Arthrology, myology Part 2 1.2 (mcqs)

Pain may result from friction of the tendon of which muscle that passes deep to the anterior fibers of the long plantar ligament.

fibularis longus (Remember: fibularis longus runs from the lateral side of the foot across the entire sole of the foot, traveling deep to the long plantar ligament. The friction between these two closely related structures may lead to discomfort.)

If the tendon of palmaris longus were transected, what movement would be affected?

flexion of the wrist (Palmaris longus is a small muscle in the anterior compartment of the arm- -it flexes the hand at the wrist and tightens the palmar aponeurosis. If this tendon was cut, it would be more difficult to flex the wrist. Flexor pollicis longus flexes the MP and IP joints of the thumb. Flexor digitorum profundus and superficialis flex the proximal IP joints of digits 2, 3, 4, and 5. Extensor carpi ulnaris, extensor carpi radialis longus and extensor carpi radialis brevis all extend the wrist.)

Development of 'tennis elbow' involves the origin of which muscle

-extensor carpi radialis brevis ("Tennis elbow" is due to repetitive use of the superficial extensor muscles of the forearm. The pain is felt on the lateral epicondyle and radiates down the posterior surface of the forearm. With tennis elbow, the repeated flexion and extension of the wrist strains the attachment of the common extensor tendon, producing inflammation of the periosteum of the lateral epicondyle and the common extensor attachment of the muscles. The only muscle listed which takes origin from the common extensor tendon is the extensor carpi radialis brevis. So, that is the correct answer. (Extensor carpi ulnaris also takes origin from the common extensor tendon, so it might be responsible for some of the symptoms too.))

While watching her boyfriend split wood, a teenager was struck on the back of her carpals by a sharp- edged flying wedge. Her extensor digitorum tendons were exposed, though not severed, indicating that the surrounding synovial sheath had been opened. What other muscle has its tendon surrounded by the same synovial sheath?

extensor indicis (Extensor indicis is a deep forearm extensor that extends the index finger only. Its tendon joins the tendon of the extensor digitorum which goes to the second digit, and both tendons insert into the extensor expansion. Since these tendons insert together, it would make sense that they would be contained in a common synovial sheath. All of the other tendons listed have their own synovial sheaths.)

The tendons on the dorsal side of the wrist are held in place by a thickening of the antebrachial fascia called the

extensor retinaculum

A pedestrian is struck by a car, and his fibular neck is fractured. There is no indication of foot drop, but he cannot evert his foot and the top of his foot is numb. This apparent nerve lesion would affect which of the following muscles?

fibularis longus (A fracture of the fibular neck commonly causes an injury to the common fibular nerve, which has two branches: the deep fibular nerve and the superficial fibular nerve. However, this case isn't as simple. If the common fibular nerve was damaged, the deep fibular nerve would also be impaired. This would mean that the anterior compartment of the leg would be denervated, and the patient would suffer from foot drop. But that's not happening here, so you know that the common fibular nerve must be intact. The superficial fibular nerve, however, innervates the lateral compartment of the leg which allows for eversion. It also provides cutaneous sensation to the dorsum of the foot. An injury to this nerve fits with the patient's symptoms. The superficial fibular nerve innervates fibularis longus and brevis, so D is your answer.)

The signs and symptoms of carpal tunnel syndrome may vary among patients, but they always result from compression of what structure in the carpal canal?

median nerve (Carpal tunnel syndrome is caused by a compression of the median nerve within the carpal tunnel. The carpal tunnel is a canal on the anterior side of the wrist. It is made of the carpal bones which are covered by the flexor retinaculum. It contains the tendon of flexor pollicis longus, the tendons of flexor digitorum superficialis and profundus, and the median nerve. If the sheath over the common flexor tendons, the ulnar bursa, becomes inflamed, this can compress the median nerve in the canal, leading to pain and weakness in the hand.)

