Revision questions Flashcards
Methotrexate is used for the treatment of Rheumatoid Arthritis. Which of the following is true of its pharmacology?
a. It activates the immune system to inhibit the production of immune mediators
b. It is the primary treatment for Gouty Arthritis
c. It inhibits Xanthine Oxidase
d. It increases Adenosine levels
e. It is co-administered with IL-6 for greater effect.
d
Which drug can be coadministered with methotrexate to treat rheumatoid arthritis?
A. Allopurinol
B. Hydroxychloroquine
C. Probenecid
D. Colchicine
E. Sulfinpyrazone
B. csDMARD
- In an injury to the upper roots of the brachial plexus, the resulting weakness will significantly affect:
a) Elevation of the scapula
b) Extension of the elbow
c) Adduction of the thumb
d) Abduction of the glenohumeral joint
e) Extension at the interphalangeal joints
Injury to the upper roots of the brachial plexus (C5 and C6) usually results from an excessive increase in angle between the neck and the shoulder; this may happen when someone is thrown off from a motorcycle or a horse, landing on the shoulder in a way that separates the shoulder and neck or when excessive stretching of the neck occurs during delivery. As a result of the injury, paralysis (Erb’s Palsy) is observed mainly in the muscles of the shoulder and arm supplied by the spinal nerves C5 and C6.
Some of these muscles include the deltoid, supplied by the axillary nerve; biceps brachii and brachialis, supplied by the musculocutaneous nerve; and rotator cuff muscles, supplied by various nerves of the brachial plexus. Considering the action of the affected muscles, Erb’s palsy is likely to most significantly affect flexion of the forearm at the elbow joint, and abduction and rotation of the glenohumeral joint. As such, the usual clinical appearance of a patient suffering from Erb’s palsy is an upper limb with an adducted shoulder, medially rotated arm and extended elbow.
- Supination of the forearm:
a) Involves the humeroulnar joint
b) Is facilitated by both the radial and musculocutaneous nerves
c) Requires the forearm to be extended
d) Is primarily caused by the supinator
e) Is impaired by injury to the lower roots of the brachial plexus
(b) The supination of the forearm is facilitated by two muscles: biceps brachii, innervated by the musculocutaneous nerve, and supinator, which is a deep muscle innervated by the radial nerve.
- It is possible to locate and identify the cephalic vein in the following places except:
a) Lateral end of the dorsal venous arch
b) Anatomical snuff box
c) Medial aspect of the arm
d) Deltopectoral groove
e) In front of the elbow
(C) Medial Aspect of the Arm
The cephalic vein is one of the superficial veins of the upper limb, which means that it is in fact visible under the skin.
It originates from the lateral aspect of the dorsal venous arch (or network), running through the anatomical snuffbox and superiorly along the lateral aspect of the forearm. Anterior to the elbow, the cephalic vein communicates with the median cubital vein, which passes obliquely across the anterior aspect of elbow in the cubital fossa and subsequently joins the basilic vein. The basilic vein is also another superficial vein present in the upper limb but unlike the cephalic vein, runs primarily on the medial aspect of the upper limb.
The cephalic vein subsequently continues along the lateral aspect of the arm, superiorly towards the shoulder. It passes between the deltoid and the pectoralis major muscles along the deltopectoral groove and enters the clavipectoral triangle to join the terminal part of the axillary vein.
In an obstruction to the 2nd part of the axillary artery, collateral circulation (to bypass the obstruction) to the arm may be established between the:
a) First and third parts of the axillary artery
b) Lateral thoracic and subscapular arteries
c) Subclavian artery and branches of the third part of the axillary artery
d) Scapular anastomosis and the brachial artery
e) Subclavian artery and the brachial artery
C
The components not significantly involved in generating the biceps tendon reflex is:
a) Muscle spindles in the biceps tendon
b) Musculocutaneous nerve
c) Selected dorsal root ganglia
d) Axons of selected motor neurons in the spinal cord
e) Sarcoplasmic reticulum in the biceps muscle fibres
A. In a typical tendon reflex such as the biceps tendon reflex, the first step involves inducing a short lengthening of the muscle by lightly tapping on the tendon. The short lengthening of the muscle stimulates the muscle spindles in the BELLY of the muscle to send signals through the afferent sensory neurons, which have their cell bodies contained within the dorsal root ganglion. The signal is passed along the afferents into the dorsal horn of the spinal cord. Thereafter, the afferent sensory neurons then synapse with the efferent motor neurons, and the signal continues to travel along the axons of the motor neurons out through the ventral horn of the spinal cord. The signal eventually returns back to the muscle fibres by way of the relevant peripheral nerve (in the case of the biceps tendon reflex, the musculocutaneous nerve), triggering the contraction of the muscle.
