Human Anatomy BRS: Lower Limb
While playing football, a 19-year-old college student receives a twisting injury to his knee when being tackled from the lateral side. Which of the following conditions most likely has occurred? (A). Tear of the medial meniscus (B). Ruptured fibular collateral ligament (C). Tenderness on pressure along the fibular collateral ligament (D). Injury of the posterior cruciate ligament (E). Swelling on the back of the knee joint
The answer is A. The "unhappy triad" of the knee joint is characterized by tear of the medial meniscus, rupture of the tibial collateral ligament, and rupture of the anterior cruciate ligament. This injury may occur when a cleated shoe, as worn by football players, is planted firmly in the turf and the knee is struck from the lateral side.
An orthopedic surgeon ligates the posterior tibial artery at its origin. Which of the following arteries has no blood flow immediately after the ligation? (A). Peroneal (B). Dorsalis pedis (C). Superior medial genicular (D). Anterior tibial (E). Descending genicular
The answer is A. The peroneal artery is a branch of the posterior tibial artery.
A motorcyclist falls from his bike in an accident and gets a deep gash that severs the superficial peroneal nerve near its origin. Which of the following muscles is paralyzed? (A). Peroneus longus (B). Extensor hallucis longus (C). Extensor digitorum longus (D). Peroneus tertius (E). Extensor digitorum brevis
The answer is A. The superficial peroneal nerve supplies the peroneus longus and brevis muscles.
An injury to the leg of a golfer results in loss of the ability to invert the foot. Which of the following muscles is most likely paralyzed? (A). Tibialis posterior (B). Peroneus longus (C). Peroneus brevis (D). Peroneus tertius (E). Extensor digitorum longus
The answer is A. The tibialis posterior inverts the foot.
A patient experiences paralysis of the muscle that originates from the femur and contributes directly to the stability of the knee joint. Which of the following muscles is involved? (A). Vastus lateralis (B). Semimembranosus (C). Sartorius (D). Biceps femoris (long head) (E). Rectus femoris
The answer is A. The vastus lateralis muscles arise from the femur and all the other muscles originate from the hip (coxal) bone.
A 27-year-old patient exhibits a loss of skin sensation and paralysis of muscles on the plantar aspect of the medial side of the foot. Which of the following nerves is most likely damaged? (A). Common peroneal (B). Tibial (C). Superficial peroneal (D). Deep peroneal (E). Sural
The answer is B. The common peroneal nerve divides into the deep peroneal nerve, which innervates the anterior muscles of the leg and supplies the adjacent skin of the first and second toes, and the superficial peroneal nerve, which innervates the lateral muscles of the leg and supplies the skin on the side of the lower leg and the dorsum of the ankle and foot.
A 14-year-old gymnastic silver medalist falls from the parallel bar and complains of pains from the knee and ankle joints. On physical examination, her physician found that the muscle responsible for flexing the leg at the knee joint and plantar flexing the foot is severely weakened. Which of the following muscles involved in both movements was most likely damaged in this accident? (A). Tibialis posterior (B). Gastrocnemius (C). Soleus (D). Peroneus longus (E). Flexor digitorum longus
The answer is B. The gastrocnemius can flex the knee joint and also plantar flex the foot.
A 32-year-old carpenter fell from the roof. The lateral longitudinal arch of his foot was flattened from fracture and displacement of the keystone for the arch. Which of the following bones is damaged? (A). Calcaneus (B). Cuboid bone (C). Head of the talus (D). Medial cuneiform (E). Navicular bone
The answer is B. The keystone for the lateral longitudinal arch is the cuboid bone, whereas the keystone for the medial longitudinal arch is the head of the talus
A 10-year-old boy falls from a tree house. The resultant heavy compression of the sole of his foot against the ground caused a fracture of the head of the talus. Which of the following structures is unable to function normally? (A). Transverse arch (B). Medial longitudinal arch (C). Lateral longitudinal arch (D). Tendon of the peroneus longus (E). Long plantar ligament
The answer is B. The keystone of the medial longitudinal arch of the foot is the head of the talus, which is located at the summit between the sustentaculum tali and the navicular bone.
If the lateral (fibular) collateral ligament is torn by this fracture, which of the following conditions may occur? (A). Abnormal passive abduction of the extended leg (B). Abnormal passive adduction of the extended leg (C). Anterior displacement of the femur on the tibia (D). Posterior displacement of the femur on the tibia (E). Maximal flexion of the leg
The answer is B. The lateral (fibular) collateral ligament prevents adduction at the knee.
