Flashcards in MSK clinical Deck (256):
What causes Erb's palsy?
Damage to ROOTS C5 and C6 from excessive increase in the angle between neck and shoulder. This can happen in a difficult birth or due to shoulder trauma
What are the symptoms and signs of Erb's palsy?
Affects nerves derived from primarily C5 and C6:
1. Waiter's tip deformity
In Erb's palsy why the following muscles are paralysed: biceps brachii, brachialis, coracobrachialis, supraspinatous, infraspinatous, subclavius, deltoid and teres minor
C5 and C6 nerve roots make up the following peripheral nerves:
1. Musculocutaneous: BBC muscles
2. Axillary: deltoid, teres minor (triceps brachii long head - triceps not paralysed due to lateral head innervation by radial nerve)
3. Suprascapular nerve: innervates supraspinatous and infraspinatous
4. Subclavian nerve: innervates subclavius
The following movements are lost or greatly weakened in Erb's palsy– abduction at shoulder, lateral rotation of arm, supination of forearm, and flexion at shoulder. Why is shoulder abduction affected?
Supraspinatous - first 15 degrees of arm
Deltoid - 15-90 degrees
Both muscles are paralysed due to loss of C5,C6 innervation
The following movements are lost or greatly weakened in Erb's palsy– abduction at shoulder, lateral rotation of arm, supination of forearm, and flexion at shoulder. Why is lateral rotation of the arm affected?
Deltoid (posterior fibres), infraspinatous and teres minor are involved in lateral (external) rotation. These are weakened/paralysed in Erb's palsy
The following movements are lost or greatly weakened in Erb's palsy– abduction at shoulder, lateral rotation of arm, supination of forearm, and flexion at shoulder. Why is supination of the forearm affected?
The main supinator of the forearm is biceps brachii which is paralysed by lack of innervation by the musculocutaneous nerve
The following movements are lost or greatly weakened in Erb's palsy– abduction at shoulder, lateral rotation of arm, supination of forearm, and flexion at shoulder. Why is flexion at the shoulder affected?
(Coracobrachialis), biceps brachii, deltoid (anterior fibres) and pectoralis major contribute to shoulder flexion. In Erb's palsy coracobrachilais, biceps, deltoid are all paralysed leaving pec major unable to complete the action fully on its own
Why is there a loss of sensation down the lateral side of the arm in Erb's palsy?
Due to the loss of sensory innervation by the cutanous branches of the axillary and musculocutaneous nerves
Describe the actions affected that give the 'waiter's tip' deformity that is seen in Erb's palsy
The arm hangs limply. There is unopposed medial rotation by Pec major (the external rotators of the deltoid and infraspinatous are paralysed) and the forearm is pronated due to loss of the main supinator, biceps brachii
Klumpke's palsy is a lower brachial plexus injury. It is less common than the upper brachial plexus injury, Erb's palsy. What causes it?
Excessive abduction of the arm e.g. catching hold of a branch of a tree when falling
What nerve root and therefore peripheral nerves are affected by Klumpke's palsy?
It affects T1 nerve root and therefore mainly the ulnar and median nerves
Why in Klumpke's palsy are the small intrinsic muscles of the hand affected by not the flexors of the forearm?
The T1 nerve root is affected, therefore affecting mainly the ulnar and median nerves. These nerves together supply all the flexor muscles of the forearm and the intrinsic muscle of the hand. However the flexor muscle of the forearm are innervated by different roots of the median and ulnar nerves and are therefore unaffected
Where is sensory loss felt in Klumpke's palsy?
Along the medial side of the arm - T1 dermatome
What would you observe if a patient had damage to their long thoracic nerve and pushed their arms against a wall?
Winging of the scapula due to paralysis of the serratus anterior muscles - these muscles no longer hold the scapula against the ribcage whilst their upper limbs reach anteriorly
How can the long thoracic nerve become damaged?
Axillary node clearance for breast cancer
What is a common cause of damage to the axillary nerve?
Fractures of the upper humerus where the axillary nerve wraps around
What movements of the arm would be impaired with axillary nerve damage?
Abduction of the arm - beyond 15 degrees
The median nerve is not commonly damaged at the brachial plexus. Where is it vulnerable to damage?
Elbow - supracondylar fractures of the elbow
Wrist - lacerations, carpal tunnel syndrome
If the median nerve is damaged at the elbow causing LONG-STANDING DAMAGE what would you observe?
Hand of benediction - when asking a patient to form a fist they would be able to flex their 4th and 5th digit but not their 1st, 2nd or 3rd - due to the paralysis of their lateral two lumbricals, long flexors of the forearm and the lateral half of FDP. The 4th and 5th digit are unaffected because they are innervated by the ulnar nerve
What signs of short-term damage to the median nerve may you observe?
Almost unopposed extension and supination
Hand signs may occur (including loss of thumb flexion)
Why might a superficial laceration at the wrist cause loss of sensation of the lateral palmar surface of the hand and first digit but not a loss of sensation on palmar surface of the 2nd,3rd and half of the 4th digit and dorsal surface of the tips of the 1st, 2nd and 3rd digits?
In the wrist the median nerve throws off a branch called the palmar cutaneous branch before it enters the flexor retinaculum. Superficial cuts at the wrist can damage this cutaneous nerve but not affect the median nerve below which is protected by the thick connective tissue of the retinaculum. The median nerve then throws off digital cutaneous branches which supply the dorsal tips of the lateral three digits and the palmar surface of the 2nd, 3rd and half of the 4th digit
What is a common cause of radial nerve damage?
Injuries can occur in the axilla, commonly form shoulder dislocation - which pulls on the radial nerve due to its close connection with the humerus in the radial groove
What would be the signs of radial damage at the brachial plexus in a patient?
Paralysis of the triceps (lateral and medius heads) and the extensors of the forearm, leading to wrist drop (unopposed flexion).
Loss of sensation of the posterior and lateral upper arm and posterior forearm
What shoulder position causes the least protection to the contents of the axilla - puts them most at risk of damage?
