Nerve Innervation and Muscle Function Quiz

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Questions and Answers

Which nerve is primarily responsible for the extension of all joints in the arm?

Median nerve

Musculocutaneous nerve

Ulnar nerve

Radial nerve (correct)

Which nerve is mainly responsible for sensory innervation of the pinky side of the hand?

Axillary nerve

Median nerve

Radial nerve

Ulnar nerve (correct)

What is the role of the median nerve in the hand?

It extends the proximal fingers.

It supports wrist function on the thumb side. (correct)

It innervates the pinky side of the hand.

It is responsible for cutaneous innervation of the elbow.

Which cutaneous nerve branch is associated with the lateral innervation of the forearm?

Lateral cutaneous nerve of forearm Signup and view all the answers

The trigeminal nerve is primarily responsible for which type of innervation?

Sensory innervation of the face Signup and view all the answers

Which nerve innervates the flexor digitorum profundus for the second and third digits?

Median nerve Signup and view all the answers

At which joints is finger flexion best tested?

Distal interphalangeal joints Signup and view all the answers

Which muscle is primarily responsible for flexion at the distal interphalangeal joint?

Flexor digitorum profundus Signup and view all the answers

Which nerve innervates the flexor digiti minimi for the fifth digit?

Ulnar nerve Signup and view all the answers

Which muscles contribute to flexion at the proximal interphalangeal joint?

Flexor digitorum superficialis and profundus Signup and view all the answers

Which muscles are responsible for extension at the distal interphalangeal joint?

Extensor digitorum and extensor indicis Signup and view all the answers

What mnemonic is often used to remember the nerves acting on the thumb?

RUM (Radial, Ulnar, Median) Signup and view all the answers

Which muscle does NOT contribute to finger flexion at the distal interphalangeal joint?

Extensor digitorum Signup and view all the answers

Which condition is NOT included in the differential diagnosis for C8 and T1 radiculopathy?

Ulnar neuropathy Signup and view all the answers

What is a characteristic symptom of entrapment in the cubital canal at the elbow?

Weakness of finger adduction Signup and view all the answers

Which symptom is associated with femoral neuropathy?

Loss of the patellar reflex Signup and view all the answers

What result can occur from prolonged leaning forward while cycling?

Compression of the ulnar nerve in Guyon’s canal Signup and view all the answers

What combination of conditions can lead to a 'simian hand' appearance?

Combination of chronic median and ulnar nerve lesions Signup and view all the answers

Which neurological deficit is NOT associated with femoral neuropathy?

Sensory loss in the posterior thigh Signup and view all the answers

What is a common cause of sciatic neuropathy?

Posterior hip dislocation Signup and view all the answers

Which feature is typically NOT associated with L3 or L4 radiculopathy?

Weakness of knee extension Signup and view all the answers

What is the likely cause of the left brachial plexus upper trunk injury in the patient?

Traction of the left shoulder during delivery Signup and view all the answers

Which muscle groups are affected by the left brachial plexus upper trunk injury?

C5 and C6 innervated muscles Signup and view all the answers

At what age was the patient able to lift her arm off the table?

7 weeks Signup and view all the answers

What is the condition referred to as Erb–Duchenne palsy associated with?

C5 and C6 nerve root injury Signup and view all the answers

What was the strength of the left biceps when the patient was pulled to a seated position at 4 months?

4+/5 Signup and view all the answers

Which symptoms indicate the possibility of a lesion in the upper medial arm of the 38-year-old man?

Weakness in thumb opposition Signup and view all the answers

Which of the following was not a symptom displayed by the patient with Erb–Duchenne palsy?

Loss of sensation in the arm Signup and view all the answers

What does the continued improvement after initiation of physical therapy suggest?

Reinforcement of nerve connections Signup and view all the answers

What action is primarily associated with the posterior tibial nerve?

Foot plantar flexion and inversion Signup and view all the answers

Which nerve is primarily involved in foot eversion?

Superficial peroneal nerve Signup and view all the answers

What is a common cause of upper trunk injury in the brachial plexus?

Traction during childbirth Signup and view all the answers

Which condition mainly causes common mononeuropathies and plexus syndromes according to the content?

