MRCS Part B Revision · Anatomy
Shoulder — MRCS Part B Anatomy
By Dr Richard Miller, MBChB FRCS · Reviewed
Shoulder is a surgical anatomy station. Three of the seventeen examined stations in the MRCS Part B OSCE are surgical anatomy. The anatomy stations put a prosected specimen, a model or an image in front of you and ask you to identify structures and say what they do, what they relate to and what happens when they are injured.
What you need to know for the Shoulder station
The Shoulder
The Glenohumeral Joint
The shoulder joint has a loose capsule that is lax inferiorly and therefore is at risk of dislocation inferiorly. The long head of the biceps brachii muscle travels inside the capsule to attach to the supraglenoid tubercle of the scapula.
Because the tendon is inside the capsule, it requires a synovial tendon sheath to minimize friction.
A number of bursae in the capsule aid mobility. Namely, they are the subdeltoid bursa (between the joint capsule and deltoid muscle), subcoracoid bursa (between joint capsule and coracoid process of scapula), coracobrachial bursa (between subscapularis muscle and tendon of coracobrachialis muscle), subacromial bursa (between joint capsule and acromion of scapula) and the subscapular bursa (between joint capsule and tendon of subscapularis muscle, also known as subtendinous bursa of subscapularis muscle). The bursa are formed by the synovial membrane of the joint capsule. An inferior pouching of the joint capsule between teres minor and subscapularis is known as the axillary recess.
The shoulder joint is a muscle dependent joint as it lacks strong ligaments. The primary stabilizers of the shoulder include the biceps brachii on the anterior side of the arm, and tendons of the rotator cuff; which are fused to all sides of the capsule except the inferior margin. The tendon of the long head of the biceps brachii passes through the intertubercular groove on the humerus and inserts on the superior margin of the glenoid cavity to press the head of the humerus against the glenoid cavity.
The tendons of the rotator cuff and their respective muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) stabilize and fix the joint. The supraspinatus, infraspinatus and teres minor muscles aid in abduction and external rotation of the shoulder, while the subscapularis aids in internal rotation of the humerus.
Movements
- Flexion is by the Anterior Fibres of the Deltoid, Pectoralis Major and the Coracobrachialis.
- Extension is done by Latissimus Dorsi, Posterior Fibres of the Deltoid.
- Abduction is done by Deltoid and the Supraspinatus in the first 90 degree. From 90-180 degree it is the Trapezius and the Serratus Anterior.
- Adduction is done by Pectoralis Major, Lattisimus Dorsi, Teres Major and Subscapularis.
- Internal Rotation is done by Anterior Fibres of Deltoid, Teres Major, Subscapularis, Pectoralis Major and the Lattissimus Dorsi.
- External Rotation is done by Posterior Fibres of the Deltoid, Infraspinatus and the Teres Minor.
Images from this station
What are you asked at the Shoulder station?
The station runs to 12 questions over nine minutes. These are the questions as they are put to you; the model answers are in the question bank.
- Identify attachments 1-3
- Identify attachments 4-6
- Identify attachments 7 and 8
- Identify ligaments 9-11
- What muscle attaches over area 1
- Which muscles attach at areas 2 and 3?
- Which muscles attach at areas 4 and 5?
- Which rotator cuff muscles attach at 6, 7 and 8?
- What attaches at 9?
- Which muscle attaches at both point 10 and point 11?
- What structures attach at 12-14
- Identify ligament 15
How is the anatomy station marked in MRCS Part B?
An anatomy station is marked out of 20, and all 20 marks go to clinical knowledge and its application. No communication, technical-skill or professionalism marks are available in an anatomy bay, which is unusual: in most other stations more than half the marks sit outside your factual knowledge.
FAQ
What does the Shoulder station ask?
It opens with "Identify attachments 1-3" and runs to 12 questions over nine minutes. An anatomy station is marked out of 20, and all 20 marks go to clinical knowledge and its application. No communication, technical-skill or professionalism marks are available in an anatomy bay, which is unusual: in most other stations more than half the marks sit outside your factual knowledge.
How many anatomy stations are there in MRCS Part B?
Three of the seventeen examined stations are surgical anatomy, and two more are surgical pathology. Together they make up the five Anatomy and surgical pathology stations of the Applied Knowledge component.
How are the anatomy stations marked?
Each station is marked out of 20 and all 20 marks are awarded for clinical knowledge and its application. You also receive a separate global rating of pass, borderline or fail for the station.
Are the specimens real?
Yes. Anatomy bays use prosected cadaveric specimens, models and images. Candidates report being shown photographs of specimens as well as the specimens themselves, so practise on real dissection photography rather than diagrams alone.
What happens if I get an early question wrong?
The intercollegiate guidance says that if a wrong answer would affect your performance on later questions at the same station, the examiner gives you the correct answer before moving on. One mistake does not have to cost you the whole bay.
How many stations are in the MRCS Part B OSCE?
Seventeen examined stations of nine minutes each, with a minute to read the task before each one. Two preparation stations and at least one rest station bring the circuit to about twenty, and the exam takes about three and a half hours.
What is the pass mark for MRCS Part B?
There is no published pass mark. The cut score is set separately for Applied Knowledge and Applied Skills, for each circuit, by borderline regression. Published pass rates across the 2024/25 diets ranged from 51% to 66%.
Can I fail a station and still pass?
Yes. There is no rule about how many stations you may fail: the cut score applies to your total mark in each component, so a weak station costs the marks you lost on it and strong stations elsewhere can make them back. Applied Knowledge and Applied Skills are passed separately and must both be passed at the same sitting, so a strong anatomy performance cannot rescue a weak communication one.
Dr Richard Miller, MBChB FRCS
Station summaries are reviewed against the current intercollegiate MRCS syllabus and the published marking blueprint. Guidance changes between diets: check the royal colleges' own pages before relying on a date, a fee or a threshold.
Practise this station
The question bank carries the model answer to every question above, with the rest of the anatomy stations.
More anatomy stations