Muscular Skeletal Quiz Answers



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Muscular Skeletal Quiz Answers

1.

The __________ muscle participates in downward rotation of the scapula.



A) levator scapulae

B) lower (inferior) fibers of serratus anterior

C) teres minor

D) lower (inferior ) fibers of trapezius

Feedback: A. The levator scapulae elevates the scapula and tilts the glenoid cavity inferiorly by rotating the scapula (downward rotation). B. The lower fibers of the serratus anterior elevate the glenoid cavity (upward rotation). C. The teres minor laterally rotates the arm, which does not cause rotation of the scapula. D. The lower fibers of the trapezius rotate the glenoid cavity superiorly (upward rotation).

Correct Answer(s): A

2.

Weeks after a nasty fall forward onto both hands, a patient arrives in the doctor’s office complaining of clumsiness with the right thumb. The patient has no problem holding paper between any two fingers and has no difficulty in flexing the metacarpophalangeal (MP) joints and extending the interphalangeal (IP) joints of the fingers. Flexion and abduction of the thumb are weak and the thenar eminence is flat. However, sensation is normal over the thenar eminence, and extension and adduction of the thumb are normal. The nerve most likely affected is the



A) recurrent branch of the median nerve.

B) palmar cutaneous branch of the median nerve.

C) median nerve in the cubital fossa.

D) deep ulnar nerve.

E) deep radial (posterior interosseous) nerve.

Feedback: A. The recurrent branch of the median nerve serves the thenar muscles: Abductor pollicis brevis abducts thumb (and helps oppose it), flexor pollicis brevis flexes thumb, opponens pollicis flexes and medially rotates the 1st metacarpal during opposition. Damage to this nerve therefore compromises abduction, flexion and opposition of the thumb. The thenar muscles form the thenar eminence on the lateral surface of the palm. If these muscles are not used they will undergo atrophy and the thenar eminence will be flatter than normal. B. The palmar cutaneous branch of the median nerve supplies the skin of the thenar eminence. Since sensation is normal over the thenar eminence it cannot be affected. C. If the median nerve in the cubital fossa were affected the patient would not be able to flex the MP joints and extend the IP joints of the 2nd and 3rd digits because the median nerve supplies the lateral two lumbricals. D. If the deep ulnar nerve were affected patient would not be able to flex the MP joints and extend the IP joints due to paralysis of the palmar and dorsal interossei muscles and the medial two lumbricals. Paralysis of these same muscles would affect abduction and adduction of the digits and the patient would not be able to hold the paper between their fingers. E. Injury of the deep radial nerve would result in difficulty extending the thumb (extensor pollicis brevis and longus). It would also compromise abduction of the thumb (abductor pollicis longus) that this patient exhibits, but both extension and abduction of the thumb would have to be compromised for the deep radial nerve to be involved.

Correct Answer(s): A

3.

The __________ muscles cross the metacarpophalangeal (MP) joint of the thumb.



A) abductor pollicis longus and oponens pollicis

B) oponens pollicis and flexor pollicis brevis

C) flexor pollicis brevis and extensor pollicis brevis

D) extensor pollicis brevis and abductor pollicis longus

Feedback: The flexor pollicis brevis and the extensor pollicis brevis cross the MP joint of the thumb, as their distal attachment is on the base of the proximal phalanx of the thumb. The abductor pollicis longus and opponens pollicis do not cross the MP joint, as they attach to the first metacarpal.

Correct Answer(s): C

4.

Two muscles that medially (internally) rotate the glenohumeral joint are the



A) infraspinatus and subscapularis.

B) subscapularis and pectoralis major.

C) latissimus dorsi and infraspinatus.

D) teres minor and teres major.

Feedback: The pectoralis major, subscapularis, latissimus dorsi and teres major medially (internally) rotate at the glenohumeral joint. The infraspinatus and teres minor laterally (externally) rotate at the glenohumeral joint.

Correct Answer(s): B

5.

Examination of a patient’s injured upper limb reveals normal extension at the elbow, but sensory deficits on the thumb, marked weakness in supination and an inability to extend at the wrist (wrist drop) or the metacarpophalangeal (MP) joints. These findings would suggest that the __________ has been severed.



