Anatomy Questions - Hip, Thigh, Posterior Leg

The femoral artery enters the popliteal fossa (becoming the popliteal artery) by passing through the: A. Adductor hiatus B. Femoral canal C. Femoral sheath D. Femoral triangle E. Saphenous opening

A. Adductor hiatus The adductor hiatus is a split in the adductor magnus muscle found at the end of the adductor canal. At the adductor hiatus, the femoral vessels pass through to reach the posterior surface of the leg, changing names to become the popliteal vessels. The femoral triangle is an area in the proximal anteromedial thigh, bounded by the inguinal ligament, sartorius, and the medial edge of adductor longus. It contains the femoral nerve and the three structures covered by the femoral sheath: the femoral artery, vein, and canal. The femoral canal is a structure in the femoral sheath that usually holds a deep inguinal lymph node; it may also be the site of a femoral hernia. The saphenous opening is an opening in the fascia lata where the great saphenous vein passes deep to join the femoral vein.

A patient complains of localized pain in a swollen lower calf and cannot strongly plantar flex his foot. What tendon may have ruptured? A. calcaneal B. fibularis tertius C. flexor digitorum longus D. flexor hallucis longus E. tibialis anterior

A. Calcaneal Gastrocnemius and soleus insert on the calcaneus via the calcaneal tendon, a tendon of the lower calf which is the thickest and strongest tendon of the body. These muscles are important plantarflexors of the foot, so it is likely that the tendon connected to these muscles has been damaged. The other tendons/muscles listed and their actions are as follows: Fibularis teritus: everts the foot; flexor digitorum longus: flexes toes 2-5; flexor hallucis longus: flexes toe 1; tibialis anterior: inverts and dorsiflexes the foot. Since none of these actions is disrupted, the other tendons are probably fine.

A patient with painful swelling in the distal calf cannot plantar flex at the ankle with any power. Which tendon was likely ruptured? A. Calcaneal B. Extensor digitorum longus C. Extensor hallucis longus D. Plantaris E. Tibialis anterior

A. Calcaneal The calcaneal tendon is the thickest and strongest tendon of the body. It is the tendon that gastrocnemius and soleus--the major plantarflexors of the posterior compartment--use to insert on the dorsum of calcaneus. Tearing this tendon is painful, and it means that a patient won't be able to plantarflex the foot. So, the symptoms of this patient fit with a rupture to the calcaneal tendon. Extensor digitorum longus is important for extending the digits, while extensor hallucis longus allows the great toe to extend. Tibialis anterior is important for dorsiflexion. These three muscles are all in the anterior compartment of the leg, so injuries to these tendons would not fit with pain in the distal calf. Plantaris is a very small muscle in the posterior compartment which flexes the leg and plantar flexes the foot--an injury to plantaris would not cause such severe symptoms.

The short head of biceps femoris muscle is innervated by which nerve? A. Common fibular B. Femoral C. Inferior gluteal D. Obturator E. Tibial

A. Common fibular The short head of biceps femoris is innervated by the common fibular nerve; all the other muscles in the hamstring compartment are innervated by the tibial nerve. Both of these nerves are branches of the sciatic nerve. The inferior gluteal nerve innervates gluteus maximus. The obturator nerve innervates the medial, adductor compartment of the thigh. The femoral nerve innervates the muscles of the anterior thigh.

The hamstrings muscles are supplied by branches of which artery? A. Deep femoral B. Fibular C. Obturator D. Pudendal E. Superficial femoral

A. Deep femoral The deep femoral artery supplies the posterior compartment of the thigh with three to four perforating arteries. These arteries pierce adductor magnus and supply blood to the hamstrings--biceps femoris, semitendinosus, and semimembranosus. The fibular artery is a branch of the posterior tibial artery which supplies the muscles and fascia of the lateral leg and ankle. The obturator artery comes from the anterior division of the internal iliac artery; it delivers blood to the medial thigh and hip. The internal pudendal artery is the major source of blood to the perineum. The superficial femoral artery is the name used clinically for the femoral artery after the deep femoral is given off. Therefore, the short segment of femoral artery proximal to the deep/superficial division is sometimes called the common femoral.

