Clinical Correlation 4- Lower extremity

Question 1

The patella slides through which groove?

Answer 1

Patellofemoral groove

Question 2

The ends of bony structures are covered in what substance to facilitate sliding motion and prevent bone degradation?

Answer 2

Articular cartilage

Question 3

What does the ACL do?

Answer 3

It prevents anterior dislocation of the tibia to a fixed femur (aka hyperextension of the knee)

Question 4

What do the menisci do in relation to articular cartilage?

Answer 4

They distribute weight on the tibial condyle so that there is not a single point of weight concentration which prevents injury or degradation to the articular cartilage. They also make the knee joint more stable

Question 5

What is the normal degree of flexion of the knee? Extension?

Answer 5

140;0

Question 6

What is crepitus?

Answer 6

crackling/grinding sensation that occurs across the patella with flexion of the knee. If positive, it is suggestive of degenerative joint disease (DJD)

Question 7

What is DJD?

Answer 7

loss of the cartilage in joints resulting in a loss of smooth motion between articulating surfaces. DJD is suggested by pain that gets progressively more limiting over time

Question 8

What is an effusion?

Answer 8

Accumulation of fluid in a joint space, resulting in swelling of the knee. Effusions resulting from inflammatory arthritis (e.g. infection, gout, rheumatoid arthritis) are associated with other signs of inflammation, including: warmth, redness, pain with any movement

Question 9

What are useful tests for diagnosing effusions?

Answer 9

1. Ballotment (helpful if the effusion is large)

Slightly flex the knee which is to be examined.
Place one hand on the supra-pateallar pouch, which is above the patella and communicates with the joint space. Gently push down and towards the patella, forcing any fluid to accumulate in the central part of the joint.
Gently push down on the patella with your thumb.
If there is a sizable effusion, the patella will feel as if it’s floating and “bounce” back up when pushed down.

2. Milking (helpful for detecting small effusions)

Gently stroke upwards along the medial aspect of the patella, pushing fluid towards the top and lateral aspects of the joint.
Gently push on the lateral aspect of the joint. If there’s a small effusion, the fluid which was milked to the lateral aspect will be pushed back towards the medial area of the joint, causing the medial skin to bulge out slightly.

Question 10

Identifying the precise cause of inflammatory arthritis (IA) is critical as it directs the clinician towards the best treatment, limiting permanent damage to the joint. How is this best accomplished?

Answer 10

This usually requires aspiration and examination of the joint fluid. Inflammatory fluid has a high white cell count and should contain other clues as to its origin (e.g. gout –> crystals on microscopy; infection –> bacteria on gram stain and culture; etc). Fluid from those with degenerative effusions has relatively few white cells.

Clinically, patients with DJD have few signs of inflammation and some degree of preserved range of motion (ROM). Historical information also helps distinguish DJD from IA. DJD is usually slowly progressive while those with IA more often have an acute presentation. Additionally, those with IA may have characteristic patterns of recurrence (e.g. great toe MTP in gout, MCPs of hands in RA), systemic symptoms, suggestive joint deformities (e.g. ulnar deviation of the hands in RA), and particular radiographic changes

Question 11

How do you test for joint line tenderness?

Answer 11

Have the patient slightly flex their knee. This positions the joint such that other stabilizing elements do not interfere with the structure that is being tested.
Define the joint space along its lateral and medial margins. The joint line is perpendicular to the long axis of the tibia.
Gently palpate along first the medial and then the lateral margins. Pain suggests that the underlying meniscus is damaged. Osteoarthritis can also cause joint line tenderness. Note that only a portion of the meniscus lies near the joint line. The remainder of the meniscus cannot be assessed with this technique.

Question 12

What is McMurray’s test?

Answer 12

When examining the right knee, place your left hand so that your middle, index, and ring fingers are aligned along the medial joint line.
Grasp the foot with your right hand and fully flex the knee.
Gently turn the ankle so that the foot is pointed outward (everted). Then direct the knee so that it is pointed outward as well (valgus stress).
While holding the foot in this everted position, gently extend and flex the knee. If there is medial meniscal injury, you will feel a “click” with the hand on the knee as it is extended. This may also elicit pain.

Question 13

What is the Appley Grind test?

