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Lab 7— Posterior Leg & Skeletal—QuesƟons 1 of 1

1. A 32-year-old carpenter fell from the roof. The lateral 5. A 12-year-old boy is brought to the emergency room by longitudinal arch of his foot was flattened from fracture his mother following being pushed out of the neighbor’s and displacement of the keystone for the arch. Which of tree house, about 10 ft off the ground. He can walk but his the following bones is damaged? right hurts every time he puts weight on it. When you A. Calcaneus examine his foot it is tender to pressure on both the medi- B. Cuboid bone al and lateral aspects of the heel inferior to the . You C. Head of the talus order plain films of his right lower extremity because you D. Medial cuneiform suspect he has fractured which of the following? E. Navicular bone A. Calcaneus B. Fibula C. Tibia D. Navicular E. Cuneiform

2. An ossification center is present in which of the follow- 6. A 10-year-old boy falls from a tree house. The resultant ing bones of the foot at six months of intra-uterine life heavy compression of the sole of his foot against the (I.U.L) of the fetus? ground caused a fracture of the head of the talus. Which A. Calcaneus of the following structures is unable to function normally? B. Cuboid A. Transverse arch C. Talus B. Medial longitudinal arch D. Medial cuneiform C. Lateral longitudinal arch E. Lateral cuneiform D. Tendon of the E. Long plantar ligament

3. During recruitment by the local representative for the Marines, a young college student presents with the condi- tion known as flat foot. His foot is displaced laterally and everted, and the head of the talus is no longer supported. Which of the following ligaments probably is stretched? A. Plantar calcaneonavicular (spring) B. Calcaneofibular C. Anterior talofibular D. Plantar calcaneocuboid (short plantar) E. Anterior tibiotalar

4. A 21-year-old man falls from the attic and is brought to the emergency room. Examination and radiogram reveal that the lateral longitudinal arch of his foot is flattened. Which of the following bones is displaced? A. Talus B. Medial three metatarsals C. Navicular D. Cuneiform E. Cuboid

1 Lab 7— Posterior Leg & Foot Skeletal—Answers

1. Answer B. (1) The keystone for the lateral longitudi- 5. Answer A. (7)The calcaneus is the most frequently nal arch is the cuboid bone, whereas the keystone for the broken of the tarsal bones. The weight of the body is medial longitudinal arch is the head of the talus. The cal- transmitted down the tibia and onto the talus, which acts caneus, navicular, and medial cuneiform bones form a as a wedge cracking the calcaneus inferiorly. Unfortunate- part of the medial longitudinal arch, but they are not key- ly, this fracture normally involves the cartilaginous articular stones. The calcaneus also forms a part of the lateral lon- surface, complicating the healing process, increasing the gitudinal arch. likelihood of developing an arthritic subtalar joint. These fractures often must be held together with screws or plates for optimal healing. Since the pain was bilateral, and only the calcaneus is bilateral across the heel, none of the oth- er bones (answers b, c, d, and e) listed are possible sites of fracture. The distal end of the tibia (answer c) would have carried the bulk of the force, but the pain location is inconsistent with a distal tibial fracture.

2. Answer A. (1) Primary ossification centres of tarsal 6. Answer B. (1) The keystone of the medial longitudi- bones appear in the following sequence: nal arch of the foot is the head of the talus, which is locat- Calcaneus - 6th month of intra-uterine life (I.U.L) ed at the summit between the sustentaculum tali and the Talus - 7th month of I.U.L navicular bone. The medial longitudinal arch is supported Cuboid - 9th month of I.U.L (at or around birth in a full term by the spring ligament and the tendon of the flexor hallu- born) cis longus muscle. The cuboid bone serves as the key- Lateral cuneiform - 1 year stone of the lateral longitudinal arch, which is supported Medial cuneiform - 3 years by the peroneus longus tendon and the long and short Intermediate cuneiform - 4 years plantar ligaments. The transverse arch is formed by the Hence, the question of viability of a dead born fetus may navicular, three cuneiform, the cuboid, and five metatarsal be assessed by presence or absence of ossification centre bones and is supported by the peroneus longus tendon in calcaneus. Similarly, the presence of an ossification cen- and the transverse head of the adductor halluces. ter in cuboid also helps in assessing the age of the fetus.

3. Answer A. (5) Flat foot is characterized by disap- pearance of the medial portion of the longitudinal arch, which appears completely flattened. The plantar calcane- onavicular (spring) ligament supports the head of the ta- lus and the medial side of the longitudinal arch. The pla- nar calcaneocuboid (short plantar) ligament supports the lateral portion of the longitudinal arch. The other liga- ments support the joint.

4. Answer E. (5) The lateral longitudinal arch is formed by the calcaneus, cuboid bone, and lateral two metatarsal bones, whereas the medial longitudinal arch of the foot is formed by the talus, calcaneus, navicular bone, cuneiform bones, and medial three metatarsal bones.

2 Lab 7— Posterior Leg & Foot Muscles; Tendons — QuesƟons 1 of 4

1. The process of unlocking the fully extended in 5. A 20-year-old college student is brought to the emer- preparation for flexion requires initial contraction of which gency room straight from the soccer field. He had just of the following? started to sprint after the ball, when he heard a loud snap A. Gastrocnemius, soleus, and plantaris muscles and felt sharp pain in his left as if somebody had B. muscles kicked him in the back of his leg. He cannot stand on tip- C. and Thompson test is positive on the left, which sug- D. Quadriceps femoris muscle gests rupture of the . E. Sartorius muscle and short head of the biceps femoris What muscle is affected by this injury? muscle A. M. peroneus longus B. M. triceps surae (soleus and gastrocnemius) C. M. biceps femoris D. M. tibialis anterior E. M. semimembranosus

2. A 19-year-old teenager was dancing in clogs in an eth- 6. What is the function of the M. flexor digitorum longus? nic street festival when she inverted her left foot. She pre- A. Dorsiflexion and inversion sents to your office the next day with a swollen foot, but B. Dorsiflexion and eversion mainly complains about tenderness on the lateral aspect C. Plantarflexion and inversion of the foot along the plantar surface. You carefully palpate D. Plantarflexion and eversion her foot and determine that she has tenderness over the E. Dorsal flexion and both inversion and eversion tuberosity of the . What muscle has avulsed from its insertion on to the tuberosity of the fifth metatarsal? A. Abductor digiti minimi B. Fibularis (Peroneus) brevis C. Fibularis (Peroneus) longus D. Tibialis anterior E. Tibialis posterior

3. A construction worker is hit on the leg with a concrete 7. The arrow refers to which block and is subsequently unable to plantar flex and invert tendon? his foot. Which of the following muscles is most likely damaged? A. Extensor hallucis longus A. Extensor digitorum longus B. Extensor digitorum longus B. Tibialis anterior C. Tibialis anterior C. Tibialis posterior D. D. Peroneus longus E. Peroneus longus E.