Abduction of the shoulder
Why are the axillary nodes cleared in some cases of breast cancer?
75% of lymph from the breast drains into the axillary lymph nodes (along with lymph from the upper arm). If breast cancer is found these nodes are sampled to look for spread. If any contamination these nodes need to be surgically cleared
In knee injuries which ligaments are commonly damaged?
Sometimes all three = 'unhappy triad'
If you damage the medial collateral ligament what else is likely to be damaged?
Medial meniscus- they are firmly attached to each other
How are you likely to get the 'unhappy triad' knee injury?
1. Blows to the side of the knee
2. Lateral twisting of the knee
When is the anterior cruciate ligament susceptible to injury?
When the knee is flexed because it is taut.
What is meant by the unhappy triad?
1. anterior cruciate ligament
2. tibial collateral ligament
3. medial meniscus
A blow to the inside of the knee opens up which side of the knee?
Lateral side of the knee
What movements does the anterior cruciate ligament limit?
1. Femur sliding posteriorly on the tibia
3. Medial rotation of femur when foot is on ground and leg is flexed
How can you test for anterior cruciate ligament damage?
Anterior draw sign
How can the posterior cruciate ligament be damaged?
Falling onto the tibial tuberosity with a flexed knee
How can you test for posterior cruciate ligament damage?
Posterior draw sign
What movements does the posterior cruciate ligament limit?
1. Prevents the femur from sliding anteriorly on the tibia (particularly when the knee is flexed)
What direction do patella dislocations normally occur?
What causes patella dislocations?
Direct trauma/ twisting movement
How can patella fractures occur?
1. Direct force
2. Severe force from extensors
Name three important types of bursitis that can occur in the knee joint
2. Pre-patellar - house maid's knee
3. Superficial infra-patellar - clergyman's or roofer's knee
What is the worry with suprapatellar bursitis?
Infection can spread to knee joint due to communication.
What causes bursitis?
Chronic friction of direct trauma.
What is a popliteal cyst (Baker's cyst)? How should it be treated?
It is abnormal fluid filled sacs of synovial membrane in the popliteal fossa and is a sign of chronic knee effusion. There is no point draining it as it connects to the synovium of the knee joint and it may cause infection.
What methods are used to investigate the knee?
1. Imaging - plain films/MRI (NOT X-ray as doesn't show soft tissue, MRI is gold standard
2. Arthroscopy -diagnostic and therapeutic
4. Clinical examination
What can herniation of the nucleus pulposus impinge upon?
What is syndactyly?
Fusion of digits - may involve just connective tissue or bones may be fused. It is a defect in the sculpting of the digital rays.
What is polydactyly?
A genetic recessive trait which causes the formation of extra digits.
What is amelia?
Complete absence of a limb.
What is meromelia?
Partial absence of one or more limb structures.
What is phocomelia? What can cause it and why?
A rare congenital deformity in which the hands or feet are attached close to the trunk, the limbs being grossly underdeveloped or absent. This occurs as a consequence the teratogen phalidomide which is toxic to the AER and other tissues. It causes loss of AER and therefore loss of further extension of the limb bud.
Why are radiographs of epithyseal growth plates tricky to analyse?
Soft tissue like cartilage is translucent.
What can damage to epithyseal plates in children cause?
Deformities of long bones.
What is avascular necrosis?
Death of bone due to interruption of blood supply.
What can be the causes of avascular necrosis?
It has varied causes: fracture, dislocation, steroid use, radiation, decompression sickness (O2 bubbles in blood cut off blood supply).
What are the consequences of avascular necrosis?
It leads to collapse of the necrotic segment and secondary osteoarthritis.
What are the features of synovial joints?
1. Synovial membrane
2. Diarthrosis - freely moveable
3. Articular cartilage - usually hyaline
4. Fibrous capsule
6. Tendon sheaths
7. Synovial fluid
8. Intra-articular menisci/disc
9. Fat pads
What does the articular capsule of a synovial joint consist of?
Fibrous capsule and synovial membrane.
What is the role of the articular cartilage of synovial joints?
1. Smooth, low friction in movement
2. Resists compression
The articular cartilage in synovial joints is usually hyaline cartilage, in which joints is there are exceptions?
In the following atypical synocial joints, fibrocartilage is used instead: acromioclavicular, sternoclavicular and temporomandibular.
What is occurring when you crack you joints?
1. Bones are pulled away from each other
2. Synovial cavity expands
3. Synovial fluid volume stays constant
4. Partial vacuum produced
5. Gasses dissolved in synovial fluid are pulled out of solution
5. Makes a popping sound
What are the effects of ageing on joints?
1. Decreased production of synovial fluid
2. Thinning of articular cartilage (due to wear)
3. Shortening of ligaments and decreased flexibility
4. Degenerative changes
What is arthritis?
It is inflammation and stiffness of a joint (not in itself a diagnosis). There are over 100 different forms. Symptoms include: pain, swelling, stiffness. Signs: redness, swelling, deformity, tenderness, reduced range of movement, abnormal gait (if present in lower limbs).
What is the most common form of arthritis?
Osteoarthritis - localised loss of cartilage, remodelling of adjacent bone, eroding mensicus and associated inflammation caused by wear and tear.
On an X-ray what would you may you see in an osteoarthritic joint?
1. Osteophytes - protrusions of bone around the joint
2. Reduced joint space
3. subarticular schlerosis - increased calcification
4. Bone cysts - ingress of synovial fluid
What can occur due to fragments of cartilage breaking of an osteoarthritic joint?
What is rheumatoid arthritis?
An autoimmune disorder in which autoantibodies (rheumatoid factor) attack the synovium causing synovial inflammation. This leads to joint erosion (bone and cartilage loss) and deformity especially notable in the MCP and PIP joints, cervical spine, feet but it can involve larger joint.
What is the aetiology of rheumatoid arthritis?
1. Peak age 40-50 (can be juvenile)
2. Women more commonly affected (2-3:1)
3. 1% of population
What other organs can be damaged by rheumatoid arthritis?