As a patient with paralyzed gluteus medius and minimus muscles on the left side attempts to stand on the left limb only, the right side of the pelvis typically: A. Drops B. Elevates C. Rotates laterally D. Rotates medially E. Thrusts forward

A. Drops When gluteus medius and minimus are injured, a patient will show a positive Trendelenburg sign. This means that when this patient attempts to stand on the left leg only, the uninjured right hip will drop. This is because gluteus medius and minimus on the stable left leg support the pelvis so that it will remain level when the right leg is lifted--when these muscles are injured on the supported left side, the right side of the pelvis will drop. Make sure you understand what Trendelenburg sign is, what it means, and why the pelvis drops on the uninjured side!

When, in approximately 12% of people, the common fibular nerve passes through the piriformis muscle, the nerve may be compressed. This would affect part of which muscle? A. Adductor magnus B. Biceps femoris C. Gluteus maximus D. Semimembranosus E. Semitendinosus

B. Biceps femoris To answer this question, you need to determine the innervations of all the muscles listed. Biceps femoris, semimembranosus, and semitendinosus are all part of the hamstrings compartment, which is innervated by the tibial nerve. But, the short head of biceps femoris is the one part of the hamstring compartment that is innervated by the common fibular nerve instead of the tibial nerve. So biceps femoris is the answer you're looking for! Adductor magnus is innervated by the obturator nerve--it's in the medial compartment of the leg. Gluteus maximus is innervated by the inferior gluteal nerve.

An elderly patient complains of difficulty in walking up stairs. Tests by her doctor reveal weakness in extension at her hip, but no change in hip flexion, or flexion or extension of the knee. Based upon these results, what muscle is most likely not functioning properly. A. Adductor magnus B. Gluteus maximus C. Gluteus medius D. Iliopsoas E. Semitendinosus

B. Gluteus maximus Gluteus maximus is the most important muscle for powerfully extending the thigh. This is the muscle that is used for forceful extension at the hip joint, which is what you need to go up the stairs or to jump powerfully. That's why gluteus maximus is the answer. Semitendinosus is the other muscle mentioned which extends the thigh--it's one of the hamstrings muscles in the posterior compartment of the thigh. However, semitendinosus flexes the leg, and there is no weakness with this motion. Also, you should remember that gluteus maximus is the key muscle for very forceful extension--not semitendinosus. Adductor magnus adducts and medially rotates the thigh, while gluteus medius abducts and medially rotates the thigh. Iliopsoas is a hip flexor. There is no weakness in any of these movements, so you should know that these muscles are not injured.

What muscle passes through the lesser sciatic foramen? A. Gluteus minimus B. Obturator internus C. Piriformis D. Quadratus femoris E. Superior gemellus

B. Obturator internus Obturator internus leaves the pelvis by passing through the lesser sciatic foramen. It eventually inserts on the greater trochanter of the femur and helps to laterally rotate and abduct the thigh. Piriformis leaves the pelvis through the greater sciatic foramen and also inserts of the greater trochanter of the femur. It helps with the same movements as obturator internus--lateral rotation and abduction of the thigh. The other muscles listed act at the hip, but they are not related to the greater or lesser sciatic foramen. Gluteus minimus originates on the ilium and inserts on the greater trochanter of the femur--it abducts and medially rotates the thigh. Quadratus femoris is a lateral rotator of the thigh which originates on the ischial tuberosity and inserts on the quadrate line. Superior gemellus is another lateral rotator of the thigh which inserts with obturator internus on the obturator tendon.

In a hunting accident, an arrow pierces the mid-calf of a hunter. A major artery is lacerated in the posterior leg, and you notice that the sole of his foot is cold and pale. The dorsum of the foot is warm and normally colored. The artery that seems to be injured is the: A. fibular artery B. posterior tibial artery C. femoral artery D. popliteal artery E. medial plantar artery

B. Posterior tibial artery The popliteal artery divides into two arteries: the posterior tibial artery and anterior tibial artery. The posterior tibial artery supplies the posterior compartment of the leg with blood. It also passes into the sole of the foot, where it branches to form the medial and lateral plantar arteries. So, the injury to the posterior surface of the leg and the lack of perfusion to the foot all point to an injury to the posterior tibial artery. The fibular artery is a branch of the posterior tibial artery that gets blood to the fibular compartment of the leg. You can tell that this was not the main artery damaged because this artery is not important for perfusing the foot. The femoral artery is an artery of the anterior thigh--it would not be damaged by a mid-calf injury. The popliteal artery is the artery that branches to form the posterior and anterior tibial arteries. It is clear that this artery is intact because the anterior of the leg and dorsum of the foot--areas supplied by the anterior tibial artery and its continuation, dorsalis pedis--are normal. Finally, the medial plantar artery is found on the plantar side of the foot--it would not even be close to an arrow in the mid-calf.