4. An injury to the leg of a golfer results in loss of the abil- 8. The largest plantar flexors in the superficial layer of the ity to invert the foot. Which of the following muscles is posterior compartment are the triceps surae. The muscles most likely paralyzed? of the triceps surae all insert into the calcaneus. When A. Tibialis posterior evaluating the muscle-tendon for injury, one must test B. Peroneus longus with the knee straight and bent to isolate the muscles for C. Peroneus brevis evaluation. Which one of the muscles originates below D. Peroneus tertius the knee joint? E. Extensor digitorum longus A. Gastrocnemius B. Soleus C. Flexor digitorum longus D. Flexor hallucis longus E. Plantaris

3 Lab 7— Posterior Leg & Foot Muscles; Tendons — Answers

1. Answer C. (7) To unscrew a knee from its locked 5. Answer B. (2) The triceps surae consists of the so- and slightly hyperextended position, the popliteus muscle leus, which origins at the tibia and fibula and the gas- contracts and causes medial rotation of the tibia or, if the trocnemius, which origins at the medial and lateral con- foot is planted, lateral rotation of the . This move- dyle of the femur. Both insert to the calcaneus via the ment frees the medial femoral condyle from its posterior Achilles tendon. They are both innervated by the tibial position on the tibial condylar surface. The quadriceps and plantar and it flexes the foot, with the gas- femoris (answer d) then relaxes, and knee flexion occurs trocnemius also flexing the knee. In the Thompson test, by contraction of the hamstring muscles (answer b), as- squeezing the calf results in a passive plantar flexion of sisted by the short head of the biceps femoris, sartorius the foot with intact Achilles tendon. This does not happen (answer e), gracilis, and gastrocnemius muscles (answer with a ruptured tendon and then the test is considered a). positive. Treatment is a long leg casting for four weeks, short leg walking cast for four weeks, heel lift for four weeks, or open surgical repair.

2. Answer B. (7) The fibularis (peroneus) brevis, a 6. Answer C. (2) To decide which muscles perform pronator and everter of the foot, inserts into the tubercle what functions, one has to focus on where the tendons at the base of the fifth metatarsal. Inversion of the foot is pass in relation to the axis of the talocrural and subtalar a common means of avulsing this tendon from the tuber- joints. osity of the fifth metatarsal and is called Jones fracture for In the talocrural joint, muscles whose tendons lie in front the doctor that causes his own fracture while dancing of its axis dorsiflex the foot, while muscles whose tendons around a pole. It is normally treated by placing the patient lie posterior to the joint's axis plantarflex the foot. in a short walking cast. The fibularis (peroneus)longus In the subtalar joint, muscles whose tendons lie medial of (answer c)passes under the tarsal arch to insert onto the its axis invert the foot, while muscles whose tendons lie plantar aspect of the first metatarsal. The tibialis posterior lateral to the joint's axis evert the foot. (answer e) inserts onto the navicular bone, whereas the tibialis anterior (answer d) inserts into the first cuneiform and first metatarsal. The abductor digiti minimi (answer a) inserts onto the proximal phalanx of the fifth toe.

3. Answer C. (1) The tibialis posterior can plantar flex 7. Answer C. (2) The structure referred to in the pho- and invert the foot. The extensor digitorum longus can tograph by the arrow is the tibialis anterior tendon. dorsiflex and evert the foot, the tibialis anterior can dorsi- This tendon is innervated by the deep peroneal nerve and flex and invert the foot, and the peroneus longus and often receives a branch from the . brevis can plantar flex and evert the foot. The tibialis anterior originates from the lateral condyle of the tibia, from the upper two thirds of the lateral surface of its shaft, and from the interosseous membrane. It is in- serted into the medial side of the medial cuneiform and the base of the first metatarsal. It dorsiflexes and inverts the foot.

4. Answer A. (1) The tibialis posterior inverts the foot. 8. Answer B. (2) The origi- The peroneus longus, brevis, and tertius and extensor nates from the posterior medial and lateral epicondyles of digitorum longus can evert the foot. the femur. The plantaris originates medially adjacent to the lateral head of the gastrocnemius muscle on the femur. The soleus originates in a horseshoe fashion from the posterior aspect of the tibia and fibula. The flexor digitorum longus and the flexor hallucis longus are not part of the triceps surae. This is not an option.

4 Lab 7— Posterior Leg & Foot Muscles; Tendons — QuesƟons 2 of 4

9. You have a patient in a BK cast for 8 weeks. He under- 13. You diagnose your patient with a tibial fracture and stands that his leg muscles will decrease in size and place a BK cast on for 8 weeks. He understands that his strength. You suggest some exercises to be done each leg muscles will decrease in size and strength. You sug- day at home. One of the exercises is to "bring his to gest some exercises to be done each day at home. One his nose" and release. With this exercise, he will be using of the exercises is to "scrunch up" a towel on the floor his extensor muscles. Which muscle extends the digits at with his toes. In this exercise, he is using his digital flexor the MTPJ? muscles. Which muscle is the major flexor of the DIPJ A. Extensor digitorum longus and is innervated by the ? B. Lumbricales A. Extensor digitorum longus C. Tibialis posterior B. Lumbricales D. Flexor digitorum brevis C. Tibialis posterior E. Flexor digitorum longus D. Flexor digitorum brevis E. Flexor digitorum longus

