Musculoskeletal, Skin, and Connective Tissue

Question 1

Knee Bones

Answer 1

Femur
Tibia
Fibula
Patella

Question 2

Knee Ligaments

Answer 2

Anterior Cruciate
Posterior Cruciate
Medial Collateral
Lateral Collateral

Question 3

Knee Menisci

Answer 3

Medial Menisci

Lateral Menisci

Question 4

Valgus

Answer 4

Knock Kneed

Lower leg abducted

Question 5

Varus

Answer 5

Bow Legged

Lower leg adducted

Question 6

ACL Injury

Anterior Cruciate Ligament

Answer 6

Most commonly injured knee ligament
Often a noncontact athletic injury (running, jumping, sudden change of direction)
Classically senses as a “pop”
ANTERIOR DRAWER SIGN
Supine, bend knee at 90 deg, tibia drawn forward, forward movement greater than normal in ACL tear)
LACHMAN TEST
Same as draer but 30 deg

Question 7

PCL Injury

Posterior Cruciate Ligament

Answer 7

Often from trauma (force directed posteriorly at knee, classic cause “dashboard injury”)
POSTERIOR DRAWER SIGN
Supine, bend knee at 90 deg, tibia moves backward more than normal

Question 8

MCL Injury

Medial Collateral Ligament

Answer 8

Damaged by valgus stress
ABNORMAL PASSIVE ABDUCTION
Force from lateral side (valgus), lower leg away from midline (abduction), medial space widens

Question 9

Unhappy Triad

Answer 9

Lateral force applied to knee when foot is planted
Anterior cruciate ligament (ACL) tear
Medial collateral ligament (MCL) tear
Medial meniscal tear
(modern update: lateral meniscus more common)

Question 10

LCL Injury

Lateral Collateral Ligament

Answer 10

Rarely injured in isolation. often trauma to medial knee.
ABNORMAL PASSIVE ADDUCTION
Force form medial side (varus), lower leg toward midline (adduction), lateral space widens

Question 11

Meniscal Tear

Answer 11

Often occurs when foot is planted. Sudden change in direction, twisting of knee.
Pain and swelling following injury. Pain worse with twisting or pivoting

Question 12

McMurray Test

Answer 12

Patient Supine.
Flexed/bent knee held by examiner’s hand.
Foot held by examiner’s other hand.
Extend knee while rotating foot
Pain or “pop” = positive McMurray test
Internal rotation tibia -> tests lateral meniscus (foot toward midline)
External rotation -> test medial meniscus (foot away midline)

Question 13

Prepatellar Bursitis

Answer 13

Inflammation of prepatellar bursa
Often caused by repeated kneeling "housemaid's knee"
Other causes: infection, gout
pain with activity
Swelling anterior to patella
Warmth

Question 14

Baker’s Cyst (Popliteal Cyst)

Answer 14

Popliteal fluid collection
Gastrocnemius-semimembranosus bursa (bursa between two muscle tendons, found in back of knee)
Often communicates with synovial space.
Often related to chronic joint disease (degenerative, inflammatory, joint injury)
May cause posterior knee pain. Pain with prolonged standing.

Question 15

Osgood-Schlatter Disease

Tibial tuberosity avulsion

Answer 15

Occurs in children
Pain/swelling at tibial tubercle from overuse
Secondary ossification center of tibia

Question 16

Patellar Fracture

Answer 16

Results from trauma to knee
Swollen, painful knee
Cannot extend knee against gravity (indicated loss of knee extension)
Diagnosis: x-ray

Question 17

Achondroplasia

Answer 17

Chromosome 4
Failure of longitudinal bone growth (endochondral ossification) -> short limbs. Membranous ossification is not affected -> large head relative to limbs. Constitutive activation of fibroblast growth receptor (FGFR3) actually inhibits chondrocyte proliferation. >85% of mutations occur sporadically; autosomal dominant with full penetrance (homozygosity is lethal). Associated with increased paternal age. Most common cause of short-limbed dwarfism.

Question 18

Wrist Bones

Answer 18

"some lovers try positions they can't handle"
Scaphoid
Lunate
Triquetrum
Pisiform
Trapezium
Trapezoid
Capitate
Hamate

Question 19

FOOSH Injury

Answer 19

Falling On an Out-Stretched Hand
Scaphoid = most commonly fractured carpal bone
Palpable in anatomic snuff box
Complications of fracture = avascular necrosis & nonunion

Question 20

Avascular necrosis

Answer 20

loss of blood supply

Question 21

Nonunion

Answer 21

failure of bone to heal

Question 22

Greenstick Fracture

Answer 22

BENDING STRESS

Bone fails on tension side.

Question 23

Torus Fracture

Answer 23

AXIAL FORCE TRAUMA
“buckle fracture”
Tension side remains solid