Answer 13

Have the patient lie on their stomach.
Grasp one ankle and foot with both of your hands and gently flex the knee to ninety degrees. Hold the patients leg down by gently placing your leg over the back of their thigh.
Push down gently while rotating the ankle back and forth.
This maneuver places direct pressure on the menisci. If injured, it will cause pain.
Test the opposite leg in the same fashion.

Question 14

How do you test MCL injury?

Answer 14

Slightly flex the right knee (~30 degrees).
Place your left hand along the lateral aspect of the knee.
Place your right hand on the ankle or calf.
Push steadily inward with your left hand while supplying an opposite force with the right. If the MCL is completely torn, the joint will “open up” along the medial aspect.

Question 15

How do you perform a Posterior Drawer test?

Answer 15

Have the patient lie down, the right knee flexed to 90 degrees, foot flat on the table.
Gently sit on the foot. Grasp below the knee with both hands, with your thumbs meeting along the front of the tibia.
Gently push backward, gauging how much the tibia moves in that direction in relation to the femur. The intact PCL will give a discrete end point.

Compare this to the other side by simply shifting your hands to the same position on the opposite leg and repeating.
If the PCL is completely torn, the tibia will feel unrestrained in the degree to which it moves backwards.

Question 16

Patello-Femoral Syndrome: A problem with the way in which the patellar articulates with the femur and moves (tracks) during flexion and extension. As a result, cartilage lining the undersurface of the patella becomes irritated and worn down. Known as Chondromalacia, this process causes anterior knee pain with activity and often after prolonged sitting. How can you test for this?

Answer 16

Have the patient slightly flex the leg to be tested.
Gently push down on the patella with both thumbs, which may elicit pain in the setting of Chondromalacia.
Now, gently move the patella from side to side and try to palpate its undersurface. This may elicit pain in the setting of Chondromalacia.
Hold the patella in place with your hand and ask the patient to contract their quadriceps muscle. This will force the inferior surface of the patella onto the femur, eliciting pain in the setting of Chondromalacia.

Question 17

What are the main bursa of the knee?

Answer 17

prepatellar- located directly under the patella. Most frequently affected due to direct trauma, as may occur with people who spend a lot of time on their knees (e.g. carpet layers, carepenters).
infrapatellar (ancerine)- Below the knee. Also affected by direct trauma, as with the prepatella bursa.

Question 18

95% of hernias occur at which vertebral levels?

Answer 18

L5 and S1

Question 19

An L4 hernia would be manifested how?

Answer 19

pain in the back and SHIN, weakness in ankle dorsiflexors, change in knee jerk reflex

Question 20

An L5 hernia would be manifested how?

Answer 20

numbness in the top of the foot and great toe, weakness in extensor hallicus longus, and no reflex changes

Question 21

An S1 hernia would be manifested how?

Answer 21

numbness of lateral foot and sole, weakness in gastrocnemius and soleus, and change in an ankle reflex

Question 22

What are radioculopathies characterized by?

Answer 22

sensory deficit consistent with the known distribution of a single nerve root (i.e., one dermatome) and weakness in all muscles innervated by that root (which usually includes several peripheral Nn.)

Question 23

Peripheral polyneuropathies

Answer 23

Some systemic disorders generally affect peripheral nerves. When nerve cell bodies or axons are damaged, the axons ‘die back’ from the periphery (since the distal end of the axon is farthest removed from neuron’s cell body). Because of this, affected neurons with the longest axons become symptomatic first and elicit the most severe symptoms. It is therefore not surprising, given the length of the legs, that such peripheral polyneuropathies present first in the feet and ankles, and that symptoms are bilateral and symmetric.
As the underlying disease progresses, the hands may also become symptomatic, producing the classic “glove and stocking” distribution. Symptoms are predictable, and are illustrated in the figure. Peripheral polyneuropathies often produce a particularly noxious and persistent “neuropathic”, burning type of pain along with diminished sensation. Symptoms cannot be explained by any single peripheral nerve, root, or plexopathy; the symmetrically peripheral distribution defines the syndrome.

Diabetes is the most common cause of peripheral polyneuropathy. A wide variety of other systemic metabolic and inflammatory disorders, alcoholism, toxins, and nutritional deficiencies can also cause peripheral polyneuropathies.