10. What is the function 14. Some muscles have a dual function. This function is of the tendon referred determined by its origin or attachment/insertion. Which to? one of the following are an extensor of the PIPJ's and a flexor of the MTPJ's of the lateral 4 digits? A. Everts and plantar A. Extensor digitorum longus flexes the foot B. Lumbricales B. Inverts and dorsiflex- C. Tibialis posterior es the foot D. Flexor digitorum brevis C. Everts and dorsiflex- E. Flexor digitorum longus es the foot D. Inverts and plantar flexes the foot E. Extends the toes

11. A 22-year-old patient is unable to “unlock” the knee 15. Some muscles have a dual innervation. Many times joint to permit flexion of the leg. Which of the following this occurs because of the placement of the muscle in muscles is most likely damaged? relationship to the . Which of the following is inner- A. Rectus femoris vated by the medial AND ? B. Semimembranosus A. Extensor digitorum longus C. Popliteus B. Lumbricales D. Gastrocnemius C. Tibialis posterior E. Biceps femoris D. Flexor digitorum brevis E. Flexor digitorum longus

12. A construction worker falls feet first from a roof. He 16. A 9-year-old boy presents to the emergency room sustains a fracture of the groove on the undersurface of after stepping on glass. The radiograph shows a 0.5cm the sustentaculum tali of the calcaneus bone. Which of foreign body in the superficial layer of the foot. As you the following muscle tendons is most likely torn? prepare to remove the foreign body, you review the anat- A. Flexor digitorum brevis omy of the foot. The intrinsic muscles of the foot lie in four B. Flexor digitorum longus layers. The superficial layer lies in what position in com- C. Flexor hallucis brevis parison to the plantar ? D. Flexor hallucis longus A. Deep E. Tibialis posterior B. Superficial C. Medial D. Lateral E. Distal F. Proximal

5 Lab 7— Posterior Leg & Foot Muscles; Tendons — Answers

9. Answer A. (2) The flexor digitorum longus is the ma- 13. Answer E. (2) The flexor digitorum longus is the major jor flexor of the DIPJ's of the 2-5 digits. It is innervated by flexor of the DIPJ's of the 2-5 digits. It is innervated by the tibial the tibial nerve (L5,S1). nerve (L5,S1). The extensor digitorum longus is innervated by the deep The extensor digitorum longus is innervated by the deep pero- peroneal nerve (L4, L5, and S1). It is part of the "hood neal nerve (L4, L5, and S1). mechanism" and is an extensor of the digits at the MTPJ. It is part of the "hood mechanism" and is an extensor of the dig- The lumbricales, with the interossei, cause flexion of the its at the MTPJ. The lumbricales, with the interossei, cause flexion of the MTPJ MTPJ and extension of the PIPJ's. Innervation is by the and extension of the medial and lateral plantar nerve. PIPJ's. Innervation is by the medial and lateral plantar nerve. The tibialis posterior inverts and plantar flexes the ankle. It The tibialis posterior inverts and plantar flexes the ankle. It has has no direct effect on the digits. The innervation is by the no direct effect on the digits. The innervation is by the tibial tibial nerve (L4, L5, and S1). nerve (L4, L5, and S1). The flexor digitorum brevis causes flexion of the PIPJ of The flexor digitorum brevis causes flexion of the PIPJ of digits 2- digits 2-5. The innervation is by the 5. The innervation is by the medial plantar nerve (L4, L5, and (L4, L5, and S1). S1).

10. Answer A. (2) The peroneus longus everts and 14. Answer B. (2) The flexor digitorum longus is the major plantar flexes the foot. This muscle arises from the lateral flexor of the DIPJ's of the 2-5 digits. It is innervated by the tibial condyle of the tibia, from the head of the fibula, and from nerve (L5,S1). the upper two-thirds of the lateral surface of the shaft of The extensor digitorum longus is innervated by the deep pero- neal nerve (L4, L5, and S1). the fibula. The tendon curves behind the lateral , It is part of the "hood mechanism" and is an extensor of the dig- deep to the superior peroneal retinaculum, in a common its at the MTPJ. synovial sheath with the peroneus brevis. On the lateral The lumbricales, with the interossei, cause flexion of the MTPJ side of the calcaneus, behind and below the peroneal and extension of the trochlea, it lies deep to the inferior peroneal retinaculum. PIPJ's. Innervation is by the medial and lateral plantar nerve. After passing through a notch on the lateral side of the The tibialis posterior inverts and plantar flexes the ankle. It has cuboid, it crosses the sole of the foot obliquely to be in- no direct effect on the digits. The innervation is by the tibial serted into the lateral side of the medial cuneiform and nerve (L4, L5, and S1). the adjacent base of the first metatarsal. The peroneus The flexor digitorum brevis causes flexion of the PIPJ of digits 2- 5. The innervation is by the medial plantar nerve (L4, L5, and longus is innervated by the superficial peroneal nerve. S1).

11. Answer C. (1) The popliteus muscle rotates the 15. Answer B. (2) The flexor digitorum longus is the major femur laterally (“unlocks” the knee) or rotates the tibia flexor of the DIPJ's of the 2-5 digits. It is innervated by the tibial medially, depending on which bone is fixed. This action nerve (L5, S1). results in unlocking of the knee joint to initiate flexion of The extensor digitorum longus is innervated by the deep perone- al nerve (L4, L5, and S1). It is part of the "hood mechanism" and the leg at the joint. The rectus femoris flexes the and is an extensor of the digits at the MTPJ. extends the knee. The gastrocnemius flexes the knee and plantar flexes the foot. The semimembranosus extends The lumbricales, with the interossei, cause flexion of the MTPJ the thigh and flexes and rotates the leg medially. The bi- and extension of the PIPJ's. Innervation is by the medial and ceps femoris extends the thigh and flexes and rotates the lateral plantar nerve. leg laterally. The tibialis posterior inverts and plantar flexes the ankle. It has no direct effect on the digits. The innervation is by the tibial nerve (L4, L5, and S1). The flexor digitorum brevis causes flexion of the PIPJ of digits 2- 5. The innervation is by the medial plantar nerve (L4, L5, and S1).

