MSK Flashcards
What is an avulsion fracture? Where does it commonly occur?
A piece of bone is torn away by a tendon due to trauma. Greater tubercle of the humerus/ medial malleolus
What innervates serratus anterior?
Long thoracic nerve (Nerve of Bell) from C5 c6 and c7
Where would a you find a Colles fracture?
Radius protrudes through anterior face of wrist
Distal fragment (hand) moves posterior to radius
Caused by falling on an outstretched hand.
Name the 8 carpal bones.
PROXIMAL Scared - Scaphoid Lovers - Lunar Try - Triquetrum Positions - Pisiform
DISTAL That - trapezium They - trapezoid Can't - capitate Handle - hamate
Name the 3 components of a synovial joint.
Articular capsule (membrane)
Synovial fluid
Articular, hyaline cartilage
Identify 3 types of fibrous joints and give an example of each.
Sutures - skull bones
Gomphosis - teeth
Syndesmosis - flat sheath of connective tissue between the radius and ulna
What is the difference between primary and secondary cartilaginous joints?
Primary - hyaline - eg growth plates
Secondary - fibrocartilage eg pubic symphysis or intervertebral discs
What is a saddle joint?
A type of synovial joint where a concave and convex bone meet. Eg 1st carpometacarpal (base of thumb)
What is a condyloid joint?
A very motile synovial joint which allows flexion, extension, adduction, abduction and circumduction. Eg metacarpophalangeal (knuckles)
What is a compartment?
A bundle of muscles enclosed by a fascial membrane or septum. It also contains nerves and blood vessels.
What is compartment syndrome?
When there is an increase in pressure in a muscle compartment due to a bleed or a blockage. It can lead to ischaemia. It causes 6P's: Pain Parasthesia Palor Perishingly cold Pulseless Paralysis
What is a motor unit?
A motor neuron and the fibres it innervates
Why are the motor units in the eye very small, and in the buttock they are very large?
The fewer fibres per neuron, the finer the control
Give four differences between fast twitch and slow twitch muscle fibres.
Fast- Anaerobic
Slow- aerobic
Fast - few mitochondria
Slow - lots of mitochondria
Fast- few myoglobin
Slow - lots of myoglobin
Fast - suited to intense exercise
Slow - suited to prolonged exercise
Give two ways a muscle can increase the force it exerts.
Recruiting more neurons
Increasing the frequency of action potentials
What are two possible causes of low muscle tone and how would you differentiate between them?
Decreased neuronal activity - eg polyneuritis
Decreased muscle elasticity - eg myopathy
Differentiate by noting loss of reflexes for nerve damage
What is the difference between isotonic and isometric muscle contraction?
Isotonic has a constant tension but variable length
Isometric has a variable tension but constant length eg hand grip
Where does the clavicle tend to fracture and why?
Mid 1/3 shaft where it is weakest. Designed to stop forces travelling to the neck and causing damage where it is more dangerous.
What are the boundaries of the axilla?
Apex - clavicle, scapula, 1st rib Posterior - latissimus dorsi and teres major and minor Anterior - pectoralis major and minor Lateral - humerus Medial - serratus anterior Base - armpit skin
Give 3 possible causes of a winged scapula.
Describe the nerve fully
- Weak Serratus anterior - Long thoracic nerve damage C5 6 and 7
- Or other muscle wasting eg muscular dystrophy or MS - Idiopathic
- Scoliosis
Which structures can be found in the cubital fossa?
Medial to lateral Median nerve Brachial artery Biceps tendon Median cubital vein
What are the borders of the cubital fossa?
Superior - imaginary line between the epicondyles
Medial - pronator teres
Lateral - brachioradialis
What is painful arc syndrome? Name three possible causes.
Pain when raising the arm above 90 degrees due to rubbing of the supraspinatus tendon under the acromion. Can be caused by subacromial bursitis, repetitive overuse or degeneration of the tendons with old age.
Why does the shoulder tend to dislocate easily?
Weak joint because shallow glenoid fossa, little support from ligaments inferiorly, lax capsule and not much contact between articulate surfaces.
