Knowledge · Clinical Examination

Per Rectum (PR) Examination for MRCS Part B: Consent, Technique and Findings

By Dr Richard Miller, MBChB FRCS with the MRCS Part B Questions Team · Reviewed 15 September 2026

In brief

A rectal examination is an intimate examination: explain it, gain consent, offer a chaperone, position the patient in the left lateral position, inspect the perianal skin, then assess tone, the rectal wall and the prostate.

A per rectum examination is an intimate examination. Explain why it is needed, explain what it involves, tell the patient they can stop you at any time, offer a chaperone and gain consent. Then position the patient in the left lateral position, inspect, and examine tone, the rectal wall and the prostate.

Key takeaways

The GMC lists rectal examination as an intimate examination and asks you to offer a chaperone and explain their role.
A relative or friend is not a trained impartial observer and would not usually be a suitable chaperone.
Inspect the perianal skin before you insert a finger.
Assess resting tone, then squeeze, then the rectal wall through 360 degrees, then the prostate.
NICE NG12 says to refer on a suspected cancer pathway if the prostate feels malignant on digital rectal examination.

How is this station marked in MRCS Part B?

A physical examination station is marked out of 20 across four domains: clinical and technical skill carries 8 marks, and clinical knowledge and its application, communication, and professionalism carry 4 marks each. The examiner also gives the station a separate global rating of pass, borderline or fail.

Two things follow from that split. More than half the marks sit outside your knowledge of the condition, so a silent, technically correct examination scores poorly. And you are signalled at six minutes of the nine to present your findings, so the sequence has to finish inside six.

Out loud, in order, and before you touch anything. The GMC guidance on intimate examinations sets out what you must cover before you begin.

Explain why the examination is necessary and give the patient the chance to ask questions.
Explain what it will involve, in words the patient understands, including any discomfort.
Tell the patient they can ask at any time for the examination to stop.
Offer a chaperone and explain what the chaperone's role would be.
Obtain and record consent, and give the patient privacy to undress.

What equipment do I need?

Non-sterile gloves.
Lubricating jelly.
Tissues or gauze to clean the patient afterwards.
A sheet or blanket to keep the patient covered.
A light source, and a proctoscope if the examiner asks you to proceed to one.

How do I position the patient?

Ask the patient to lie on their left side with the knees drawn up towards the chest and the buttocks at the edge of the couch. Keep them covered with a sheet until the moment you examine and cover them again immediately afterwards.

What do I inspect before inserting a finger?

Part the buttocks and look at the perianal skin in a good light before you do anything else. Stanford Medicine 25 notes that anal fissures lie in the posterior midline about 90 per cent of the time.

Skin tags, external haemorrhoids, fissures and fistula openings.
Excoriation, rashes, warts and discharge.
Prolapsed haemorrhoids or rectal prolapse, and ask the patient to strain if prolapse is suspected.
Scars from previous anorectal surgery.

What is the sequence of the digital examination?

Lubricate the gloved index finger, warn the patient, and press gently on the posterior anal margin at the six o'clock position until the sphincter relaxes, then advance along the axis of the canal.

Assess resting anal tone, then ask the patient to squeeze your finger and assess voluntary tone.
Sweep the rectal wall through a full circle, feeling for masses, polyps, tenderness and induration.
Palpate the prostate anteriorly in men, or the cervix and pouch of Douglas in women.
Withdraw the finger and inspect the glove for stool colour, blood, mucus and melaena.
Clean the patient with tissues, cover them, remove your gloves and wash your hands.

What am I feeling for in the prostate?

Size, symmetry, surface, consistency, the median sulcus and tenderness. Stanford Medicine 25 gives the normal prostate as roughly the size of a walnut, about 2 to 3 cm and wider at the top.

Smooth, symmetrical and enlarged with a preserved median sulcus suggests benign enlargement.
Hard, craggy, asymmetrical or nodular with a lost median sulcus suggests malignancy.
Exquisitely tender and boggy suggests prostatitis.

NICE NG12 recommendation 1.6.1 is to refer using a suspected cancer pathway referral if the prostate feels malignant on digital rectal examination, and 1.6.2 is to consider a PSA test and digital rectal examination in anyone with lower urinary tract symptoms, erectile dysfunction or visible haematuria.

What is the examiner marking, and what goes wrong?

This station is usually performed on a manikin, and the professionalism around it is marked as heavily as the technique, across the four Intercollegiate domains.

Starting the explanation after gloving up rather than before.
Not offering a chaperone, or offering the patient's relative as one.
Skipping inspection of the perianal skin.
Forgetting to inspect the glove, which is where the melaena or fresh blood is.
Leaving the patient uncovered or not cleaning off the lubricant.
Describing the prostate without mentioning the median sulcus.

MRCS Part B Questions has a rectal examination station with a marked checklist at /Sample-Questions. Reviewed and updated 15 September 2026.

Key evidence

Intimate examinations and chaperones — General Medical Council (2024)
Suspected cancer: recognition and referral (NG12), recommendations by site of cancer — NICE (2023)
Rectal Exam — Stanford Medicine 25

FAQ

Who can act as a chaperone?

The GMC says a chaperone should usually be a health professional, trained for the role, familiar with the procedure and able to stay for the whole examination and see what you are doing. A relative or friend is not a trained impartial observer and would not usually be suitable, although the patient may have both present if they wish.

What if the patient declines a chaperone?

Record the offer and the declining of it, and proceed if you are comfortable doing so. The GMC also says you should not assume the patient does not want one, and that if no suitable chaperone is available you may offer to delay the examination, provided the delay would not harm the patient.

Which position should the patient be in?

The left lateral position with the knees drawn up is the standard for a surgical rectal examination in the UK and is what the station expects. Other positions exist for specific purposes, but naming and using the left lateral position confidently is what earns the mark.

Do I comment on the stool on the glove?

Always. Inspecting the glove is part of the examination and it is where fresh blood, mucus and melaena are found. Say what you see, including when it is normal brown stool, and include it in your presentation to the examiner.

What do I do if the examination is too painful to continue?

Stop. The GMC says you must stop if the patient asks you to and be alert to signs of discomfort or distress. A severely painful examination is itself a finding, most often an anal fissure, and saying that you would stop and consider examination under anaesthesia is the correct answer.

The MRCS Part B Questions Team

Written and maintained by doctors who have sat and scored well at this interview, and reviewed against the current published guideline in each case. Guidance changes — check the source before you rely on a threshold.

Last reviewed 15 September 2026

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