REIDER PART 2
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Chapter 9_Lumbar Spine 347

Figurę 9-13. Modificd silup demonstrates abdominal musclc strength.

Figurę 9-14. Activc cxtension demonstrates erector spinae strength.

table and the number of repctitions possiblc vary widely among patients according to flexibility, fitness level, and training. The pain associated with disorders of the poste-rior elements of the lumbar spine, such as spondylolysis or facet joint arthritis, or of spinał stenosis may be exac-erbated by this test.

Neurologie Examination

Sensory Examination

The approximate areas of sensory innervation from the lumbar and the sacral nerve roots are shown in Figurę 9-15. As with the ccrvical and the thoracic nerve roots, thcrc is considcrable overlap in the sensory dermatomes, and the exact distribution of each dermatomc varies somewhat from one individual to another. The initial screening for sensory deficits is usually done with light touch and sharp-dull discrimination testing, as described in Chapter 8, Cervical and Thoracic Spine. The sensory, motor, and reflex tests for each dermatome are summa-rized in Table 9-1.

The LI, L2, and L3 dermatomes run in broad bands obliquely across the anterior thigh. LI sensation is tested in the anterior proximal thigh near the inguinal ligament (Fig. 9-16A). Sensation supplied by the L2 nerve root is tested over the anteromedial thigh, midway between the inguinal ligament and the patella (Fig. 9-16B). L3 sensation may be evaluated by testing the skin just proximal or medial to the patella (Fig. 9-16C). The L4 nerve root sup-plies sensation to the medial leg and the ankle. It is best tested by examining the sensation in the area just proxi-mal to the medial malleolus (Fig. 9-16D). The L5 dermatome includes the lateral and the anterolateral leg and the dorsum of the foot. L5 sensation is usually tested by examining the area just proximal to the first web space (Fig. 9-16E).

The sensory distribution of the SI nerve root includes the posterior calf, the plantar surface of the foot, and the lateral toes. SI sensation may be reliably tested over the posterolateral aspect of the heel (see Fig. 9-16F). The S2 nerve root supplies the posterior thigh and the proximal calf. S2 sensory function may be tested by eval-uating sensation in the center of the popliteal fossa (see Fig. 9-16G). The lower sacral nerve roots (S3, S4, S5) sup-ply the sensation in the perianal area. The dermatomes are arranged in concentric rings around the anus, with the S3 dermatome being the most pcriphcral and the S5 being the most central.

PHYSICAL FINDINGS IN LUMBOSACRAL RADICULOPATHIES

Dermatome	Sensory Testing	Motor Testing	Reflex Testing
LI	Anterior proximal thigh	Iliopsoas (seated hip flexion)
	near inguinal ligament
L2	Mid anteromedial thigh	Iliopsoas (seated hip flexion)
L3	Just proximal or medial to patella	Quadriceps	Patellar tendon reflex (secondary)
1.4	Medial lower leg and ankle	Tibialis anterior	Patcllar tendon reflex
L5	Lateral and anterolateral	Extensor hallucis longus	Tibialis posterior reflex
	leg and dorsal foot	Extensor digitorum brevis	Medial hamstring reflex
		Gluteus medius
SI	Posterior calf, plantar foot,	Gastrocsoleus	Achilles’ reflcx
	and lateral toes	Peronei
		Gluteus maximus
S2	Posterior thigh and proximal calf	Rectal examination
S3, S4, S5	Perianal area	Rectal examination