A tennis player feels a "pop" in her calf as she is playing. Her calf becomes tender and there is some slight amount of swelling. Upon examination, her physician informs her that she has ruptured the slender tendon of a small muscle that attaches to the calcaneus. She has apparently ruptured the: A. gastrocnemius B. plantaris C. popliteus D. soleus E. tibialis posterior

B. plantaris Plantaris is a very small muscle in the posterior compartment of the leg. It has a very long and thin tendon that attaches directly to the calcaneus--it does not insert on the calcaneal tendon along with gastrocnemius and soleus. Plantaris acts to flex the leg and plantarflex the foot, but is is not the major muscle responsible for either of these motions. Like the other muscles of the posterior compartment, it is innervated by the tibial nerve. Gastrocnemius and soleus are large muscles of the posterior compartment that attach to calcaneus via the thick calcaneal tendon. If that tendon was ruptured, the patient would have impaired plantarflexion and significant pain. Popliteus is a muscle on the posterior knee which allows the knee to rotate medially and unlock to initiate flexion of the knee. Tibialis posterior is also a muscle in the posterior compartment of leg--it plantarflexes and inverts the foot.

In order to avoid injury to the sciatic nerve, intramuscular injections should be given in which quadrant of the buttock? A. upper medial B. upper lateral C. lower medial D. lower lateral E. middle

B. upper lateral An injection in the posterior hip region is best placed in the upper, outer quadrant of the hip, just inferior and posterior to the anterior superior iliac spine. This is an area where there are not many nerves and vessels that could be injured by the injection. There are several nerves in the posterior hip region that may be injured if intramuscular injections are carelessly placed in the other quadrants of the buttock, including the sciatic nerve, posterior femoral cutaneous nerve, inferior gluteal nerve, and superior gluteal nerve.

Weakness in climbing stairs or jumping would indicate a lesion of which nerve? A. Tibial B. Superior gluteal C. Inferior gluteal D. Obturator E. Femoral

C. Inferior gluteal The first thing that you want to do with this question is determine which muscle was impaired. Since the question specifies that there is a weakness when climbing steps or jumping, you should know that there is a problem with powerfully extending the hip. And that's what gluteus maximus does. The nerve to gluteus maximus, the inferior gluteal nerve, must be the nerve that was injured. The tibial nerve innervates the hamstring compartment. Although the hamstrings are involved in extending the hip, they are not the most important muscles for these powerful motions. Gluteus maximus and the inferior gluteal nerve enable the type of powerful extension used to climb steps or jump The superior gluteal nerve innervates gluteus minimus and medius. These muscles are important for stabilizing the pelvis on the supported side of the hip when the opposite leg is lifted. If the superior gluteal nerve is damaged on the supported side of the hip, the unsupported side of the hip will drop. This is called Trendelenburg gait. The obturator nerve innervates the medial, adductor compartment of the hip. The femoral nerve innervates the anterior compartment of the hip, including the quadriceps. This nerve allows for extension at the knee.

The medial thigh muscles rotate the femur medially, counterbalanced by muscles of the _____________ thigh, including the ___________ muscle, which rotates the femur laterally. A. Lateral; tensor fasciae latae B. Anterior; rectus femoris C. Lateral; piriformis D. Posterior; biceps femoris E. Posterior; quadriceps femoris

C. Lateral; piriformis A good way to answer this question is to look for a muscle that is a lateral rotator of the thigh and then make sure that the compartment that it is listed with is correct. Piriformis laterally rotates the thigh; it is a member of the lateral compartment which includes other muscles that laterally rotate the thigh, like obturator internus and the superior and inferior gemellus muscles. So, this is the best answer. Tensor fasciae latae is in the lateral compartment, but it's a medial rotator of the thigh, so this is not a correct answer. Rectus femoris is one of the quadriceps muscles, found in the anterior compartment of the thigh. This compartment extends the knee and flexes the hip, but these muscles do not rotate the thigh. Biceps femoris is a muscle in the posterior compartment--it's a hamstring muscle that extends the hip and flexes the knee.

