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)
Name the muscles in the posterior thigh from medial to lateral?
-Adductor magnus-Semimembranosus-Semitendinosus-Biceps femoris long head-Biceps femoris shirt head underneath long head
What is the function of Semimembranosus?
-Extension of the hip joint-Flexion and internal rotation of the knee joint
What is the function of semitendinosus?
-Extension of the hip joint-Flexion and internal rotation of the knee joint
What is the function of biceps femoris?
-Long head -> Flexion and external rotation of the knee-Short head -> Flexion of the knee
Describe the nerve supply to the posterior thigh
-Sciatic nerve enters posterior thigh through greater sciatic foramen-Branches into the tibial and common fibular nerve-Pass down into the leg and tibial nerve supplies all posterior thigh muscles except short head of biceps femoris which is common fibular nerve
Describe the blood supply to the posterior thigh
-Perforating branches of the deep artery of the thigh serves the posterior thigh-Inferior gluteal and popliteal artery also contributes
What artery passes through adductor Magnus into posterior thigh and into the leg?
-femoral artery
What makes the superiomedial border of the popliteal fossa?
-Sememembranosus
What makes the superiolateral border of the popliiteal fossa?
-Biceps femoris
What makes the inferiomedial border of the popliteal fossa?
-Medial head of gastronemuis
What makes the inferiolateral border of the popliteal fossa?
-Lateral head of gastronemius and plantaris
What are the contents of the popliteal fossa, from lateral to medial?
-Common fibular nerve-Tibial nerve-Popliteal vein-Popliteal artery
Where specifically can the common fibular nerve be found?
-Lateral margin following biceps femoris tendon
What vein pierces the popliteal fossa and drains into the popliteal vein?
-Small saphenous vein
Where does the popliteal artery arise from?
-Continuation of femoral artery
What does the popliteal artery branch into?
-Circumflex fibular artery-Anterior and posterior tibial arteries
What are the main two causes of a mass in the popliteal fossa?
-Baker’s cyst-Popliteal aneurysm
What is a baker’s cyst?
-Inflammation and swelling of the semimembranosus bursa
What do baker’s cysts usually arise in conjunction with?
-Arthritis
What are the usual outcomes of a baker’s cyst?
-Usually self resolves-Can rupture and produce symptoms similar to DVT
Why do the other structures in the popliteal fossa become compressed in a popliteal aneurysm?
-The popliteal fascia which makes the roof is tough and non-extensible
How are popliteal aneurysms detected?
-Obvious palpable pulsation in the popliteal fossa with abnormal arterial sounds
What nerve innervates the anterior compartment of the leg?
-Deep fibular (peroneal) nerve
What artery accompanies the deep fibular nerve and supplies the anterior compartment of the leg?
-Anterior tibial artery
What nerve innervates the lateral compartment of the leg?
-Superficial fibular nerve
Name the muscles in the anteriolateral leg
-Tibularis anterior-Extensor digitorum longus-Extensor hallucis longus-Fibularis Tertius-Fibularis longus-Fibularis brevis
Why is it too late to wait for symptoms such as parasthesia and loss of pulses in compartment syndrome?
-Ischaemia will often have already ensued and muscle cannot regenerate
What are the key features used to recognise compartment syndrome?
-Pain that doesnt respond to analgesia-Tightness-Swelling
What is the function of the anterior compartment of the leg?
-Dorsiflexion (extension) of the foot
What are the muscles in the anterior compartment of the leg from deep to superficial?
-Fibularis tertius-Extensor Hallucis Longus-Extensor Digitorum Longus-Tibialis Anterior
What covers all the tendons of the anterior compartment of the leg as they enter the foot?
-Extensor retinaculum
What is the function of tibialis anterior?
-Dorsiflexion-Inversion
What muscles are in the lateral compartment of the leg?
-Fibularis longus-Fibularis brevis
What are the function of the lateral compartement of the leg?
-Evert-Weakly plantarflex
How does the lateral compartment of the leg receive its blood supply?
-Perforating arteries from anterior tibial artery and fibular artery
What are the common signs of common fibular nerve damage?
-Footdrop (due to unopposed plantarflexion)-Highstepping gait (lift plantarflexed foot)-Weakened eversion (lateral compartement paralysed)-Sensory loss of lower lateral leg and dorsum of foot
What is a pathological fracture?
-A fracture which occurs to abnormal bone under physiological load
What are local causes of pathological fractures?
-Infection-Tumour
Name some systemic causes of pathological fractures?
