Free ST3 Orthopaedic Sample Questions

Boundaries
The antecubital fossa is a triangular space on the anterior aspect of the elbow bounded:

• Superiorly: By an imaginary line between the medial and lateral condyles
• Medially: By the lateral border of pronator teres
• Laterally: By the medial border of brachioradialis
• Floor: Brachialis and supinator muscles
• Roof: Fascia and skin

Contents
From lateral to medial the contents can be remembered by ‘TAN’:

• Tendon of biceps
• Brachial artery
• Median nerve
• (The cephalic, basilic and median cubital veins are considered to be superficial to the fossa).

Alternative Diagram
Further Info

The radial nerve is a branch of the posterior cord of the brachial plexus. It leaves the axilla though the triangular interval with the profunda brachii artery in the spiral groove of the humerus lying in the posterior compartment of the arm.
It pierces the lateral intermuscular septum to leave the posterior compartment and enter the cubital fossa at the lateral epicondyle. Here it divides into the superficial radial nerve (sensory) and the posterior interosseous nerve (motor).

Superficial Radial Nerve
The superficial radial nerve runs on the lateral side of the radial artery beneath brachioradialis in the forearm. Its terminal branches pass superficial to the tendons of the anatomical snuff box to supply the dorsum of the hand.

Posterior Interosseous Nerve (PIN)
At its origin in the cubital fossa the PIN pierces supinator 3cm distal to the head of the radius and runs in the extensor compartment of the forearm beneath the interosseous membrane to the wrist. It supplies supinator and all the forearm extensors.

Sensory: skin over anatomical snuffbox (reliably supplied by superficial radial)
Motor: wrist extension (PIN - extensors of forearm)

The radial nerve proper gives off branches to supply triceps, anconeus, brachioradialis and extensor carpi radialis longus before dividing.
It also gives off thee sensory, cutaneous branches (posterior cutaneous nerves of arm and forearm and lateral cutaneous nerve of the arm) to supply the skin of the arm and forearm.

This question tests your knowledge of open fracture management, BOAST guidelines and appreciation of the high energy nature of the injury.
Key facts to mention are that this is an emergent case that is potentially limb threatening so should be treated with diligence, expedience and contacting other specialties and seniors.

Example Answer:
I would assess this gentleman using ATLS principles. This is a high energy injury and I would be concerned about other injuries and vascular damage leading to haemodynamic instability.

Although it should be classified at debridement in theatre this is likely a Gustillo-Anderson III C injury and I would manage the open injury based on the BOA/BAPRAS BOAST 4 guidelines.

After ensuring the patient is haemodynamically stable my initial management would include assessment of neurovascualr status distal to the injury. Specifically I would ensure accurate documentation of pulse, CRT and median, ulna and radial nerve examination.

Due to the potential vascular injury I would contact the vascular surgeons, on call anaesthetist and theatres to ensure there is space to take the patient to theatre for vascular repair if required.

I would give IV antibiotics and ensure the patient's tetanus status is up to date. I would handle the wound only to remove gross contamination, photograph the wound and then make early contact with plastic surgeons to formulate a plan for management of the soft tissues.

I would request an X-Ray of the elbow, forearm and wrist, provide the patient with analgesia and work the patient up for theatre.”