ganglion VISCERAL MOTOR prottt gland SOMATIC MOTOR Utyloptiaryngwt Fig. 29 Cranial nerves 9 and 10. S.g., superior ganglion I.g., inferior ganglion. y_ Peripteral gutjfti I VISCERAL MOTOR thoraoto

Nystagmus

Nystagmus Test Squirt Water Eye

Nystagmus is a repetitive, tremor-like oscillating movement of the eyes. The most common form of nystagmus is horizontal jerk nystagmus, wherein the eyes repetitively move slowly toward one side and then quickly back. It is normal to have a slight degree of such nystagmus on attempted extreme lateral gaze, but marked degrees are abnormal and found in a variety of clinical conditions. Vertical nystagmus is always abnormal, signifying a disorder in brain stem function. Pendular nystagmus, in...

Brain Stem

Brain Stem Motor Nuclei Images

In evaluating a patient, the neurologist asks a sequence of questions. First, where is the lesion spinal cord, brain stem, cerebrum, etc. Second, what is the lesion tumor, infection, hemorrhage, etc. third, what can be done to help the patient medication, surgery, etc. The neurologist tries to determine if a single lesion can account for the patient's symptoms and signs. If multiple lesions must be postulated, this generally implies either metastatic disease, multiple sclerosis, the presence of...

Cn

Brain Stem Cross Sections

SOMATIC MOTOR stsrnoclwiomottOMii tropuiut SOMATIC MOTOR stsrnoclwiomottOMii tropuiut -IOIOotmI molw nue. 9,I0 Nuc omtugvjys Fig. 25 Basilar anterior view of the brain stem. The outlines of four representative cross sections are shown at the levels of the horizontal lines. Structures that are externally visible in the intact brain stem are labelled in the cross sections. MB, midbrain, c, optic chiasm p, pituitary gland m, mammillary bodies A, anterior nuc., nucleus. Numbers refer to the...

Conjugate Gaze

Conjugate Gaze Deviation

Damage to the motor areas of the cerebral cortex produces contralateral paralysis of the extremities. It does not produce loss of all the contralateral eye muscle movements, but rather loss of the ability of either eye to look toward the contralateral environment. Following a lesion to the left visuo-motor area Brodmann's area 8 see Fig. 52 , the patient cannot look to the right. His eyes tend to deviate to the left. In essence, they look at the lesion. This occurs because the pathway from the...

Pupillary Constriction to Light

Pupillary Light Reflex

Unlike the pathways mediating vision, which involve a synapse in the lateral geniculate body, the pupillary light reflex involves a direct pathway Fig. 36 The pathways for the pupillary light reflex and accommodation. LGB, lateral geniculate body. The depicted lesions presumably also interrupt light reflex fibers crossing from the opposite side of the brain stem. The pathway shown innervating the eye is highly schematic the light reflex pathway involves only pupillary constriction, whereas the...

The Three Sensory Nerves

Sensory Distribution Face

The nucleus of CN8 lies in its appropriate area Fig. 26 . After synapsing, the auditory fibers partly cross and travel to both inferior colliculi Fig. 22 , synapse again, extend to the medial geniculate bodies Fig. 22 , synapse, and then travel to both cerebral hemispheres auditory area, Fig. 52 . CNs 1 and 2, not belonging to the brain stem, will be discussed later. If you have memorized figure 19, the four mixed nerves will then become predictable and easy, after the following story about the...

The Long Tracts

Brainstem Motor

The main pathways through the brain stem are illustrated in Figure 33. The corticospinal tract, medial lemniscus, spinothalamic tract, and spinocerebellar tracts are the most important clinically. Not shown is the cortico-bulbar tract, which accompanies the corticospinal tract and connects, among other things, with the various brain stem motor nuclei. Unilateral damage facial motor nucleus-Internal acoustic meatus - Taste anterior 2 3 of tongue and Submaxillary and sublingual glands salivation...

Cranial Nerve 7 The Facial Nerve

Cranial Nerve Face

CN7 a hook Fig. 30 pulls down, closing the eye, whereas CN3 3 pillars Fig. 30 opens the eye. This is a vital clinical point. Figure 31 illustrates the clinical difference between upper motor neuron and lower motor neuron damage to CN7. If one severs CN7, which innervates one entire side of the face, including the eyelids and eyebrows, that entire side of the face becomes paralyzed. The forehead on the affected side appears Fig. 31 Facial paralysis caused by upper and lower MN lesions of CN7....

The Visual System

Parietal Lobe Lesion Quadrantanopia

Destruction of a cerebral hemisphere results in dense paralysis and sensory loss in the contralateral extremities. Such lesions do not result in corresponding visual loss or ocular paralysis confined to the contralateral eye. Rather, both eyes are affected partially. Neither eye can move to the contralateral side and neither eye sees the contralateral environment Fig. 34 . CALCARINE FISSURE Area below calcarine fissure from inferior retina PARIETAL LOBE OPTIC RADIATION superior retinal TEMPORAL...

General Organization

Rolando Sulcus

The central nervous system CNS includes the cerebrum, cerebellum, brain stem, and spinal cord Fig. 1 plus a few scary-sounding structures situated between the brain stem and cerebrum namely, the diencephalon Which includes everything with the name thalamus i.e. the thalamus, hypothalamus, epithalamus and subthalamus and the basal ganglia which includes the caudate nucleus, the globus pallidus, the putamen, claustrum, and amygdala . Fortunately, it is clinically unimportant to have a detailed...

Spinal Cord

Proprioception And Stereognosis Pathway

The spinal cord, as seen in cross section Fig. 14 , contains central grey matter and peripheral white matter. The grey matter contains many neuronail cell bodies and synapses. The white matter contains ascending and descending fiber pathways. The ascending pathways relay sensory information to the brain. The descending pathways relay motor instructions down from the brain. The number of synapses within a pathway is not very important to know clinically. However, it is vital to remember the...

How to Draw the Brain Stem in Cross Section

The rostral midbrain Fig. 22A resembles a double-headed gingerbread man with two belly buttons. In the caudal midbrain Fig. 22B , the gingerbread man has lost his arms and has only one belly button. The pons Fig. 22C resembles buttocks. The rostral medulla Fig. 22D has 3 bumps posterolaterally and 3 bumps anterolaterally very convenient, for dotted lines between the bumps divide the medulla into the somatic motor, autonomic, and somatic sensory zones. The caudal medulla Fig. 22E looks something...

Willis X

Internal Jugular Vein And The Brain

They are the same structures, seen from different angles. In figure 10 the brain is seen from below, so the carotid arteries are seen in cross section. Figure 10 also explains why the vertebral artery changes its name twice. At first the two vertebral arteries fuse to form one basilar artery. The basilar artery then divides again into two posterior cerebral arteries. An occlusion of the basilar artery at the junction of the two posterior cerebral arteries will result in total blindness, as the...

Blood Supply Meninges And Spinal Fluid

Blood Supply The Brain Mca Aca

Two main pairs of arteries supply the brain the two internal carotid arteries and the two vertebral arteries. The vertebral artery changes its name. It's called the basilar artery at the level of the pons and the posterior cerebral artery at the level of the cerebrum Fig. 6 . You'll see why when we discuss Willis, the spider. Fig. 6 The major arterial supply to the brain. ACA, anterior cerebral artery MCA, middle cerebral artery PCA, posterior cerebral artery PAD, pia, arachnoid, dura. Note the...