A) posterior cord

B) radial nerve at its origin

C) radial nerve just distal to the spiral (radial) groove

D) deep radial (posterior interosseous) nerve at its origin

E) superficial radial nerve at its origin

Feedback: A. Severing the posterior cord would result in paralysis of the triceps as well as the other symptoms exhibited by this patient. All of these deficits would have to be present if the posterior cord were severed. B. Severing the radial nerve at its origin would result in paralysis of the triceps as well as the other symptoms exhibited by this patient. C. The radial nerve gives branches to the triceps within or proximal to the spiral (radial) groove. Severing the nerve distal to the groove will not affect triceps, therefore extension at the elbow will be normal. All the other deficits exhibited by the patient are explained by injury at this point since both the deep and superficial radial nerves will be affected. D. Damage to the deep radial nerve affects the posterior compartment of the forearm and results in an inability to extend the wrist or MP joints. It innervates the supinator, thus damage will weaken supination (but not eliminate, as the biceps brachii also supinates). The deep radial nerve does not have any cutaneous distribution, so damage could not account for the sensory deficits on the thumb. E. The superficial radial nerve is entirely cutaneous in distribution, supplying parts of the thumb (and also parts of the dorsal hand and digits). Damage to this nerve could not account for any muscular weakness.

Points Earned: 0.0/1.0

Correct Answer(s): C

6.

Fractures of the olecranon are usually transverse. The proximal fragment is pulled superiorly by the _____________ muscle and the ___________ nerve may be damaged.



A) biceps brachii --- median

B) triceps brachii --- ulnar

C) supinator --- deep radial (posterior interosseous)

D) extensor carpi ulnaris --- deep radial (posterior interosseous)

Feedback: A. The distal attachment of biceps brachii is not on the olecranon (it’s on the radial tuberosity and bicipital aponeurosis). The median nerve is too anterior to the olecranon to be affected (it’s on the medial side of the cubital fossa). B. A distal attachment of triceps is the proximal end of the olecranon. The ulnar nerve lies in the groove for the ulnar nerve on the posterior aspect of the medial epicondyle of the humerus. This is just lateral to the olecranon fossa. C. The supinator has no attachments to the olecranon (all posterior attachments are inferior to olecranon). The deep radial nerve is too anterior to the olecranon to be affected. D. The extensor carpi ulnaris has no attachments to the olecranon (it’s proximal attachment is the lateral epicondyle of humerus and posterior border of ulna). The deep radial nerve is too anterior to the olecranon to be affected.

Correct Answer(s): B

7.

The __________ muscle is probably torn when a gymnast experiences sudden lumbar pain and muscle spasm while doing pulls-ups (chin-ups) on a high bar (extension against resistance).



A) erector spinae

B) deltoid

C) latissimus dorsi

D) trapezius

E) serratus anterior

Feedback: The erector spinae, deltoid, trapezius and serratus anterior do not cause extension at the shoulder joint. The latissimus dorsi is the important climbing muscle, as it raises the trunk to the arm (extension at the shoulder joint).

Correct Answer(s): C

8.

The tapering inferior part of the spinal cord is called the



A) conus medullaris (medullary cone).

B) lumbosacral enlargement.

C) filum terminale.

D) cauda equina.

E) denticulate ligament.

Feedback: A. The tapering inferior part of the spinal cord is called the conus medullaris. B. The lumbosacral enlargement is superior to the conus medullaris. It extends from the T11 to L1 segments of spinal cord. C. The filum terminale starts at the inferior end of the conus medullaris, descends with the spinal nerve roots in the cauda equina and attaches to the coccyx. D. The cauda equina is a bundle of spinal nerve ventral and dorsal roots caudal to the end of the spinal cord. E. Denticulate ligaments are lateral extensions of the pia mater that hold the spinal cord in position within the subarachnoid space.

Correct Answer(s): A

9.

The ligamenta flava are elastic ________ joints that stretch during _______ of the vertebral column.



A) synarthrodial --- flexion

B) synarthrodial --- extension

C) diarthrodial (synovial) --- flexion

D) diarthrodial (synovial) --- extension

Feedback: Ligamenta flava are elastic fibrous tissue that connects the laminae of adjacent vertebrae. The space between laminae is increased when the vertebral column is flexed, thereby stretching the ligamenta flava. Joints with a solid (i.e. fibrous or cartilaginous) connection between bones are considered synarthrodial.

