Musculo/Derm 1 Flashcards
Where does the Anterior Cruciate Ligament run from?
Lateral femoral condyle to anterior tibia
Where does the Posterior Cruciate Ligament run from?
Medial femoral condyle to posterior tibia
What is a Valgus deformity?
Knock kneed, lower leg abducted
What is a Varus deformity?
Bow legged, lower leg adducted
What stress does the Medial Collateral Ligament resist?
Resist valgus stress
What stress does the Lateral Collateral Ligament resist?
Resists varus stress
What are the attachments of the Lateral Collateral Ligament?
Lateral epicondyle of femur and head of fibula
What are common presentations of knee injuries?
Swelling, instability, sensation that knee will ‘give out’
What is the most commonly injured knee ligament?
ACL
What often causes ACL injury?
Noncontact athletic injury, e.g., running/jumping, sudden change of direction
What are two tests for ACL injury?
Anterior drawer: bend knee 90 degrees
Lachman test: bend knee 30 degrees
What often causes PCL injury?
Trauma, dashboard injury
How does MCL injury present?
Abnormal passive abduction of lower leg, medial space widens
What is the Unhappy triad?
Triad of injury common in contact sports, includes: ACL tear, MCL tear/sprain, Medial meniscal tear
What force leads to an Unhappy triad?
Lateral to medial force applied to knee when foot planted
What often causes LCL injury?
Trauma to medial knee
How does LCL injury present?
Abnormal passive adduction of lower leg
When does a Meniscal Tear often occur?
When foot is planted and there is sudden change in direction, twisting the knee
How to perform McMurray test?
Patient supine with knee flexed, extend knee while rotating foot
-Internal rotation tibia → tests lateral meniscus
-External rotation → tests medial meniscus
What type of joint is the knee?
Synovial joint
What is a bursa?
Synovial lined sac that acts as a cushion between bones and tendons/muscles
What often causes Prepatellar Bursitis?
Repeated kneeling (‘Housemaid’s knee’), Gout, infection
How does Prepatellar Bursitis present?
Swelling and warmth anterior to patella
What is a Baker’s Cyst?
Fluid collection in the Gastrocnemius-semimembranosus bursa (Popliteal cyst)
Often related to Chronic joint disease because it communicates with synovial space
What is the clinical presentation of a Baker’s Cyst?
Often small, asymptomatic. May cause posterior knee pain/swelling that worsens with activity. Can rupture and cause acute pain that mimics DVT.
In what condition are Baker’s Cysts common?
Rheumatoid arthritis
What is Osgood Schlatter Disease?
Tibial tuberosity avulsion from overuse. Usually benign, self-limited condition. Pain/swelling at tibial tubercle (Secondary ossification center of tibia)
In what age group does Osgood Schlatter Disease usually occur?
Children
What is the clinical presentation of a Patellar Fracture?
Cannot extend knee against gravity
What can cause inability to extend knee against gravity?
Patellar fracture, Quadriceps tendon tear, Injury to patellar tendon
What is the Glenoid?
Fossa of scapular bone
What are the 4 rotator cuff muscles?
(SITS) Supraspinatus, infraspinatus, teres minor, subscapularis
What does Rotator Cuff Tendonitis cause?
Pain with abduction
What does a Rotator Cuff tear lead to?
Inability to abduct
What is the action of the Supraspinatus?
Initial abduction (0-15°)
Innervation: Suprascapular nerve
What is the most common rotator cuff injury?
Supraspinatus
Why is the Supraspinatus vulnerable to impingement?
Tendon travels between humeral head and acromion process of scapula. Inflammation or tear can occur.
What are two tests that can identify Supraspinatus injury?
Empty Can Test, Full Can Test
What is the action of the Infraspinatus?
Assists in external rotation/abduction of shoulder
What nerve innervates the Infraspinatus?
Suprascapular
Who commonly injures the Infraspinatus?
Overhead throwers (pitchers)
What is the action of Teres Minor?
External rotation/adduction of shoulder
Innervation: Axillary nerve
What is the action of Subscapularis?
Internal rotation
Innervation: Upper/lower subscapular nerves
What muscles are responsible for full range abduction of the arm?
Supraspinatus: First 15°, Deltoid: up to 90°, Trapezius/serratus anterior: abduction beyond 90°
What type of dislocation typically occurs in shoulder dislocation?
Anterior dislocation of the humeral head
What nerve is commonly injured in shoulder dislocation?
Axillary nerve, leading to sensory loss of deltoid and weak abduction (usually too painful to move)
Where does a Humerus Fracture often occur?
Proximal humerus, which may disrupt blood supply leading to avascular necrosis of head and injury to axillary nerve causing loss of arm abduction
What is Epicondylitis?
Pain at epicondyle from overuse, few inflammatory cells + disorganized tissue/vessels
What causes elbow pain in Lateral epicondylitis?
Wrist extension (tennis elbow)
What causes elbow pain in Medial epicondylitis?
Wrist flexion (golfer’s elbow)
What is nursemaid elbow?
Radial head subluxation caused by axial traction on pronated forearm, leading to annular ligament slipping over head of radius
What is the most common pediatric elbow fracture?
Supracondylar Fracture, often occurring from falling on an outstretched arm
What is at risk for injury in a Supracondylar Fracture?
Brachial artery and Median nerve (travels with brachial artery) → most common neurovascular artery, Radial or ulnar nerves
What are two muscles innervated by the axillary nerve?
Teres minor, deltoid
What are the presentations of Radial Nerve Lesions?
Triceps weakness, Wrist drop, Sensory loss of back of hand/forearm
What are common causes of Radial Nerve Lesions?
Midshaft humeral fracture, Crutches, ‘Saturday night palsy’
Where does the Radial Nerve run?
Spiral/radial groove
What is the presentation of a radial nerve lesion at the radial groove?
Triceps spared, Most sensory nerves (arm/forearm) unaffected, Weakness wrist/finger extensors, Sensory loss of dorsal hand
What are the nerve roots for Musculocutaneous Nerve?
C5-C7 (lateral cord of brachial plexus)
What does the Musculocutaneous Nerve innervate?
Biceps and sensation to lateral forearm
What is Erb’s palsy?
Upper plexus (C5-C6) injury caused by excessive angle at neck/shoulder. Classic cause: Birth Trauma
What nerves are injured in Erb’s palsy?
Axillary, Musculocutaneous, Suprascapular
What is the clinical presentation of Erb’s palsy?
Arm straight at side + internally rotated (‘Waiter’s tip’)
What is Klumpke Palsy?
Lower Plexus (C8-T1) Injury caused by excessive abduction of arm, e.g., catching a tree branch while falling
What nerves are injured in Klumpke Palsy?
Median and Ulnar
What is the clinical presentation of Klumpke Palsy?
Clawed hand: MCP hyperextended, IP joint flexed (other flexors at wrist are spared)
What is Thoracic Outlet Syndrome?
Compression of nerves/vessels leaving thorax, occurs above first rib and behind clavicle (Scalene triangle)