Eyes, skin, lungs, heart and blood vessels, kidneys and blood (erythrocytes -> anaemia).
What are the X-ray features of rheumatoid arthritis?
1. Narrowing of joint space
2. Ulnar sublaxation and gross deformity
3. Juxta-articular bony erosions (in non-cartilage protected bone)
4. Perarticular osteopenia - less matrix in bone
Pannus formation occurs in RA. What is it?
In RA, the hypertrophied synovium (also called pannus) invades and erodes contiguous cartilage and bone.
When does subacromail bursitis cause pain? What is this called?
On abduction of the arm between 50-130 degrees. This is called 'painful arc syndrome'.
What is the function of the subscapular bursa?
It facilitates the movement of the subscapularis tendon over the scapula. It communicates the joint cavity.
What two joints move during shoulder joint movement?
Glenohumeral joint and scapulothoracic joint (2:1)
What is the scapulathoracic joint?
The scapula moves over the thorax as if it was a joint.
What is vulnerable if intramuscular injection into the deltoid muscle is given higher than 4cm from the acromion end?
The axillary nerve
What is vulnerable from shoulder dislocation and fractures of the surgical neck?
Axillary nerve damage.
Which part of the glenohumeral joint is least supported? Therefore which direction is shoulder dislocation most likely to occur?
When does shoulder dislocation occur? What type of dislocation is this classifies as? How does the dislocated shoulder appear?
Usually caused by trauma on a fully abducted arm. It is clinically defined as anterior dislocation because the humeral head locates anteriorly, due to the pull of pectoralis major (powerful adductors). Squaring off of the shoulder occurs because the humeral head comes to lie below the coracoid process.
Why may a previous shoulder dislocation cause recurrent dislocation?
The capsule and rotator cuff may tear and lead to instability of the joint.
How do you test for axillary nerve damage in a shoulder dislocation?
1. Loss of sensation in the regimental badge area - supplied by a branch of the axillary nerve called the lateral cutaneous nerve of the arm.
2. DO NOT test motor function as this could cause more soft tissue damage and injure the axillary nerve.
What causes painful arc syndrome?
The suprspinatous tendon rubbing under the coracoacromial arch causing irritation and inflammation of the supraspinatous tendon and bursa. This can lead to sub acromial bursitis (+/-calcification), supraspinatous tendonitis (+/-calcification) and degeneration and rupture of tendons.
What are predisposing factors for painful arc syndrome?
1. Repetitive overuse - sports (rachet, swimming), work involving overhead use of arms
2. Age - degenerative changes in tendons
3. Avascularity of supraspinatous tendon
4. Slight differences in anatomy may make impingement more likely
How would you treat supraspinatous tendinitis?
1. Conservative treatment: rest, analgesia and physiotherapy
2. Severe cases - steroid injections and surgery can be considered
What is the cause of lateral epicondylitis or 'tennis elbow'?
It is caused by repeated use of superificial extensor muscles which strains their common tendinous attachment to the lateral epicondyle. It causes inflammation of the periosteum of the lateral epicondyle.
What age groups is lateral epicondylitis most commonly seen in?
Peak age of onset is 40-50 year olds.
Which artery can be palpated in the cubital fossa to measure a pulse? How can this artery be located?
Brachial artery. It is medial to the biceps tendon and can be located by getting the patient to briefly flex their bicep mucscles.
When measuring blood pressure which artery in the cubital fossa is the stethoscope placed over to listen to the korotkoff sounds?
Which vein located in the roof of the cubital fossa is commonly used in venepuncture? What veins is it a branch of?
Median cubital vein. It is a branch between the basilic and cephalic veins.
How can a supracondylar fracture of the humerus occur?
Usually by falling on a flexed elbow.
What is a supracondylar fracture of the humerus?
A transverse fracture spanning between the two epicondyles.
What can be the consequences of a supracondylar fracture of the humerus?
The displaced fracture fragments can impinge on the contents of the cubital fossa and cause median or radial nerve damage and Volkmann's ischaemic contracture.
What is Volkmann's ischaemic contracture? How is it caused?
Interference to the blood supply of the brachial artery to the forearm (e.g. a supracondylar fracture of the humerus causing direct trauma or post-fracture swelling. The resulting ischaemia causes flexor muscle to become fibrotic and shortened resulting in uncontrolled flexion of the hand.
What is fasiculation? What disease can it be an early sign of?
They are small, local, involuntary muscle contraction and relaxation, which may be visible under the skin. Most the time this is normal but it can be a sign of early motor neurone disease.
When are the contents of the axilla at most risk of injury?
When the arm is fully abducted because the axillary region is at its smallest.
What is thoracic outlet syndrome?
Compression of vessels and nerves between the superior border of the scapula, lateral border of the first rib and posterior surface of the clavicle (axillary inlet).
What can cause thoracic outlet syndrome?
Common causes are trauma (e.g. fracture of the clavicle) and repetitive use (commonly seen in profession where lift arms frequently).
What are the symptoms of thoracic outlet syndrome?
Pain in the affected limb (where depends on nerve damage), tingling, muscle weakness and discolouration.
Why are axillary lymph nodes biposied?
~75% of breast lymph drains into axillary nodes therefore they are biopsied if breast cancer is suspected.
If breast cancer is found what operation of the axillary lymph nodes may be carried out? Why? What can be the complications of this operation?
Axillary clearance. To prevent the cancer spreading. The long thoracic nerve may be damaged as it lies near the lymph nodes.
How can damage to the long thoracic nerve be assessed?
Get patient to push hands against a wall and look for winging of the scapula - the medial angle of the scapula moving away from the thoracic rib cage due to serratus anterior weakness.
What causes the symptoms of carpal tunnel syndrome?
Compression of the median nerve within the carpal tunnel.
What is the aetiology of carpal tunnel syndrome?
Can be caused by thickening of the tendons and synovial sheaths that pass through the carpal tunnel, however in the majority of cases the cause is unknown.
