Podcast
Questions and Answers
A patient presents with an inability to abduct their arm beyond 90 degrees and reports sensory loss over the lateral aspect of their upper arm. Which nerve is MOST likely injured?
A patient presents with an inability to abduct their arm beyond 90 degrees and reports sensory loss over the lateral aspect of their upper arm. Which nerve is MOST likely injured?
- Radial nerve
- Suprascapular nerve
- Axillary nerve (correct)
- Musculocutaneous nerve
A surgeon inadvertently damages a nerve during a procedure in the axilla. Post-operatively, the patient exhibits weakness in forearm supination and elbow flexion, along with sensory loss along the lateral forearm. Which nerve was MOST likely damaged?
A surgeon inadvertently damages a nerve during a procedure in the axilla. Post-operatively, the patient exhibits weakness in forearm supination and elbow flexion, along with sensory loss along the lateral forearm. Which nerve was MOST likely damaged?
- Median nerve
- Musculocutaneous nerve (correct)
- Axillary nerve
- Radial nerve
Following a humeral fracture, a patient is unable to extend their wrist or fingers. Elbow extension is intact. Which specific branch of the radial nerve is MOST likely affected?
Following a humeral fracture, a patient is unable to extend their wrist or fingers. Elbow extension is intact. Which specific branch of the radial nerve is MOST likely affected?
- The radial nerve proximal to the spiral groove
- Superficial branch of the radial nerve
- Deep branch of the radial nerve (posterior interosseous nerve) (correct)
- The radial nerve at the level of the elbow
A patient presents with thenar muscle atrophy and an inability to oppose the thumb. Sensory examination reveals loss of sensation in the thumb, index, and middle fingers. Where is the MOST likely location of the nerve injury causing these deficits?
A patient presents with thenar muscle atrophy and an inability to oppose the thumb. Sensory examination reveals loss of sensation in the thumb, index, and middle fingers. Where is the MOST likely location of the nerve injury causing these deficits?
A patient demonstrates weakness in finger abduction and adduction, and exhibits a positive Froment's sign. Sensory loss is noted on the palmar and dorsal aspects of the little finger and ulnar half of the ring finger. Which nerve is MOST likely injured?
A patient demonstrates weakness in finger abduction and adduction, and exhibits a positive Froment's sign. Sensory loss is noted on the palmar and dorsal aspects of the little finger and ulnar half of the ring finger. Which nerve is MOST likely injured?
A patient who sustained a deep laceration to the anterior forearm reports difficulty making a tight fist. Examination reveals weakness in flexion of the index and middle fingers, but flexion of the ring and little fingers is intact. Which nerve is MOST likely injured?
A patient who sustained a deep laceration to the anterior forearm reports difficulty making a tight fist. Examination reveals weakness in flexion of the index and middle fingers, but flexion of the ring and little fingers is intact. Which nerve is MOST likely injured?
Following a traumatic injury, a patient exhibits a 'waiter's tip' deformity. Which nerve roots are MOST likely involved in this injury pattern?
Following a traumatic injury, a patient exhibits a 'waiter's tip' deformity. Which nerve roots are MOST likely involved in this injury pattern?
A patient presents with a 'claw hand' deformity after a motorcycle accident. The patient has intact wrist flexion, but experiences sensory loss over the medial aspect of the hand. Which nerve roots are MOST likely affected?
A patient presents with a 'claw hand' deformity after a motorcycle accident. The patient has intact wrist flexion, but experiences sensory loss over the medial aspect of the hand. Which nerve roots are MOST likely affected?
A patient is diagnosed with carpal tunnel syndrome. Which of the following clinical findings would be LEAST likely to be associated with this condition?
A patient is diagnosed with carpal tunnel syndrome. Which of the following clinical findings would be LEAST likely to be associated with this condition?
A patient has wrist drop, intact elbow extension, and an inability to abduct the thumb in the plane of the palm. Sensation is reduced on the dorsolateral aspect of the hand. Where is the MOST likely location of the nerve lesion?
A patient has wrist drop, intact elbow extension, and an inability to abduct the thumb in the plane of the palm. Sensation is reduced on the dorsolateral aspect of the hand. Where is the MOST likely location of the nerve lesion?
Flashcards
Erb-Duchenne palsy
Erb-Duchenne palsy
Affects C5-C6 nerve roots, causing adduction, internal rotation, and extension of the arm.
Klumpke's palsy
Klumpke's palsy
Involves C8-T1 nerve roots, affecting intrinsic hand muscles and causing claw hand deformity.