- Injury to the lateral cord of brachial plexus is most likely to cause:
a) Weakness of abduction
b) Weakness of supination
c) Wrist drop
d) Numbness of little finger
e) Difficulty in doing push-ups
(b) Weakness of supination is to be expected because the biceps brachii, a strong supinator of the forearm, is innervated by the musculocutaneous nerve, which is a branch of the lateral cord of the brachial plexus. Lesion of the lateral cord will effectively result in denervation of the biceps brachii muscle and cause weakness of supination, especially so when the elbow joint is flexed. *The supinator is however not affected because it is supplied by the radial nerve, which is a branch of the posterior cord.
- Abduction of the arm to the vertical position is not caused by:
a) Levator scapulae
b) Trapezius
c) Deltoid
d) Supraspinatus
e) Serratus anterior
- (A) Levator scapulae
Abduction of the arm to the vertical position can be split in three segments:
(a) Initial abduction of the arm (15°): Supraspinatus muscle carries out the initial abduction of the arm. Note that patients with a paralyzed supraspinatus tend to passively carry out the initial abduction by tilting their trunk to abduct their arms before the deltoid takes over. This is something noteworthy to keep at the back of the mind.
(b) Abduction of the arm up to 120°: The deltoid muscle takes over as the primary abductor of the arm after the initial 15°, assisted by the supraspinatus. The scapulo-humeral mechanism comes into play: for every 3° of abduction of the arm, 2° abduction occurs in the glenohumeral joint while the other degree occurs by rotation of the scapula. The rotation of the scapula lateral to the spinal column is carried out by the descending fibres of the trapezius and the serratus anterior muscle.
(c) Abduction of the arm up to 180° from 120°: At about 120° of abduction, the greater tubercle of the humerus comes into contact with the lateral edge of the acromion. Further abduction of the arm is carried out purely by the rotation of the scapula up till the vertical position.
The levator scapulae elevates the scapula and does not participate in the overhead abduction of the arm.
- Axillary lymph nodes are least likely to receive lymph from:
a) Side of the neck
b) Breast
c) Epigastrium
d) Scapula region
e) Hand
(A) Side of the neck
The axillary lymph nodes can be divided into five groups: humeral (lateral) lymph nodes, central lymph nodes, apical lymph nodes, subscapular (posterior) lymph nodes and pectoral (anterior) lymph nodes. Lymph is then directed towards the clavicular lymph nodes. The subclavian trunk then fuses with the jugular and bronchomediastinal trunk to form the right lymphatic duct. On the left, the subclavian trunk commonly joins the thoracic duct.
(a) Most of the superficial tissues of the neck are drained by lymphatic vessels that enter the superficial cervical lymph nodes. Lymph then continues to drain into the inferior deep cervical lymph nodes, which fuse to form the jugular lymphatic trunk. On the right side, jugular lymphatic trunk continues to join the right lymphatic duct while on the left, the trunk continues into the thoracic duct.
(b) The pectoral (anterior) axillary lymph nodes receive lymph from most of the breast, especially the superolateral aspect of the breast and the subareolar plexus. Lymph from the medial aspect of the breast drains towards the parasternal lymph nodes.
(c) Lymph from regions of the anterolateral abdominal wall superior to the transumbilical plane drain mainly to the axillary lymph nodes, though a few of the superficial lymphatic vessels may drain into the parasternal lymph nodes. *Lymph from the regions inferior to the transumbilical plane drain mainly to the superficial inguinal lymph nodes.
(d) The subscapular (posterior) nodes receive lymph from the posterior aspect of the thoracic wall and scapular region. These nodes lie along the posterior axillary fold and subscapular blood vessels.
(e) Lymph from the hand, in fact most of the upper limb, primarily drains towards the humeral (lateral) lymph nodes. These nodes receive nearly all the lymph from the upper limb, except that carried by the lymphatic vessels accompanying the cephalic vein, which primarily drains towards the apical axillary and infraclavicular nodes.
