Lower Limbs

Trunk




Key Point



The shape and range of motion of the spine are evaluated with the patient standing. Sensation is tested with the patient lying down; particular attention should be paid to a sensory level or to a deficit in a saddle or genital distribution. The motor innervation of the trunk is assessed with the intrinsic abdominal muscle reflexes and the extrinsic reflexes (abdominal skin reflex, cremasteric reflex).


3.5.1 Back and Spine


The back and spine are examined with the patient standing. Inspection may reveal scoliosis or a deviation from the normal lordosis or kyphosis of particular segments of the vertebral column. Protruding ribs on one side (often visible only when the patient bends forward) are a sign of torsional scoliosis. As one looks at the patient from behind, there is a triangular gap to either side of the patient’s waist, formed by the dependent arm, the rib cage, and the upper border of the pelvis; asymmetry of this gap is a further sign of scoliosis. A plumb line from the spinous process of C7 should overlie the natal cleft; deviations should be measured and documented (preferably in centimeters, rather than fingerbreadths). One should also look for stepping of the lumbosacral vertebrae (e.g., in spondylolisthesis, described in section ▶ 14.5.2) or tenderness of the spinous processes to pressure or percussion. Techniques for testing the mobility of the cervical spine were described in section ▶ 3.3.1. The mobility of the thoracolumbar spine is tested by having the patient bend the trunk forward, backward, and to either side, and then rotate it to either side. On forward bending with extended knees, young patients should be able to touch the ground (finger-to-ground distance: 0 cm). Spinal mobility can be quantified with the two Schober tests: the small Schober index pertains to the lumbosacral spineand the large Schober index to the thoracic spine.




  • To measure the small Schober index, place a mark on the patient’s skin 10 cm above the spinous process of L5, have the patient bend forward as far as possible, and measure the distance again; it should now be at least 15 cm.



  • The large Schober index is measured similarly, starting from a point 30 cm below the spinous process of C7, which on maximal forward bending should move to at least 32 cm below it.


Any diminution of the normal cervical lordosis is best seen when the patient stands with shoulders and heels to the wall and bends the head as far back as possible. The back of the patient’s head normally touches the wall; if not, the distance from the occipital protuberance to the wall should be measured in centimeters. An abnormality of this type is found, for example, in ankylosing spondylitis.


3.5.2 Reflexes


The abdominal skin reflexes are extrinsic muscle reflexes. They are tested by rapid stroking of the abdominal skin (e.g., with a wooden stick) from lateral to medial, at three different segmental levels, on either side ( ▶ Fig. 3.30a). They can be enhanced, if necessary, by having the patient lift his or her head off the headrest ( ▶ Fig. 3.28b). Diminution of the abdominal skin reflexes indicates a lesion of the pyramidal pathway. A diminished or absent reflex at only one level on one side suggests a segmental peripheral lesion. Total bilateral absence is usually an artifact of deficient examining technique, but may also be caused by an obese or flaccid abdominal wall (e.g., after pregnancy). “True” bilateral absence of all abdominal skin reflexes is seen in bilateral lesions of the pyramidal pathway; an accompanying sign in such patients is unusual briskness of the intrinsic reflexes of the abdominal musculature. These are tested by tapping at the sites of muscle attachment, for example, at the costal margin or the symphysis pubis ( ▶ Fig. 3.30b). Alternatively, the examiner can place his or her own hand on the abdomen and tap on it.



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Fig. 3.30 The abdominal skin reflexes. a Elicitation of the extrinsic reflexes by stroking the abdominal skin from lateral to medial. b The intrinsic reflexes are elicited by striking the sites of muscle attachment.


The cremaster reflex is tested (in males) by stroking the medial surface of the thigh or by forceful pressure with a finger near the origin of the adductor muscles. The anal reflex is tested by lightly scratching the perianal skin with, for example, a pointed wooden stick. This induces reflex contraction of the anal sphincter. The anal reflex is sometimes easier to appreciate on rectal examination with a gloved finger (with which the examiner can also assess sphincter tone); it is abolished by lesions of the cauda equina and conus medullaris (described in section ▶ 7.1.2).