During surgical repair of a popliteal artery aneurism, ligation of the femoral artery at mid-thigh would not interrupt supply to the hamstring muscles because the A. Genicular anastomosis ensures blood supply to the posterior thigh B. Cruciate anastomosis ensures blood supply to the posterior thigh C. Perforating branches of the deep femoral artery supply the posterior thigh D. Obturator artery supplies the posterior thigh E. Anterior and posterior femoral circumflex arteries anastomose with the inferior gluteal artery

C. Perforating branches of the deep femoral artery supply the posterior thigh The deep femoral artery supplies the posterior compartment of the thigh with three to four perforating arteries. These arteries pierce adductor magnus and supply blood to the hamstrings--biceps femoris, semitendinosus, and semimembranosus. Genicular anastomosis supply the knee joint, not the posterior thigh. The cruciate anastomosis supply blood to the area around the head of the femur. The medial and lateral circumflex arteries and the inferior gluteal artery also supply the hip joint. The obturator artery supplies the medial hip and thigh.

When the femur is fractured, the broken distal end often turns posteriorly to enter the popliteal fossa due to muscle traction. Because of its position deepest in the fossa, which structure is most vulnerable to laceration? A. Common fibular n. B. Lesser saphenous v. C. Popliteal a. D. Popliteal v. E. Tibial n.

C. Popliteal a. The popliteal fossa contains the popliteal artery, popliteal vein, common fibular nerve, and tibial nerve. The popliteal artery is the deepest structure in the fossa--it lies on the posterior side of the knee joint. So, it is the structure that would be most likely to be lacerated by the broken distal end of the femur. The popliteal vein lies superficial to the artery, and the tibial nerve lies superficial to the popliteal vein. These three structures are right in the middle of the fossa. The common fibular nerve descends toward the fibular neck, on the lateral side of the popliteal fossa. The lesser saphenous vein drains the superficial posterolateral lower limb. It eventually terminates in the popliteal vein.

When the distal femur is fractured, the sharp broken ends of the bone often damage the structure that lies closest to the femur in the popliteal fossa, i.e., the: A. Descending genicular artery B. Greater saphenous vein C. Popliteal artery D. Popliteal vein E. Sciatic nerve

C. Popliteal artery The popliteal fossa contains the popliteal artery, popliteal vein, common fibular nerve, and tibial nerve. The popliteal artery is the deepest structure in the fossa--it lies on the posterior side of the knee joint. So, it is the structure that would be most likely to be lacerated by the broken distal end of the femur. The descending genicular artery is one of the arteries that supplies the knee through the genicular anastomoses. It is found on the medial side of the knee, not in the popliteal fossa. The greater saphenous vein is a superficial vein that drains the lower limb. It is found traveling posterior to the medial epicondyle, but it's not in the popliteal fossa. The sciatic nerve is found in the superior part of the thigh--it quickly splits into the common fibular and tibial nerves which are found in the popliteal fossa.

The team doctor tells a football player that he has "a pulled hamstring" muscle. This results from a tearing of the origin of a hamstring muscle from the: A. sacrum B. posterior gluteal line C. ischial tuberosity D. obturator membrane E. iliac tubercle

C. ischial tuberosity The hamstring muscles are: biceps femoris, semimembranosus, and semitendinosus. They originate from the ischial tuberosity and insert on the tibia and fibula (biceps). They comprise the posterior compartment of the thigh and are innervated by the tibial nerve, with the exception of the short head of biceps femoris which is innervated by the common fibular nerve. These muscles allow for extension at the hip and flexion at the knee. The anterior sacrum is the origin of the piriformis muscle, while the posterior sacrum and ilium posterior to the superior gluteal line serve as the origin of gluteus maximus. Obturator internus and externus take origin from the obturator membrane and the margins of the obturator foramen.