Axillary nerve injury
Axillary nerve injury
Results in weakness in shoulder abduction (deltoid) and external rotation (teres minor); sensory loss over the lateral aspect of the upper arm.
Musculocutaneous nerve injury
Musculocutaneous nerve injury
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Radial nerve injury
Radial nerve injury
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High median nerve injury
High median nerve injury
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Carpal tunnel syndrome
Carpal tunnel syndrome
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Ulnar nerve injury
Ulnar nerve injury
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Claw hand deformity
Claw hand deformity
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Froment's sign
Froment's sign
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Study Notes
- Nerve lesions in the upper limb can result in specific motor and sensory deficits, based on the nerve affected
Brachial Plexus Injuries
- Brachial plexus injuries arise from trauma, compression, or inflammation, impacting multiple nerves and muscle groups
- Upper brachial plexus injuries (Erb-Duchenne palsy) typically involve C5-C6 nerve roots, causing a "waiter's tip" deformity
- Waiter's tip deformity involves adduction, internal rotation, and extension of the arm
- Lower brachial plexus injuries (Klumpke's palsy) involve C8-T1 nerve roots, affecting intrinsic hand muscles and resulting in claw hand deformity
Axillary Nerve Injury
- The axillary nerve originates from the posterior cord of the brachial plexus (C5-C6)
- It supplies innervation to the deltoid and teres minor muscles
- Axillary nerve injury often results from shoulder dislocation or fracture of the surgical neck of the humerus
- Damage to the axillary nerve leads to weakness in shoulder abduction (primarily deltoid) and external rotation (teres minor)
- Sensory loss might occur over the lateral aspect of the upper arm
Musculocutaneous Nerve Injury
- The musculocutaneous nerve stems from the lateral cord of the brachial plexus (C5-C7)
- It provides innervation to the biceps brachii, brachialis, and coracobrachialis muscles
- Musculocutaneous nerve injury is relatively rare, but can occur due to trauma or iatrogenic causes
- Musculocutaneous nerve damage causes weakness in elbow flexion and supination
- Sensory loss occurs along the lateral side of the forearm
Radial Nerve Injury
- The radial nerve, the largest branch of the brachial plexus, arises from the posterior cord (C5-T1)
- It provides innervation to the triceps brachii, brachioradialis, supinator, and wrist/finger extensor muscles
- Radial nerve injury can occur due to humeral fractures, compression (Saturday night palsy), or repetitive movements
- High radial nerve injuries (above the elbow) result in weakness or paralysis of elbow extension, wrist extension (wrist drop), finger extension, and thumb abduction
- Sensory loss occurs over the posterior aspect of the arm and forearm, as well as the dorsolateral hand
- Radial nerve injury can induce weakness in forearm supination
- Injury to the deep branch of the radial nerve (posterior interosseous nerve) spares elbow extension
- Wrist drop and finger extension weakness are still the results of injury to the deep branch of the radial nerve
Median Nerve Injury
- The median nerve arises from the medial and lateral cords of the brachial plexus (C6-T1)
- It provides innervation to forearm flexors (excluding flexor carpi ulnaris) and thenar muscles of the hand
- Median nerve injury can occur at the elbow or wrist (carpal tunnel syndrome)
- High median nerve injuries (at the elbow) result in weakness of forearm pronation, wrist flexion, finger flexion (digits 1-3), and thumb opposition
- Carpal tunnel syndrome involves compression of the median nerve at the wrist
- Numbness, tingling, and pain in the thumb, index, middle, and radial half of the ring finger are the results of carpal tunnel syndrome
- Carpal tunnel syndrome can cause weakness of the thenar muscles, resulting in ape hand deformity
- Sensory loss occurs over the palmar aspect of the thumb, index, middle, and radial half of the ring finger
Ulnar Nerve Injury
- The ulnar nerve arises from the medial cord of the brachial plexus (C8-T1)
- It innervates the flexor carpi ulnaris and the intrinsic hand muscles (except the thenar muscles and two lateral lumbricals)
- Ulnar nerve injury can occur at the elbow (cubital tunnel syndrome) or wrist (Guyon's canal)
- Ulnar nerve lesions result in weakness of wrist flexion and adduction, finger abduction and adduction, and thumb adduction
- Injury to the ulnar nerve causes a claw hand deformity
- Claw hand deformity involves hyperextension of the MCP joints and flexion of the IP joints of the ring and little fingers
- Sensory loss occurs over the palmar and dorsal aspects of the little finger and ulnar half of the ring finger
- Froment's sign is positive in ulnar nerve palsy due to weakness of adductor pollicis
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