A deep laceration, 2 cm in length, immediately posterior to the medial malleolus, may injure

tibial nerve; tendon of tibialis posterior m. ; tendon of flexor digitorum longus m. ; tendon of flexor hallucis longus m but it wouldn't injure the fibular artery (The flexor retinaculum is immediately posterior to the medial malleolus. So, any of the tendons or structures coming from the posterior compartment and crossing under flexor retinaculum to the plantar surface of the foot might be injured. The fibular artery is a branch of the posterior tibial artery that delivers blood to the lateral compartment of the leg. It does not cross into the foot, and it is nowhere near the medial malleolus. So that's your answer. All of the other listed structures are coming from the posterior, flexor compartment- -these structures are all organized behind the flexor retinaculum in a very characteristic way. From anterior to posterior the structures are: tendon of Tibialis posterior, tendon of flexor Digitorum longus, posterior tibial Artery (and vein), tibial Nerve, and tendon of flexor Hallucis longus. So, T, D, A, N, H equals Tom, Dick, ANd Harry. This is an important relationship to remember!)

While at the beach in Florida after final exams, a medical student steps on a stingray, which responds by stinging her in the ankle. The stinger pierces the skin, subcutaneous tissue, and flexor retinaculum of the ankle. Which other structure passing under the retinaculum may be injured?

tibialis anterior (The flexor retinaculum is immediately posterior to the medial malleolus. The structures which pass under the flexor retinaculum are coming from the posterior compartment of the leg to enter the foot. These tendons, vessels, and nerve are all organized behind the flexor retinaculum in a very characteristic way. From anterior to posterior the structures are: tendon of Tibialis posterior, tendon of flexor Digitorum longus, posterior tibial Artery (and vein), tibial Nerve, and tendon of flexor Hallucis longus. Tom, Dick, ANd Harry! Out of all the answer choices, the tibial nerve is the only one which lies behind the flexor retinaculum, so that's your answer.)

Compression of the lateral plantar nerve as it passes between the flexor digitorum brevis and quadratus plantae could result in weakness of

B. adduction of the middle toe C. abduction of the little toe D. adduction of the great toe E. abduction of the middle to but not the abduction of the reat toe (he medial plantar nerve innervates abductor hallucis, so this muscle would be saved if the lateral plantar nerve was disrupted. The muscles responsible for all the rest of the actions listed are innervated by the lateral plantar nerve, or its branch, the deep lateral plantar nerve: Adduction of the middle toe: plantar interosseus muscles (deep branch); Abduction of the little toe: abductor digiti minimi (lateral plantar); Adduction of the great toe: adductor hallucis (deep branch); Abduction of the middle toe: third dorsal interosseus muscle (deep branch)

If the musculocutaneous nerve is severed at its origin from the brachial plexus, flexion at the elbow is greatly weakened but not abolished. What muscle remains operative and can contribute to flexion?

brachioradialis (Brachioradialis is a muscle innervated by the radial nerve--it flexes the elbow and assists in pronating and supinating the arm. Brachialis, coracobrachialis, and both heads of biceps brachii are all muscles which flex the arm and/or forearm, but they are all innervated by the musculocutaneous nerve. These muscles would be denervated if the musculocutaneous nerve was severed at its origin from the brachial plexus.)

A car strikes a pedestrian on the lateral side of her leg. Following the accident, she has "foot drop". her foot hangs loosely in plantar flexion when she raises it off the ground. She can still invert her foot, but cannot evert it. She can flex but not extend her toes. Which nerve is most likely to have been crushed in her accident? :

common fibular (All of these symptoms are consistent with damage to the common fibular nerve, whose branches, the deep and superficial fibular nerves, innervate the anterior and lateral compartments.)

A patient with a fracture to the left upper tibia was treated with a plaster cast. A few days later he started to develop progressive numbness over the dorsum of the foot and weakness in dorsiflexion. The cast was quickly changed and the signs were attributed to nerve compression. The compressed nerve was most likely the:

common fibular nerve (The common fibular nerve must have been compressed in the cast. You can figure this out by thinking about the two branches of the common fibular nerve. The first branch is the deep fibular nerve which innervates the anterior compartment of the leg and is responsible for dorsiflexion of the foot. The second branch, the superficial fibular nerve, innervates the lateral (everter) compartment and provides cutaneous innervation to the dorsum of the foot. The combination of symptoms (impaired dorsiflexion and a loss of cutaneous sensation on the dorsum of the foot) suggests that both nerves are injured. So the common fibular nerve, which both nerves branch from, must be the structure that was damaged.)