What can occur if carpal tunnel syndrome is left untreated?
Weakness and atrophy of the thenar muscles - supplied by the median nerve.
What are the symptoms associated with carpal tunnel syndrome? When do these symptoms appear worst?
Pain, tingling and numbness in the distribution of the median nerve, with pain that often radiates up the forearm. Symtpoms can often wake an individual up at night and appear worst in the morning.
What carpal tunnel tests can be done in a physical examination?
1. Tinel's sign: tapping the nerve in the carpal tunnel to ilicit pain in the median nerve distribution
2. Phalen's manoeuvre: hold the wrist in flexion for 60s to ilicit numbness/pain in the median nerve distribution.
How can carpal tunnel be treated:
1. Try splinting wrist overnight in dorsiflexion to relieve symptoms
2. Corticosteroid injections into the carpal tunnel, if that doesn't work
3. In sever cases, surgical decompression of the carpal tunnel may be required.
What carpal bone takes most of the force in a fall to an outstretched hand? Why?
Scaphoid bone. The scaphoid and radius articulate to form part of the wrist joint and a lot of the force of the fall is transmitted through this articulation.
What is the most likely cause of localised pain in the anatomical snuffbox?
What is unique about the blood supply to the scaphoid? What is the consequence of this on a scaphoid fracture?
The blood supply runs distal to proximal to supply the scaphoid. A fracture of the scaphoid can disrupt the blood flow to the PROXIMAL section. This is a medical emergency because failure to revascularise the scaphoid can result in avascular necrosis and future arthritis for the patient.
How can the long thoracic nerve be damage?
1. axillary clearance
2. trauma to the shoulder
3. repetitive movements involving the shoulder
4. Nearby structures becoming inflamed and pressing on the nerve
Lesion of what nerve causes ulnar claw deformity? Where does this lesion occur?
The deformity is caused by long-standing ulnar nerve damage at the wrist.
What muscles are affected to create the ulnar claw deformity?
Medial two lumbricals
Why does paralysis of the medial two lumbricals cause the ulnar claw deformity?
Lumbricals flex at the MCP joints and extend at the IP joints, therefore:
1. The MCP joints of the medial two digits are hyperextended due to unopposed extension from the long extensor muscles in the posterior compartment of the forearm
2. The IP joints are flexed due to unopposed flexion from the long flexor muscles in the anterior compartment of the arm. The extensor muscles cannot extend at the IP joints as their energy is dissipated in hyperextending the MCP joints.
What is the ulnar paradox?
When ulnar nerve damage occurs at the elbow the medial half of FDP and flexor carpi ulnaris are also paralysed. Paralysis of FDP causes a less noticeable ulnar claw because it reduces the flexion at the distal IP joints of the medial two digits (hyperextension at the MCP joint and hyperflexion at the proximal IP joint remain). This is a 'paradox' because you would expect greater damage to the nerve to create a greater deformity not less of one.
What nerve is damaged to create the 'hand of benediction'? Where does this damage occur?
Median nerve damage that has occurred at the elbow.
How does the 'hand of benediction' become apparent? What happens?
When a patient is asked to make a fist - only the medial two fingers flex.
What is the muscle paralysis behind the 'hand of benediction'?
Paralysis of the long flexors of the forearm and the lateral two lumbrical. The medial half of FDP and the lateral two lumbricals are not affected as they are innervated by the ulnar nerve, therefore the medial two fingers can still flex but the rest remain unflexed thus creating a claw shape..
What is the difference in nerve damage in an ulnar claw deformity vs a hand of benediction deformity?
Ulnar nerve vs median nerve.
What is the difference in presentaion in an ulnar claw deformity vs a hand of benediction deformity?
Ulnar claw occurs due to long-standing ulnar nerve damage whereas 'hand of benediction' occurs when a patient tries to make a fist.
What fingers are affected in ulnar claw vs hand of benediction?
Ulnar claw - medial two fingers
HOB - lateral two fingers (and thumb apart from adductor pollis).
Which muscles are paralysed in ulnar claw vs hand of benediction?
Ulnar claw - Medial two lumbricals
HOB - Lateral half of FDP and lateral two lumbricals
What movements are involved in ulnar claw vs hand of benediction?
Ulnar claw - unopposed extension at MCP joints and unopposed flexion at distal IP joints of medial two digits
HOB - INABILITY to perform flexion at IP joints and MCP joints of lateral two fingers.
What is Dupytren's contracture? What is the pathology behind it?
It is the partial flexion of one or more fingers due to thickening of the palmar fascia due to fibrosis. The actual cause is unknown but it can sometimes be hereditary.
Where can the femoral pulse be palpated? What is the significance of the presence of a pulse?
It can be palpated in the femoral triangle just inferior to the inguinal ligament (it crosses underneath the inguinal ligament midway between the ASIS and the pubic symphysis). Presence of a pulse means that blood is reaching the lower extremity.
What procedures use the femoral artery as an easy access to the circulation?
Coronary angiography and to draw arterial blood gases.
During coronary angiography which blood vessels does the catheter travel up to inject dye into the coronary vessels?
The catheter is inserted into the femoral artery, then the tube passes into the external iliac -> common iliac -> abdominal aorta -> thoracic aorta -> aortic arch and through the aortic sinus into the coronary arteries where it injects radioactive dye that is visualised by X-ray.
What is a femoral hernia? How does it present? How is it treated?
It is when part of the small intestine pushes through the femoral canal, underneath the inguinal ligament. It manifests itself as a lump or bulge in the area of the femoral triangle (inferolaterally to the pubic tubercle). It normally requires surgery to treat.
What is a hernia?
Where an internal part of the body pushes through a weakness in the muscle or surrounding tissue wall.
Why are femoral hernias more common in women?
They have a wider bony pelvis.
Why are femoral hernias at risk of strangulation? What is strangulation?
Strangulation is when the blood supply to the hernia becomes compromised. The femoral canal has tough walls that do not extend, therefore they can compress the herniated bowel and compromise its blood supply.
What is adductor canal block?
