MSK Exam Prep Flashcards
What is a sprain?
Ligament tears.
What is a strain?
Stretch or tear to muscle or tendon.
What are the grades of sprains and strains?
• Grade 1: Stretching and small tears.
• Grade 2: Larger tear.
• Grade 3: Complete tear.
What is the physiological healing process of a sprain or strain?
Inflammatory reaction after injury; collagen begins to repair 4-5 days after injury, and collagen fibers help form a new enthesis.
Recurrent injury can lead to poor healing or excess scar tissue.
What is tendinopathy?
Inflammatory condition of tendon.
True or false: Inflammatory changes due to tendinopathy can lead to scar tissue formation.
True.
What is the typical presentation of someone with bursitis?
• Normal ROM.
• Swelling.
• Warmth.
• Erythema.
What is the grading system for muscle strain?
• Grade 1: Pain but no deformity, muscle overstretched/overworked.
• Grade 2: Muscle body is intact but there are some torn fibers, swelling, pain, and bruising.
• Grade 3: Trauma resulting in tearing of the fascia and muscle, will see notable deformity.
What is the process of muscle strain healing?
- First, involved fibers will necrose and begin the inflammatory reaction.
- Hematoma will form around/between the damaged areas.
- Monocytes infiltrate the area and phagocytize the necrotic tissue-activation of myoblasts.
- Myoblasts fill in scar tissue, new capillary bed begins to form.
- Remodeling occurs so contractile tissue reforms, typically takes up to six weeks.
What other damage can dislocation cause?
Fracture, capsular disruption, tearing or stretching of nerves, damage to vasculature.
What is an extracapsular fracture?
Fracture line outside of joint space; joint capsule not affected.
What is an intracapsular fracture?
Fracture line extends into joint capsule; increases risk of OA and long-term joint dysfunction.
What is a torus fracture?
Also known as a buckle fracture; cortex squishes down and bulges outward but bone does not break.
What is a bowing fracture?
Bone bends instead of snapping or cracking.
What cancers most commonly metastasize to the bone?
Breast cancer, lung cancer, thyroid cancer, kidney cancer, prostate cancer.
What is the most common site of bone metastases?
Spine.
What is the direct healing process of a fracture?
Primary healing: The cortex of the bone aligns, often through ORIF.
What is the indirect healing process of a fracture?
Secondary healing: Where callus forms around uneven bone surfaces, eventually having remodeling.
What is a transchondral fracture?
Fracture of articular surface of bone; can be a compression fracture of trabeculae or avulsion fracture.
What is nonunion?
Gap edges between fractured pieces of bone fill with tissue instead of bone.
What is delayed union?
Healing still occurring 8-9 months after initial injury.
What is malunion?
Incorrect alignment of bone.
What is synarthrosis?
Immovable joint.
What is amphiarthrosis?
Joint with some movement.
What is diarthrosis?
Most mobile and complex joints.
Example: Hip, shoulder, knee.
What structures are involved in diarthroses joints?
Fibrous joint capsule, synovial membrane, joint cavity, synovial fluid, articular cartilage.
What is a fibrous joint?
Direct connection of bone to bone via fibrous connective tissue. Immovable.
Example: Skull suture.
What are the types of fibrous joints?
Suture, syndesmosis, gomphosis.
What is a suture?
Interlocking of flat bones with dense fibrous tissue.
What is syndesmosis?
Ligaments attach permitting some movement.
What is gomphosis?
Projection from one bone fits into a socket with stability gained from ligament.
What is a cartilaginous joint?
Slightly moveable joint held together with cartilage.
Example: Joint between ribs and sternum.
What are the types of cartilaginous joints?
Symphyses and synchondroses.
What is a symphysis?
Connected via pad/disk of fibrocartilage allowing for shock absorption.
What is synchondrosis?
Bones connected via hyaline cartilage.
What is a synovial joint?
Diarthrosis, most mobile and complex joints.
Example: Hip, shoulder, knee.
What are the two layers of the synovial membrane?
Subintima (outer vascular layer) and intima (inner layer).
What does articular cartilage do?
Decreases joint friction and shares the forces placed on the joint.
What is a plane joint?
Gliding joint, such as TMT joints.
What is a plane joint?
A gliding joint, such as TMT joints.
What is a pivot joint?
A joint that allows bones to rotate around a single axis.
Example: Atlantoaxial joint
What is a condyloid joint?
Similar to a ball and socket joint but not as deep. Allows for flexion/extension, abduction/adduction, and circumduction.
Example: Wrist
What is a saddle joint?
A joint with concave/convex articulation, allowing for flexion/extension, abduction/adduction, and circumduction.
Example: Thumb
What is secreted by osteoblasts that form ropes and form the dense bone structure?
Collagen
What are proteoglycans?
Proteins that transport calcium and help organize the extracellular matrix
What is calcium phosphatase?
Forms to create hydroxyapatite crystals
What is released in response to changes in PTH and what does it do?
Osteocalcin which promotes bone resorption
What determines the rate of osteoclast formation?
RANKL
What is released by the thyroid to stimulate calcium to be deposited in the bones?
