MSK Flashcards
What is the most common site of fracture of the humerus?
-Surgical neck
Name the anatomical landmarks of the humerus
- Head, anatomical neck, surgical neck
- Greater tubercle, lesser tubercle, intertubecular groove
- Deltoid tuberosity, radial groove
- Lateral epicondyle, medial epicondyle, olecranon fossa, capitulum (radius), trochlea (ulna)
Name the anatomical landmarks of the radius
- Head, neck
- Radial tuberosity
- Styloid process
Name the anatomical landmarks of the ulna
- Olecranon
- Trochlear notch
- Coracoid process
- Ulnar styloid process
Name the carpals of the hand
- Scaphoid
- Lunate
- triquetral
- Pisiform
- Trapezium
- Trapezoid
- Capitate
- Hamate
What are the 3 defining features of a synovial joint? What disease affects these?
- Articular capsule (synovium)
- Synovial fluid
- Articular cartilage
- Rheumatoid Arthritis
Give 3 causes of hypotonia
- Cerebella lesion
- LMN lesion
- Primary degeneration of muscles (myopathies)
- Loss of sensory afferents from muscle spindle
Explain the processes which occur at a NMJ
- AP arrives at end plate causing influx of Ca
- Causing binding of vesicles containing neurotransmitter to fuse with pre-synaptic membrane via synaptotagmin
- Ach released
- 2 molecules of Ach bind to 1 nicotinic receptor
- Opening of Na channels
- AP continues
What is unfused and fused tetanus? State a disease which is linked to this
- Unfused tetanus is a series of action potentials causing muscle twitching in which muscles have time to relax before next ap delivered
- Fused tetanus is when the ap are delivered at a frequency which does not allow the muscle fibre to relax and sustained contraction occurs.
- Clostridium tetani produces a toxin causing tetanis carachterised by painful muscle spasms
What are the nerve roots of the brachial plexus and where do they emerge?
- C5-T1
- C5-c8 above c5-t1 vertebrae and t1 below t1
name the 5 branches of the brachial plexus and the nerve roots of each
- Musculocutaneous (C5,6,7)
- Axillary (C5,6)
- Median (C6,7,8,T1)
- Radial (C5,6,7,8,T1)
- Ulna (C8,T1)
Briefly describe development of the limbs
- limb buds elongate and develop thickened ridge distally known as apical ectodermal ridge
- AER drives elongation and prevents differentiation by releasing signalling molecules
- The proximal portion of the limb buds are too far away to be influenced so begin differentiating whilst the distal keeps elongating
- AER begins to regress except for primordia of digits.
- Interdigital spaces undergo apoptosis and elongation of fingers occurs
- Mesenchyme turns to cartilaginous model and endochondral ossification occurs
What is the zone of proliferating activity in the developing limb buds
-Area which controls dorsal-ventral patterning
What is a dermatome? Demonstrate them on the upper and lower limb
-Strip of skin supplied by a single spinal nerve
What nerve innervates trapezius?
-CNXI
Describe the different muscles whcih abduct the arm and their associated degrees
- Supraspinatus -> 0-15
- Deltoid -> 15-90
- Trapezius -> 90+
What nerve supplies the deltoid and why is examination of the deltoid particularly relevant?
- Axillary
- Loss of sensation over regimental badge shows damage to axillary nerve
- Biggest muscle group in arm so wasting is easily visible
Name the muscles of the rotator cuff and state its main function
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
- Stabilise the soulder joint
What factors make the shoulder joint unstable? In which direction is it most likely to dislocate? What local structures are most at risk of damage
- Shallow glenoid cavity
- Disproportionate articular surfaces
- Multiplanar movements
- Anterior inferior from an abducted position
- Rotator cuff, axillary nerve
What is the coracoacromial arch and its clinical significance
- Made be coracoid process, acromion and coaracoacromial ligament
- prevents upper dislocation of humerous
- Painful arc syndrome -> supraspinatus tendon inpingement under CAA -> irritation and inflammation producing pain on abduction between 50-130 degrees
Give risk factors for painful arc syndrome
- Repetitive use -> racquet sports or occupation involving arms over head
- Age
What are bursae? List the diseases you know involving bursae
- Synovial membrane-lined sacs filled with synovium to facillitate movements of tendons and muscles over bone by reducing friction
- Bakers cyst -> popliteal bursitis
- Housemades knee -> infrapatella bursitis
- Clergymens knee -> pre-patella bursitis
- Painful arc -> subacromial bursitis
Which movements flex, extend, abduct and adduct the shoulder?
