Advanced Posterior Compartment of the Arm Quiz

Q1. Which structures principally help separate the posterior compartment of the arm from the anterior compartment?

• Flexor and extensor retinacula
• Medial and lateral intermuscular septa and the humerus
• Radius, ulna, and interosseous membrane
• Clavicle and coracoid process

Q2. A fracture through the midshaft of the humerus places which nerve at particular risk because of its course in the radial groove?

• Median nerve
• Radial nerve
• Ulnar nerve
• Musculocutaneous nerve

Q3. Which artery may also be injured in a humeral shaft fracture involving the radial groove?

• Radial artery at the wrist
• Deep brachial artery
• Anterior interosseous artery
• Superficial palmar arch

Q4. A radial nerve injury in the radial groove may spare some elbow extension. What best explains this finding?

• Triceps brachii is supplied mainly by the median nerve
• The radial nerve does not supply triceps brachii
• Some motor branches to triceps arise proximal to the lesion
• Elbow extension is produced only by brachialis

Q5. Which deficit is especially characteristic of a radial nerve lesion at the humeral shaft?

• Loss of thumb opposition only
• Wrist drop
• Inability to pronate the forearm
• Loss of finger abduction only

Q6. Why can the long head of triceps brachii act at both the shoulder and elbow?

• It crosses both the glenohumeral and elbow joints
• It attaches directly to the radius
• It crosses the wrist as well as the elbow
• It originates and inserts entirely on the humerus

Q7. The long head of triceps passes between teres minor and teres major and helps divide the posterior shoulder region. Which space lies lateral to the long head and transmits the axillary nerve?

• Quadrangular space
• Triangular space
• Carpal tunnel
• Cubital tunnel

Q8. Which space is bounded partly by the long head of triceps and transmits the circumflex scapular artery?

• Triangular space
• Cubital fossa
• Quadrangular space
• Triangular interval

Q9. Through which posterior shoulder passage do the radial nerve and deep brachial artery enter the posterior arm?

• Triangular space
• Quadrangular space
• Triangular interval
• Carpal tunnel

Q10. Which description best summarizes the anatomical organization of the posterior compartment of the arm?

• It is supplied primarily by the median nerve and brachial artery
• It is an extensor compartment dominated by triceps brachii, supplied by the radial nerve and closely associated with the deep brachial artery
• It is a flexor compartment containing biceps brachii, brachialis, and coracobrachialis
• It contains the principal wrist and finger flexors of the upper limb