Which nerve is most at risk of damage when the shoulder dislocates and how would you test for its function?
Axillary nerve because shoulders tend to make anterior dislocations. Test axillary nerve by checking loss of sensation at the regimental badge area.
Which muscles are found in the anterior compartment of the upper arm and which nerve innervates them?
BBC - biceps, brachialis and coracobrachialis. Innervates by the musculocutaneous nerve.
Which muscles are found in the posterior compartment of the upper arm and which nerve innervates them?
Triceps
Radial nerve
Which nerves innervate the muscles of the cubital fossa?
Brachioradialis innervated by radial nerve
Pronator teres innervated by median nerve
Describe the venous drainage of the arm.
Cephalic - Subclavian vein brachiocephalic
Basilica - axillary - subclavian - brachiocephalic
Median cubital vein between basilic and Cephalic in the cubital fossa
What are the four rotator cuff muscles?
SITS Supraspinatus Infraspinatus Teres minor Subscapularis
What are the six ligaments of the rotator cuff? (3 inside and 3 outside the capsule)
Superior, middle and inferior glenohumeral ligaments inside the capsule. Plus outside the capsule ... Coracoacromial Coracohumeral Transverse humeral
Which nerves originate in the lateral cord of the brachial plexus?
Musculocutaneous and medial nerves
Which nerves originate in the medial cord of the brachial plexus?
Medial and ulnar nerves
Which nerves originate in the posterior cord of the brachial plexus?
Axillary and radial
Which germ layer do the somites arise from and what do they develop into?
Paraxial mesoderm - somites - dermatomes, myotomes, sclerotomes
What germ layer do the limb buds arise from?
Somatic mesoderm
What initiates the formation of the primitive hands and feet “paddles”?
The apical ectodermal ridge. An area of thick ectoderm at the apex of the limb bud.
By what process do the primitive hands and feet interdigitate?
Apoptosis - programmed cell death
Which direction do the upper and lower limbs rotate as they form? (Think about the anatomical position)
Upper - laterally
Lower - medially
What embryological disorder was caused by thalidomide?
Phocomelia - a type of Meromelia which is a partial absence of a limb
What are the defining symptoms of syndactyly and polydactyly?
Syndactyly - fusion of the digits (at the bone or skin level)
Polydactyly - extra digits
Where does the axillary artery become the brachial artery?
After it passes teres major
Which artery and nerve are most at risk when the humerus is fractured?
Surgical neck - Circumflex artery and axillary nerve
Mid shaft - Deep brachial artery and Radial nerve (in the spiral groove)
Which muscles are involved in the abduction of the arm?
Supraspinatus - first 15 degrees
Deltoid - up to 90 degrees when the humerus bumps into acromion
Trapezius and serratus anterior - up to 180 degrees
Recite the rhyme which reminds you the roots which supply the nerves of the brachial plexus.
3 musketeers Assassinate 5 rats 5 mice And 2 unicorns
Outline the motor and sensory function of the musculocutaneous nerve. Plus its nerve roots.
Motor - BBC above elbow
Sensory - lateral anterior forearm
C5, C6, C7
Outline the motor and sensory function of the axillary nerve. Plus its nerve roots.
Motor - deltoid, teres minor, triceps
Sensory - regimental badge
C5, C6
Outline the motor and sensory function of the median nerve.
Motor - forearm flexors, lateral hand (thenar eminence and 2 lateral lumbricals)
Sensory - lateral Palm
C5 - T1
Outline the motor and sensory function of the radial nerve. Plus its nerve roots.
Motor - extensors of the arm
Sensory - posterior hand
C5 - T1
Outline the motor and sensory function of the ulnar nerve. Plus its nerve roots.
Motor - hand (except lateral)
Sensory - 3rd and 4th fingers
C8 - T1
Outline the motor and sensory function of the femoral nerve.
Motor - anterior thigh
Sensory - anterior thigh and medial leg
L2 - L4
Outline the motor and sensory function of the obturator nerve. Plus its nerve roots.