The fourth dorsal interosseous muscle is innervated by the:

deep branch of the ulnar nerve (The deep branch of the ulnar nerve innervates the intrinsic muscles of the hand (with the exception of the thenar compartment). This includes the dorsal interosseous muscles, the palmar interosseous muscles, the two lumbrical muscles on the medial side of the hand, and the muscles to the 5th digit (digiti minimi). The dorsal branch of the ulnar nerve innervates the skin of the dorsal surface of the medial 1.5 digits and the skin of the medial side of the back of the hand. The recurrent motor branch of the median nerve innervates the thenar compartment. The superficial branch of the radial nerve provides sensory the hand, including the radial 3.5 digits. Finally, the superficial branch of the ulnar nerve innervates the skin of the palmar surface of the medial 1.5 digits as well as the skin of the medial side of the front of the hand.)

A patient sustained multiple deep lacerations on the palm of his hand and anterior surface of his wrist. During examination, the physician put a piece of paper between adjacent surfaces of the patient's index and middle fingers and found him unable to squeeze them together with sufficient force to hold the paper. The most specific nerve branch to the tested muscles is the:

deep branch of unlar nerve

Along distance runner complained of swelling and pain of his shin (tibia). At physical examination, skin testino sho»ed normal cutaneous sensation of the leg. However, muscular strength tests showed marked weakness of dorsiflexion and impaired inversion of the foot. Which nerve sen es the muscles involved?

deep fibular (The deep fibular nerve provides motor innervaton to the anterior compartment of the leg. This compartment contains tibialis anterior, a muscle that allows for dorsiflexion and inversion of the foot. If a patient is unable to dorsiflex the ankle, he or she will have foot drop.)

What arterial vessel accompanies the deep branch of the ulnar nerve across the palm?

deep palmar arterial arch (The deep palmar arterial arch is made by the radial artery and the deep branch of the ulnar artery. It runs deep in the hand, along with the deep ulnar nerve which innervates the intrinsic muscles of the hand.)

A patient has stepped on a board with a long nail sticking up from it, and the nail penetrated the patient's foot between the bases of the first and second metatarsals. What artery is most likely injured at this location?

deep plantar (The deep plantar artery is a branch of dorsalis pedis, the major artery supplying blood to the dorsum of the foot. The deep plantar artery dives from the dorsum of the foot to the sole of the foot between the two heads of the dorsal interosseous muscle between the first and second toes, It then unites with the lateral plantar artery to form the plantar arterial arch. The arcuate artery is on the dorsum of the foot. It would be unlikely to injure this artery from the plantar surface. The medial plantar artery is also on the medial side of the foot and it does distribute to the area where the injury occured. However, the medial plantar artery supplies blood to the superficial plantar surface of the foot, and the scenario in the question points to an injury that would disturb deep structures in the foot. So, deep plantar artery is the best answer.

After suffering a cut deep to the hypothenar eminence, the patient is unable to hold a sheet of paper between the second and third digits. The nerve most likely injured was the:

deep ulnar (Remember--the deep ulnar nerve innervates all the muscles in the hand, except for the thenar compartment and the first two lumbricals. Those muscles are innervated by the median nerve!)

. While water skiing following final exams, a medical student falls and twists her ankle. Her foot is forcibly everted, which could cause a sprain of which ligament?

deltoid (The deltoid ligament connects medial malleolus with talus, navicular & calcaneus. It is on the medial side of the ankle joint, and its role is to prevent the ankle from dislocating when forcibly everted. So, if a foot was strongly everted, the deltoid ligament might tear.)