It is a nerve block of the saphenous nerve in isolation , or together with the nerve to the vastus medialis. It is used to provide sensory anasethesis for operations involving the distal thigh and femur or the knee and medial lower leg.
How can the saphenous nerve be located for an adductor canal block?
By using the anatomical landmarks of the sartorius and the femoral artery.
What is adductor canal compression syndrome?
It is a rare condition where the neurovascular bundle in the adductor canal becomes compressed, usually due to hypertrophy of the surrounding muscle e.g. vastus medialis.
What are the symptoms associated with adductor canal compression syndrome? What group of individuals does it most commonly affect?
Most commonly it is claudication symptoms due to femoral occlusion but it can also present with neurological symptoms due to the compression of the saphenous nerve. Young males.
In which age group are clavicular fractures most common?
How are clavicular fractures commonly caused?
FOOSH - the indirect force transmitted through the bones of the forearm to the shoulder. It can also be caused by a fall directly on the shoulder.
Where is the clavicle most commonly broken?
At the junction between the medial and lateral thirds, where it is at its weakest.
What happens to the lateral and medial components of a fractured clavicle?
The medial fragment is elevated by the sternocleidomastoid muscle and therefore because of its subcutaneous position the fractured end can often be palpated or seen tenting the skin.
The lateral fragment is usually prevented from dislocating at the coracoacromial joint by the strong coracoclavicular ligament and therefore the trapezius is unable to hold up the weight of the arm and therefore the shoulder droops. The lateral fragment may also be pulled medially by the adductor muscles of the arm, such as pectoralis major. This can cause overriding of the bone fragments which shortens the clavicle.
What is a greenstick fracture?
A fracture of the bone, occurring typically in children, in which one side of the bone is broken and the other only bent.
What is the last epiphysis of the long bones to fuse?
Clavicle - its is the first long bone to start ossification and the last to finish (completely fused by 25-31 years of age).
How is the scapula fractured?
Usually as the result of sever trauma e.g. in pedestrian-vehicle accidents. Usually there are also fractured ribs. They also usually involve the protruding subcutaneous acromion.
What is the treatment for a fractured scapula?
Most of the time they require little treatment because the scapula is covered on both sides by muscle.
What is the most common injury of the proximal end of the humerus?
Fractures of the surgical neck.
Who is most at risk of fractures of the surgical neck of the humerus?
Elderly people with osteoporosis.
What is an impacted fracture? What are the consequences of impaction at the surgical neck of the humerus on the symptoms experienced?
When one fragment of the fracture is driven into the spongy bone of the other fragment. This can sometimes cause the fractures site to be quite stable and the person is able to move the arm passively with little pain.
What can cause an avulsion fracture of the greater tubercle of the humerus?
Fall on the point of the shoulder (the acromion). This is most commonly seen in middle-aged and elderly people. In younger people it usually results from a fall on the hand when the arm is abducted.
Why is the arm medially rotated in an avulsion fracture of the greater tubercle of the humerus?
Due to the muscles (especially subscapularis) which are attached to the humerus and pull the limb into medial rotation.
What causes a transverse fracture of the shaft of the humerus? What happens to the most proximal fragment?
A direct blow to the arm. The pull of the deltoid muscle carries the proximal fragment laterally.
What can cause a spiral fracture of the humeral shaft? What can occur to the oblique ends of this fracture?
Indirect injury resulting from a fall on an outstretched hand. The oblique ends can override which may result in foreshortening.
How well do humeral fractures repair?
The bone fragments usually unite well due because the humerus is surrounded by muscle and has a well-developed periosteum.
What causes an intercondylar fracture of the humerus?
A severe fall on a flexed elbow. This cause the olecranon to be driven like a wedge between the medial and lateral parts of the condyles, separating one or both parts from the humeral shaft.
Which nerve is in direct contact with the surgical neck of the humerus?
Which nerve is in direct contact with the radial groove of the humerus?
Which nerve is in direct contact with the distal end of the humerus?
Which nerve is in direct contact with the medial epicondyle of the humerus?
Why is the fracture of one of the radius or ulna often associated with dislocation of the nearest joint?
Because the radius and ulnar are tightly bound together by the interosseous membrane.
Why is fractures of the distal end of the radius common in adults over 50? Who in particular?
Decreased bone density. This is the case in particular with women because their bones are more commonly weakened by osteoporosis.
What is the most common fracture of the forearm? What does it involve?
A colles fracture. This is a complete transverse fracture of the distal 2cm of the radius. The distal fragments is displaced dorsally and is often comminuted (broken into pieces). This results from forced dorsiflexion of the hand, usually as a result of FOOSH. Often the ulnar styloid is avulsed (broken off).
In a Colles fracture what changes in the relationship between the ulnar and radial styloid processes?
Normally the radial styloid process projects farther distally than the ulnar styloid. When a Colles fracture occurs this relationship is reversed due to shortening of the radius.
Why is the deformity caused by a Colles fracture called a 'dinner fork' deformity?
Because a posterior angulation occurs in the forearm just proximal to the wrist and the normal anterior curvature of the relaxed hand.
What can happen in fractures to the distal radius in children?
The fracture line may extend through the epiphyseal growth plate. The healing process may result in malalignment of the epiphyseal growth plate and disturbance of radial growth.
Which are the main bones articulating at the elbow?
Humerus and ulnar.
Which are the main bones articulating at the wrist?
Radius and carpal bones (scaphoid, lunate and triquetrium).
What is the most commonly fractures carpal bone?
What causes a scaphoid fracture? Where does the fracture most commonly occur?
A fall onto the palm of the hand when the hand is abducted. The fracture occurs across the narrow part of the scaphoid, the "waist".
In a scaphoid fracture, where is pain felt?
Primarily on the lateral side of the wrist, especially during dorsiflexion and abduction of the hand.
Why after radiography is a scaphoid fracture often mis-diagnosed as a severely sprained wrist?
Initial radiographs may not reveal a fracture. Radiographs taken 10-14 days later reveal a fracture because of bone resorption that has occured.
