Cứng và phản ứng thành bụng không tự chủ

Mô tả: The constant involuntary contraction of the abdominal musculature where the abdomen is literally ‘rigid’ to palpation. There will also be tenderness present. When the left lower quadrant is palpated, pain is felt over the right lower quadrant.

Nguyên nhân: • Causes of peritonism Traditionally appendicitis; however, in theory inflammation of any organ in the right lower quadrant may elicit Rovsing’s sign.

Cơ chế: Inflammation of the peritoneum stimulates a reflex arc resulting in the contraction of the abdominal muscles. The parietal peritoneum is innervated by somatic nerve fibres that produce sharp localised pain (unlike the visceral peritoneum). When a pathological process (e.g. appendicitis) occurs and affects or inflames the parietal peritoneum, somatic sensory neurons are stimulated, which travel via the spinal nerves and synapse in the dorsal horn of the spinal cord. Here they then interconnect with a motor neuron in the ventral horn of the spinal cord that stimulates a localised area of abdominal muscle to contract, forming a reflex arc (Figure 6.29). As the initial reflex bypasses the brain, the patient has little control over it and, hence, it is involuntary. When the left side of the abdomen is palpated, the peritoneum is stretched tight over the inflamed appendix, thus irritating the appendix and peritoneum and localising the pain to the right lower quadrant.

Ý nghĩa lâm sàng: Rigidity, if present, is a valuable sign with a sensitivity of 6–40%, specificity of 86–100% and a PLR of 3.6.13 White matter Gray matter Dorsal Dorsal root Central canal Ventral Ventral root Cell body of motor neuron Cell body of sensory neuron Sensory neuron Inter- neuron Motor neuron Abdominal (muscle) Receptor (in skin) Parietal peritoneum Sensitivity of 22–68% and specificity of 58–96%, PLR of 2.5 and NLR of 0.7.13