A medical student goes for a swim while on vacation after final exams. A barracuda bites his foot, severing an artery on the dorsum of his foot just below his ankle. Which artery has been severed?

dorsalis pedis

A construction worker lacerates the dorsum of his foot just below his ankle. Profuse bleeding that occurs would result from cutting which vessel?

dorsalis pedis artery (The dorsalis pedis is an extension of the anterior tibial artery that supplies the dorsal aspect of the foot. (The name change occurs at the level of the ankle, so that's why this isn't the anterior tibial artery.)

In order to check the pulse of a child whose forearm is in a cast, the pediatrician presses her finger into the depth of the "anatomical cuffbox. The tendon lying immediately medial (ulnar) to the physician's finger belongs to what muscle?

extensor pollocis longus (The anatomical snuff box is bounded on the ulnar side by the tendon of extensor pollicis longus. It is bounded radially by the tendons of abductor pollicis longus and extensor pollicis brevis. The radial artery lies in the floor of the snuff box, and scaphoid can be felt in the floor of the anatomical snuff box. Extensor carpi radialis longus and brevis attach their tendons to the base of the second and third metacarpals, respectively. Brachioradialis inserts its tendon on the lateral side of the base of the styloid process of the radius.)

What movement of the thumb would be most affected by lesion of the median nerve in the cubital fossa:

flexion (If the median innervated by the median nerve which are found distal to the cubital fossa would be injured. The thenar compartment of the hand and the flexor muscles of the forearm would be denervated (with the exception of flexor carpi ulnaris and the ulnar half of flexor digitorum profundus--both of these muscles are innervated by the ulnar nerve). This means that none of the muscles which allow for flexion of the thumb would be intact. Flexor pollicis brevis is innervated by the recurrent branch of the median nerve and flexor pillicis longus is innervated by the median nerve. Both of these muscles would be denervated. Abduction is performed by abductor pollicis longus (innervated by the radial nerve) and abductor pollicis brevis (innervated by the median nerve). So, abduction might be weakened, but it would not be completely lost following damage to the median nerve. Adduction is performed by adductor pollicis, which is a muscle in the medial compartment of the hand, innervated by the deep ulnar nerve. Extending the thumb is accomplished by extensor pollicis longus and brevis, which are both innervated by the deep radial nerve.)

In an attempt to commit suicide by slashing the ventral side of the wrist, the two tendons of the flexor digitorum superficialis located most superficially were completely severed. What movement would be affected?

flexion of the PIP joints of digits 3 and 4 (When cutting the ventral side of the wrist, the first tendons cut would be metacarpophalangeal (MP) and proximal interphalangeal (PIP) joints, but not the distal interphalangeal (DIP) joints. Flexor digitorum profundus (which has deeper tendons) is responsible for flexing the distal interphalangeal joints.The tendons of flexor digitorum superficialis are arranged in a packet with two superficial tendons and two deeper tendons. The tendons that go to fingers 3 and 4 are superficial, while the ones to finger 2 and 5 are the tendons of flexor digitorum superficialis. These tendons help flex the of the proximal interphalangeal joints of digits 3 and 4.) underneath. So, the tendons to fingers 3 and 4 will be cut, impairing flexion

The pulse of the radial artery at the wrist is felt immediately lateral to which tendon?

flexor carpi radialis (The radial artery runs on the radial side of the wrist, lateral to the tendon of flexor carpi radialis. So, the radial pulse will be felt immediately lateral to this tendon. Remember--the radial artery enters the wrist on the anterior side. This means that the extensor tendons, which are on the posterior side of the wrist, will not be involved with the radial artery! The tendons for flexor digitorum profundus and superficialis are found more towards the center of the wrist, not on the wrist's lateral side. These tendons cross under the flexor retinaculum to reach the hand.)