12. Answer D. (1) The tendon of the flexor hallucis 16. Answer A. (2) The superficial layer of the intrinsic longus muscle occupies first the groove on the posterior plantar muscles lie deep to the plantar aponeurosis. The surface of the talus and then the groove on the undersur- most superficial structure of the plantar aspect of the foot of the sustentaculum is the plantar aponeurosis followed by the first (flexor digi- tali. None of the other tendons would have been affected torum brevis, abductor hallucis, and abductor digiti mini- in such an injury. mi), second (quadratus plantae and lumbricals), third (flexor hallucis brevis, adductor hallucis, and flexor digiti minimi brevis), and forth (interossei) muscle layers.

6 Lab 7— Posterior Leg & Foot Muscles; Tendons — QuesƟons 3 of 4

17. A 54-year-old female patient reports a "sore foot" x 2 21. A 20-year-old patient cannot flex and medially rotate days. Upon muscle testing you discover that active dorsi- the thigh while running and climbing. Which of the follow- flexion and plantarflexion at the ankle elicits little pain. ing muscles is most likely damaged? However, palpation of the dorsal aspect of the foot elicits A. Semimembranosus pain. What is the only intrinsic muscle on the dorsum of B. Sartorius the foot? C. Rectus femoris A. Extensor digitorum longus D. Vastus intermedius B. Extensor digitorum brevis E. Tensor fasciae latae C. Flexor digitorum longus D. Flexor digitorum brevis E. Peroneal longus F. Peroneal brevis

18. A 12-year-old female presents to the emergency room 22. A healthy 37-year-old woman sustained a hairline after stepping on coral at the beach. The radiograph fracture of the left tibia. Her leg is put in a cast and immo- shows a 0.5cm foreign body in the superficial layer of the bilized. 6 weeks later, the cast is removed from her leg. A foot. As you prepare to remove the foreign body, you re- repeat X-ray shows healing of the fracture line. What best view the anatomy of the foot. The intrinsic plantar mus- characterizes her gastrocnemius muscle at this time? cles lie in four layers. Which intrinsic muscle lies in the A. Muscle undergoes fibrosis first layer? B. Increased fat deposition A. Abductor digiti minimi C. Decrease in number of myofibrils B. Quadratus plantae D. Increase in calcium levels C. Flexor digit minimi E. Increase in number of satellite cells D. Interossei E. Adductor hallucis

19. A 9-year-old boy presents to the emergency room 23. A 14-year-old gymnastic silver medalist falls from the after stepping on a . The radiograph shows a 0.5cm parallel bar and complains of pains from the knee and foreign body in the deep layer of the foot. As you prepare ankle joints. On physical examination, her physician found to remove the foreign body, you review the anatomy of that the muscle responsible for flexing the leg at the knee the foot. Which of the muscles is the deepest layer? joint and plantar flexing the foot is severely weakened. A. Abductor digiti minimi Which of the following muscles involved in both move- B. Quadratus plantae ments was most likely damaged in this accident? C. Flexor digit minimi A. Tibialis posterior D. Interossei B. Gastrocnemius E. Abductor hallucis C. Soleus D. Peroneus longus E. Flexor digitorum longus

20. A 9-year-old boy presents to the emergency room 24. A 28-year-old basketball player falls while rebounding after stepping on coral at the beach. The radiograph and is unable to run and jump. On physical examination, shows a 0.5cm foreign body in the foot. As you prepare to he has pain and weakness when extending his thigh and remove the foreign body, you review the anatomy of the flexing his leg. Which muscle involved in both movements foot. Which muscle is in the second plantar layer of the is most likely injured? foot? A. Short head of biceps femoris A. Abductor digiti minimi B. Adductor magnus B. Quadratus plantae C. Semitendinosus C. Flexor digit minimi D. Sartorius D. Interossei E. Gracilis E. Abductor hallucis

7 Lab 7— Posterior Leg & Foot Muscles; Tendons — Answers

17. Answer B. (2) The extensor digitorum brevis arises 21. Answer E. (1) The tensor fasciae latae can flex and from the superior "beak" of the calcaneus and inserts in the medially rotate the thigh, so this is the muscle most likely dorsolateral capsules of the metatarsophalangeal joints of damaged. The hamstring muscles (semitendinosus, semi- the toes. This is the only intrinsic muscle on the dorsum of membranosus, and biceps femoris) can extend the thigh the foot. and flex the leg. The sartorius can flex the thigh and leg. The extensor digitorum longus is located on the dorsum of The rectus femoris can flex the thigh and extend the leg. the foot. However, it originates from the proximal fibula and The vastus intermedius can extend the leg. inserts into the foot. This is not an intrinsic muscle. The flexor digitorum longus/brevis and peroneal longus/ brevis are not located on the dorsum of the foot. Therefore, these are not options.

18. Answer A. (2) The superficial layer or the first lay- 22. Answer C. (2) Due to long term restriction of activity, the er consists of the flexor digitorum brevis, abductor gastrocnemius muscle is expected to undergo disuse atrophy. hallucis, and the abductor digiti minimi muscles. The muscle fibers decrease in size and there is a decrease in The second layer consists of the quadratus plantae and number of myofibrils. The muscle fiber type (fast or slow fiber) is determined by the the lumbrical muscles. type of innervation. Whether training and detraining can inter- The third layer includes the flexor hallucis brevis, adduc- change the muscle fiber types is controversial, although there is tor hallucis, and the flexor digiti more support to the idea of fast fibers converting to slow fibers minimi brevis. with detraining. The fourth layer, the deepest layer, contains the interos- Satellite cells are normally quiescent cells in that sei muscles. become active in regeneration and hypertrophy.