Calcitonin
What is released when calcium levels become too low in the bloodstream?
Parathyroid hormone
What type of border do osteoclasts leave behind?
ruffled, resorption lacunae
What do podosomes do?
Allow osteoclasts to attach to a specified area
What does osteoclast secrete to dissolve the mineral contained within the bone?
hydrochloric acid
What is the process of bone development?
- Begins as hyaline cartilage cells near the epiphysis
- Cells proliferate and begin to arrange themselves into columns.
- Hypertrophy of these cells occur and calcium deposits within the matrix.
- Channels begin to form and fill in with marrow from the diaphysis which increases the number of osteoblasts formed.
- True bone formation occurs with osteon formation.
What are the primary hormone drivers for bone development?
- Growth hormone
- Testosterone
- Estrogens
When is bone development typically complete?
In females ages 13-15, and males 15-17
Why is the epiphysis of long bones broader?
Supports weight bearing
What is the structure of a flat bone?
plate of compact bone running parallel with a small layer of spongy bone
What are examples of cuboidal bones?
carpal and tarsal bones
What joint uses a pulley system?
proximal radius and ulna
True or false, tendons and ligaments pass through the periosteum into the layers of compact bone.
true
Explain stage 1 of bone healing (days 1-5).
*Hematoma forms between and around fracture fragments
*Hematoma acts as the initial scaffolding for healing
*An inflammatory reaction occurs when cytokines are released. Macrophages, monocytes, and lymphocytes are stimulated.
Explain stage 2 of bone healing (days 5-11).
*Vascular endothelial growth factor helps to promote angiogenesis
*cellular differentiation occurs, leading to chondrogenesis at the fracture fragment ends.
Explain stage 3 of bone healing (days 11-28).
*Ossification of the callus begins
*Cartilaginous callus is resorbed and calcified
*Angiogenesis continues
*At this point, bone is in an immature, calcified, and woven form
Explain stage 4 of bone healing (Days 18+).
*Breakdown of callus with resorption alongside new bone formation
*Compact bone formed
How long does it typically take for a fracture to heal and how long does remodeling take?
Six weeks, months to years
What is synovial fluid made up of?
*Highly filtrated plasma with bound hyaluronate.
*Phagocytes
What covers articular cartilage?
Hyaline cartilage
What is articular cartilage made up of?
cross-linked collagen fibers and chondrocytes
What pumps fluid into the articular cartilage?
Proteoglycans
What is the fascia?
Connective tissue that encases the muscles individually
What are the layers of the fascia from the outside in?
Epimysium, perimysium, endomysium
What does the perimysium surround?
Fascicle
What does the endomysium surround?
Muscle fiber
What are muscle fibers made up of?
Myofibrils
What are fast twitch fibers?
Fibers that have large, fast conducting nerves innervating them, but are able to contract for shorter periods of time. May briefly utilize anaerobic metabolism
What are slow-twitch fibers?
Composed of small, slower-conducting fibers, but can contract for longer periods. Utilize aerobic metabolism
What does the sarcolemma do?
Allows for rapid spread of electrical conduction, and assists with nutritional transport and protein synthesis.
What chemicals are released and absorbed in the sarcolemma?
Sodium and potassium
What does the sarcoplasmic reticulum do?
Stores and transports calcium
What chemical is released at the neuromuscular junction and what does it do?
Acetylcholine, triggers release of calcium
Explain what occurs with calcium during muscle contraction.
- Acetylcholine released from the axon terminal and binds to receptors on the sarcolemma. 2. An action potential is generated and travels down the T tubule. 3. Calcium is released from the sarcoplasmic reticulum due to a response from a change in voltage. 4. Calcium binds troponin. Cross bridges form between actin and myosin. 5. Acetylcholinesterase removes acetylcholine from the synaptic cleft. 6. Calcium is transported back into the sarcoplasmic reticulum. 7. Tropomyosin binds active sites on actin causing cross bridge to detach.
Where does the musculocutaneous nerve supply sensation to?
Lateral forearm
Where does the axillary nerve supply sensation to?
Posterior/lateral deltoid
Where does the radial nerve supply sensation to?
Dorsal lateral aspect of the hand and thumb
Where does the median nerve supply sensation to?
Ventral and lateral palm (up to the middle of the fourth finger), dorsal side of second and third fingers
Where does the ulnar nerve supply sensation to?
Ventral and dorsal medial aspect of the hand (fifth and half of the fourth finger)
What causes brachial plexopathy?
*Trauma: pull/stretch
*Thoracic outlet
*Tumor invasion
*Post operative complication (sternotomy)
*Radiation
What does a brachial plexus lesion of C5 and/or C6 cause?
Paralysis of supraspinatus, infraspinatus, biceps, brachialis, coracobrachialis, deltoid
What does a brachial plexus lesion of C8 and/or T1 cause?
Median and ulnar nerve are involved, so hand function will be impaired
How would an upper brachial plexus lesion be caused?
Head pulled to one side with shoulder depression (e.g., trauma, difficult delivery)
How would a lower brachial plexus lesion be caused?