If the medial epicondyle of the humerus is fractured and the nerve passing dorsal to it is injured, which muscle would be most affected?

flexor carpi ulnaris C (The nerve passing dorsal to the medial epicondyle of the humerus is the ulnar nerve. In the forearm, the ulnar nerve innervates flexor carpi ulnaris and the ulnar side of flexor digitorum profundus. So, flexor carpi ulnaris would be most affected if the ulnar nerve was disrupted. What other symptoms might you see? Paralysis of hand muscles (except for the thenar compartment and the first two lumbricals) and numbness over the ulnar 1.5 digits in the hand!)

What muscle is innervated by branches of both the median and ulnar nerves?

flexor digitorum profundus

A patient has been diagnosed with bone cancer in the fibula that necessitates its removal. Which of the follos oing muscles would be least affected following removal of the fibula?

flexor digitrum longus (Flexor digitorum longus is the most medial muscle in the deep posterior compartment of the leg. This means that it takes origin from the middle half of the posterior surface of the tibia and is not attached to the fibula in any way. Biceps femoris inserts on the head of the fibula and the lateral condyle of the tibia. Extensor digitorum longus is a muscle on the lateral side of the anterior compartment of the leg. This means that it takes origin from the fibula, and would be affected by its removal. Flexor hallucis longus is the most lateral muscle in the posterior compartment, so it originates from the fibula, too. Finally, fibularis (peroneus) longus and brevis, the two muscles of the lateral compartment, both take origin from the fibula.)

Aworker falls from a height and lands on his feet. Radiographs reveal a fracture of the sustentaculum tali. The muscle passing immediately beneath it that would be adversely affected is the:

flexor hallucis longus (The tendon of flexor hallucius longus passes under sustentaculum tali, creating a groove in the bone. The sustentaculum tali is a shelf-like, medial projection of the calcaneus, which supports the talus. So, if the sustenaculum tali was fractured, the tendon of flexor hallucis longus would be displaced from its usual position and the muscle would be affected. The fibularis longus tendon enters the foot on the lateral side. It grooves the cuboid bone and travels deep to the long plantar ligament to insert on the medial cuneiform bone. The tendon of flexor digitorum longus crosses onto the plantar surface anterior to sustentaculum tali and eventually divides into 4 tendons that insert into the bases of the distal phalanges of digits 2-5. The tendon from tibialis anterior crosses the dorsal side of the foot and inserts on the medial surface of the first cuneiform and the first metatarsal. Finally, the tibialis posterior tendon crosses under the foot on the medial side, anterior to both flexor hallucis longus and flexor digitorum longus. It inserts on navicular, the medial cuneiform, and metatarsals 2-4. So, you should not see any of these other tendons associated with sustenaculum tali.)

In carpal tunnel syndrome, compression of the median nerve in the carpal tunnel affects which hand muscle?

flexor pollicis brevis (The recurrent branch of the median nerve innervates the thenar compartment, including abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis. If the median nerve was damaged, any of these muscles might be denervated. Adductor pollicis, the palmar interosseus muscles, and opponens digiti minimi are all innervated by the deep branch of the ulnar nerve.)

What muscle tendon is enclosed within its own synovial sheath in the carpal canal?

flexor pollicis longus (Flexor pollicis longus is enclosed in its own synovial sheath in the carpal canal, called the radial bursa. The tendons from flexor digitorum profundus and flexor digitorum superficialis are all contained in a common synovial sheath, called the ulnar bursa. The ulnar bursa and radial bursa are both in the carpal tunnel, along with the median nerve. Flexor carpi ulnaris and palmaris longus are not located in the carpal tunnel.)

A player is kicked on the front of his leg during a soccer game, and a large bruise develops. A hematoma deep to the crural fascia can create extreme pressure within the anterior compartment of the leg, compressing structures within it. The most likely finding resulting from this anterior compartment syndrome is:

foot drop (Anterior compartment syndrome leads to foot drop due to the compression of the deep fibular nerve. Since the deep fibular nerve innervates tibialis anterior, an important dorsiflexer, injuring this nerve will impair dorsiflexion and cause the foot to drop. Numbness on the dorsum of the foot would suggest an injury to the superficial fibular nerve. An inability to evert the foot might also be due to an injury to the superficial fibular nerve, since that nerve supplies the lateral, everter compartment. Damage to the deep fibular nerve might also impair inversion since that is an action of tibialis anterior, but this would be a more subtle finding. Also, remember that tibialis posterior is also an inverter, so that muscle might be able to compensate for the injury to the anterior compartment. Finally, an inability to plantarflex the foot would stem from damage to the tibial nerve and the posterior compartment.)