19. Answer D. (2) The superficial layer or the first lay- 23. Answer B. (1) The gastrocnemius can flex the er consists of the flexor digitorum brevis, abductor hallu- knee joint and also plantar flex the foot. The tibialis poste- cis, and the abductor digiti minimi muscles. rior can plantar flex and invert the foot. The soleus can The second layer consists of the quadratus plantae and plantar flex the foot. The peroneus longus can plantar flex the lumbrical muscles. and evert the foot. The flexor digitorum longus can plantar The third layer includes the flexor hallucis brevis, adduc- flex the foot and flex the lateral four toes. tor hallucis, and the flexor digiti minimi brevis. The fourth layer, the deepest layer, contains the interos- sei muscles.

20. Answer B. (2) The superficial layer or the first lay- 24. Answer C. (1) The semitendinosus extends the er consists of the flexor digitorum brevis, abductor hallu- thigh and flexes the leg. The short head of the biceps cis, and the abductor digiti minimi muscles. femoris flexes the leg. The adductor magnus adducts, The second layer consists of the quadratus plantae and flexes, and extends the thigh. The sartorius and gracilis the lumbrical muscles. can flex the thigh and leg. The third layer includes the flexor hallucis brevis, adduc- tor hallucis, and the flexor digiti minimi brevis. The fourth layer, the deepest layer, contains the interos- sei muscles.

8 Lab 7— Posterior Leg & Foot Muscles; Tendons — QuesƟons 4 of 4

25. Your patient just took up jogging in the evening for exer- cise and complains that after a mile or so his left leg begins to hurt. You question him on regions of the body or move- ments that do or do not evoke pain and find that it is wide- spread throughout his left lower . Based on the location of the constriction of the (indicated by the arrow), what compartment or movement would you think would be LEAST affected by the reduced arterial blood flow?

A. Gluteal region B. Flexion of the thigh C. Extension of the leg D. Posterior thigh E. Plantar flexion of the foot

25.

26. In a presurgical patient, the great saphenous vein was cannulated in the vicinity of the ankle. During the proce- dure, the patient experienced severe pain that radiated along the medial border of the foot. Which of the following nerves was accidentally included in a ligature during this procedure? A. Medial femoral cutaneous nerve B. C. Superficial fibular nerve D. Sural cutaneous nerve E. Tibial nerve

27. A football player has suffered severe trauma to the lateral part of the left leg just below the knee. He drags his left toe when he walks and cannot feel the dorsum of the foot. Which of the following will still be intact? A. Dorsiflexion B. Inversion C. Eversion D. Cutaneous sensation of the medial leg E. Cutaneous sensation between the great toe and the second toe

9 Lab 7— Posterior Leg & Foot Muscles; Tendons — Answers

25. Answer B. (7) Flexion of the thigh would be least affected. The lesion involves the common iliac artery just proximal to its division into the internal and external iliac branches. Blood flow would be compromised to the external iliac artery and its downstream branches including the femo- ral, deep femoral, popliteal, tibial, fibular, and plantar arter- ies. Blood flow would also be diminished to branches of the internal iliac artery, including gluteal (answer a) and visceral . One of the most powerful flexors of the thigh is the psoas muscle, which originates from the lumbar vertebrae and receives most of its blood from the aorta and common iliac artery and thus would be unaffected by the lesion. All functions more distal to the blockage would likely be affect- ed [thus not (answers c, d, and e)].

26. Answer B. (7) The saphenous nerve accompanies the great saphenous vein along the medial aspect of the leg and foot as far as the great toe. The medial femoral cutaneous nerve (answer a) innervates the dorsal aspect of the leg. The superficial fibular nerve (answer c) inner- vates the central portion of the dorsum of the foot. The sural cutaneous nerve (answer d) innervates the lateral aspect of the foot. The medial and lateral plantar branch- es of the tibial nerve (answer e) supply the sole of the foot.

27. Answer D. (6) Cutaneous sensation of the medial leg is provided by the saphenous nerve, a branch of the that would be unaffected by this lesion, which has lacerated the common peroneal nerve.

10 Lab 7— Posterior Leg & Foot Nerves—QuesƟons 1 of 3

1. A 42-year-old woman presents with a 5-day history of 5. A 19-year-old woman comes to the emergency depart- progressive weakness in the right foot, as well as a loss ment after falling while on roller-blades. There is a 3-cm of sensation. She states that she hit her knee. Physical laceration over the lateral aspect of the knee penetrating exam findings are a bruise on the anteroloateral aspect of so deep that the head of the fibula is apparent. A radio- the knee, numbness on the upper anterior part of the leg, graph of the leg is negative for any fractures. A noticeable and weakness of the eversion of the foot. This clinical foot-drop occurs while the patient walks. Further examina- picture is suggestive of a lesion on what nerve? tion reveals inability to dorsiflex or evert the foot. Which of A. Deep peroneal nerve the following best explains her injury? B. Femoral nerve A. The common peroneal nerve was severed C. Common peroneal nerve B. The peroneal muscles were detached from the head of D. Superficial peroneal nerve the fibula E. Tibial nerve C. The superficial peroneal nerve was severed D. The tibial nerve was severed

2. A 30-year-old woman presents with progressive pain 6. A patient presents to the physician complaining of on the dorsum of the left foot. The physical exam shows "something wrong with her foot" that causes her to trip that the patient has a mass on the external area of the and fall. Physical examination reveals an inability to dorsi- leg, abnormal sensation on the dorsum of the foot, and flex (extend) the foot and a loss of sensation between the limited eversion of the foot. This clinical picture is sugges- first and second toes. There is no other motor or sensory tive of a lesion on what nerve? loss. Which of the following nerves was most likely in- A. Deep peroneal nerve jured? B. Femoral nerve A. Deep peroneal C. Peroneal common nerve B. Femoral D. Superficial peroneal nerve C. Superficial peroneal E. Tibial nerve D. Sural E. Tibial

3. A 14-year-old girl broke her left tibia just above the an- 7. A man interviewing for a new administrative position as kle while skiing a year ago. At a small hospital near the hospital chief executive officer (CEO) notices difficulty slopes, a doctor put a cast on her leg. When the cast was walking after sitting with his leg crossed for 2 hours. He removed at the medical center, it was obvious that she was nervous during the interview but even more so now had a severe foot-drop due to muscle paralysis, possibly that he is attempting to stand to follow two board mem- due to the treatment. The condition remains unchanged bers for a tour of the hospital. Which of the following ac- and now may be the cause of a legal suit for damages. tions is most seriously affected by compression and tem- Which nerve was involved? porary paralysis of the deep peroneal nerve? A. Lateral sural cutaneous A. Plantar flexion of the foot B. Tibial B. Dorsiflexion of the foot C. Common peroneal C. Abduction of the toes D. Femoral D. Adduction of the toes E. Saphenous E. Inversion of the foot