Because of its muscle attachments, a fracture to the ischial tuberosity would affect which movement of the lower limb? A. Abduction of the thigh B. Dorsiflexion of the foot C. Extension of the leg D. Flexion of the leg E. Flexion of the thigh

D. Flexion of the leg The correct answer is: Flexion of the leg The ischial tuberosity is the origin of the hamstrings muscles, so fracturing this bone would disrupt this origin. The hamstrings are important for flexing the leg and extending the thigh; this means that these motions would be impaired following the fracture. Gluteus minimus and medius are important abductors of the hip. These muscles both take origin from the ilium. So, a fracture to the ilium might impair abduction of the hip, although these muscles are more commonly impaired by damage to the superior gluteal nerve. The tibialis anterior, in the anterior compartment of the leg, is responsible for dorsiflexion of the foot. It originates on the lateral condyle of the tibia, so breaking off the lateral condyle of the tibia might impair dorsiflexion. The quadriceps, in the anterior compartment of the thigh, are responsible for extending the leg. Rectus femoris takes origin from the anterior inferior iliac spine, while the vastus muscles originate from the body of the femur. Finally, the muscles responsible for flexing the hip are pectineus, iliopsoas, sartorius, and rectus femoris. Pectineus originates from the pecten pubis, iliopsoas originates on the lumbar vertebrae and the iliac fossa, and sartorius originates on the anterior superior iliac spine.

The deep femoral artery is the principle blood source for the muscles in which compartment of the thigh? A. Anterior B. Lateral (gluteal) C. Medial (adductor) D. Posterior (hamstring)

D. Posterior (hamstring) The deep femoral artery supplies the posterior compartment of the thigh with three to four perforating arteries. These arteries pierce adductor magnus and supply blood to the hamstrings--biceps femoris, semitendinosus, and semimembranosus. The anterior compartment of the thigh (the quadriceps) receives blood from the femoral artery. The medial compartment of the thigh receives blood from the obturator artery and medial circumflex femoral artery, as well as the deep femoral. The gluteal region receives blood from the superior and inferior gluteal arteries.

If the head of the femur is dislocated postero-medially, compression of which nerve is likely to result? A. Femoral B. Lumbosacral trunk C. Obturator D. Sciatic E. Superior gluteal

D. Sciatic The sciatic nerve is closely related to the posterior hip joint, which makes this nerve very vulnerable in cases where the femur is dislocated postero-medially. If the sciatic nerve was completely paralyzed, the compartments innervated by its two branches: the common fibular and tibial nerves, would lose function. This would mean that the hamstrings and all the muscles of below the knee would lose their innervation. (Luckily, complete paralysis of the sciatic nerve is very rare.) The hip joint is very stable, so it is difficult to dislocate the femur. Most dislocations occur when the hip is flexed and the thigh is adducted. In flexion, the joint capsule is lax, and the femoral head tends to dislocate posteriorly when forces drive the femur posteriorly. This means that the sciatic nerve will be very vulnerable when the femur is dislocated! The other nerves listed in the question are not closely related to the hip joint. The femoral nerve innervates the quadriceps and is on the anterior of the thigh. The lumbosacral trunk is located in the pelvis. The obturator nerve innervates the adductor compartment, and is on the anteromedial side of the thigh. Although the superior gluteal nerve innervates muscles near the hip socket (gluteus medius, minimus, and tensor fasciae latae), it would not be damaged by a dislocated hip.

Of the branches of the internal iliac artery, the one exiting from the greater sciatic foramen superior to the piriformis muscle is the: A. Iliolumbar artery B. Internal pudendal artery C. Lateral sacral artery D. Superior gluteal artery

