The kidney in chronic renal failure, due to glomerular nephritis and nephrotic syndrome, is not usually palpable, but solitary or polycystic disease, hydronephrosis, pyonephrosis and neoplasms may become so, as can a perinephric abscess. Hematuria must be fully investigated; causes are considered in table 10; figure 44a–d provides examples of the use of imaging in the urogenital system.

The contents of the lumbar region are best felt bimanually. Place your left hand behind the right loin, in line with the right, and press your two hands together when the patient takes a deep breath (figure 45a). Rolling the patient slightly to the opposite side, placing their right arm across their chest, can facilitate palpation of a normal or abnormal kidney (figure 45b).

Table 10 Hematuria

To examine the left lumbar region, either pass your left hand across behind the subject’s back, or lean over the subject to slide your left hand behind the loin (figure 46a,b). Rolling the patient onto the opposite side may again facilitate palpation (figure 46c).

Renal tenderness is usually maximum posteriorly. The kidneys descend on inspiration and may be felt between your two hands. The lower poles may be palpable in normal subjects, particularly that of the lower placed right kidney. A large low-lying or mobile kidney may be caught between your two hands, and felt to recoil when let go. The surface marking of the kidneys is shown in figure 47 and, although renal biopsy is usually undertaken under ultrasonic guidance, anatomical knowledge is essential (figure 48).

A renal mass may be resonant (rather than dull) to percussion, due to overlying colonic gas. A colonic mass is more anteriorly placed and may be dull to percussion.

Figure 47 Surface anatomy of kidneys

1. Spleen
2. Lower border of lung
3. Eleventh rib
4. Lower border of pleura
5. Twelfth rib
6. Kidney
7. Ureter
8. Spine of fourth lumbar vertebra (supracristal plane)