4. A child steps on some glass on the sole of his 8. A 47-year-old woman is unable to invert her foot after foot and complains of numbness of the small toe. What she stumbled on her driveway. Which of the following nerve has he injured? nerves are most likely injured? A. Medial plantar B. Lateral plantar A. Superficial and deep peroneal C. Tibial B. Deep peroneal and tibial D. Superficial peroneal C. Superficial peroneal and tibial E. Deep peroneal D. Medial and lateral plantar E. Obturator and tibial

11 Lab 7— Posterior Leg & Foot Nerves—Answers

1. Answer D. (2) A lesion of the common peroneal nerve mani- 5. Answer A. (4) The common peroneal nerve wraps around fests as a combination of symptoms showing deficits of the deep the lateral aspect of the head of the fibula and is highly susceptible and the superficial peroneal nerves. The nerve runs subcutaneous- to damage during lacerations or blunt injuries to the lateral knee. ly, winding around the of the fibula; this makes it very vulnera- Foot-drop with loss of dorsiflexion or eversion is characteristic. ble to lesions caused by trauma or pressure. Only the peroneus longus completely attaches to the fibular head A lesion of the deep peroneal nerve produces a weak inversion, (choice B). Other muscles that attach in other places along the loss of extension of the toes, an abnormal sensation of the web tibia and fibula provide dorsiflexion and eversion for the foot (e.g., space area of the 1 toe, and foot drop. A lesion of the femoral extensor digitorum longus, peroneus brevis, extensor hallucis lon- nerve produces a weakness in knee extension and sensorial ab- gus, and tibialis anterior). The common peroneal nerve then normalities on the anterior thigh and the medial area of the leg. branches into the superficial (choice C) and deep peroneal nerves, Proximal lesions can cause weak flexion. which supply the muscles of the anterior compartment of the leg A lesion of the superficial peroneal nerve produces sensorial ab- and cutaneous areas of the distal anterior leg, dorsum of the foot, normalities on the dorsum of the foot, (except the 1 web space) and most of the digits. and the inability to evert the foot. A lesion of the tibial nerve produc- The tibial nerve (choice D) supplies all the muscles in the posterior es a weakness in the flexion of the knee and toes, abnormal sensa- compartment of the leg (e.g., tibialis posterior, flexor digitorum tion on the back of the leg and sole, and weak plantar flexion. longus, gastrocnemius, and soleus).

2. Answer D. (2) A lesion of the superficial peroneal nerve pro- 6. Answer A. (4) The deep peroneal nerve arises from the com- duces sensorial abnormalities on the dorsum of the foot (except the mon peroneal nerve (L4-S2). It innervates the muscles of the anterior 1 web space) and an inability to evert the foot. A lesion of the deep compartment of the leg, which dorsiflex (extend) the foot. Damage to peroneal nerve produces a weak inversion, loss of extension of the the nerve therefore produces "foot-drop"-a classic clue to deep pero- toes, abnormal sensation of the web space of the 1 toe, and foot neal nerve pathology. The nerve gives rise to many branches, one of drop. which innervates the between the first and second toes. The A lesion of the femoral nerve produces a weakness in knee exten- femoral nerve (choice B) contains fibers from L2L4. It supplies flexor sion and sensorial abnormalities on the anterior thigh and the medi- muscles of the thigh, extensors at the knee joint, and cutaneous are- al area of the leg. Proximal lesions can cause weak hip flexion. as of the thigh. The saphenous nerve branches off it and supplies the A lesion of the common peroneal nerve manifests with a combina- knee joint and the skin on the medial aspect of the foot. The superfi- tion of symptoms that present with a deficit of the deep and the su- cial peroneal nerve (choice C) supplies the muscles of the lateral perficial peroneal nerves. The nerve runs subcutaneously, winding compartment of the leg and is responsible for foot eversion. It also around the neck of the fibula; this makes it very vulnerable to le- conveys sensory information from most of the dorsal surface of the sions caused by trauma or pressure. foot. The (choice D) arises from the common peroneal A lesion of the tibial nerve produces weakness in the flexion of the and tibial nerves and innervates the skin of the calf. The tibial nerve knee and toes, abnormal sensation on the back of the leg and sole, (choice E) innervates the , as well as muscles of the calf and weak plantar flexion. and sole of the foot

3. Answer C. (2) The common peroneal nerve branches as the 7. Answer B. (5) The deep peroneal nerve innervates the lateral division of the at the superior aspect of the pop- dorsiflexors of the foot, which include the tibialis anterior, exten- liteal fossa, and then courses along the lateral boundary of the fossa sor hallucis longus, extensor digitorum longus, and peroneus with the tendon of the . Crossing the head of tertius muscles. The plantar flexors include the triceps surae, the fibula, from which it is separated by a film of soleus, it comes tibialis posterior, flexor digitorum longus, and flexor hallucis lon- finally into direct contact with the lateral side of the neck of the fibula gus, which are innervated by the tibial nerve; and peroneus lon- to enter the leg. It then divides into its 2 clinically important terminal gus and brevis, which are innervated by the superficial peroneal branches: Deep peroneal nerve and superficial peroneal nerve. nerve. The toes are abducted and adducted by dorsal and plan- Here it is vulnerable to damage due to fracture of the fibula or com- tar interosseous muscles, which are innervated by the medial pression, which was caused by the cast as in this case. The superficial peroneal branch supplies the peroneal muscles and and lateral plantar nerves. The foot is inverted by the tibialis the skin of most of the toes. The deep branch supplies all the exten- anterior and posterior, triceps surae, and extensor hallucis lon- sor muscles and the great dorsiflexorinvertor-hence the foot drop gus, which are innervated by the tibial nerve suffered by this patient and the skin between toes 1 and 2. The slender fibula is only palpable at its two ends- head and the lateral malleolus.