Motor - medial thigh
Sensory - medial thigh
L2 - L4
Outline the motor and sensory function of the pudendal nerve.
Motor - s2 3 and 4 keeps the shit off the floor
Sensory - penis and clitoris
Outline the motor and sensory function of the sciatic nerve. Plus its nerve roots.
Motor - posterior thigh
Sensory - n/a
L4 - S1
Outline the borders of the anatomical snuff box.
Medial - Extensor pollicis longus
Lateral - Extensor pollicis brevis and Abductor pollicis longus
What passes through the carpal tunnel?
Recurrent branch of Median nerve and the intermediate and deep tendons
(Flexor pollicis longus
Flexor digitorum profundus
Flexor digitorum superficialis)
Which artery runs alongside the medial nerve?
Brachial
Which artery runs alongside the radial nerve?
Profunda brachii
Which artery runs alongside the ulnar nerve?
Ulnar artery
Which artery runs alongside the axillary nerve?
Circumflex artery
What runs just above the carpal tunnel?
Guyon’s canal - ulnar artery and nerve
Describe the motor innervation of the hand.
Ulnar except
LOAF
Are median
Describe the sensory innervation of the hand.
FRONT
Thumb, first 2 fingers and medial palm are median
Last 2 fingers and lateral palm are ulnar
BACK
Last 2 fingers and lateral dorsum are ulnar
Tips of thumb and first 2 fingers are median
Dorsum of thumb and first 2 fingers are radial
What is the difference between a sensory nerve territory and a dermatome?
Sensory nerve territory is an area whose sensory nerve function is supplied by an individual nerve.
Dermatome is an area whose sensory function is supplied by an individual nerve root.
Where can the dermatome for c4 be found?
Skin above deltoid
Where can the dermatome for c7 be found?
Fingers and central forearm
Where can the dermatome for t2 be found?
Armpit
Which muscle does the lumbar plexus travel through?
Psoas major
What nerve roots make up the lumbar plexus?
L1 to L5
What are the contents of the femoral triangle? What are its borders?
NAVEL Femoral nerve Femoral artery Femoral vein Empty space (canal) Lymph
Inguinal canal
Medial border of Sartorius
Medial border of adductor longus
Floor: adductor longus and pectineus
What are the borders of the femoral canal? What are its contents?
Superior - inguinal ligament
Inferior - pectineus
Lateral - femoral vein
Medial - lacunar ligament
Contains lymph vessel and empty space to allow expansion of femoral vein
What are the borders of the popliteal fossa?
Superior-medial: semi membranosus
Superior-lateral: biceps femoris
Inferior: both heads of gastrocnemius
What are the contents of the popliteal fossa?
Common fibular nerve
Tibial nerve
Popliteal vein
Popliteal artery
Give 5 differences between the male and female pelvic (innominate) bones.
Female:
- Wider sub pubic angle
- Circular rather than heart shaped pelvic inlet
- Smaller ischial spines
- More rounded greater sciatic notch
- More curved sacrum
Name the ligaments of the hip joint.
Iliofemoral
Pubofemoral
Ischiofemoral
Give 3 reasons why the hip joint is rarely dislocated.
Joint strengthened by:
Lots of muscular attachments
Tight capsule
Acetabular labrum deepens the acetabulum creating a more secure pocket
When are hip dislocations most often seen?
Hip dysplasia at birth. The head of the femur and acetabulum are underdeveloped in utero and dislocates during birth.
What is the difference between osteo and rheumatoid arthritis?
Osteo is damage to cartilage caused by mechanical grinding.
Rheumatoid is an autoimmune inflammatory response beginning in the synovium. Later cartilage may be damaged leading to mechanical problems.
Give two functions of the menisci in the knee.
- Deepen the articular surfaces
2. Act as shock absorbers
Name 4 ligaments which stabilise the knee joint.
Anterior cruciate
Posterior cruciate
Medial collateral
Lateral collateral
Which ligamentous attachment in the knee can lead to a common triad of injuries?
Medial meniscus attaches to the medial collateral ligament.
Means both are often injured along with acl.