A 25-year-old gladiator sustains a penetrating injury that severs the superficial peroneal nerve. This will most likely cause paralysis of which of the following muscles? (A). Peroneus tertius (B). Peroneus brevis (C). Flexor hallucis longus (D). Tibialis anterior (E). Tibialis posterior
The answer is B. The peroneus brevis muscle is innervated by the superficial peroneal nerve.
A basketball player was hit in the thigh by an opponent's knee. Which of the following arteries is likely to compress and cause ischemia because of the bruise and damage to the extensor muscles of the leg? (A). Popliteal (B). Deep femoral (C). Anterior tibial (D). Posterior tibial (E). Peroneal
The answer is C. A muscular spasm or hypertrophy of the extensor muscles of the leg may compress the anterior tibial artery, causing ischemia.
A 34-year-old woman sustains a deep cut on the dorsum 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 injured 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
The answer is C. 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 continuation of the anterior tibial artery.
If the acetabulum is fractured at its posterosuperior margin by dislocation of the hip joint, which of the following bones could be involved? (A). Pubis (B). Ischium (C). Ilium (D). Sacrum (E). Head of the femur
The answer is C. The acetabulum is a cup-shaped cavity on the lateral side of the hip bone and is formed superiorly by the ilium, posteroinferiorly by the ischium, and anteromedially by the pubis.
A 17-year-old boy was stabbed during a gang fight, resulting in the transection of the obturator nerve. Which of the following muscles is completely paralyzed? (A). Pectineus (B). Adductor magnus (C). Adductor longus (D). Biceps femoris (E). Semimembranosus
The answer is C. The adductor longus is innervated by only the obturator nerve.
Which of the following arteries could also be damaged by this fracture? (A). Popliteal (B). Posterior tibial (C). Anterior tibial (D). Peroneal (E). Lateral inferior genicular
The answer is C. The anterior tibial artery, which arises from the popliteal artery, enters the anterior compartment by passing through the gap between the fibula and tibia at the upper end of the interosseous membrane.
A 20-year-old college student receives a severe blow on the inferolateral side of the left knee joint while playing football. Radiographic examination reveals a fracture of the head and neck of the fibula. Which of the following nerves is damaged? (A). Sciatic (B). Tibial (C). Common peroneal (D). Deep peroneal (E). Superficial peronea
The answer is C. The common peroneal nerve is vulnerable to injury as it passes behind the head of the fibula and then winds around the neck of the fibula and pierces the peroneus longus muscle, where it divides into the deep and superficial peroneal nerves.
7. A patient presents with sensory loss on adjacent sides of the great and second toes and impaired dorsiflexion of the foot. These signs probably indicate damage to which of the following nerves? (A). Superficial peroneal (B). Lateral plantar (C). Deep peroneal (D). Sural (E). Tibial
The answer is C. The deep peroneal nerve supplies the anterior muscles of the leg, including the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus tertius muscles, which dorsiflex the foot.
After injury to the common fibular, which of the following muscles could be paralyzed? (A). Gastrocnemius (B). Popliteus (C). Extensor hallucis longus (D). Flexor digitorum longus (E). Tibialis posterior
The answer is C. The extensor hallucis longus is innervated by the deep peroneal nerve, whereas other muscles are innervated by the posterior tibial nerve.
A 21-year-old man was involved in a motorcycle accident, resulting in destruction of the groove in the lower surface of the cuboid bone. Which of the following muscle tendons is most likely damaged? (A). Flexor hallucis longus (B). Peroneus brevis (C). Peroneus longus (D). Tibialis anterior (E). Tibialis posterior
The answer is C. The groove in the lower surface of the cuboid bone is occupied by the tendon of the peroneus longus muscle.
A patient presents with a thrombosis in the popliteal vein. This thrombosis most likely causes reduction of blood flow in which of the following veins? (A). Greater saphenous (B). Lesser saphenous (C). Femoral (D). Posterior tibial (E). Anterior tibial
The answer is C. The popliteal vein drains blood into the femoral vein; thus, blood flow in the femoral vein is reduced.
A 22-year-old patient is unable to "unlock" the knee joint to permit flexion of the leg. Which of the following muscles is most likely damaged? (A). Rectus femoris (B). Semimembranosus (C). Popliteus (D). Gastrocnemius (E). Biceps femoris
The answer is C. The popliteus muscle rotates the femur laterally ("unlocks" the knee) or rotates the tibia medially, depending on which bone is fixed.