Due to falling and catching themselves, nerve may tear
What nerves may be involved in a proximal humerus fracture?
Axillary nerve or suprascapular nerve
What is a major risk of a fracture of the proximal neck of the humerus?
Disruption of the axillary artery leading to AVN
What nerve may be affected with a humeral shaft fracture?
Radial nerve
What is a major risk of a distal humerus fracture?
May involve the median, radial, ulnar, or brachial arteries
What are the four joints of the shoulder?
*Glenohumeral
*Acromioclavicular
*Sternoclavicular
*Scapulothoracic
What are the risks of shoulder dislocations?
*Can disrupt the axillary nerve
*Can disrupt radial artery
*Can cause rotator cuff injury
What is the function of the labrum?
Fibrocartilaginous structure that deepens the glenoid fossa and aids in stability. Other supporting ligaments attach to it
What is an inferior tear of the labrum associated with?
Dislocations, bankart lesion
What is a superior tear of the labrum associated with?
Biceps strain, SLAP tear
What motion is the supraspinatus responsible for?
Abduction
What motion is the infraspinatus responsible for?
External rotation
What motion is the teres minor responsible for?
External rotation
What motion is subscapularis responsible for?
Internal rotation
What does the anterior compartment of the upper arm contain?
*Biceps
*Brachialis
*Musculocutaneous nerve
What does the posterior compartment of the upper arm contain?
*Radial nerve
*Triceps
Why is it easy for the supraspinatus to contribute to shoulder impingement syndrome?
The muscle runs between the humoral head and the acromion
What are the stages of subacromial impingement syndrome?
Stage I: Edema and hemorrhage
Stage 2: Fibrosis and tendonitis
Stage 3: Rotator cuff tearing and/or biceps rupture
What is the pathophysiology of adhesive capsulitis?
Inflammatory process in which there is increased fibroblastic activity and the joint capsule becomes thickened, fibrotic, and there will be scarring of the tissues together
What are the physiological stages of adhesive capsulitis?
Stage 1: fibrinous synovitis
Stage 2: Contraction of the capsule with adhesion formation
Stage 3: Increased contraction, inflammation will be decreasing
Stage 4: Severe contraction
What does the long head of the biceps assist with and where does it attach proximally?
Abduction and internal rotation, attaches to the labrum
What does the short head of the biceps assist with and where does it attach?
Adduction, attaches to the coracoid process
What can biceps tendonitis progress to?
SLAP (superior labrum anterior to posterior) lesion
With biceps tendon rupture is it the long head or the short head of the biceps?
Long head, typically at the bicipital groove (proximal)
What deformity will someone with a bicep tear present with?
Popeye deformity
What can cause olecranon bursitis?
Trauma, pressure, overuse, gout, infection
What does a bursa do?
Allows for the muscles to move smoothly over prominent areas
What causes medial epicondylitis?
Overuse from repetitive loading to the flexor-pronator insertion
What is the physiological presentation of someone with medial epicondylitis?
Will have microtrauma to insertion site of pronator teres. Will start with inflammation, progress to angiofibroblastic hyperplasia, and ultimately fibrose or calcify
Which bone of the wrist is at the greatest risk of AVN when fractured?
Scaphoid bone
What are the compartments of the hands and where are they located?
*Thenar: thumb
*Hypothenar: ulnar side
*Adductor: lateral side
*Central: central palm
What is the pathophysiology of De Quervains Tendinopathy?
*Associated with prolonged or repetitive abduction
*Results in myxoid degeneration of the collagen
*Thickening of the tendon at the fibro-ossous tunnel over the radial styloid
*Swelling and narrowing of the first dorsal compartment
What is the pathophysiology of Dupuytrens contracture?
Fibrosis of the palmar fascia, results from a proliferative disorder of myofibroblasts: collagen is laid down in a disorganized fashion, fascia thickens, and inflammatory response causes T-cell mediated response causing puckering of the skin
What is the pathophysiology of trigger finger?
Overgrowth of fibrocartilaginous tissue which causes narrowing of the first annular pulley passage
What is the presentation of trigger finger?
Catching, locking, popping; in extreme cases finger can become stuck but typically painless
What is the pathophysiology of carpal tunnel syndrome?
Median nerve compression within the carpal tunnel resulting in neuropathy. Repetitive activities that put pressure on the carpal tunnel result in inflammation of the synovium
What are the associated risks with carpal tunnel syndrome?
*Pressure on vascular structures can lead to nerve ischemia
*Nerve fiber degeneration
What is the pathophysiology of ganglion cyst?
Believed to be an extension from the tendon sheath, ligaments, or joint capsule that has a tract that is able to fill with mucinous fluid
What is the risk associated with a distal radius fracture?
*High likelihood for intraarticular involvement
*Risk of median nerve compression
*Compartment syndrome
What is the pathophysiology of buckle (torus) fracture?
Typically occurs in distal metaphysis where the bone is more porous and likely to ‘buckle’ under pressure
Where will pain be located with a scaphoid fracture?
Over the anatomical snuff box