Correct Answer(s): A

10.

A patient's subclavian artery is ligated just lateral to the anterior scalene muscle between the suprascapular artery and the thyrocervical trunk. In this patient, the dorsal scapular and transverse cervical arteries are branches of the thyrocervical trunk. The suprascapular artery is a direct branch of the subclavian. To fill the distal subclavian & the axillary arteries, the flow of blood reverses direction in both the ________ and _________ arteries.



A) transverse cervical --- posterior intercostal

B) dorsal scapular --- circumflex scapular

C) suprascapular --- dorsal scapular

D) circumflex scapular --- suprascapular

E) dorsal scapular --- transverse cervical

F) posterior intercostal --- circumflex scapular

Feedback: Blood flow will reverse in arteries distal to the ligation, including the circumflex scapular and suprascapular arteries. Blood flow in arteries proximal to the ligation will not reverse direction (i.e. thyrocervical trunk, dorsal scapular, transverse cervical, posterior intercostals).

Correct Answer(s): D

11.

The radial nerve lies on the posterior surface of the humerus between the humeral attachments of the __________ heads of the triceps and is accompanied by the ________.



A) long & lateral --- deep artery of the arm (profunda brachii)

B) long & lateral --- brachial artery

C) long & medial --- deep artery of the arm (profunda brachii)

D) long & medial --- brachial artery

E) lateral & medial --- deep artery of the arm (profunda brachii)

F) lateral & medial --- brachial artery

Feedback: Only the lateral and medial heads of the triceps have proximal attachments to the humerus. The radial groove lies in between these attachments. The proximal attachment of the long head is to the infraglenoid tubercle of the scapula. The deep artery of the arm accompanies the radial nerve through the radial groove in the humerus. The brachial artery lies medial and/or anterior to the humerus.

Correct Answer(s): E

12.

Release of acetylcholine results in contraction of the



A) arrector pili muscles in the skin.

B) walls of blood vessels in the body wall (vasoconstriction).

C) biceps muscle.

Feedback: Acetylcholine is released by motoneurons at the neuromuscular junction and results in contraction of skeletal muscles (i.e. biceps). Postsynaptic sympathetic axons that innervate arrector pili and the walls of blood vessels in the body wall release norepinephrine.

Correct Answer(s): C

13.


Glial cells called __________ surround all axons in the peripheral nervous system. A connective tissue layer called the __________ surrounds each myelinated axon.

A) oligodendrocytes --- epineurium

B) oligodendrocytes --- perineurium

C) oligodendrocytes --- endoneurium

D) Schwann cells --- epineurium

E) Schwann cells --- perineurium

F) Schwann cells --- endoneurium

Feedback: Glia that surround axons in the peripheral nervous system are called Schwann cells. In the central nervous system, they are called oligodendrocytes. The endoneurium surrounds each myelinated axon. The perineurium encloses a bundle (fascicle) of nerve fibers. The epineurium is a loose connective tissue that surrounds the perineurium wrapped nerve bundles.

Correct Answer(s): F

14.


Dendrites are characterized by the _________ of Nissl substance and a _________ thickness from their proximal to distal ends.

A) absence --- constant

B) absence --- decreasing

C) presence --- constant

D) presence --- decreasing

Feedback: Dendrites and the neuronal cell bodies have Nissl substance. Axons and axon hillocks do no have Nissl. Nissl represents the presence of ribosomes. Dendrites have a tapering diameter from proximal to distal ends. Axons retain their diameter.

Correct Answer(s): D

15.


Imagine a radiograph of a normal elbow in the AP projection. The __________ will have their shadows at least partially superimposed on this image.

A) olecranon and trochlea

B) head of the radius and the medial epicondyle of the humerus

C) coronoid process of the ulna and capitulum

D) lateral epicondyle of the humerus and the shaft of the radius

Feedback: A. The olecranon (on the posterior ulna) lies posterior to the trochlea (on the anterior humerus). Their region over overlap can best be appreciated by the presence of the trochlear notch on the anterior surface of the olecranon. B. The medial epicondyle of the humerus is supero-medial to the head of the radius. C. The coronoid process of the ulna is infero-medial to the capitulum of the humerus. D. The lateral epicondyle of the humerus is superior to the shaft of the radius.