Name 3 common sites of bursitis in the knee.
Supra patellar
Pre patellar - housemaids knee
Infra patellar - clergymans knee
What are Baker’s cysts?
Abnormal fluid filled sacs of synovial membrane in the popliteal fossa.
When does the femoral artery turn into the popliteal artery?
At the knee
Which muscle do the perforating branches of profunda femoris travel through?
Adductor Magnus
What is the name of the connective tissue which the great saphenous vein travels through?
Fascia lata
Where can the great saphenous vein be palpated?
Medial border of the patella
Describe the venous drainage of the leg.
External iliac Femoral vein Deep femoral vein Great saphenous vein Popliteal Anterior tibial, Peroneal, Posterior tibial
Describe the arterial supply to the leg.
External iliac
Femoral artery
Profunda femoris and perforating branches
Lateral circumflex
Popliteal
Anterior tibial- dorsalis pedis, Peroneal, posterior tibial
What are the names given to the curves of the spine?
Concave - lordosis
Convex - kyphosis
How many vertebrae belong to each of the sections of the spine?
Cervical - 7
Thoracic - 12
Lumbar - 5
Sacral - 5
What travels through the intervertebral foramen?
Nerves pass out from the spinal cord to the body
What travels through the intravertebral foramen?
Spinal cord
Give 3 identifying features of a cervical vertebra.
Bifid spinous process
Large triangular vertebral foramen
Rectangular body
Give 3 identifying features of a thoracic vertebra.
Spinous process sloping down
Small round foramen
Heart shaped body
Give 3 identifying features of a lumbar vertebra.
Short blunt spinous process
Small triangular foramen
Large kidney shaped body
Describe the structure of an intervertebral disc
Outer fibrocollagenous annulus fibrosus
Inner nucleus pulposus from notochord
What is meant by a green stick fracture?
A fracture in a young child whose bone is not fully ossified, so that the fracture does not break all the way through
What is meant by varus and valgus deformity?
Angle of inclination at the joint is
Increased - varus (airus) - bow legged
Decreased - valgus - knock kneed
Give two examples of bursitis in the hip region.
Trochanteric
Ischial
What is the pathophysiology of dupuytren’s contracture?
Palmar fascia becomes fibrotic, shortens and thickens, closing the hand.
What is the pathophysiology of shin splints?
Mild anterior compartment syndrome
What is meant by parasthesia?
Pins and needles
What happens to tendons with age or overuse?
Ossification
Which muscles would be affected by a radial nerve injury? What symptom would you observe?
Particularly brachioradialis so wrist drop
Which nerve can be damaged during mastectomy? Which muscle would be affected?
Thoracodorsal - latissimus dorsi
What is the difference between the hand of benediction and the ulnar claw?
Hand of benediction:
Median nerve damage prevents 1st and 2nd finger curling
Ulnar claw:
Ulnar damage prevents 4th and 5th uncurling
What constitutes a failed trendelenberg test? Which nerve is implicated?
Ask to lift left leg, left hip drops because weak right gluteus minimums and medius.
Superior gluteal nerve
Which nerve is implicated in foot drop?
Common Fibular
How does a muscle relax?
Ca ATPase pumps Ca back into the sarcoplasmic reticulum so that tropomyosin returns and blocks the actin binding sites.
Some Ca binds to calmodulin
Which muscles are involved in medial rotation of the hip?
Gluteus medius and gluteus minimus
Tensor fascia lata
Which muscles are involved in medial rotation of the shoulder?
Pectoralis major Deltoid (anterior fibres) Latissimus dorsi Subscapularis Teres major
Which muscles are involved in extension of the shoulder?
Deltoid
Latissimus dorsi
Teres major
How is the shoulder stabilised?
Rotator cuff muscles
Ligaments
Glenoid labrum deepens the glenoid fossa
How are the thoracic vertebrae adapted to protect the spinal cord?
Spinous process points down and forward to protect the spinal cord at the kyphosis.
How does a vitamin A deficiency affect the MSK system?