Mechanical factors or diabetes Signup and view all the answers

Which of the following actions is performed by the deep peroneal nerve?

Foot dorsiflexion and toe extension Signup and view all the answers

What is the most significant clinical focus related to neuropathy in the text?

Clinical localization of common neuropathies Signup and view all the answers

What is an example of trauma that causes nerve injury mentioned in the content?

Motorcycle accidents Signup and view all the answers

In the context of peripheral nerves, what key aspect should be covered for sensory loss?

Regions of sensory loss Signup and view all the answers

Study Notes

Sensory Innervation

The radial nerve is responsible for extending all the joints in the arm and proximal fingers
The median nerve controls the thumb side of the hand and wrist
The ulnar nerve controls the pinky side of the hand and wrist

Muscle Flexion & Extension

The flexor digitorum profundus is responsible for flexion at the distal interphalangeal joint
The flexor digitorum superficialis and the flexor digiti minimi muscles contribute to flexion of the proximal interphalangeal joint
Muscles contributing to extension of the distal interphalangeal joint are the extensor digitorum, extensor indicis, and extensor digiti minimi

Thumb Muscles

Muscles contributing to movement of the thumb are innervated by the following nerves: radial, ulnar, median
The nerves are easily remembered by the mnemonic RUM, which means radial, ulnar, median
The superficial peroneal nerve controls eversion of the foot
The deep peroneal nerve controls dorsiflexion of the foot and toe extension
The tibial nerve controls plantar flexion, inversion, and toe flexion

Common Plexus and Nerve Syndromes

The brachial plexus is located in the neck and shoulder and is often affected by trauma
Brachial plexus injuries can cause upper trunk injury (Erb-Duchenne palsy)
The symptoms of Erb-Duchenne palsy are weakness of external rotation, abduction and elbow flexion of the arm, as well as decreased tone and absent biceps reflex
The ulnar nerve can be compressed in the cubital canal at the elbow, which can be treated by surgically translocating the nerve to the flexor side
Ulnar nerve entrapment in the hand can occur when it passes over the hamate bone, resulting in weakness in finger adduction and abduction
Chronic median and ulnar nerve lesions result in thenar and hypothenar atrophy
The femoral nerve can be injured by pelvic surgery, retroperitoneal hematoma, or pelvic mass
Sciatic neuropathy can be caused by posterior hip dislocation, acetabular fracture, or intramuscular injection in the buttocks

Common Plexus and Nerve Syndromes (Continued)

Femoral neuropathy can be caused by compression of the femoral nerve by a retroperitoneal hematoma or pelvic mass
- weakness of thigh flexion and knee extension, loss of the patellar reflex, and sensory loss in the anterior thigh
Sciatic neuropathy can be caused by posterior hip dislocation, acetabular fracture, or intramuscular injection in the buttocks
- weakness of all foot and ankle muscles and of knee flexion, loss of the Achilles tendon reflex, and sensory loss in the foot and lateral leg below the knee

Clinical Cases

Case 9.1: A patient presents with weakness in left arm external rotation, abduction, and elbow flexion, with decreased tone and absent biceps reflex
- The patient was diagnosed with Erb-Duchenne palsy, affecting C5 and C6 innervated muscles, caused by left shoulder traction at birth
Case 9.2: A patient presents with right apical lung cancer extending into the region of the brachial plexus
- T1-weighted coronal MRI scan of the chest reveals a tumor, causing compression of the brachial plexus
- Symptomology in such a case may include Horner’s syndrome, sensory changes in the T1 dermatome of the upper medial arm or involvement of hand muscles innervated by the median nerve
Case 9.3: A patient presents with hand weakness and numbness following a blow to the medial arm
- The patient had decreased pinprick and light touch sense along the lateral surface of the hand, and their thumb opposition, second and third finger flexors, and wrist flexion and abduction were weakened
- The patient experienced compression of the median nerve and ulnar nerve resulting from damage to the brachial plexus due to the blow to the medial arm

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Description

Test your knowledge on the sensory innervation and muscle functions related to the radial, median, and ulnar nerves. This quiz covers key muscles involved in flexion and extension, as well as the mnemonic for remembering the nerves associated with thumb movement. Perfect for anatomy students or those interested in human physiology.