4. Answer B. (2) The lateral plantar nerve supplies sensa- 8. Answer B. (1) The deep peroneal and tibial nerves inner- tion to the distal lateral sole, the plantar aspect of the small toe vate the chief evertors of the foot, which are the tibialis anterior, and the lateral plantar surface of the fourth toe. Muscular tibialis posterior, triceps surae, and extensor halluces longus branches are given to the quadratus plantae, abductor digiti muscles. The tibialis anterior and extensor hallucis longus mus- minimi, flexor digiti minimi brevis, the interossei, the second, cles are innervated by the deep peroneal nerve, and the tibialis third, and fourth lumbricals, and the adductor hallucis posterior and triceps surae are innervated by the tibial nerve.

12 Lab 7— Posterior Leg & Foot Nerves—QuesƟons 2 of 3

9. The flexor hallucis longus tendon is damaged in a 11. The medial longitudinal arch of the foot is flattened groove on the posterior surface of a tarsal bone. Which because the spring ligament is torn. Which bone in the bone in the radiograph is likely fractured radiograph is most likely fractured?

10. The tibialis anterior and peroneus longus muscles are 12. The peroneus longus muscle tendon is damaged in a weakened. Which bone in the radiograph is most likely groove of a tarsal bone by fracture. Which bone in the fractured? radiograph is most likely fractured?

13 Lab 7— Posterior Leg & Foot Vessels—QuesƟons

9. Answer A. (1) The body of the talus has a groove 11. Answer D. (1) The spring (plantar calcaneonavic- on its posterior surface for the flexor hallucis longus ten- ular) ligament extends from the sustentaculum tali of the don. This tendon also occupies the groove on the under- calcaneus to the navicular bone. surface of the sustentaculum tali.

10. Answer E. (1) The first or medial cuneiform bone 12. Answer B. (1) The cuboid bone has a groove for the pe- provides insertions for the tibialis anterior, tibialis posteri- roneus longus muscle tendon. or, and peroneus longus muscles.

14 Lab 7— Posterior Leg & Foot Nerves—QuesƟons 3 of 3

13. The ankle jerk is a reflex twitch of the triceps surae 17. A 27-year-old man is admitted for neurologic evalua- (gastrocnemius and soleus) induced by tapping the tendo tion of a gunshot wound received 5 days previously. A 9- calcaneus (Achilles tendon). Where is the reflex center? mm bullet had passed through both the medial and lateral heads of the gastrocnemius muscle. The exit wound on A. The 5 lumbar or 1 sacral segment the lateral head of the muscle was somewhat deeper than B. The 1 or 2 sacral segment the entrance wound in the medial head. The bullet did not C. The 4 or 5 lumbar segment strike bone or significant arteries although significant tis- D. The 4 or 3 lumbar segment sue damage, suppuration, and swelling were found E. The 2 or 3 sacral segment around the exit wound. Neurologic examination reveals losses of dorsiflexion and eversion of the left foot. The patient cannot feel pinprick or touch on the dorsum of the left foot or anterolateral surface of the left leg. Which nerve was most likely involved in the injury?

A. Sciatic nerve B. Femoral nerve 14. Sensory loss between the first and second toes is a C. Sural nerve result of injury to which nerve? D. Common fibular (peroneal) nerve A. Superficial peroneal nerve E. Tibial nerve B. Deep peroneal nerve C. Tibial nerve D. Medial plantar nerve E. Lateral plantar nerve

15. A 21-year-old soccer player is tackled via a high- 18. A 12-year-old girl suffers from a type of neural tithe defect impact sweeping injury about the right knee causing a called tethered cord syndrome, a congenital anomaly that re- posterior knee dislocation. Soon after, he is unable to sults from defective closure of the neural tube. This syndrome plantar flex his right ankle or flex his toes. He also experi- is characterized by an abnormally low conus medullaris, which ences loss of sensation on the sole of his right foot. is tethered by a short, thickened filum lerminale, leading to Which of the following nerves is most likely injured? progressive neurologic defects in the legs and feet. 72. This girl has strong muscle function of the flexors of the A. Saphenous nerve thigh, but she has weakness of the extensors (hamstrings). A B. Tibial nerve lesion has occurred at which of the following spinal cord lev- C. Deep peroneal nerve els? D. Superficial peroneal nerve A. T12 E. Common peroneal nerve B. Ll C. L3 D. L5 E. 55

16. A patient has altered sensation in the sole of the foot and has weakness in the ability to plantar flex at the an- kle. The nerve that has been lesioned is the A. common peroneal B. sural C. saphenous D. femoral E. tibial

15 Lab 7— Posterior Leg & Foot Nerves—Answers

13. Answer B. (2) The ankle jerk reflex center is in the 17. Answer D. (7) The common fibular (peroneal) 1 sacral or 2 sacral segment of the spinal cord. nerve is the lateral terminal branch of the sciatic nerve. After arising near the apex of the popliteal fossa, it de- scends on the popliteus muscle and winds superficially around the fibular neck. It is extremely vulnerable in this position and is the most often injured nerve in the lower extremity. The common fibular nerve innervates all mus- cles in the anterior and lateral compartments of the leg. In addition, it provides sensory innervation to the dorsum of the foot and the anterolateral surface of the legs via the superficial and sural (answer c)/lateral sural cutaneous nerves, respectively. The tibial nerve innervates plantar flexors of the posterior compartment. The sciatic nerve (answer a) generally divides into the tibial (answer e) and common peroneal nerves superior to the popliteal fossa. Damage to it might result in deficits in both plantar flexion 14. Answer B. (2) The deep peroneal nerve supplies and dorsiflexion. The femoral nerve (answer b) innervates sensation to the skin between the first and second toes. the quadriceps muscles of the anterior thigh. Damage to it The superficial peroneal nerve supplies sensation to the would impair flexion of the thigh at the hip. lateral aspect of the leg and the dorsum of the foot. The tibial nerve supplies sensation to the sole of the foot. The medial and plantar nerves are terminal branches of the tibial nerve.