The most usual site for feeling the pulsations of the dorsalis pedis artery in the foot is:

just lateral to the tendon of extensor hallucis longus (The dorsalis pedis artery is the continuation of the anterior tibial artery which continues on to the dorsum of the foot. The name change from anterior tibial to dorsalis pedis occurs at the level of the ankle. As the artery crosses into the foot, it lies just lateral to the tendon of extensor hallucis longus, so that's where you would feel a pulse. he pulse of the posterior tibial artery, which comes from the posterior compartment of the leg, might be felt behind the medial malleolus. The pulse of the fibular artery might be felt behind the lateral malleolus, but that pulse would be very weak. There are no special pulses associated with the tendon of fibularis tertius or the second dorsal metatarsal space.)

While walking barefoot on the beach following final exams, a medical student steps on a sharp shell which punctures the sole of her foot. She notices that she can no longer spread her toes apart (without using her hands, that is). Which nerve must have been injured?

lateral plantar (his medical student is unable to abduct her toes--this must mean that her dorsal interosseus muscles are denervated. These dorsal interosseus muscles are innervated by the deep branch of the lateral plantar nerve, so this must be the nerve that was damaged.)

When falling on an outstretched hand, the most commonly dislocated carpal bone is the

lunate (It is fairly common for the lunate to be dislocated anteriorly--this injury may result from a fall on an extended wrist. The lunate may be pushed out of its place on the floor of the carpal tunnel and move toward the palm of the wrist. This dislocation may compress the median nerve and lead to carpal tunnel syndrome. Also remember: scaphoid, the lateral bone in the proximal row of carpals, is frequently fractured when someone falls on an outstretched wrist! Capitate, hamate, and trapezoid are not commonly injured in these falls.)

The point of insertion of the flexor digitorum superficialis tendon to the index finger is on the:

middle phalanx (The flexor digitorum superficialis tendon inserts on the middle phalanx of fingers 2-5; the flexor digitorum profundus tendon inserts on the base of the distal phalanx of fingers 2-5. Both muscles flex the metacarpophalangeal and proximal interphalangeal joints, but flexor digitorum profundus is the only muscle that flexes the distal interphalangeal joints.)

In an accident involving farm machinery, a farmer recieves a cut on the dorsum of his ankle. As you inspect the wound and test for functional and sensory deficits, you find that no tendons have been cut, but the dorsalis pedis artery and the accompanying nerve have been cut. You would expect to find:

numbness between the first and second toes (The nerve running with the dorsalis pedis artery is the deep fibular nerve. This nerve innervates the anterior compartment of the leg and the extensors on the dorsum of the foot. At the point where it was cut, the nerve had already given off all its branches to the anterior compartment of the leg, So,the farmer should still be able to dorsiflex his foot (preventing foot drop), and all of the muscles that invert his foot should be intact. Although extensor hallucis brevis (on the dorsum of the foot) has been denervated, extensor hallucis longus is in the anterior compartment of the leg, and that muscle should still be able to extend the great toe. However, the deep fibular nerve would have been cut before it could supply fibers to the area of cutaneous innervation between the first and second toe. So, there would be numbness in that area of skin. Club foot is a congenital anomaly which refers to a foot that has been twisted out of position. In cases of club foot, the foot is inverted, the ankle is plantarflexed, and the forefoot is adducted.)