Causes an imbalance of osteoclasts and osteoblasts which can decrease growth rate
What is the purpose of bursae?
Reduce friction within joints
What are the attachments of biceps brachii?
Long head - supraglenoid tubercle of scapula
Short head - coracoid process
Tendon - radial tuberosity
Where does the brachial artery bifurcate? What does it divide into?
Distal ends of the cubital fossa. Radial and ulnar arteries.
Where can the pulse in your foot be found?
Dorsalis pedis artery, from the anterior tibial artery, between the extensor hallucis longus tendon and the extensor digitorum tendon of the second toe.
Outline the motor and sensory function of the deep fibular nerve.
Motor - anterior leg = dorsiflexion
Sensory - area above dorsalis pedis pulse
Outline the motor and sensory function of the superficial fibular nerve.
Motor - lateral compartment = stop inversion
Sensory - anterior foot and ankle
Which artery and nerve always travel together through the anterior compartment of the leg?
Anterior tibial artery and deep Peroneal nerve
What innervates the lateral compartment of the anterior leg?
Superficial Peroneal nerve
Which compartment of the leg contains the Peroneal artery?
Posterior - just outside the lateral compartment
What is the proper name for the houseman’s vein? Where is it?
Long saphenous vein - anterior to the medial maleolus
Describe the process of a saphenous cut down.
Incision into long saphenous vein in an emergency situation to get fluids in.
How are varicose veins formed?
Perforating branches of the superficial veins of the leg lead to deep veins. This allows pooling blood to drain via the deep veins which are helped by the pumping muscles.
Varicose veins are caused by damage to the perforating branches.
What is another name for the Achilles tendon?
Calcaneal tendon
Name the muscles which attach to the calcaneal tendon.
Superficial muscles of posterior compartment:
Gastrocnemius
Soleus
Plantaris
Which useless muscle has a really long tendon which can be used to fix other tendons eg ACL
Plantaris
Name the pulses of the lower limb.
Femoral
Popliteal
Dorsalis pedis
Posterior tibial
What are you concerned about with a neck of femur fracture?
Avascular necrosis of the head
Particularly in intracapsular fractures, because risk to medial circumflex artery.
What is the adductor hiatus? What passes through it?
Hole in adductor Magnus
Femoral artery and vein
Describe the deep venous drainage of the leg.
Travel as venae comitantes with the arteries.
Name four functions of bone.
Protection
Support
Locomotive lever
Calcium regulation
What are the effects of ageing on the MSK system?
Decreased bone density - osteopenia
Cartilage degeneration
Fatty infiltration of muscle
Decrease in muscle mass - sarcopenia
What test would measure bone density?
DEXA scan
What drugs are used to slow down osteoporosis?
Bisphosphonates - decrease action of osteoclasts
Name the four radiological features of osteoarthritis
L - loss of joint space
O- Osteophytes - mini bone calluses where it is repairing
S - Sclerosis - increased bone density
S - subchondral cysts - fluid filled holes
Give some complications of a hip replacement operation.
Infection DVT Leg length Loosening after 10 years Nerve damage
What nerve is likely to be damaged in a patient with wrist drop? What other symptoms would there be?
Radial nerve
Unable to extend elbow because innervates triceps
What nerve palsy is caused by upper brachial plexus injury (c5 and c6)?
Erb Duchenne (waiter’s tip)
Describe how erb Duchenne - waiter’s tip can be caused.
Pulled arm at delivery
Falling on shoulder - shoulder depressed, head turned
What muscles are affected by erb Duchenne palsy?
Shoulder abduction - deltoid, supraspinatus
External rotation - infraspinatus
Elbow flexion - biceps brachii, brachialis
What nerve palsy is caused by lower brachial plexus injury (c8 and t1)?
Klumpke’s
Claw hand
What muscles are affected by Klumpke’s palsy?
(Forearm Flexors)
Small muscles of the hand
Which actions occur at the talocrural joint?
Dorsi flexion and plantar flexion
Name the three joints where inversion and eversion of the foot occur.
Subtalar
Calcaneocuboid
Talocalcaneonavicular
What factors stabilise the ankle joint?