15. Answer B. (5) The tibial nerve innervates the tri- 18. Answer D. (5) The quadratus femoris muscles— ceps surae, plantaris, and posterior tibialis, which plantar the flexors of the thigh—are innervated by the femoral flex; innervates the flexor digitorum longus and brevis, nerve, which originates from the spinal cord at L2 to L4. In flexor hallucis longus and brevis, and flexor digiti minimi contrast, the hamstring muscles—the extensors of the brevis, which flex toes; and supplies sensory innervation thigh—are innervated by the sciatic nerve, which origi- on the sole of the foot. The common peroneal nerve di- nates from L4 to S3. Therefore, the lesion occurs at the vides into the deep peroneal nerve, which innervates level of LS (between L4 and S3). muscles of the anterior compartment that dorsiflex the foot, and the superficial peroneal nerve, which innervates the peroneus longus and brevis that dorsiflex the foot. The saphenous nerve is cutaneous nerve and does not supply the muscles.

16. Answer E. (6) The tibial nerve provides cutaneous sensation in the sole of the foot and innervates most of the muscles (including the gastrocnemius and soleus) that plantar flex the foot at the ankle.

16 Lab 7— Posterior Leg & Foot Vessels—QuesƟons 1 of 1

1. A knife wound penetrates the superficial vein that ter- 5. Deep venous thrombosis is a common complication minates in the popliteal vein. Bleeding occurs from which from sitting in one position for a prolonged period of time, of the following vessels? such as during a long car trip or a long plane flight. The first vascular channels likely to be obstructed or occluded A. Posterior tibial vein by an embolus from the deep veins of a lower limb are B. Anterior tibial vein the: C. Peroneal vein A. Tributaries of the renal veins D. Great saphenous vein B. Branches of the coronary arteries E. Lesser saphenous vein C. Sinusoids of the liver D. Tributaries of the pulmonary veins E. Branches of the pulmonary arteries

2. An orthopedic surgeon ligates the posterior tibial artery 6. An intern is undertaking an annual physical examination of at its origin. Which of the following arteries has no blood a fit and healthy 42-year-old male. All findings are within nor- flow immediately after the ligation? mal limits until the intern discovers that he can feel no pulses A. Peroneal on the dorsal aspects of the feet lateral to the extensor hallu- B. Dorsalis pedis cis longus tendons. The patient's feet are of normal color, C. Superior medial genicular appearance, and temperature, and the patient reports no pain or tingling in his feet. The MOST LIKELY interpretation is that D. Anterior tibial A. The intern should have palpated medial to the extensor E. Descending genicular hallucis tendons B. The patient has diabetes and is showing symptoms of dia- betic neuropathy C. The patient has pulseless disease (Takayasu's arteritis) D. An anatomical variation has caused congenitally non- palpable pulses E. An embolism has blocked the posterior tibial artery

3. A 34-year-old woman sustains a deep cut on the dor- sum of the foot just distal to her ankle joint by a falling kitchen knife. A physician in the emergency department has ligated the dorsalis pedis artery proximal to the in- jured area. Which of the following conditions most likely occurs as a result of the injury? A. Ischemia in the peroneus longus muscle B. Aneurysm in the plantar arterial arch C. Reduction of blood flow in the medial tarsal artery D. Low blood pressure in the anterior tibial artery E. High blood pressure in the arcuate artery

4. You are examining a 34-year-old police officer for his severe motor, sensory, and circulatory problems in the leg and foot. He was shot through the left lower thigh while apprehending a burglar 4 weeks ago. There is slight dis- coloration of the skin in the popliteal area, and when you auscultate on the back of his left knee, you hear a loud "roaring" noise corresponding with each heartbeat. The cause for this anomaly is A. Atheromatous plaque in the popliteal artery B. Hemangioma of the popliteal artery C. Arteriovenous anastomosis between popliteal vessels D. Varicosity of the popliteal vein E. Aneurysm of popliteal artery

17 Lab 7— Posterior Leg & Foot Vessels—Answers

1. Answer E. (1) The lesser (small) saphenous vein 5. Answer E. (5) An embolus from the deep veins of ascends on the back of the leg in company with the sural the lower limb would travel through the , the nerve and terminates in the popliteal vein. The peroneal iliac veins, the inferior vena cava, the right atrium, the vein empties into the posterior tibial vein. The anterior and right ventricle, the pulmonary trunk, and into the pulmo- posterior tibial veins are deep veins and join to form the nary arteries, where it could obstruct and occlude these popliteal vein. The great saphenous vein drains into the vessels. If not obstructed, blood from the pulmonary ar- femoral vein. tery passes to the lungs, pulmonary veins, left atrium, left ventricle, ascending aorta, and coronary arteries; to the body tissues; and then to the venous system including the renal veins and sinusoids of the liver.

2. Answer A. (1) The peroneal artery is a branch of the 6. Answer D. (2) Anatomical variation is a fact of the posterior tibial artery. The dorsalis pedis artery begins and should always be considered in physical anterior to the ankle as the continuation of the anterior findings. Congenitally absent dorsalis pedis pulses usual- tibial artery. The superior medial genicular artery is a ly occur bilateral. branch of the popliteal artery, and the descending genicu- lar artery arises from the

3. Answer C. (1) Reduction of blood flow in the medial tarsal artery occurs because it is a branch of the dorsalis pedis artery, which begins at the ankle joint as the contin- uation of the anterior tibial artery. The anterior tibial and peroneal arteries supply the peroneus longus muscle. The deep plantar arterial arch is formed mainly by the . Blood pressure in the anterior tibial artery should be higher than normal. The arcuate artery should have a low blood pressure because it is a terminal branch of the dorsalis pedis artery.

4. Answer C. (2) The popliteal artery and vein are so intimately bound together in a fascial sheath that they usually share penetrating injuries and may develop large arteriovenous anastomosis, through which arterial blood is pumped into the vein. This explains the loud roaring noise upon auscultation. The defect can be repaired through an elective operation later on.

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