A 24-year-old woman presents to her physician with weakness in flexing the hip joint and extending the knee joint. Which muscle is most likely involved in this scenario? (A). Sartorius (B). Gracilis (C). Rectus femoris (D). Vastus medialis (E). Semimembranosus
The answer is C. The rectus femoris flexes the thigh and extends the leg.
A 28-year-old basketball player falls while rebounding and is unable to run and jump. On physical examination, he has pain and weakness when extending his thigh and flexing his leg. Which muscle involved in both movements is most likely injured? (A). Short head of biceps femoris (B). Adductor magnus (C). Semitendinosus (D). Sartorius (E). Gracilis
The answer is C. The semitendinosus extends the thigh and flexes the leg.
The woman undergoes hip surgery. If all of the arteries that are part of the cruciate anastomosis of the upper thigh are ligated, which of the following arteries maintains blood flow? (A). Medial femoral circumflex (B). Lateral femoral circumflex (C). Superior gluteal (D). Inferior gluteal (E). First perforating
The answer is C. The superior gluteal artery does not participate in the cruciate anastomosis of the thigh
2. A patient with a deep knife wound in the buttock walks with a waddling gait that is characterized by the pelvis falling toward one side at each step. Which of the following nerves is damaged? (A). Obturator nerve (B). Nerve to obturator internus (C). Superior gluteal nerve (D). Inferior gluteal nerve (E). Femoral nerve
The answer is C. The superior gluteal nerve innervates the gluteus medius muscle. Paralysis of this muscle causes gluteal gait, a waddling gait characterized by a falling of the pelvis toward the unaffected side at each step.
A patient experiences weakness in dorsiflexing and inverting the foot. Which of the following muscles is damaged? (A). Peroneus longus (B). Peroneus brevis (C). Tibialis anterior (D). Extensor digitorum longus (E). Peroneus tertius
The answer is C. The tibialis anterior can dorsiflex and invert the foot.
A 35-year-old man has difficulty in dorsiflexing the foot. Which of the following muscles is most likely damaged? (A). Tibialis posterior (B). Flexor digitorum longus (C). Tibialis anterior (D). Peroneus longus (E). Peroneus brevis
The answer is C. The tibialis anterior muscle can dorsiflex the foot, whereas all other muscles are able to plantar flex the foot.
A construction worker is hit on the leg with a concrete block and is subsequently unable to plantar flex and invert his foot. Which of the following muscles is most likely damaged? (A). Extensor digitorum longus (B). Tibialis anterior (C). Tibialis posterior (D). Peroneus longus (E). Peroneus brevis
The answer is C. The tibialis posterior can plantar flex and invert the foot.
Which of the following conditions would occur from this fracture? (A). Ischemia in the gastrocnemius (B). Loss of plantar flexion (C). Trendelenburg sign (D). Anterior tibial compartment syndrome (E). Flat foot
The answer is D. Anterior tibial compartment syndrome is characterized by ischemic necrosis of the muscles of the anterior tibial compartment of the leg resulting from damage to the anterior tibial artery
27. A patient with hereditary blood clotting problems presents with pain in the back of her knee. An arteriograph reveals a blood clot in the popliteal artery at its proximal end. Which of the following arteries will allow blood to reach the foot? (A). Anterior tibial (B). Posterior tibial (C). Peroneal (D). Lateral circumflex femoral (E). Superior medial genicular
The answer is D. If the proximal end of the popliteal artery is blocked, blood may reach the foot by way of the descending branch of the lateral circumflex femoral artery, which participates in the anastomosis around the knee joint.
Fracture of the neck of the femur results in avascular necrosis of the femoral head, probably resulting from lack of blood supply from which of the following arteries? (A). Obturator (B). Superior gluteal (C). Inferior gluteal (D). Medial femoral circumflex (E). Lateral femoral circumflex
The answer is D. In adults, the chief arterial supply to the head of the femur is from the branches of the medial femoral circumflex artery. The lateral femoral circumflex artery may supply the femoral head by anastomosing with the medial femoral circumflex artery.
The obturator nerve and the sciatic (tibial portion) nerve of a 15-year-old boy are transected as a result of a motorcycle accident. This injury would result in complete paralysis of which of the following muscles? (A). Rectus femoris (B). Biceps femoris, short head (C). Pectineus (D). Adductor magnus (E). Sartorius
The answer is D. The adductor magnus is innervated by both the obturator and sciatic (tibial portion) nerves.