Suprascapular nerve supplies the:
a) Subscapularis
b) Teres minor
c) Rhomboid Minor
d) Infraspinatus
e) Latissimus dorsi
D
In a supracondylar fracture, which of the following structures is most likely to be injured:
a) Radial nerve
b) Median nerve
c) Ulnar nerve
d) Circumflex artery
e) Axillary nerve
(B) Median Nerve. A supracondylar fracture usually occurs from a fall on an outstretched hand with the elbow extended. The pull of the triceps brachii muscle on the distal fragment causes the posterior dislocation of the distal fragment. As a result, the proximal humeral fragment usually overrides the distal fragment.
The danger of a supracondylar fracture lies in the entrapment of the brachial artery and the median nerve (sometimes the radial nerve may be entrapped as well).
Entrapment of the brachial artery can potentially cut off blood supply to the muscles of the forearm (and hand) and if the entrapment persists for more than a few hours, permanent muscle damage (and even death) might likely occur. Systemic complications can also arise from hyperkalemia and release of myoglobin.
On the other hand, entrapment of the median nerve can cause loss of sensation over the palmar surface of radial 3½ digits, and loss of function of some of the short muscles of the hand (L.O.A.F.s) and the muscles in the flexor compartment of the forearm. So, careful management is required if a supracondylar fracture is suspected.
In the upper extremity, a pulse may be palpated at all of the following locations except:
a) In the arm against the humerus just distal to the pectoralis minor
b) In the cubital fossa medial to the biceps brachii tendon
c) In the wrist at the radial side of the tendon of the flexor carpi radialis muscle
d) At the wrist at the radial side of the pisiform bone
e) In the hand between the tendons of the extensor pollicis brevis and abductor pollicis longus muscles
Which of the following statements describing the pectoralis minor muscle is correct:
a) It attaches to the acromion process of the scapula
b) It crosses anterior to the cords of the brachial plexus
c) It is an adductor and medial rotator of the humerus
d) It is innervated by the middle subscapular (thoracodorsal) nerve
e) It originates deep to the axillary artery
(B) It crosses anterior to the cords of the brachial plexus.
(a) The pectoralis minor muscle originates (proximal attachment) from the 3rd to 5th ribs near their costal cartilages, while the muscle inserts (distal attachment) at the medial border and superior surface of the coracoid process of the scapula.
(b) In fact, it crosses anterior to most of the neurovascular structures passing from the trunk into the upper limb, such as the brachial plexus, axillary artery and axillary vein. The neurovascular structures which run anterior to the pectoralis minor muscle are the thoraco-acromial artery and the cephalic vein (one of the superficial veins of the upper limb).
(c) It stabilizes the scapula by drawing it inferiorly and anteriorly against the thoracic wall. Note that the pectoralis minor muscle does not carry out adduction and medial rotation of the humerus because it is attached proximally to the ribs and distally to the scapula, and not the humerus.
(d) It is innervated by the medial pectoral nerve. The medial pectoral nerve also supplies the sternocostal part of the pectoralis major muscle. On the other hand, the thoracodorsal nerve innervates the latissimus dorsi muscle.
(e) It passes anterior to the axillary artery. In fact, the pectoralis minor muscle is used as a form of landmark to demarcate the first part of the axillary artery (proximal to the muscle), the second part (deep to the muscle), and the third part (distal to the muscle).
The ulnar nerve innervates which of the following muscles of the thumb:
a) Abductor pollicis brevis
b) Abductor pollicis longus
c) Deep head of the flexor pollicis brevis
d) Opponens pollicis
C
- Which of the following muscles originates from the medial epicondyle of the humerus:
a) Brachioradialis
b) Extensor carpi ulnaris
c) Flexor carpi radialis
d) Flexor pollicis longus
e) Supinator
C.
The muscle which originates from the medial epicondyle of the humerus is the flexor carpi radialis muscle. Here, the concept to keep in mind is that the medial epicondyle serves as a common flexor origin, where many of the flexors in the forearm originate from. This includes palmaris longus, the humeral head of flexor carpi ulnaris and the humeral head of pronator teres, other than FCR.
On the other hand, the lateral epicondyle serves as a common extensor origin, where many of the extensors in the forearm originate from. Some of the muscles include extensor carpi ulnaris, extensor digitorum, extensor digiti minimi and extensor carpi radialis brevis.