Correct Answer(s): A

16.


An untreated pin prick in the index finger (1st finger, 2nd digit) may result in an infection which leads to pain, tenderness and inflammation in the ________________. If the synovial membrane of this structure were to rupture, the infection and accompanying symptoms would most likely spread to the _____________ space.

A) radial bursa --- midpalmar

B) radial bursa --- thenar

C) digital synovial sheath of index finger --- midpalmar

D) digital synovial sheath of index finger --- thenar

Feedback: The digital synovial sheath surrounding the flexor digitorum superficialis and profundus in the index finger can be punctured by a deep pin prick. The radial bursa is the synovial sheath that encloses the tendon of flexor pollicis longus and goes to the thumb. There are two fascial spaces deep to the palmar aponeurosis. The thenar space is the lateral space that contains flexor pollicis longus tendon and the other flexor tendons of the index finger. The midpalmar space is the medial space that contains the flexor tendons of the medial three digits.

Correct Answer(s): D

17.


The presence of an anomalous, unilateral accessory rib articulating with vertebra C7 and attaching on rib 1 causes increasing pain, tingling and/or numbness along the medial side of the arm, forearm and hand of an elderly patient. There are no other cutaneous sensory deficits. Furthermore, examination revealed weakness in initiating pronation against resistance and weakness in flexion of the proximal (PIP) and distal (DIP) interphalangeal joints of the fingers and the interphalangeal joints of the thumb. There is no muscle weakness when extending the neck and upper part of the vertebral column. These neurological signs indicate that the rib may be stretching and exerting pressure on some axons of the __________. (All symptoms are from one injury site only)

A) dorsal root of spinal nerve C7

B) dorsal ramus of spinal nerve C7

C) medial cord of the brachial plexus

D) middle trunk of the brachial plexus

E) dorsal root of spinal nerve C8

F) dorsal ramus of spinal nerve C8

Feedback: The skin on the medial side of the arm, forearm and hand is supplied by C8 (5th digit, medial side of hand, and forearm) and T1 (middle of forearm to axilla). This is where there is tingling. The pronator quadratus initiates pronation and is assisted by the pronator teres. The pronator quadratus is innervated by the anterior interosseous nerve (C8, T1 - a branch of the median nerve). Initiation of pronation is compromised. The flexor digitorum superficialis flexes the medial 4 digits at the PIP. It is innervated by the median nerve (C7, C8, and T1). Flexor digitorum profundus flexes the medial 4 digits at the DIP. It is innervated by the medial part of ulnar nerve (C8, T1) and the lateral part of median nerve (C8, T1). The flexor pollicis longus flexes the phalanges of the thumb. It is innervated by the anterior interosseous nerve (C8, T1 - a branch of the median nerve). These movements are compromised. Extension of the neck and upper vertebral column is done by the intrinsic back muscles. These muscles are innervated by the dorsal rami of spinal nerves. This function is normal. Therefore B and F are wrong. Since there is muscular weakness, damage to a dorsal root (all GA axons) would not account for the deficits seen in this patient. Therefore A and E are wrong. The deficits can be explained by damage to the ventral rami of C8 and T1. Damage to the medial cord would affect both (answer C). The middle trunk is entirely C7 (answer D).

Correct Answer(s): C

18.


All or part of the ______________ lies directly posterior to the anterior scalene muscle.

A) phrenic nerve

B) subclavian artery

C) subclavian vein

D) subclavius muscle

E) suprascapular nerve

Feedback: A. The phrenic nerves are located anterior to the anterior scalene muscles. B. Each subclavian artery arches superiorly, posteriorly, and laterally. As the arteries ascend and reach their apex, they pass posterior to the anterior scalene muscles. C. The subclavian vein, the continuation of the axillary vein, passes over the 1st rib parallel to the subclavian artery, but it is separated from it by the anterior scalene muscle. Thus, subclavian vein passes anterior to the anterior scalene. D. The proximal attachment of subclavius is the junction of the 1st rib and the costal cartilage. It lies almost horizontally in anatomical position, attaching to the inferior surface of middle third of clavicle. The anterior scalene also attaches to the 1st rib, but more posteriorly and laterally. Thus, subclavius lies anterior to anterior scalene (and also lies anterior to subclavian vein). E. The suprascapular nerve arises from the superior trunk of the brachial plexus, and runs laterally across the posterior triangle. It is the roots of the brachial plexus that emerge posterior to anterior scalene.