Question 24

Low back pain, suspected herniated intervertebral disc, vertebral osteoarthritis, cancer or vertebral infection
would be manifested by what?

Answer 24

Radiculopathy

Question 25

The lumbosacral (LS) plexus is susceptible to diseases or trauma involving the nearby abdominal & pelvic viscera; e.g. after hysterectomy, labor, aortic aneurysm, pelvic tumors, or radiation. Unlike the brachial plexus, LS plexopathies tend to affect the entire leg. Discrete upper & lower plexus syndromes are rare.

Answer 25

Lumbosacral plexopathy

may be unilateral or bilateral, depending on cause

Question 26

Fracture of upper femur or hip surgery, abscess or hematoma of psoas muscle

Answer 26

Femoral N. palsy

Question 27

Psoas muscle abscess or hematoma, labor, pelvic trauma

Answer 27

Obturator N. palsy

Question 28

Hip dislocation, penetrating injury, misplaced intramuscular injection

Answer 28

Sciatic N. injury

Question 29

Trauma to head of fibula, prolonged crossing of legs

Answer 29

Peroneal N. palsy

Question 30

Trauma in the popliteal fossa or fracture of the tibia

Answer 30

Tibial N. palsy

Question 31

Diabetics, alcoholics, those w/other toxin exposures and systemic diseases who present with distal pain and sensory loss in a symmetrical “glove and stocking” distribution.

Answer 31

Peripheral polyneuropathy

Question 32

What would you do to test motor function of nerve root L2?

Answer 32

Hip flexion

Question 33

What would you do to test motor function of nerve root L3?

Answer 33

Hip extension

Question 34

What would you do to test motor function of nerve root L4?

Answer 34

Ankle dorsiflexion

Question 35

What would you do to test motor function of nerve root L5?

Answer 35

Extension of great toe

Question 36

What would you do to test motor function of nerve root S1?

Answer 36

Ankle plantar flexion

Question 37

What would a peripheral nerve lesion be characterized by?

Answer 37

deficits are consistent with the known sensory and motor distribution of a single peripheral nerve

Question 38

When would you suspect a plexopathy (disease of the corresponding plexus)?

Answer 38

likely when signs and symptoms suggest involvement of multiple nerve roots (i.e., polyradiculopathy) but the pattern doesn’t conform to the distribution of individual roots or peripheral nerves. Sensory loss will involve multiple adjacent dermatomes.

Question 39

The knee jerk test tests which motor neuron root(s)?

Answer 39

L3-L4

Question 40

The ankle jerk test tests which motor neuron root(s)?

Answer 40

S1

Question 41

Lumbar radiculopathies are usually caused by what?

Answer 41

Herniated lumbar disc. With aging, the nucleus pulposus of the intervertebral discs tend to desiccate, diminishing their effectiveness as spinal “shock absorbers”. When excessive forces are transmitted, as with lifting, the central nucleus pulposus may protrude through the surrounding annulus. This most commonly results in lateral herniation of the disc material (figure a.) with resultant impingement on the nerve root as it exits the neural foramen below the affected disc (e.g., an L4-5 disc herniation would impinge the L5 nerve root). Occasionally the herniation occurs centrally, compressing the cauda equina (figure b.); this can be a neurologic emergency.
Degenerative arthritis of the lumbar spine. Over time, “wear and tear” changes may produce degeneration and focal bony hypertrophy (bony excrescences known as osteophytes) of the vertebral bodies and/or facet joints (figure c.). This can also result in impingement on nerve roots within the neural foramina.

Note, however, that tumors and abscesses can also involve vertebrae, causing an radiculopathies or compression of the cauda equina. Always consider this possibility in patients at risk for, or with other signs and symptoms suggestive of, these diseases.

Question 42

Based on what you know about the anatomy of each, can you explain why cruciate ligament tears are associated with significant and immediate knee swelling, whereas meniscus injuries are associated with less and more delayed swelling?

Answer 42

The immediate swelling that occurs with cruciate tears is in part due to bleeding, as disruption of these ligaments causes more bleeding that the less vascular cartilage.

Question 43

What is stenoses?

Answer 43

abnormal narrowing of a blood vessel