- Flexion -> pec major, coracobrachialis, biceps brachii, anterior deltoid
- Extension -> posterior deltoid, lat dorsi, teres major
- ABduction -> supraspinatus, deltoid, trapazius, serratus anterior
- ADduction -> lat dorsi, pec majr and teres major
Which arteries supply the glenohumeral joint?
-Anterior and posterior circumflex
Which muscles does musculocutaneous innervate and what are their actions
- Biceps brachi -> flexion of elbow and shoulder, and main supinator
- Brachialis -> flexion of elbow
- Coracobrachialis -> shoulder flexion, medial rotation
Which muscles does radial nerve innervate in the arm and what are their functions?
-Triceps brachii -> extension
What nerves supplies the anterior forearm?
- Ulnar nerve supplies FCU and medial half of FDP
- Median nerve serves the rest
What are the muscles of the anterior forearm?
- 4 superficial =Pronator teres, Flexi Carpi Radialis, Palmaris longus, Flexi carpi ulnaris
- 4 Deep = Flexor digitorum superficialis, Flexor digitorum profundus, Flexor pollicis longus, pronator quadratus
What are the functions of FCR?
- Flexion of the wrist
- Abduction of the hand (radial deviation)
What are the functions of FCU?
- Flexion of wrist
- ADduction of hand (ulnar deviation)
What artery supplies the superficial group of the anterior forearm?
-Ulnar
Which muscle in the forearm is absent in 15% population?
-Palmaris longus
What is the main function of the muscles in the anterior forarm?
-Flexion of the wrist and fingers
What are the functions of FDS?
- Flexion of MCP
- Flexion of proximal IP
What are the functions of FDP?
- Flexion of wrist
- Flexion of MCP
- Flexion of all IPs
What are the functions of FPL?
- Abduction of the wrist
- Flexion of the carpometacarpal, metacarpophalangeal and interphalangeal joints of 1st digit
What are the functions of Pronator quadratus?
- Pronation
- Stabilisation of radioulnar joint
How is FDP in relation to FDS?
-FDP beings deep to FDS but becomes superficial as it passes through the tendon of FDS at the digits
Compression of the median nerve at the wrist results in atrophy of which muscles? (Carpal tunnel)
-Thenar eminence
Give some causes for carpal tunnel
-Median Trap (myxoedema, enforced flexion, diabetic neuropathy, idiopathic, acromegaly, neoplasm, tumours, rheumatoid arthritis/repetitive strain, amyloidosis, pregnancy, sarcoid)
What is the bicipital aponeurosis?
- Fascia at the elbow which protects the brachial artery and median nerve
- Separates superficial structures from deep structures eg medial cubital vein from brachial artery
What forms the carpal tunnel?
-Deep carpal arch-Superficial flexor retinaculum
What structures are in the carpal tunnel?
- 4 tendons of FDS
- 4 tendons of FDP
- Median nerve
- Tendon of FPL
What nerve supplies the posterior forearm?
-Radial
Name the muscles of the posterior forearm
- 3 to the wrist -> ECRL, ECRB and ECU
- 3 to the fingers -> ED, EDM, EI
- 3 to the thumb -> EPL, EPB, ABPL
- 3 misc -> brachioradialis, Anconeous, Supinator
What is the function of the muscles in the posterior forearm?
-Extension at the wrist and fingers
What is the function of brachioradialis?
-Flexion of elbow (especially in half pronated position)
What are the functions of extensor carpi radialis longus and brevis?
-ABdution and extension of the wrist
What is the function of extensor digitorum?
-Main extensor of the fingers at MCP and both IP joints
What is the function of extensor carpi ulnaris?
- Extension of the wrist
- ADduction
-What is Lateral epicondylitis?