Points Earned: 0.0/1.0

Correct Answer(s): B

19.


The upper and lower subscapular nerves both arise from the ______________ cord of the brachial plexus. They can be differentially identified based on the innervation of the ________________ muscle.

A) lateral --- subscapularis

B) lateral --- teres major

C) posterior --- subscapularis

D) posterior --- teres major

E) medial --- subscapularis

F) medial --- teres major

Feedback: The upper subscapular and lower subscapular nerves both arise from the posterior cord. The upper subscapular nerve only innervates the subscapularis while lower subscapular nerve innervates the subscapularis and teres major.

Correct Answer(s): D

20.


The ventral roots of thoracic spinal nerves contain

A) presynaptic (preganglionic) sympathetic axons.

B) presynaptic (preganglionic) parasympathetic axons.

C) postsynaptic (postganglionic) sympathetic axons.

D) postsynaptic (postganglionic) parasympathetic axons.

Feedback: Presynaptic sympathetic neuronal cell bodies are located in the spinal cord from T1 through L2, therefore the ventral roots of thoracic spinal nerves will contain presynaptic sympathetic axons. Postsynaptic sympathetic axons would be found in the ventral and dorsal rami of all spinal nerves. Presynaptic parasympathetic axons would be found in the ventral roots of S2 to S4. Postsynaptic parasympathetic axons never distribute with spinal nerves.

Correct Answer(s): A

21.


The intervertebral foramen between vertebrae L3 and L4 contains spinal nerve _____. The segment of spinal cord giving rise to this nerve is __________ to this intervertebral foramen.

A) L3 --- superior

B) L3 --- adjacent

C) L3 --- inferior

D) L4 --- superior

E) L4 --- adjacent

F) L4 --- inferior

Feedback: Lumbar spinal nerves emerge inferior to the vertebra with the same number. Therefore the spinal nerve between vertebrae L3 and L4 will be spinal nerve L3. Due to differential growth, the lumbar spinal cord segments are superior to the lumbar vertebrae.

Correct Answer(s): A

22.


The axon hillock is located within the __________. It __________ contain Nissl bodies.

A) cell body --- does

B) cell body --- does not

C) axon terminal --- does

D) axon terminal --- does not

Feedback: The axon hillock is located at the proximal end of the axon, within the cell body. The axon terminal is the distal end of the axon. Axons and axon hillocks do no have Nissl bodies. Nissl bodies represent the presence of ribosomes. Dendrites and the neuronal cell bodies have Nissl bodies.

Correct Answer(s): B

23.


A surgeon (not from Downstate) excises a tumor from the apex of the left lung and accidentally cuts the anterior division of the superior trunk of the brachial plexus. As a result, there is Wallerian degeneration in the

A) superior trunk.

B) axillary nerve.

C) lateral cord.

D) median nerve.

E) superior trunk and axillary nerve.

F) lateral cord and median nerve.

G) superior trunk, axillary nerve, lateral cord and median nerve.

Feedback: Wallerian degeneration occurs in a nerve distal to a cut. The lateral cord, median nerve, and musculocutaneous nerve are all distal to the anterior division of the superior trunk. The superior trunk is proximal to the cut, thus is incorrect. The axillary nerve is distal to the posterior division of the superior trunk, thus will be intact.

Correct Answer(s): F

24.

The nerve that innervates all or most of the clavicular head of the pectoralis major is a branch of the ________ cord of the brachial plexus. It ________ have cutaneous branches that innervate the skin over the clavicle.



A) lateral --- does

B) lateral --- does not

C) medial --- does

D) medial --- does not

Feedback: The lateral pectoral nerve, a branch of the lateral cord, innervates the clavicular head of the pectoralis major while the medial pectoral nerve, a branch of the medial cord, innervates the sternocostal head of the pectoralis major. Neither the lateral nor medial pectoral nerves have a cutaneous component. The supraclavicular nerves innervate the skin over the clavicle.

Correct Answer(s): B

25.

____________ a prominent characteristic of all cervical vertebrae.

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