- All of the following statements concerning the veins of the cubital region are true except:
a) At the level of the midaxilla, the basilic vein is joined by the cephalic vein to form the axillary vein
b) The basilic vein runs along the medial aspect of the forearm
c) The cephalic vein originates on the radial side of the dorsum of the hand
d) The median cubital vein links the cephalic and basilic veins in the cubital fossa
e) The median cubital vein is separated from the brachial artery by the bicipital aponeurosis
The distal attachment (insertion) of the triceps brachii muscle is:
a) Coronoid process of the ulna
b) Olencranon process of the ulna
c) Styloid process of the ulna
d) Radial notch of ulnar
e) Ulnar tuberosity
(B) Olecranon process of the ulna
The triceps brachii muscle is the main extensor of the elbow joint, innervated by the radial nerve (one of the terminal branches of the posterior cord of the brachial plexus) and supplied by the profunda brachii artery. Its name is derived as such because it has three heads:
(a) Long head of the triceps: Originates from the infraglenoid tubercle of the scapula
(b) Medial head of the triceps: Originates from the posterior surface of the humerus, inferior to the radial groove
(c) Lateral head of the triceps: Originates also from the posterior surface of the humerus, superior to the radial groove
The three heads share a common distal attachment: the olecranon process of the ulna and the fascia of the forearm.
- Most of the muscles that act on the shoulder girdle and upper limb joints are supplied by branches of the brachial plexus. Which of the following is not:
a) Trapezius
b) Teres minor
c) Latissimus dorsi
d) Rhomboid major
e) Levator scapulae
A
- Increasing muscle mass and tone is the aim of many people who work out at the gym. This is done by contracting the muscle against resistance. If you want to increase the muscle mass of the latissimus dorsi muscle, which of the following actions would you be most likely to perform:
a) Depression of the scapula
b) Abduction of the arm
c) Extension of the arm
d) Flexion of the arm
e) Lateral rotation of the arm
- (C) Extension of the arm
The latissimus dorsi muscle originates from the inferior 3 or 4 ribs, the inferior angle of the scapula and the spinous processes of T7 to T12 vertebra and the posterior 1/3 of the iliac crest. It attaches onto the floor of the intertubercular groove of the humerus. Take note that the fibres wind medial to the humerus towards its insertion. With that in mind, one can imagine as the muscle contracts, it will extend, adduct and internally rotate the arm. These are the larger motions carried out by the latissimus dorsi muscle.
*Considering that it also originates from the inferior angle of the scapula, it can also, to a lesser degree, depress the scapula. However, if one wants to work the muscle, a larger motion like extension of the arm would definitely be preferable.
The true statement about the posterior compartment of the arm is:
a) It receives its motor supply from the median nerve
b) It contains the profunda brachii artery and radial nerve
c) It contains a single elbow flexor
d) Its major artery is the brachial artery
e) It contains the ulnar nerve in its distal part
B
Label A to E
A: Greater tubercle of the humerus
B: Head of the humerus
C: Coracoid process
D: Acromion of the scapula
E: Lesser tubercle of the humerus
A structure found in the deltopectoral groove is the:
a) Cephalic vein
b) Basilic vein
c) Brachial vein
d) Radial vein
e) Musculocutaneous nerve
A. It passes between the deltoid and the pectoralis major muscles along the deltopectoral groove and enters the clavipectoral triangle to join the terminal part of the axillary vein.
In the cubital fossa, the median cubital vein is frequently used for venipuncture. This vein is separated from the underlying neurovascular structures by the:
a) Investing fascia of the brachialis muscle
b) Crural fascia
c) Bicipital aponeurosis
d) Anconeus muscle
e) Tendon of the biceps brachialis muscle
(C) Bicipital aponeurosis.
A 52-year-old man was brought to the emergency room after being found in the park where he had apparently lain overnight after a fall. He complained of severe pain in the left arm. Physical examination suggested a broken humerus, which was confirmed radiologically. The patient was able to extend the forearm at the elbow, but supination appeared somewhat weak; the hand grasp was weak when compared with the uninjured arm. Neurologic examination revealed an inability to extend the wrist (“wrist drop”). Since these findings pointing to apparent nerve damage, the patient was scheduled for a surgical reduction of the fracture.
The observations that extension at the elbow appeared normal, but supination of the forearm weak, warrants localization of the injured nerve to the:
a) Posterior division of the brachial plexus
b) Posterior cord of the brachial plexus in the axilla
c) Radial nerve at the distal third of the humerus
d) Radial nerve in the vicinity of the head of the radius
e) Radial nerve in the mid-forearm
C
- The thumb action that is totally affected by radial nerve trauma is:
a) Abduction
b) Adduction
c) Extension
d) Flexion
e) Opposition
c) Extension
Explanation
The radial nerve is responsible for innervating the extensor muscles of the forearm, which are crucial for extending the wrist and fingers, including the thumb. When the radial nerve is injured, it leads to a condition known as “wrist drop,” where the individual cannot extend the wrist or fingers effectively. This includes the inability to extend the thumb, as the extensor pollicis longus and extensor pollicis brevis muscles, which facilitate thumb extension, are innervated by the radial nerve.