-Osteomalacia-Malabsorption-Tumour
What factors influence how bones heal?
-Local factors -> soft tissue injury, type of bone involved, treatment-Regional factors -> blood supply, muscle cover-Systemic factors -> age, co-morbidity, bone pathology
What is malunion? What are the consequences of malunion?
-When bones don’t heal in the right place-Deformity-Late arthritis
Briefly describe fracture healing by callus
-Haematoma formation -Soft callus formation as cartilage is laid down and calcified -> granulation tissue forms-Bony callus formation->Soft callus becomes cancellous bone-Remodelling
Name some early local complications which can occur with fractures?
-Nerve injury, vascular injury, compartment syndrome, infection, avascular necrosis
What is compartment syndrome?
-Raised pressure within an enclosed fascial space leading to localised tissue ischaemia
Name the deep muscles of the posterior leg
-Tibialis posterior-Flexor digitorum longus-Flexor hallucis longus-Popliteus
What tendons make the Achilles tendon?
-Gastronemius-Plantaris-Soleus
What runs through the tarsal tunnel?
-Tibialis posterior (Tom)-Flexor digitorum longus (Dick)-Posterior tibial artery (And)-Posterior tibial vein (Very)-Flexor hallucis longus (Harry)
What are the superficial veins of the posterior leg and where do they lie?
-Small saphenous lies laterally-Great saphenous lies medially
Where does the great saphenous drain into?
-Femoral vein through Saphenous ring of femoral triangle
Where does the small saphenous vein drain into?
-Popliteal vein within the popliteal fossa
What nerve supplies posterior leg?
-Tibial
What is the arterial supply to the posterior leg?
-Posterior tibial artery-Fibular artery-Popliteal artery
Where does the achilles tendon attach?
-Calcaneous
What are the functions of the posterior leg?
-Plantarflexion-Involved in gait -Propulsion to walk forward-Flexion of the knee-Inversion
Name the intrinsic muscles of the hand
-Interossei (7; 3 palmar 4 dorsal)-Lumbricals (4)-Thenar eminence (3)-Hypothenar eminence (3)-Adductor pollicis (1)-Palmaris brevis (1)
What is the function of the interossei?
-Flex the straight finger (metacarpophalageal joint)-Adduction-Abduction
Which interossei adduct and which abduct?
-PAD and DAB-Palmar adduct-Dorsal abduct
What are the functions of the lumbricals?
-Extension of the interphalangeal joints-Flexion of the metacarpophalangeal joint
What is the consequence of denervation of the lumbricals?
-Ulnar claw (medial two)-Hand of benediction (lateral two)
What three muscles make the thenar eminence?
-Opponens pollicis-Abductor pollicis brevis-Flexor pollicis brevis
What muscles make the hypothenar eminence?
-Abductor digiti minimi-Flexor digiti minimi-Opponens digiti minimi
What nerve damage is associated with atrophy of the thenar eminence
-Median nerve compression ie carpal tunnel
What passes between the two heads of adductor pollicis?
-Radial artery
Where does the blood supply to the hand originate from?
-The radial and ulnar arteries
Describe venous supply to the hand
-A dorsal network of veins drains into the superficial cephalic and basilic veins
What does the median nerve supply in the hand? (motor and sensory)
-Innervates Thenar eminance and lateral two lumbricals-Sensory innervation of lateral 3 and a half digits, the associated palm (except for small area over thenar eminence) and the back of the 3 and half finger tips
What does the radial nerve supply in the hand?
-No motor function-Supplies sensory innervation to dorsal lateral 3 and half fingers (except the fingertips) and the associated dorsum-Also supplies an area over the thenar eminence
What does the ulnar nerve supply in the hand? (motor and sensory)
-Medial 1 and a half fingers and associated palmar and dorsal area-Medial two lumbricals-Interossei-Hypothenar eminence-Adductor pollicis-Palmaris brevis
What does the ulnar nerve travel down the forearm with?
-Ulnar artery
How does the ulnar nerve enter the hand?
-Passes over flexor retinaculum through guyons canal
What is the presentation of ulnar claw?
-Hyperextension of the MCP joints and unopposed flexion of the IP joints of the 4th and 5th digits
What causes ulnar claw?
-Long standing ulnar nerve damage at the wrist causing ulnar claw by paralysis of the medial 2 lumbricals (flex MCP + extend IP)-Hyperextension at MCP occurs because of unopposed extension from extensor digitorum-Flexion at IP due to unnopposed flexion from FDP
What is ulnar paradox?
