Lower Limb

The nerve damaged is the lateral plantar nerve that innervates the third lumbrical. The medial plantar nerve innervates the flexor hallucis brevis, first lumbrical, and abductor hallucis. The deep branch of the common fibular nerve innervates the fibularis tertius.

A 12-year-old girl arrives at the emergency department after stepping on a piece of broken glass. A physical examination demonstrates a loss of sensation on the lateral third of the sole of the foot. Knowing that, which of the following muscles is most likely paralyzed?

Of the structures listed, only the tibial nerve passes posterior to the medial malleolus. Accompanying the nerve in this location are tendons of the flexor hallucis longus, flexor digitorum longus, tibialis posterior, and the posterior tibial artery. The tendon of the tibialis anterior muscle and the superficial fibular nerve pass anterior to the medial malleolus. The tendon of the fibularis longus and the sural nerve pass lateral to the medial malleolus.

A 12-year-old girl is brought to the emergency department after falling on the sharp edge of a tin can. She has a deep cut immediately posterior to the medial malleolus. Which of the following structures is most likely injured?

The common fibular nerve innervates the muscles in the anterior compartment of the leg that are responsible for dorsiflexion of the foot at the ankle joint.

A 16-year-old girl is hit with a softball bat on the lateral side of her leg, immediately below the knee. She is brought to the emergency department, and during the examination, it is discovered that she is unable to dorsiflex her foot. The nerve most likely injured is which of the following?

The common fibular nerve innervates the anterior lateral surface of the leg and the dorsum of the foot. This nerve is in a position to be compressed as it swings around the neck of the fibula to enter the lateral compartment of the leg.

A 19-year-old man has numbness of the anterolateral surface of his right leg and dorsum of his right foot when he wears tight, knee-high boots during his dance routine. Which of the following nerves is most likely compressed?

The lateral femorotibial ligament. An area of the fibrous membrane of the knee joint capsule deep to the fibular collateral ligament connects the femur to the lateral tibia. This often thickened region of the capsule is known clinically as the lateral femorotibial ligament. In this patient, the small avulsion fracture of this ligament is of little clinical consequence, because the fibular collateral ligament remains intact.

A patient came to the clinic with a ruptured anterior cruciate ligament. An anteroposterior radiograph demonstrated a small bony flake fracture of the lateral tibia just beneath the tibial plateau. Which ligament has been avulsed?

The anterior cruciate ligament attaches posteriorly on the femur and anteriorly on the tibia. Thus, it prevents anterior movement of the tibia in relation to the femur. If this ligament is torn, the tibia would be able to be moved anteriorly in relation to the femur (a positive drawer test). The posterior cruciate ligament prevents posterior movement of the tibia in relation to the femur. The collateral ligaments prevent medial and lateral instability of the joint. The lateral meniscus is a C-shaped piece of cartilage on the tibial surface.

A 22-year-old woman is examined by the team physician after injuring her right leg during a basketball game. The physician is able to demonstrate significant anterior movement of the tibia in relation to the femur. What of the following structures is most likely torn?

Of the bones listed, the cuboid is the only one that does not articulate with the talus.

A 28-year-old woman develops degenerative joint disease of the feet and ankles from years of ballet dancing. X-ray films show severe changes at the articular surfaces of the talus and at each of the bones that articulate with the talus. Which of the following bones has most likely been spared from this degenerative process?

The talus articulates with the tibia, fibula, calcaneus, and navicular.

A 32-year-old ballet dancer has degenerative joint disease of his feet and ankles. X-ray films show severe degenerative changes at the articular surfaces of the talus and at each of the bones that articulate with the talus. Which of the following bones would be involved in this degenerative process?

The tibial division of the sciatic nerve innervates all of the musculature in the posterior compartment of the leg and plantar surface of the foot. These muscles are responsible for flexion of the leg at the knee joint, plantar flexion of the foot at the ankle joint, and flexion of the toes. It also carries sensory fibers from the skin on the posterior aspect of the leg and the plantar surface of the foot. The correct answer is plantar flexion at the ankle joint.

A 38-year-old woman sustains a penetrating injury to the left gluteal region that damages the tibial division of the sciatic nerve. Which of the following deficits is most likely to result from this injury?

If her foot is dorsiflexed and everted, the innervation to the muscles in the anterior and lateral compartments, the deep and superficial fibular nerves, are still intact. In her case, the innervation to the muscles in the posterior compartment has been lost. These muscles are innervated by the tibial nerve.

A 45-year-old woman arrives at the emergency department after being injured in an automobile collision. Her right foot is dorsiflexed and everted. Which of the following nerves has most likely been injured?

The muscles in the posterior compartment of the thigh are innervated by branches of the sciatic nerve. Thus, this nerve is most likely compressed, causing her muscle weakness. The saphenous nerve is cutaneous to the medial aspect of the leg. The pudendal nerve is the nerve to the area referred to as the perineum. The obturator and femoral nerves innervate structures in the medial and anterior compartment of the thigh, respectively.

A 63-year-old woman has blood-stained stools and is unable to completely empty her rectum. An examination by her physician also shows bilateral weakness of her posterior thigh muscles. Additional studies indicate a neoplasm in the posterior wall of the rectum. Compression of which of the following nerves is the most likely cause of her muscle weakness?