A girl playing softball cuts the palm of her hand as she scoops up a piece of glass along with the ball. If the only nerve damaged is the recurrent branch of the median nerve, she would lose what movement of the thumb?

opposition (If the recurrent branch of the median nerve was injured, abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis would be denervated. Opponens is the only muscle that allows for opposition of the thumb. So, by denervating opponens, the girl would no longer be able to oppose her thumb. Although abductor pollicis brevis would be denervated, abductor pollicis longus would still be functional, so she could abduct her thumb. Adductor pollicis is in the adductor/ interosseous compartment, deep in the center of the hand, and it is innervated by the deep branch of the ulnar nerve. This means that adduction would not be affected by the injury to the recurrent branch of the median nerve. Although flexor pollicis brevis was denervated, this is not the flexor that is responsible for flexion at the distal phalanx. Flexor pollicis longus controls flexion at the distal phalanx, and it is a muscle of the forearm which is innervated by the median nerve.)

In order to evaluate the carpal-metacarpal joint of the thumb, the median nerve must be deadened at the wrist (causing paralysis of the muscles supplied by it distal to the injection) to test the joint. Which movement of the thumb would be most affected by the anesthetic?

opposition (f the median nerve was deadened at the wrist, a patient would lose the use of the thenar compartment of the hand. Abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis would be paralyzed. Opponens is the only muscle that allows for opposition of the thumb, so a patient would no longer be able to oppose the thumb to the fingers.)

What sesamoid bone develops in the tendon of the flexor capri ulnaris and is therefore not a part of the wrist joint?

pisiform (The pisiform is a sesamoid bone in the tendon of the flexor carpi ulnaris muscle. It is in the proximal row of carpal bones. It bears the forces generated by the tendon as the tendon rides across triquetrum, especially during wrist extension. The carpal bones participating in wrist joint formation are: Scaphoid, Lunate and Triquetral. Capitate is the largest carpal bone. It is in the distal row of carpal bones, and it transmits forces generated in the hand to lunate and then to the radius.)

A soldier developed "fallen arches" from marching with a heavy pack in boots that lacked arch support. The ligament that normally supports the head of the talus and is primarily responsible for holding up the medial longitudinal arch of the foot is the:

plantar calcaneonavicular (spring) D (The plantar calcaneonavicular ligament (spring ligament) connects the sustentaculum tali with the plantar surface of the navicular bone. It provides major support for the medial longitudinal arch of the foot, so this must be the ligament that the soldier injured. The calcaneometatarsal ligament is a superficial ligament in the foot--it is the lateral band of the plantar aponeurosis. The long plantar ligament connects calcaneus with cuboid and the bases of the lateral 3 metatarsals. The long plantar ligament is generally important in maintaining all the arches of the foot, but the spring ligament is specifically associated with the medial longitudinal arch and the head of the talus. The deltoid ligament is on the medial side of the ankle--this ligament stabilizes the ankle joint during eversion and prevents the ankle from dislocating. The short plantar ligament is deep to the long plantar ligament-- it extends from the anterior aspect of the inferior surface of the calcaneus to the inferior surface of the cuboid.)

A boy fell onto a sharp object and cut his deep radial nerve as it emerged from the supinator muscle. The artery joining it at this point was also injured. The injured artery is the

posterior interosseous (The deep radial nerve emerges from the supinator muscle and runs in the deep layer of the posterior forearm. It runs next to the posterior interosseous artery, which, along with the anterior interosseous artery, is a branch of the common interosseous artery.)

Structures within the carpal tunnel include:

raidial bursa (The flexor retinaculum spans between the carpal bones to make the carpal tunnel. The contents of the carpal tunnel are: the tendons of flexor digitorum superficialis and flexor digitorum profundus (all contained in the ulnar bursa); the tendon of flexor pollicis longus (contained in the radial bursa) and the median nerve. So, the radial bursa is the only listed structure that is found in the carpal tunnel. The ulnar nerve is superficial to the flexor retinaculum - it's not in the carpal tunnel. The palmar aponeurosis and superficial palmar arterial arch are found on the superficial surface of the palm of the hand-- they are not structures found at the wrist. Adductor pollicis is a muscle in the adductor-interosseous compartment of the hand - it is not found near the wrist.)