D. Superior gluteal artery Piriformis is the key to the posterior thigh, and there are many important nerves and arteries that exit the greater sciatic foramen and enter the posterior thigh either above or below piriformis. The superior gluteal artery and nerve are 2 structures that travel through the greater sciatic foramen superior to piriformis. There are many structures that travel through the greater sciatic foramen inferior to piriformis and lie in the posterior thigh. From medial to lateral, these structures are: pudendal nerve, nerve to obturator internus, nerve to quadratus femoris, inferior gluteal artery, posterior femoral cutaneous nerve, inferior gluteal nerve, and sciatic nerve. See Netter plates 502 and 503 for a picture. You should know what nerves and vessels are superior and inferior to piriformis! None of the other arteries mentioned travel superior to piriformis to reach the posterior thigh. The iliolumbar artery is a branch of the posterior division of the internal iliac. It travels on the posterior body wall to supply blood to the iliacus, psoas major, and quadratus lumborum. The internal pudendal artery is a branch from the anterior division of the internal iliac artery. It leaves the pelvis with the inferior gluteal artery, traveling inferior to piriformis. It enters the perineum through the lesser sciatic foramen to supply muscles, skin, and the erectile bodies there. Finally, the lateral sacral arteries are branches of the posterior division of the internal iliac artery--they are on the posterior body wall and they supply the sacrum, sacral nerve rootlets, meninges, and the nearby muscles.

A fracture of the ischial tuberosity might be expected to most directly affect the muscles that produce which lower limb movement? A. Abduction at the hip B. Adduction at the hip C. Extension at the knee D. Flexion at the hip E. Flexion at the knee

E. Flexion at the knee The ischial tuberosity is the origin for the hamstrings muscles which are the muscles that allow for extension at the hip and flexion at the knee. If the ischial tuberosity was fractured, the hamstrings would be separated from their origin and would not function properly. The most important hip abductors are gluteus medius and minimus. These muscles are most commonly damaged by an injury to the superior gluteal nerve. The hip adductors are adductor longus, brevis and magnus, which insert on the linea aspera of the femur and are innervated by the obturator nerve. The muscles responsible for extending the knee are the quadriceps. They take origin from the surface of the femur and the anterior inferior iliac spine (rectus femoris). The quadriceps are innervated by the femoral nerve. Finally, the hip flexors are rectus femoris (from the quadriceps), pectineus, iliopsoas, and sartorius. These muscles have diverse origins, and are mostly innervated by the femoral nerve.

After suffering a deep stab wound in the medial upper quadrant of the right buttock, an emergency room patient found walking to be very difficult. The basic problem was that, during stepping, her left hip sagged down as soon as the left foot was lifted off the ground to swing forward. What nerve was damaged? A. Femoral B. Inferior gluteal C. Obturator D. Pudendal E. Superior gluteal

E. Superior gluteal The superior gluteal nerve supplies gluteus minimus and medius--two muscles that are important abductors of the hip--and tensor fasciae latae. These muscles stabilize the pelvis when walking. They work in such a way that when you are standing on your right leg only, the muscles on the right side are holding the left side of the pelvis level. When you are standing on your left leg only, the muscles of the left side are supporting the right side of the pelvis. So, if a patient exhibits this characteristic hip drop on the uninjured side while standing on the injured side, this is called Trendelenburg sign. It demonstrates that the superior gluteal nerve was injured and the gluteus minimus and medius can no longer support the hip.

Following a major operation, a patient was placed on a course of antibiotics which were delivered via intramuscular injection to the buttocks. After one injection in the right buttock, the patient complained of more pain than usual in the region of the injection. Later, as he was walking in the hall, the nurse noticed that he had a limp that had not been present before--his left hip dropped every time he lifted his left foot off the floor. Which nerve had been injured by the injection? A. Femoral B. Inferior gluteal C. Obturator D. Sciatic E. Superior gluteal

E. Superior gluteal The superior gluteal nerve supplies gluteus minimus and medius--two muscles that are important abductors of the hip. These muscles stabilize the pelvis when walking. They work in such a way that when you are standing on your right limb only, the muscles on the right side are holding the left side of the pelvis level. When you are standing on your left leg only, the muscles of the left side are supporting the right side of the pelvis. This patient has injured his right superior gluteal nerve. He is exhibiting a characteristic hip drop on the uninjured side while standing on the injured side--a positive Trendelenburg sign. The superior gluteal nerve was evidently damaged during the injection. This is why it's important to place injections in the upper, outer quadrant of the buttock--that's the quadrant of the buttock that has fewer nerves that might be damaged by a needle. Nerves that could be injured from careless injections include the sciatic nerve, posterior femoral cutaneous nerve, inferior gluteal nerve, and superior gluteal nerve. An injury to the femoral nerve would weaken the quadriceps--the patient would not be able to extend his leg. An injury to the obturator nerve would denervate the adductors and impair adduction of the hip. Damage to the sciatic nerve would paralyze the hamstrings and all the muscles in the leg and foot. Finally, injuring the inferior gluteal nerve would paralyze gluteus maximus and impair extension of the hip.