3.5.3 Sensation


Sensation on the trunk is tested to localize a possible sensory level (segmentally delimited sensory deficit) due to a spinal cord lesion. A sensory level caused by a bilateral lesion of one or more spinal nerve roots is limited to one or a few dermatomes; one caused by spinal cord transection covers the entire region of the body from the toes up to the rostral border of the injured spinal segment. A sensory level should be localized to a particular numbered segment as precisely as possible by testing both from above and from below. If a lesion of the cauda equina is suspected, sensation should be meticulously tested in the sacral dermatomes, the so-called saddle area.


3.6 Lower Limbs




Key Point



The examination of the lower limbs, too, begins with inspection: the examiner assesses the posture and spontaneous movements of the legs and feet, muscle bulk, skin condition, and any abnormal movements that may be present. Next, the mobility of the major joints is tested, and the pulses are palpated. The neurologic examination per se then follows, with testing of strength, reflexes, coordination, and sensation.


3.6.1 General Aspects


The procedure here is the same as in the upper limbs (cf. section ▶ 3.4). The muscles are inspected and palpated for tone and bulk. Atrophy of individual muscle groups should be looked for (especially the tibialis anterior muscle); any fasciculations (definition: ▶ Table 5.3) should be noted. Involuntary movements should be observed, if present. The mobility of the larger joints, particularly the hip joints, should be tested individually. The Lasègue sign (see section ▶ 13.1.2, Radicular Syndromes due to Intervertebral Disk Herniation) should be tested, and the examiner should check for tenderness of the peripheral nerve trunks. The trophic state of the skin and the peripheral pulses should be assessed as well. The pedal and popliteal pulses should be palpated; the pulses in the abdominal vessels should be examined by auscultation, as should those of the femoral artery, both in the groin and in the proximal adductor canal. The Ratschow test is a provocative test of the blood supply to the leg: the examiner holds up both legs of the supine patient and the patient rotates the feet back and forth. A normal individual can do this for several minutes without difficulty, but, if arterial insufficiency is present, pain soon arises. In addition, when the legs are brought back to the horizontal position, the skin takes a longer time than normal to regain its usual pink color (in patients of light complexion) and venous refilling is likewise delayed.


3.6.2 Coordination and Strength


The following motor tests should be performed:




  • In the heel–knee–shin test, the patient closes the eyes, brings the heel of one leg through the air in a wide arc to place it on the opposite knee, then slides the heel down the shin to the front of the ankle, and finally back up to the knee ( ▶ Fig. 3.31). Unsteadiness indicates ataxia.



  • In the postural test, the patient lies supine, raises the lower limbs so that the hips and knees are at right angles, and holds them in this position ( ▶ Fig. 3.32). The examiner looks for possible sinking of a leg, indicating (mild) paresis.



  • Strength, too, should be tested in the supine patient. Additional special tests are used for individual muscle groups. For example, a patient with quadriceps weakness has trouble stepping up onto a stool or chair, or standing up from a sitting position (if the weakness is bilateral). The dorsiflexors of the feet and toes should always be tested, because these distal muscles are frequently weakened early in the course of many different neurologic disorders. Dorsiflexion of the big toe, for example, is weak in L5 radiculopathy. In suspected polyneuropathy, it may be useful to palpate the contractions of the muscles of the dorsum of the foot and to compare the patient’s ability to spread the toes on the two sides. Mild weakness of the calf muscles (i.e., of dorsiflexion of the foot) is best tested by having the patient hop on one foot or stand repeatedly on the tip of one foot (see ▶ Fig. 13.66).



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    Fig. 3.31 The heel–knee–shin test. With eyes closed, the patient touches one heel to the opposite knee and then slides it down the shin.

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Dec 28, 2017 | Posted by in NEUROLOGY | Comments Off on Lower Limbs
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