Examination of the anus

This requires careful attention to circumstances. The examin­ing couch should be of sufficient height to allow easy inspection and access for any necessary manoeuvres. A good light is mandatory. The Sims (left lateral) or the lithotomy position is satisfactory: the latter is less convenient for an elderly patient and can cause social embarrassment to young women. A protective glove should be worn. The patient should be relaxed and able to co-operate. A few quiet words from the doctor can prevent many loud ones from the patient.

Inspection

With the buttocks opened, the anus is inspected. Note is made of any lesions, e.g. inflammatory skin changes, haemorrhoids, fissure (‘sentinel pile’) or fistula. The patient is asked to strain down before inspection is concluded.

Digital examination with the index finger

A good lubricant is necessary neither too little nor too much. Any secretions should be sampled before applying lubricant to the anal verge.

Extreme gentleness should be the rule so that pain is not caused. Painful spasm of the anal sphincters is confirmation of a hidden fissure if the history is suggestive.

The examination should check normal, as well as abnormal, structures according to the following plan:

 

      intraluminal:

   normal: faeces,

   abnormal: polyp or carcinoma;

  intramural:

   normal: sphincter muscles and anorectal angle,

   abnormal: carcinoma or leiomyoma;

      extramural:

   normal: perianal structures,

   abnormal: abscess.

  At the same examination, the rectum is examined according to the same system. Before withdrawing the finger, the patient is asked again to strain down, and a note is made regarding the prostate in a male patient and the cervix, uterus and pouch of Douglas in a female.

Discharge

After withdrawal, the finger is examined for mucus, pus, blood and abnormal faecal material.

Proctoscopy (Fig. 61.10)

This examination is of great importance. Either the Sims position with the buttocks elevated on a small cushion, or the knee—elbow position (Fig. 61.11) may be used. The lower third of the rectum, the anorectal junction and the anal canal can be inspected as the instrument is withdrawn slowly. The patient should also be asked to strain during withdrawal as by so doing an internal intusussception may be made visible. Minor procedures can be carried out through this instrument, e.g. treatment of haemorrhoids by injection or banding (see below) and biopsy.

Sigmoidoscopy (Chapter 60)

Although this is a strictly an examination of the rectum and lower sigmoid colon, it should be carried out even when an anal lesion has been confirmed. Rectal pathology, e.g. colitis or carcinoma, is frequently the cause of an anal lesion, e.g. fissure or haemorrhoids. Not infrequently, rectal pathology is found that is independent of the anal lesion and which requires treatment.

Special investigations

These are discussed above.

Physiological studies

Manometry

Electrophysiology

Proctography

Endoluminal ultrasound