A student is rollerblading on the Diag and while trying to avoid a bicyclist falls heavily on his right wrist. After the fall he notes severe pain in the anatomical snuff box. Radiological studies reveal a fracture of the bone deep to the snuff box called the

scapoid (The scaphoid is the bone found at the floor of the anatomical snuff box. It is in the proximal row of carpals and it is frequently fractured.)

A patient sustained multiple deep lacerations on the palm of his hand and anterior surface of his wrist. During examination, the physician put a piece of paper between adjacent surfaces of the patient's index and middle fingers and found him unable to squeeze them together with sufficient force to hold the paper. What muscles are being tested?

second dorsal and first palmar interosseous muscles (When you are thinking about abducting and adducting digits in the hand, remember that the midline extends through the middle digit. So, this patient is trying to adduct his index finger by pulling it towards the midline and abduct his middle finger by pulling it away from the midline. This means that the patient is using the palmar interosseous muscle (the adductor) on his index finger and the dorsal interosseous muscle (the abductor) on his middle finger. So, the patient has damaged the first palmar interosseous muscle and the second dorsal interosseous muscle.)

A construction worker steps on a board with a nail in it. The nail pierces the sole of his boot and enters his foot 2 cm anterior to his calcaneal tuberosity, at the middle of the width of his foot. Before reaching bone, the nail would pass through, in order:

skin, plantar aponeurosis, flexor digitorum brevis, quadratus plantae, long plantar ligament (2 cm anterior to the calcaneal tuberosity, the nail would pass through skin, the plantar aponeurosis, flexor digitorum brevis (a superficial muscle), quadratus plantae (a deeper muscle), and the long plantar ligament.)

Bleeding from a superficial cut in the middle of the palm of the hand near the proximal transverse crease comes mainly from what vessel?

superficial palmar arch (The superficial palmar arch is a superficial arterial arch that crosses along the palm of the hand, so a cut in the middle of the palm would be likely to disrupt this vessel.)

The lateral plantar nerve is a branch of which nerve?

tibal nerve (The lateral and medial plantar nerves are both branches of the tibial nerve. These branches continue to the plantar surface of the foot, innervating the muscles on the plantar surface of the foot and providing cutaneous innervation to the skin of the sole.)

Your patient was struck by a car's bumper as she crossed the street, and her fibular neck is broken. After the bone has healed, she has "foot drop", i. e. she cannot dorsiflex her foot, and so it flops onto the ground during walking. Denervation (paralysis) of which of the following muscles would be associated with foot drop?

tibialis anterior (Tibialis anterior is the major dorsiflexer of the foot--if it is damaged, you will observe foot drop. It is found in the anterior compartment and is innervated by the deep fibular nerve. This patient probably damaged her common fibular nerve in the accident. This nerve wraps around the neck of the fibula before giving off its two branches: the deep fibular nerve and the superficial fibular nerve. You might hypothesize that this patient would also have a loss of cutaneous sensation on the distal third of the anterior leg and the dorsum of the foot, since those are the areas that receive cutaneous innervation from the superficial fibular nerve.)

The main source of blood to the superficial palmar arterial arch is the:

ulnar artery

A deep puncture wound in the palmar surface of the little finger near the proximal IP joint might introduce infection into which synovial cavity:

ulnar bursa (The ulnar bursa is a synovial sheath covering the digital flexor tendons- -it covers the flexor tendons as they pass under the flexor retinaculum and terminates near the center of the palm for the second, third, and fourth fingers. However, the portion of the ulnar bursa which is concerned with the fifth finger does not terminate in the middle of the palm--instead, it continues all the way into the insertion of the profundus tendon into the fifth digital phalanx. This means that a superficial cut on the palmar side of the fifth digit can introduce an infection into the ulnar bursa. The radial bursa is the other bursa associated with the flexor tendons--it is a synovial sheath for flexor pollicis longus that extends to the point where this tendon inserts on the distal phalanx of the thumb. A superficial cut on the palmar side of the thumb might introduce an infection into the radial bursa.)