Other thumb actions, such as abduction (a), adduction (b), flexion (d), and opposition (e), are primarily controlled by other nerves, including the median and ulnar nerves, and therefore are not completely affected by radial nerve trauma.
Which of the following muscles is innervated by the ulnar nerve:
a) Flexor pollicis longus
b) Extensor pollicis longus
c) Abductor pollicis brevis
d) Adductor pollicis
e) Opponens pollicis
(D) Adductor Pollicis
Recall that all the muscles of the anterior compartment of the forearm are innervated by the median nerve except the ulnar half of the flexor digitorum profundus and flexor carpi ulnaris while all the short intrinsic muscles of the hand are supplied by branches of the ulnar nerve except the L.O.A.F.s muscles.
*L.O.A.F.s is the mnemonic for 1st and 2nd lumbricals (L), opponens pollicis (O), abductor pollicis brevis (A), and the superficial head of the flexor pollicis brevis (F.s).
Hence, the only muscle innervated by the ulnar nerve amongst the options is the adductor pollicis.
- If you slide a piece of paper between a patient’s fingers, then ask the patient to hold onto the paper when you try to pull it from the fingers, and the patient is unable to perform this action, which nerve is suspected to be non-functional:
a) Radial nerve
b) Median recurrent nerve
c) Ulnar nerve
d) Deep radial nerve
e) Superficial radial nerve
(C) Ulnar nerve
The adduction of the fingers is mediated by the palmar interossei muscles (P.A.D), and these muscles are innervated by the ulnar nerve. Recall that all short intrinsic muscles of the hand are innervated by the ulnar nerve other than the L.O.A.F.s muscles. If the patient is unable to perform this action, then the suspicion would be that the integrity of the ulnar nerve has been compromised, resulting in paralysis of the palmar interossei muscles.
Which of the following muscles does not rotate the arm medially (or internally):
a) Subscapularis
b) Supraspinatus
c) Latissimus dorsi
d) Pectoralis major
e) Anterior fibres of deltoid
A
- Which of the following muscles is a lateral rotator of the arm:
a) Infraspinatus
b) Subscapularis
c) Latissimus dorsi
d) Teres major
e) Anterior fibres of deltoid
A
Which of these muscles of the forearm has a double innervation:
a) Flexor digitorum profundus
b) Flexor digitorum superficialis
c) Pronator teres
d) Flexor pollicis longus
e) Pronator quadratus
(A) Flexor Digitorum Profundus
The flexor digitorum profundus muscle receives dual nerve supply from both the median nerve and the ulnar nerve. The lateral half of the flexor digitorum profundus is innervated by the median nerve, while the medial half of the muscle is innervated by the ulnar nerve. Therefore, palsy of either nerve will present with different deformities.
*Short notes on the other muscles:
* Flexor pollicis longus, flexor digitorum profundus, pronator teres and pronator quadratus are all innervated by the median nerve
- The muscle that forms the bulk of the anterior axillary fold is the:
a) Latissimus dorsi
b) Pectoralis major
c) Subscapularis
d) Teres minor
e) Teres major
B
- The infraglenoid tubercle serves as an attachment for the:
a) Long head of biceps
b) Long head of triceps
c) Medial head of triceps
d) Coracobrachialis
e) Subscapularis
B.
Muscles of the hypothenar eminence are innervated by the:
a) Median nerve
b) Ulnar nerve
c) Radial nerve
d) Median and radial nerves
e) Median and ulnar nerves
B) Ulnar Nerve
Recall that:
The ulnar nerve supplies all the short intrinsic muscles of the hand other than the L.O.A.F.s muscles which are supplied by the median nerve; while the median nerve supplies all the muscles in the anterior compartment of the forearm other than the ulnar half of the flexor digitorum profundus and flexor carpi ulnaris, which are supplied by the ulnar nerve.
With that in mind, muscles of the hypothenar eminence – opponens digiti minimi, abductor digiti minimi, flexor digiti minimi – are all supplied by the ulnar nerve.