A football player tears his calcaneal tendon. You would expect to find weakness in: A. dorsifiexion of the foot B. eversion of the foot C. extension of the knee D. inversion of the foot E. plantarflexion of the foot

E. plantarflexion of the foot The calcaneal tendon is the thickest and strongest tendon of the body. It is the tendon that gastrocnemius and soleus--the major plantarflexors of the posterior compartment--use to insert on the dorsum of calcaneus. So, if this tendon was ruptured, gastrocnemius and soleus would not be inserting on the calcaneus, and the football player would be unable to plantarflex his leg. Dorsiflexion would be impaired if there was damage to the anterior compartment of the leg. Specifically, an injury to tibialis anterior or the deep fibular nerve would lead to a weakness in dorsiflexion. Eversion would be impared if there was an injury to the fibularis muscles--fibularis tertius, fibularis longus, and fibularis brevis--which are all responsible for everting the foot. Inversion would be impaired if there was damage to tibialis anterior and tibialis posterior. These are the two muscles which invert the foot. And remember--extending the knee is done by the quadriceps muscles in the anterior thigh. They are innervated by the femoral nerve, so an injury to this nerve or to the quadriceps muscles themselves might impair extension at the knee.

While on vacation in Florida following her final exams, a scuba diving medical student is accidentally speared by her diving partner. The end of the spear passes medial to lateral, posterior to the medial malleolus. It severs an artery there, which is the: A. anterior tibial B. dorsalis pedis C. fibular D. medial plantar E. posterior tibial

E. posterior tibial The posterior tibial artery passes from the posterior compartment of the leg, behind the medial malleolus, before entering the foot. In the foot, it splits to form the medial and lateral plantar arteries. Remember--this is one of the structures that is lined up behind the flexor retinaculum in a very characteristic way. To review, the order here is, from anterior to posterior: 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. The anterior tibial artery comes from the anterior compartment of the leg--it changes name to the dorsalis pedis artery at the level of the ankle. If the spear had stabbed the student on the dorsum of the foot or leg, either above or below the ankle, one of these two arteries might have been injured. The fibular artery is a branch of posterior tibial artery that supplies the lateral compartment of the leg--an injury to the lateral leg might damage this artery. The medial plantar artery is a branch of the posterior tibial artery in the foot--if the spear had stabbed her medial foot on the plantar surface, this is the artery that might have been injured.

During recovery from a gunshot wound of the right pelvis, the patient notices a lurch in his gait. When he lifts his left foot off of the ground, his pelvis dips down on the left side. The nerve that appears to have been injured is the: A. nerve to piriformis B. nerve to obturator internus C. sciatic nerve D. femoral nerve E. superior gluteal nerve

E. superior gluteal nerve The superior gluteal nerve supplies gluteus minimus and medius--two muscles that are important abductors of the hip--as well as tensor fasciae latae. These muscles stabilize the pelvis when walking. The gluteus medius and minimus work in such a way that when you are standing on your right leg only, the muscles on the right side are supporting the left side of the pelvis. When you are standing on your left leg only, the muscles of the left side are supporting the right side of the pelvis. If a patient exhibits a characteristic hip drop on the uninjured side (in this case, the left side) while standing on the injured side (right), this is called Trendelenburg's sign. It occurs when the superior gluteal nerve--the nerve supply to the abductors of the thigh--is disrupted due to injury or disease. Nerve to piriformis and nerve to obturator internus allow those muscles to laterally rotate the thigh. However, if one of these muscles was denervated, the other might be able to compensate and prevent a significant loss of function. The sciatic nerve has no direct muscular branches; however, its two branches, common fibular and tibial nerves, innervate the posterior compartment of the thigh and all the muscles of the leg. A disruption to the sciatic nerve would lead to a significant motor deficit. The femoral nerve innervates the quadriceps. If this nerve were damaged, a patient would present with an inability to extend the knee.