- Tennis elbow
- Inflammation of the periosteum of the lateral epicondyle
- Onset usually 40-50 years
- Caused by repetitive strain of suprficial extensors
Why is the Abductor pollicis longus tendon important?
-Makes the lateral border of the anatomical snuff box
Why is the tendon of extensor pollicis brevis important?
-Makes the lateral border of the anatomical snuff box
Why is the tendon of extensor pollicis longus important?
-Makes the medial border of the anatomical snuff box
What is wrist drop?
-Unopposed flexion of the wrist caused by radial nerve injury
Where and how are common sites of damage to the radial nerve?
- Axilla -> humeral dislocation or proximal fracture
- Radial groove -> humeral shaft fracture
What are the superficial muscles of the gluteal region?
- Gluteus maximus
- Gluteus medius
- Gluteus minimus
What are the functions of the gluteus medius and minimus?
- ABduction and medial rotation
- Secures pelvis during locomotion and prevents pelvic drop of opposite limb
What nerve supplies gluteus maximus?
-Inferior gluteal nerve
What nerve supplies gluteus medius and minimus?
-Superior gluteal nerve
What does gluteus maximus also assist in running?
-Lateral rotation
What is the function of gluteus maximus?
-Powerful extensor of flexed femur
What artery serves gluteus maximus?
-Superior anf inferior gluteal arteries
What artery serves glut med and min?
-Superior gluteal artery
What is the result of damage to superior gluteal nerve?
-Paralysis of glut med and glut min resulting in the pelvis becoming unsteady and pevic drop on opposite side during locomotion (positive trendelenberg test)
Where is the safe injection site of the gluteal region?
-Upper lateral quadrant
What are the deep muscles of the gluteal region?
- Piriformis
- Gemelli superior
- Obturator internus
- Gemelli inferior
- Quadratus femoris
What is the function of the deep gluteal muscles?
- Lateral rotation and Adduction
- Stabilisation (pull head of femur into acetabulum as attach at greater trochanter)
What nerve innervates piriformis?
-Nerve to piriformis
Why is piriformis an anatomical landmark?
- structures emerging superior to pririformis named superior eg superior gluteal artey and those inferior named inferior
- Can be used to locate sciatic nerve as mostly enters gluteal region inferior to piriformis
Name the muscles of the medial thigh
- Obturator Externus
- ADductor brevis
- ADductor longus
- ADductor magnus
- Gracilis
What is the function of obturator externus?
- Laterally rotate the hip
- ADduction
What is the relationship between ADductor longus and the femoral triangle?
-ADductor longus is the medial border of the femoral triangle
What is the function of ADductor longus?
- ADduct the hip
- Medially rotate the hip
What are the functions of Adductor magnus?
- ADduct, medial rotates the hip
- Contributes to hamstrings to extend the hip
What is significant about the nerve supply to ADductor magnus?
- Medial half supplied by obturator nerve
- Hamstring portion supplied by tibial nerve
What nerve and artery supplies the medial thigh muscles?
- Obturator nerve
- Obturator artery
What attaches to the adductor tubercle?
-Hamstring portion of ADductor magnus
What are the functions of gracilis?
- ADduct the hip
- Flex the knee
What innervates the muscles in the anterior thigh?
-Femoral nerve
Name the muscles of the anterior thigh
- Iliopsoas
- Quadreceps femoris
- Sartorius
- Pectineus
-What two muscles makes iliopsoas?
-Iliacus
-Psoas major
Form one tendon
What is the function of iliopsoas?
-Flex the hip joint-Lateral rotation of the hip
What 4 muscles comprise quadriceps femoris?
-Rectus femoris-Vastus medialis-Vastus intermedius-Vastus lateralis
How do the quadriceps femoris muscles attach?
-Blend into tendon quadriceps femoris and attach to patella
What is the function of quadriceps femoris?
-Extends the knee
What additional function does rectus femoris have apart from knee extension?
-Crosses the hip and aids flexion
What are the functions of sartorius?
-Flexor, ABductor and lateral rotator of hip-Flexor and internal rotator of knee
What are the functions of pectineus?
-ADduction and Flexion of hip
Where do the muscles of the posterior thigh attach?
-Isschial tuberosity (except short head of biceps-> linear aspera)