Orthopedics Week 1

During gastrulation, the epiblast forms embryonic endoderm, intraembryonic mesoderm, and remaining embryonic ____.

ectoderm

Nearly all musculoskeletal tissue is derived from ____.

mesoderm

The three major MSK sources are paraxial mesoderm, lateral plate mesoderm, and ____ cells.

neural crest

The notochord induces the neural tube and nearby mesoderm; its remnant becomes the ____.

nucleus pulposus

Paraxial mesoderm forms somites, which contribute to the axial skeleton, skeletal muscle, and ____.

dermis

Lateral plate mesoderm forms the somatopleure, which contributes to the anterior body wall and ____.

limbs

The sclerotome is induced primarily by ____ from the notochord and ventral neural tube.

Sonic hedgehog (Shh)

The dermomyotome is induced primarily by ____ from the dorsal neural tube and overlying ectoderm.

Wnt

The dermomyotome divides into the myotome and ____.

dermatome

The myotome gives rise primarily to ____ muscle.

skeletal

The dermatome contributes primarily to the ____.

dermis

The sclerotome forms vertebrae and the posterior ribs; its syndetome forms ____.

tendons

The ZPA secretes ____ to establish anterior-posterior limb patterning and digit identity.

Sonic hedgehog (Shh)

The AER secretes ____ to initiate and maintain proximal-distal limb outgrowth.

FGF8

The primary growth stimulus for limb bud formation is ____.

FGF10

HOX genes determine ____ along the body axis, while TBX genes help specify upper versus lower limb.

where the limb bud forms

If the AER fails because FGF8 is not expressed, the result can be ____.

amelia

Digit separation occurs when cells between the digital rays undergo ____.

apoptosis

What is the Lachman test?

A test for ACL insufficiency using anterior tibial translation and endpoint feel.

What is the posterior drawer test?

A test for PCL insufficiency by assessing posterior translation of the tibia.

What is the valgus stress test?

A test for MCL laxity, performed at 0° and 30° of knee flexion.

What is the varus stress test?

A test for LCL laxity, performed at 0° and 30° of knee flexion.

What is McMurray testing?

A meniscal maneuver in which a painful click supports a meniscal tear.

What is patellofemoral pain syndrome?

Anterior knee pain from dysfunction at the patella-trochlea articulation.

What is prepatellar bursitis?

Inflammation/fluid accumulation in the prepatellar bursa, often from kneeling.

What is patellar tendinopathy?

Pathology of the proximal patellar tendon from high tensile load and overuse.

What is a popliteal (Baker) cyst?

A fluid-filled cystic swelling behind the knee, often secondary to joint pathology.

What is osteoarthritis of the knee?

A degenerative joint disorder causing usage-related pain, stiffness, and cartilage loss.

What is a synovial joint?

A joint with a fluid-filled cavity enclosed by fibrous and synovial membranes.

What is an enthesis?

The specialized junction where a tendon, ligament, or capsule inserts into bone.

What is acute compartment syndrome?

A limb-threatening rise in closed-compartment pressure that compromises tissue perfusion.

What is a nonunion?

Failure of a fracture to consolidate by approximately 6–9 months.

What is malunion?

Healing of a fracture in abnormal alignment or position.

Phocomelia is characterized by hands or feet projecting directly from the shoulder or ____.

trunk

Syndactyly results from failure or incomplete ____ between digital rays.

apoptosis

Talipes equinovarus is another name for congenital ____.

clubfoot

The Ottawa knee rules indicate knee x-rays after trauma for age ≥____ years.

55

After traumatic knee injury, isolated patellar tenderness is an indication for ____.

x-rays

A patient unable to bear weight both immediately and in the ED meets an Ottawa knee rule for ____.

x-rays

A non-contact pivot with a sudden pop, swelling, and giving-way strongly suggests an ____ tear.

ACL

The ACL primarily resists ____ translation of the tibia on the femur.

anterior

The two ACL bundles are the anteromedial and ____ bundles.

posterolateral

A Lachman with >10 mm translation is ____ grade.

III

A Lachman endpoint described as absent, soft, or ill-defined is endpoint type ____.

B

A Segond fracture is a bony avulsion of the ____ tibial plateau and is pathognomonic for ACL rupture.

lateral

A fall onto a flexed knee or forced hyperflexion can injure the ____.

PCL

Posterior sag and a positive posterior drawer suggest a ____ tear.

PCL

A valgus force or lateral-to-medial blow most strongly suggests an ____ injury.