Before knee surgery, a surgeon ligates arteries participating in the anastomosis around the knee joint. Which of the following arteries is most likely spared? (A). Lateral superior genicular (B). Medial inferior genicular (C). Descending branch of the lateral femoral circumflex (D). Saphenous branch of the descending genicular (E). Anterior tibial recurrent
The answer is D. The descending genicular artery gives off the articular branch, which enters the anastomosis around the knee joint, and the saphenous branch, which is not involved in the anastomosis but supplies the superficial tissue and skin on the medial side of the knee.
A 24-year-old woman complains of weakness when she extends her thigh and rotates it laterally. Which of the following muscles is paralyzed? (A). Obturator externus (B). Sartorius (C). Tensor fasciae latae (D). Gluteus maximus (E). Semitendinosus
The answer is D. The gluteus maximus can extend and rotate the thigh laterally.
An elderly woman fell at home and fractured the greater trochanter of her femur. Which of the following muscles would continue to function normally? (A). Piriformis (B). Obturator internus (C). Gluteus medius (D). Gluteus maximus (E). Gluteus minimus
The answer is D. The gluteus maximus is inserted into the gluteal tuberosity of the femur and the iliotibial tract.
A 72-year-old woman complains of a cramplike pain in her thigh and leg. She was diagnosed as having a severe intermittent claudication. Following surgery, an infection was found in the adductor canal, damaging the enclosed structures. Which of the following structures remains intact? (A). Femoral artery (B). Femoral vein (C). Saphenous nerve (D). Great saphenous vein (E). Nerve to the vastus medialis
The answer is D. The great saphenous nerve remains intact because it is not in the adductor canal.
A 72-year-old woman complains of a cramplike pain in her thigh and leg. She was diagnosed as having a severe intermittent claudication. Following surgery, an infection was found in the adductor canal, damaging the enclosed structures. Which of the following structures remains intact? (A). Femoral artery (B). Femoral vein (C). Saphenous nerve (D). Great saphenous vein (E). Nerve to the vastus medialis
The answer is D. The great saphenous vein remains intact because it is not in the adductor canal.
A thoracic surgeon is going to collect a portion of the greater saphenous vein for coronary bypass surgery. He has observed that this vein runs (A). Posterior to the medial malleolus (B). Into the popliteal vein (C). Anterior to the medial condyles of the tibia and femur (D). Superficial to the fascia lata of the thigh (E). Along with the femoral artery
The answer is D. The greater saphenous vein ascends superficial to the fascia lata. It courses anterior to the medial malleolus and posterior to the medial condyles of the tibia and femur and terminates in the femoral vein by passing through the saphenous opening
A 21-year-old tennis player comes to an emergency room and complains of pain in the knee joint. On examination, he has an infection inside the knee joint capsule but outside the synovial cavity. Which of the following structures is preserved from this infection? (A). Anterior cruciate ligament (B). Posterior cruciate ligament (C). Lateral meniscus (D). Lateral collateral ligament (E). Medial meniscus
The answer is D. The lateral (fibular) collateral ligament extends between the lateral femoral epicondyle and the head of the fibula and is not attached to the lateral meniscus.
3. A patient is unable to prevent anterior displacement of the femur on the tibia when the knee is flexed. Which of the following ligaments is most likely damaged? (A). Anterior cruciate (B). Fibular collateral (C). Patellar (D). Posterior cruciate (E). Tibial collateral
The answer is D. The posterior cruciate ligament is important because it prevents forward displacement of the femur on the tibia when the knee is flexed. The anterior cruciate ligament prevents backward displacement of the femur on the tibia.
A 52-year-old woman slipped and fell and now complains of being unable to extend her leg at the knee joint. Which of the following muscles was paralyzed as a result of this accident? (A). Semitendinosus (B). Sartorius (C). Gracilis (D). Quadriceps femoris (E). Biceps femoris
The answer is D. The quadriceps femoris muscle includes the rectus femoris muscle and the vastus medialis, intermedialis, and lateralis muscles
A patient has weakness when flexing both her thigh and leg. Which of the following muscles is most likely injured? (A). Rectus femoris (B). Semitendinosus (C). Biceps femoris (D). Sartorius (E). Adductor longus
The answer is D. The sartorius can flex and rotate the thigh laterally, and flex and rotate the leg medially. The rectus femoris flexes the thigh and extends the leg. The semimembranosus extends the thigh and flexes and rotates the leg medially. The biceps femoris extends the thigh and flexes and rotates the leg laterally. The adductor longus adducts and flexes the thigh.