Why may a scaphoid fractures take at least 3 months to heal? What can be the longterm sequellae of a scaphoid fracture?
Owing to the poor blood supply of the proximal part of the scaphoid. Avascular necrosis of the proximal fragment (pathological death of bone resulting from inadequate blood supply) may occur and produce degenerative joint disease of the wrist. In some cases, it is necessary to fuse the carpals surgically (arthrodesis).
What nerve may be injured in a fracture of the hamate?
Why make a fracture of the hook of hamate result in non-union?
Becuase of traction produced by the attached muscle (flexor carpi ulnaris, flexor digiti mini).
What is a boxer's fracture? Why does it occur?
It is a fracture of the 5th metacarpal. It occurs when an unskilled person punches someone with a closed fist. The head of the bone rotates over the distal end of the shaft, producing a flexion deformity.
Why are most metacarpal fractures treated by binding adjacent digits together?
Becuase the metacarpals (except the first) are closely bound together, therefore isolated fractures tend to be stable. These bones have a good blood supply and therefore tend to heal quickly.
What type of injury to the metacarpals can produce instability of the hand?
Severe crushing injuries of the hand.
What type of injuries to the distal phalanges of the hand are common? Why are these injuries so painful?
Crushing injuries e.g. when a finger is caught in the door. These are really painful due to the highly developed sensation in the fingers. A fractures is usually comminuted and a painful haematoma (collection of blood) soon develops.
Why do phalangeal fractures need to be carefully realigned?
Becuase of their close relationship to the flexor tendons, careful realignment is required to restore normal function of the fingers.
Which muscles and other structures are absent in Poland syndrome? What is the result?
Both the pectoralis major and minor are absent. Breast hypoplasia and absence of 2-4 rib segments is also seen.
What are the consequences of long thoracic nerve injury? How can this be tested for?
Paralysis of the serratus anterior muscle which draws the scapula internally and forwards. Therefore the scapular moves posteriorly and laterally - away from the thoracic wall. This 'winging' of the scapula is especially prominent when the person presses their upper limb against a wall. When the arm is raised, the medial border and inferior angle of the scapular pull markedly away from the posterior thoracic wall.
What movement are people with a 'winged scapula' incapable of doing?
Abduction beyond 90 degrees becuase the serratus anterior is unable to rotate the glenoid cavity superiorly to allow complete abduction of the limb.
When is the long thoracic nerve vulnerable to injury?
The long thoracic nerve is exceptional in that on the superior aspect of the serratus anterior in which it supplies. It is protected when the arm is at one's side but vulnerable when the arm is elevated e.g. in a knife fight. Weapons, including bullets directed towards the thorax, are a common source of injury. It can also be injured in axillary node clearance e.g. for breast cancer.
What is the triangle of auscultation? What is it useful for examining? What movement enlarges this triangle?
It is a small triangular gap in the musculature of the back bordered by the superior horixontal border of the latissiumus dorsi, the medial border of the scapula and the inferolateral border of the trapezius. This is a good place to exmaine posterior segments of the lungs with a stethoscope. This triangle enlarges when the scapulae are drawn anteriorly by folding the arms across the chest and the trunk is flexed.
What is the primary clinical manifestation of accessory nerve palsy?
Marked ipsilateral weakeness when the shoulder are elevated (shrugged). This is because the accessory nerve innervates trapezius and the superior part of trapezius is the main muscle involved in elevation of the scapula.
What can cause injury to the thoracodorsal nerve?
Surgery in the inferior part of the axilla because this nerve passes inferiorly along the posterior wall of the axilla and enters the medial surface of the latissiumus dorsi, close to where it becomes tendionous. The nerve is also vulnerable to injury during surgery on scapular lymph nodes as its terminal part lies anterior to them and the subscapular artery.
Which activities are primarily affected by paralysis of the latissimus dorsi?
The person is unable to lift their trunk with their arms, as occurs during climbing. They also cannot use an axillary crutch because the shoulder is pushed superiorly by it. However the passive depression provided by gravity is enough for most activities.
What muscules are affected by injury to the dorsal scapular nerve?
The rhomboids. If the rhomboids on one side are paralysed, the scapula on the affected side is located farther from the midline than on the normal side.
What commonly causes axillary nerve damage?
Fractures of the surgical neck of the humerus. It can also be damaged during dislocation of the glenohumeral joint and by compression by incorrect use of crutches.
What are the consequences of axillary nerve damage?
Severe damage can cause deltoid atrophy causing loss of the rounded contour of the shoulder, giving the shoulder a flattened appearence and producing a slight hollow inferior to the acromion. Loss of sensation may occur over the lateral side of the proximal arm (area supplied by the superior lateral cutaneous nerve of the arm).
What nerve can be injured during intramuscular injection at the deltoid?
The axillary nerve which runs transversely under cover of the deltoid at the level of the surgical neck of the humerus.
In which group of people does a fracture-dislocation of the proximal humeral epiphyses occur? Why does it occur?
In children or adolescents caused by a direct blow or indirect injury of the shoulder. It occurs because the joit capsule of the glenohumeral joint (reinforced by the rotator cuff muscles)is stronger than the epiphyseal plate. In sever fractures, the shaft of the humerus is markedly displaced but the humeral head retains its normal relationship with the glenoid cavity of the scapula.
Which tendon is most commonly ruptures in a rotator cuff injury?
What is a common cause of rotator cuff injury in older people?
Degenerative tendonitis of the rotator cuff.
What is thoracic outlet syndrome? How does it present?
Compression of vessels and nerves in the apex of the axilla region (between the clavicle, first rib and scapula). This often presents with pain in the affected limb (where the pain is depends on the nerves affected), tingling, muscle weakness and discolouration.
What are common causes of thorarcic outlet syndrome?
Trauma (e.g. fractured clavicle) and repetitive (seen commonly in occupations that require lifting of the arms).
What is a possible sequelae of an axillary clearance?
Damage to the long thoracic nerve, resulting in a winged scapula.