Ligaments
Malleoli grip the talus
Is the ankle more stable in dorsi or plantar flexion?
Dorsi flexion because the talus is wider posteriorly
Which set of ligaments in the ankle are stronger? What is their function?
Medial ligaments which resist eversion
What is the difference between a sprain and a strain?
Sprain - ligament
Strain - muscle/tendon
What causes a sprained ankle? What else can occur from this injury?
Forced inversion injures the lateral ligament.
Can cause fracture of lateral malleolus
What is a Pott’s fracture? What is it caused by?
Forced eversion causes an avulsion fracture of the medial malleolus via the medial ligament
This displaces the talus and can cause fracture of the lateral malleolus or the fibular.
What causes flat feet?
Compromised medial arch by:
excessive stretching of the plantar aponeurosis and spring ligaments
What types of fracture increase susceptibility to carpal tunnel syndrome?
Supracondylar
Tibial shaft
What are the common symptoms of carpal tunnel syndrome?
Parathesia in the lateral 3 1/2 fingers
Pain
Why is the palm unaffected in carpal tunnel syndrome?
Palmar branch of the median nerve runs outside the flexor retinaculum
How would you test for carpal tunnel syndrome?
Tinel’s test - tap for pain/ tingling
Phalen’s test - flex wrists down for pain/ tingling
What is a Pancoast tumour?
An apical lung tumour that can press on the brachial plexus, especially T1. Leading to pain and parasthesia in the T1 dermatome on the medial forearm.
Where would you find a Smith’s fracture?
Reverse of Colles. Distal fragment (hand) moves anterior to radius.
Caused by forced flexion.
What is volkmanns ischaemic contracture? What is it caused by?
Ischaemia of the forearm flexors causes them to become fibrotic and short. Can be caused by compartment syndrome.
What is neuropraxia?
Saturday night palsy- Temporary nerve damage caused by lying on it overnight. Can be foot drop from common Peroneal nerve or wrist drop from radial nerve compression.
Which muscles are responsible for adduction and abduction of the fingers?
Palmar interossei - adduction (PAD)
Dorsal interossei - abduction (DAB)
Which nerve is at risk during axillary lymph node dissection for breast cancer? What would damage lead to?
Long thoracic - winged scapula
Which direction does a vertebral disc tend to herniate?
Posterolateral - that is, lateral to the posterior longitudinal ligament
Where specifically should IM injections be inserted?
Upper lateral quadrant
Above an imaginary line between the greater trochanter and the PSIS ( posterior superior iliac spine)
Where is the mid inguinal point?
Where is the mid point of the inguinal ligament?
Why are these points clinically useful?
MIP - half way between ASIS to pubic symphysis
MPIL - half way between ASIS to pubic tubercle
MIP finds the femoral artery
MPIL find the deep inguinal ring (entrance to inguinal canal)
What is the name of the gait caused by foot drop? Describe its action.
High stepping gait.
Hip flexed higher than normal to avoid catching the dorsi flexed foot.
Can also appear with an eversion flick.
What is antalgic gait?
Limp to avoid pain eg in arthritis
What are actions of the hip during the swing phase and stance phase of walking? What muscles are implicated?
- Extend by hamstrings to push off floor.
- Then flex, by iliopsoas and rectus femoris to swing
- These relax to lower leg, and gluteus maximus decelerates
- Gluteus medius, minimus and tensor fascia lata keep the pelvis level
What are actions of the knee during the swing phase and stance phase of walking? What muscles are implicated?
- Quadriceps maintain leg extension to push off floor
- Hamstrings flex leg to lift and swing through
- Quadriceps extend to strike the floor
- Quadriceps maintain leg extension to stand
What are actions of the ankle during the swing phase and stance phase of walking? What muscles are implicated?
- Plantar flexion by posterior leg especially flexor hallucis longus to push off floor
- Dorsi flexion by anterior leg especially tibialis anterior to lift leg and swing through
- Stability through standing by inverters (tibialis anterior and posterior) and everters (peroneus longus and brevis)