MCL

MCL laxity at 30° suggests superficial injury, while laxity at 0° suggests ____ injury.

deep

A varus force with or without hyperextension most strongly suggests an ____ injury.

LCL

A varus thrust gait is associated with ____ injury.

LCL

The unhappy triad consists of ACL, MCL, and ____ injury.

medial meniscus

A twisting injury with the knee flexed and foot planted plus joint-line tenderness suggests a ____ tear.

meniscal

A painful click during McMurray testing is the key positive finding; pain alone is ____.

not the finding

The meniscal vascular zones are red, red-white, and ____.

white

The outer red zone of the meniscus has better healing potential because it has a better ____ supply.

blood

A normal meniscus on T2 MRI appears as a dark ____ triangle.

black

A meniscal tear on T2 MRI requires bright signal to ____ the meniscal surface.

reach/penetrate

Patellofemoral pain syndrome usually causes diffuse ____ knee pain worsened by stairs or squatting.

anterior

Dynamic knee valgus involves knee abduction, femoral adduction, and ankle ____.

eversion

Posterior hip external rotator strengthening is used to address ____ knee valgus biomechanics.

dynamic

Prepatellar bursitis is associated with kneeling, manual labor, and ____ trauma.

penetrating

If infectious prepatellar bursitis is suspected, aspiration can be evaluated with Gram stain and ____ crystals.

urate

Patellar tendinopathy causes focal pain at the ____ patellar tendon.

proximal

Chronic patellar tendinopathy is degenerative and is termed tendin____ rather than tendinitis.

osis

Corticosteroid injection directly into a patellar tendon should be avoided because it can increase risk of ____.

rupture

Patellar subluxation usually occurs in the ____ direction.

lateral

A popliteal cyst is also called a ____ cyst.

Baker

Knee osteoarthritis classically causes usage-related pain and morning stiffness lasting ≤____ minutes.

30

For suspected knee arthritis, the x-ray gold standard uses ____-bearing views.

weight

The Merchant/sunrise view is particularly useful for evaluating the ____ joint.

patellofemoral

A weight-bearing AP knee x-ray is useful because joint-space narrowing is assessed under ____.

load

The Rosenberg view is a weight-bearing, flexed-knee ____ view.

PA

A suspected complex knee problem may require MRI, whereas ultrasound is mainly useful for detecting ____.

effusion

For knee arthritis, severe medial compartment wear produces a ____ deformity.

varus

Severe lateral compartment wear produces a ____ deformity.

valgus

For a meniscus tear, the three diagnostic clues emphasized in the notes are joint-line tenderness, joint-line pain with deep flexion, and ____ test.

McMurray

In a patient over 40 with suspected meniscal pathology, weight-bearing arthritis x-rays should be considered ____.

first

In patients over 70, MRI meniscal tears are common even when patients are ____.

asymptomatic

A locked knee or gross instability from a meniscal problem is treated as a medical ____.

urgency

A synovial joint has a cavity enclosed by an outer fibrous membrane and an inner ____ membrane.

synovial

Fibrous joints are connected primarily by dense ____ connective tissue.

fibrous

Cartilaginous joints are united by ____ tissue.

cartilage

The major function of synovial fluid is to reduce friction and permit ____ movement.

free

Ligaments connect ____ to bone.

bone

Tendons connect ____ to bone.

muscle

Mature articular cartilage is ____ and therefore has very limited healing capacity.

avascular

Flexion decreases the angle between articulating segments; extension ____ that angle.

increases

Abduction moves a limb away from the body's midline; adduction moves it ____ the midline.

toward

External rotation turns a limb away from the body around its vertical axis; internal rotation turns it ____.

toward the midline

Regular exercise helps maintain joint health and can help delay age-related loss of ____.

joint function

Aging is associated with reduced flexibility and progressive ____ of articular cartilage.

degeneration

Acute tendon inflammation is called tendinitis, whereas chronic degenerative tendon pathology is called ____.

tendinosis

The four tendon-continuum stages are reactive overload, tendon dysrepair, degeneration, and macroscopic ____.

rupture

Osteoarthritis is primarily a ____ joint disease, while rheumatoid arthritis is systemic and inflammatory.

degenerative

OA morning stiffness is typically ≤30 minutes; RA morning stiffness is generally ____.

30 minutes / prolonged

Grade I ligament sprain has mild injury with little or no ____.

laxity

Grade II ligament sprain represents a ____ tear with increased laxity but some remaining fibers.

partial

Grade III ligament sprain represents a ____ tear with marked laxity and no firm endpoint.

complete

HVLA is strictly contraindicated across joints with acute Grade ____ or Grade III ligament tears.

II