Which vein near the cubital fossa is a common site for venepuncture in the arm?
The median cubital vein which is found within the roof of the cubital fossa. It connects the basilic and cephalic veins. It is superficial and can therefore be accessed easily.
How can a supracondylar fracture of the humerus cause Volkmann's ischaemic contracture?
The displaced fracture fragments can impinge on the cubital fossa. Direct damage, or post-fracture swelling can cause interference to the blood supply of the forearm from the brachial artery. The resulting ischaemia can cause Volkmann's ischaemic contracture - uncontrolled flexion of the hand, caused by the flexor muscles becoming fibrotic and short.
What nerves can be damaged in a supracondylar fracture of the humerus?
Median or radial nerves.
What is carpal tunnel syndrome?
The most common mononeuropathy - compression of the median nerve within the carpal tunnel.
What can cause carpal tunnel syndrome?
It can be caused by thickened ligaments and tendon sheaths. However it is most often idiopathic.
How does a patient with carpal tunnels syndrome present?
Numbness, tingling and pain in the distribution of the median nerve. The pain will usually radiate to the forearm. Symptoms are often associated with waking the patient from their sleep and being worse in the mornings. If left untreated CTS can cause weakness and atrophy of the thenar muscles.
Describe the two tests for carpal tunnel syndrome:
1. Tinel's sign: tapping the nerve in the carpal tunnel to elicit pain in median nerve distribution.
2. Phalen's manoeuvre: holding the wrist in flexion for 60 sweconds to elicit numbess/pain in median nerve distribution.
How is carpal tunnel syndrome treated?
1. Splint: holds wrist in dorsiflexion overnight to relieve symptoms.
2. Corticosteroid injections if splint unsuccessful.
3. Surgical decompression of carpal tunnel (severe cases).
How can the long thoracic nerve become injured?
Trauma to the shoulder, repetitive movements involving the shoulder or by structure becoming inflamed and pressing on the nerve.
What is the most commonly fractured bone in the body?
What nerves can be damaged in a clavicular fracture?
The suprascapular nerves (medial, intermedial and lateral) by upwards movement of the medial part of the fracture. These nerves innervate the lateral rotators of the upper limb at the shoulder (supraspinatous and infraspinatous muscles). Therefore damage results in unopposed medial rotation of the upper limb (the 'waiter's tip' position.
Damage to the axillary nerve in a surgical neck of humerus fracture will cause paralysis of which muscles?
Teres minor and deltoid muscles.
What structures are at risk in a fracture of the neck of the humerus?
Axillary nerve and posterior circumflex artery.
What structures lies in the radial groove of the humerus?
Radial nerve and profunda brachii artery.
What structures could be damaged in a mid-shaft fracture of the humerus?
Radial nerve and profunda brachii artery.
What would be the consequences of radial nerve injury at the elbow?
Wrist drop - the radial nerve innervates the extensor compartment of the wrist. Paralysis of extensors causes unopposed wrist flexion.
Sensory loss - there is also some sensory loss over the dorsal lateral surface of the hand and the proximal ends of the lateral 3.5 fingers dorsally.
What structure can be damaged in a medial epicondyle fracture of the humerus?
Ulnar nerve -> ulnar claw deformity and loss of sensation over the medial 1.5 fingers of the hand on both the dorsla and palmar surfaces.
What causes fractures of the ulnar alone? Where are the fragments displaced?
Usually the result of the ulnar being hit by an object. The shaft is the most likely site for fracture. The proximal segment displaces posteriorly due to normal muscle tone.
Less commonly the olecrannon process can be fractured. How does this occur? Where are the fragments displaced?
Falling on a flexed elbow. The triceps brachii can displace part of the segment proximally.
What is a Moneggias fracture?
Usually caused by a force from behind the ulna. The proximal shaft of the ulna is fractured and the head of the radius dislocated anteriorly at the elbow.
What is a Galeazzis fracture?
A fracture to the distal radius, with the ulnar head dislocating at the distal radio-ulnar joint.
How does a fracture of the radius head occur?
Characteristically due to FOOSH. The radial head is forced into the capitulum of humerus, causing it to fracture.
What are the two most commonly fractured carpal bones? What is their normal mechanism of injury?
Scaphoid and lunate. FOOSH.
What else can be damaged in associated with a lunate fracture?
What is a Bennett's fracture? How is it caused?
Fracture of the 1st metacarpal base, extending into the carpometacarpal joint. It is caused by hyperabduction of the thumb.
What is the name of a upper brachial plexus injury? What part of the brachial plexus does it affect?
Erb's palsy. Affects the superior roots.
What is the name of a lower brachial plexus injury? What part of the brachial plexus does it affect?
Klumpke palsy. Affects the inferior roots.
What can cause Erb's palsy?
Commonly occurs where there is excessive increase in the angle between the neck and shoulder - this stretches or even tears the nerve roots, causing damage. It can result from a difficult birth or shoulder trauma (e.g. motorbike crash).
What nerves are affected in Erb's palsy?
Nerves derived from C5 and C6 roots: musculocutaneous, axillary, suprascapular and nerve to subclavius.
Which muscles are paralysed in Erb's palsy?
Biceps brachii, brachialis, coracobrachiailis, deltoid, teres minor, supraspinatous, infraspinatous and subclavius.
What movements are affected (weakened or lost) in Erb's palsy?
Abduction (C5), Shoulder flexion (C5), lateral rotation of the shoulder (C5) and supination (C5, C6).
What sensory functions are lost/affected in Erb's palsy?
Loss of sensation down the lateral side of the arm, which covers the sensory innervation of the axillary and musculocutaneous nerves.
What is the appearance of the affected limb in Erb's palsy?
The arm hangs limply, medially rotated by the unopposed action of pectoralis major. The forearm is pronated due to the loss of biceps brachii. This position is known as 'waiter's tip' and is characteristic of Erb's palsy.
What is hyperabduction syndrome?
Compression of the axillary vein and artery causing ischaemia of the upper limb and distension of superficial veins.