A construction worker falls feet first from a roof. He sustains a fracture of the groove on the undersurface of the sustentaculum tali of the calcaneus bone. Which of the following muscle tendons is most likely torn? (A). Flexor digitorum brevis (B). Flexor digitorum longus (C). Flexor hallucis brevis (D). Flexor hallucis longus (E). Tibialis posterior
The answer is D. The tendon of the flexor hallucis longus muscle occupies first the groove on the posterior surface of the talus and then the groove on the undersurface of the sustentaculum tali.
A 67-year-old patient has been given a course of antibiotics by gluteal intramuscular injections after a major abdominal surgery. To avoid damaging the sciatic nerve during an injection, the needle should be inserted into which of the following areas? (A). Over the sacrospinous ligament (B). Midway between the ischial tuberosity and the lesser trochanter (C). Midpoint of the gemelli muscles (D). Upper lateral quadrant of the gluteal region (E). Lower medial quadrant of the gluteal region
The answer is D. To avoid damaging the sciatic nerve during an intramuscular injection, the clinician should insert the needle in the upper lateral quadrant of the gluteal region.
The woman experiences weakness when abducting and medially rotating the thigh after this accident. Which of the following muscles is most likely damaged? (A). Piriformis (B). Obturator internus (C). Quadratus femoris (D). Gluteus maximus (E). Gluteus minimus
The answer is E. The gluteus medius or minimus abducts and rotates the thigh medially.
A knife wound penetrates the superficial vein that terminates in the popliteal vein. Bleeding occurs from which of the following vessels? (A). Posterior tibial vein (B). Anterior tibial vein (C). Peroneal vein (D). Great saphenous vein (E). Lesser saphenous vein
The answer is E. The lesser (small) saphenous vein ascends on the back of the leg in company with the sural nerve and terminates in the popliteal vein.
A patient is involved in a motorcycle wreck that results in avulsion of the skin over the anterolateral leg and ankle. Which of the following structures is most likely destroyed with this type of injury? (A). Deep peroneal nerve (B). Extensor digitorum longus muscle tendon (C). Dorsalis pedis artery (D). Great saphenous vein (E). Superficial peroneal nerve
The answer is E. The superficial peroneal nerve emerges between the peroneus longus and peroneus brevis muscles and descends superficial to the extensor retinaculum of the ankle on the anterolateral side of the leg and ankle, innervating the skin of the lower leg and foot.
A 20-year-old patient cannot flex and medially rotate the thigh while running and climbing. Which of the following muscles is most likely damaged? (A). Semimembranosus (B). Sartorius (C). Rectus femoris (D). Vastus intermedius (E). Tensor fasciae latae
The answer is E. The tensor fasciae latae can flex and medially rotate the thigh, so this is the muscle most likely damaged.
5. A 47-year-old woman is unable to invert her foot after she stumbled on her driveway. Which of the following nerves are most likely injured? (A). Superficial and deep peroneal (B). Deep peroneal and tibial (C). Superficial peroneal and tibial (D). Medial and lateral plantar (E). Obturator and tibial
The deep peroneal and tibial nerves innervate the chief evertors of the foot, which are the tibialis anterior, tibialis posterior, triceps surae, and extensor hallucis longus muscles.
A 52-year-old woman comes to an orthopedic surgeon complaining of an uncomfortable feeling in her knee and ankle joints. After a thorough examination, she is diagnosed as having arthritis with mild discomfort with passive movements. The muscles acting at the ankle joint appear normal with good strength. Which muscle can both dorsiflex and invert her foot? (A). Peroneus longus (B). Peroneus brevis (C). Peroneus tertius (D). Extensor hallucis longus (E). Extensor digitorum longus
extensor hallucis longus The extensor hallucis longus can dorsiflex and invert the foot.
5. A 47-year-old woman is unable to invert her foot after she stumbled on her driveway. Which of the following nerves are most likely injured? (A). Superficial and deep peroneal (B). Deep peroneal and tibial (C). Superficial peroneal and tibial (D). Medial and lateral plantar (E). Obturator and tibial
B. The deep peroneal and tibial nerves innervate the chief evertors of the foot, which are the tibialis anterior, tibialis posterior, triceps surae, and extensor hallucis longus muscles.