This is a condition known as "foot drop" and indicates that the muscles in the anterior compartment of the leg, that dorsiflex the foot at the ankle joint, have lost their nerve supply. The nerve supplying this compartment is the superficial fibular nerve, which is a branch of the common fibular nerve.

A 72-year-old woman arrives at her physician's office complaining that her right foot "drags across the ground" when she walks. Which of the following nerves is most likely injured?

The great saphenous vein begins on the dorsal surface of the foot and passes superiorly along the medial side of the ankle joint (the correct answer), anterior to the medial malleolus, and along the medial side of the leg and thigh, passing posterior to the axis of the knee joint on its medial side.

A 72-year-old woman has a portion of her great saphenous vein removed for use during a coronary artery graft procedure. The incision used to remove the vein graft should be made in which of the following locations?

Inferior Gluteal Nerve Each of the actions the patient is asked to perform tests the integrity of a specific nerve. A normal knee jerk reflex indicates that the femoral nerve is intact. Standing on her heels indicates that the common fibular nerve is intact. Standing on the balls of her feet indicates that the tibial nerve is intact. The obturator nerve is not directly involved in any of the actions described. The inferior gluteal nerve innervates the gluteus maximus muscle, which is responsible for extending the lower limb at the hip joint. This action is basic to climbing stairs. Therefore, an indication by a patient of problems in climbing stairs indicates an injury to the inferior gluteal nerve.

A 77-year-old woman has difficulty climbing stairs because of weakness in her legs. Her knee jerk reflex is normal and she is able to stand on her heels and on the "balls" of her feet. Injury to which of the following nerves is the most likely cause of these findings?

The iliotibial band is a condensation of the fascia lata, which runs directly over the lateral femoral condyle and inserts onto the anterior lateral aspect of the tibia (Gerdy's tubercle). This produces a typical iliotibial band friction syndrome.

A long distance runner complained of pain over the anterior lateral aspect of the lateral femoral condyle. What anatomical structure could rub on this region?

The common fibular nerve was injured. This nerve lies on the lateral aspect of the neck of the fibula and supplies fibularis longus and fibularis brevis. Inability to use these muscles impairs dorsiflexion and eversion, producing foot drop.

A man was kicked in the posterolateral aspect of the knee, and this fractured the neck of his fibula. What structures were damaged and why did he have foot drop?

The blood supply to the talus is derived from vessels lying within the tarsal sinus. These vessels pass posteriorly to supply the body and subtalar dome region. Disruption of the neck of the talus damages these vessels, rendering the bone ischemic and subject to disruption and collapse.

A non-united fracture of the neck of the talus produced a collapse of the talar dome. Why?

No. Only the suprapatellar bursa is in direct communication with the knee joint anteriorly. Most anterior knee bursae are usually acquired and have no communication with the knee joint.

A patient has a soft tissue bursa anterior to the patellar tendon. Does this communicate with the knee joint?

The blockage is in the right common iliac artery. If the lesion was in the right external iliac artery the patient would not have buttock claudication. If the lesion was in the right internal iliac artery the left femoral pulse would be normal.

A patient has right-sided buttock claudication and a weak right femoral pulse. The left femoral pulse is normal. Where is the blockage (stenosis or occlusion)?

This is a typical site for the apophysis of the base of metatarsal V. It is often mistaken for a fracture, but fractures run at 90° to the direction of this.

A radiograph of the foot demonstrates a small flake of bone in an anterior-to-posterior alignment at the base of metatarsal V. The flake of bone is normal. Can you account for it?

The sciatic nerve. The sciatic nerve leaves the pelvis through the greater sciatic notch, and runs posteriorly from the inferior border of piriformis to the short rotators of the hip.

A traumatic posterior dislocation of the femoral head can damage which important structure?

The physical findings described here indicate a problem with the muscles involved in abduction of the right femur at the right hip joint. The gluteus medius and minimus muscles abduct the lower limb at the hip joint and reduce pelvic drop by securing the position of the pelvis on the stance limb. They are innervated by the superior gluteal nerve.

An 83-year-old man has trouble walking. At his physician's office, he is asked to stand on his right foot and his left hip drops. Which of the following nerves is most likely damaged, causing his problem?

1. The lateral patella facet that articulates with the femoral trochlea is less acute and "flatter" than its medial component. 2. The "carrying angle" of the femur places the patella medial to the hip joint; therefore the overall force vector from quadriceps femoris contraction produces a lateral force on the patella. The carrying angle in women is greater than in men, which is a potential cause for the increased frequency of this event in women.

Give two anatomical reasons why patella dislocation tends to occur laterally.

No. There are no significant meniscocapsular attachments laterally. The medial meniscus attaches to the capsule, and meniscocapsular detachment in sports injuries is therefore common.

Is meniscocapsular disruption more common laterally?

Saphenous Nerve. Sensory fibers from the medial aspect of the leg travel in the saphenous nerve. Thus, the saphenous nerve was most likely injured. The medial femoral cutaneous nerve carries fibers from the anterior portion of the thigh. The obturator nerve carries fibers from the medial portion of the thigh. The superficial fibular nerve carries fibers from the anterior portion of the leg and dorsum of the foot. The sural nerve carries fibers from the lateral aspect of the foot.

The great saphenous vein of a 54-year-old man is being cannulated. During the cutdown procedure, as the vein is being prepared for cannulation, the patient experiences pain radiating along the medial side of his leg. Which of the following nerves is most likely to have been injured during this procedure?