How can the musculocutaneous nerve be damaged?
This is relatively uncommon but can occur with a stab wound to the axilla.
What are the affects of a musculocutaneous lesion?
1. BBC muscles are paralysed
2. Loss of sensation on lateral forearm
3. Flexion of the shoulder is weakened but can still occur by pectoralis major.
4. Flexion of the elbow is weakened but can still occur thanks to brachioradialis.
5. Supination is weakened but can still occur weakly with the supinator muscle.
How is the median nerve damaged at the elbow?
Commonly by a supracondylar fracture of the humerus.
How does median nerve damage at the elbow present?
1. Flexors and pronators of forearm are paralysed, with the exception of flexor carpi ulnaris and the medial half of flexor digotorum profundus.
2. Flexion is weak (often accompanied by adduction because of the pull of flexor carpi ulnaris).
3. The arm is constanly supinated.
4. No flexion at the thumb as FPL and FPB are paralysed.
5. Lateral two lumbricals are paralysed so patient will not be able to flex the MCP joints of those digits or extend at their IP joints.
6. Lack of sensation over the palmar lateral region of the hand and the lateral 3.5 dorsal tips of digits.
What are the characteristic signs of median nerve damage at the elbow?
1. Wasting of the thenar eminence (atrophy of thenar muscles)
2. Hand of benediction - when patient tried to make a fist, only the little and ring finger can flex completely.
How is the median nerve damaged at the wrist?
Commonly occurs due to lacerations just proximal to the flexor retinaculum.
What motor and sensory functions are impaired by median nerve damage at the wrist?
Motor: thenar muscles and lateral two lumbricals are paralysed. This affects opposition of the thumb and flexion of the index and ring fingers.
Sensory: lack of sensation over the palmar lateral region of the hand and the lateral 3.5 dorsal tips of digits.
What are the characteristic signs of median nerve damage at the wrist?
Hand of benediction (when actively try to make a fist) and thenar wasting.
How is the radial nerve commonly damaged in the axilla?
Dislocation of humerus at glenohumeral joint, fractures of proximal humerus. Can also happne via excessive presuure on the axilla e.g. a badly fitting crutch.
What are the motor effects of radial nerve damage in the axilla?
Wrist drop - loss of extension of the forearm, wrist and fingers causing unopposed flexion.
What are the sensory effects of radial nerve damage in the axilla?
All four cutansous branches of the radial nerve are damaged:
1. Inferior lateral cutaneous nerve of arm
2. Posterior cutaneous nerve of arm
3. Posterior cutaneous nerve of forearm
4. Superficial branch of radial nerve
This causes loss of sensation over the lateral and posterior upper arm, posterior forearm, and dorsal surface of lateral three and a half digits.
How is the radial nerve commonly damaged in the radial groove?
Fracture of the shaft of the humerus.
What are the motor effects of damage to the radial nerve in the radial groove?
The triceps brachii may be weakend but not paralysed (branches of the radial nerve to the long and medial heads of triceps brachii leave before it enters the radial groove. Muscles in the forearm are paralysed and wrist drop occurs.
What are the sensory effects of damage to the radial nerve in the radial groove?
The cutaneous branches to the arm and forearm have already arisen and therefore will be unaffected. The superficial branch of the radial nerve will be damaged, resulting in sensory loss on the dorsal surface of the lateral 3.5 digits and their associated palm area.
How is the deep branch of the radial nerve damaged?
It commonly occurs in fractures of the radial head, or a posterior dislocation of the radius at the elbow joint.
What are the motor effects of damage to the deep radial nerve?
Muscles in the posterior compartment of the forearm are affected, except for supinator and extensor carpi radialis longus. The extensor carpi radialis is a strong extensor at the wrist so wrist drop does not occur.
What are the sensory effects of damage to the deep radial nerve?
None as it is a motor nerve.
How is the superficial branch of the radial nerve commonly damaged?
Stabbing or laceration of the forearm.
What are the motor effects of damage to the superficial branch of the radial nerve?
None as it is a sensory nerve.
What are the sensory effects of damage to the superficial branch of the radial nerve?
Loss of sensation to the dorsal surface of the lateral 3.5 digits and their associated palmar area.
How is the ulnar nerve commonly damaged at the elbow?
The nerve is vulnerable to injury at the medial epicondyle, so fractures of the medial epicondyle is the most common way of damaging it.
How does damage of the ulnar nerve at the elbow affect its motor functions?
FCU and the medial half of FDP are paralysed. Flexion of the wrist can still occur but is accompanied by abduction. The interossei are paralysed, so abduction and adduction of the fingers cannot occur. Movement of the little and ring fingers is greatly reduced due to paralysis of the medial two lumbricals.
How does damage of the ulnar nerve at the elbow affect its sensory functions?
All sensory branches are affected therefore there will be loss of sensation over the medial 1.5 digits and associated palmar and dorsal areas.
What is a characteristic sign of ulnar damage at the elbow?
Patient cannot grip paper placed between their fingers due to loss of interossei.
How is the ulnar nerve damaged at the wrist?
Lacerations to the wrist.
How does damage of the ulnar nerve at the wrist affect its motor functions?
Interossei are paralysed so finger abduction and adduction cannot occur. Movements of the little and ring fingers is greatly reduced, due to paralysis of medial two lumbricals. The two muscle in the forearm are unaffected.
What are the characteristics signs of ulnar nerve damage at the wrist?
Patient cannot grip paper placed between fingers. For long-term cases a hand deformity called ulnar claw develops.
What causes the ulnar claw deformity in long-standing ulnar nerve damage at the wrist?
Paralysis of the medial two lumbricals which normally: flex at the MCP joints and extends at both IP joints. This paralysis causes:
1. Unopposed extension at the MCP joints (from long extensor muscles in the posterior forearm)
2. Unopposed flexion at both IP joints (due to unopposed flexion by long flexor muscles in the anterior forearm. The long extensor muscle cannot extend at the IP joints as their energy is dissipated in hyperextending the MCP joints).