-Ulnar claw but to a lesser extent as damaged occurs at the elbow -> FDP damaged so less unopposed flexion
What is the presentation of hand of benediction?
-On attempting to form a fist, there is inability to flex the 2nd and 3rd didgit
What causes hand of benediction to occur?
-Long-term median nerve damage at the elbow causes paralysis of the long flexors in anterior forearm (except FCU and med half FDP) and the lateral two lumbricals-This results in loss of flexion at the MCP and IP and the inability to make a complete fist producing a claw like shape (4th and 5th digit still work)
What are the contents of the axilla?
-Brachial Plexus-Axillary artery-Axillary vein-Lymph nodes-Tendons of Biceps Brachii and Coracobrachialis
Where does the axillary artery arise from?
-It is a continuation of the subclavian artery which becomes axillary upon passing beneath the calvicle
What is the main branch of the brachial artery in the arm?
-Profunda Brachii
What artery branches off the axillary artery within the axilla?
-Posterior circumflex
What is the main vein draining the upper limb?
-Axillary vein
What does the axillary vein drain into?
-The subclavian vein
Which two veins mainly make the axillary vein?
-The cephalic and basilic veins
What makes the lateral wall of the axilla?
-Intertubecular sculus/groove
What makes the anterior wall of the axilla?
-Pec major-Pec minor-Subclavius
What makes the medial border of the axilla?
-Upper thoracic ribs and intercostal muscles-Serratus anterior
What makes the posterior border of the axilla?
-Subscapularis-Teres major-Latissimus Dorsi
What makes the apex/inlet of the axilla?
-Between the coracoid process, posterior border of clavicle and the 1st rib
What is the main route of exit out of the axilla?
-Inferiorly
What is axillary clearance?
-Removal of all the lymph nodes in the axilla
Why are the axillary lymph nodes frequent site for metasteses of breast cancer?
-75% of breast lymph drains here
What nerve is possibly damaged during axillary clearance?
-Long thoracic nerve
What is lymphangitis of the upper limb?
-Inflammation of the lymphatic channels of the upper limb
What are the symptoms of lymphangitis?
-Rubor-Calor-Tumor-Dolor
What is thoracic outlet syndrome?
-Muscle weakness, pain and paranthesia resulting from compression of vessels and nerves in the apex/inlet
Where do the nerve roots involved in the brachial plexus emerge from?
-C5 to C7from above the C5-C7vertebre-C8 from below C7-T1 from below T1
What nerve roots make the long thoracic nerve?
-C5, C6, C7
What does the long thoracic nerve supply?
-Serratus anterior
What results from injury to the long thoracic nerve?
-Winged scapula
What nerve roots contribute to the musculocutaneous cord?
-C5, C6, C7
What does the musculocutaneous branch innvervate?
BBC-Biceps brachii-Brachialis-Coracobrachialis
What sensory function does the musculocutaneous nerve have?
-Supplies the lateral skin of the forearm (branches into lateral cutaneous nerve of forearm which supplies forearm)
What nerve roots contribute to the axillary nerve?
-C5 and C6
What sensory function does the axillary nerve have?
-Innervates the lateral skin of the arm (regimental badge area) via superior lateral cutaneous nerve of the arm
What muscles does the axillary nerve innervate?
-Deltoid-Teres minor
How is damage to axillary nerve commonly tested?
-Test regimental badge area for sensation
How is the axillary nerve most commonly injured?
-Fracture of surgical neck of humerus
What nerve roots contribute to the radial nerve?
-C5, C6, C7, C8 and T1
What is the motor function of the radial nerve?
-Innervates all the extensor muscles of the arm and forearm and brachioradialis
What is the sensory function of the radial nerve?
-Innervates most of the skin on the posterior arm and part of posterior forearm-Innervates dorsal lateral 3 and half digits, bar nail beds, and corresponding dorsum of the hand-Innervates an area over thenar eminance
Describe the anatomical course of the radial nerve
-Runs posteriorly to brachial artery down the radial groove to the lateral epicondyle through the cubital fossa. On entering the forearm the radial nerve spilts into superficial and deep branches
How does the radial nerve commonly become damaged in the axilla?
-Dislocation of glenohumeral joint or fractures of proximal humerus
What are the consequences of damaging the radial nerve in the axilla?
-Posterior compartment of arm and forearm paralysed-Patient unale to extend forearm, wrist and fingers-Unopposed flexion occurs ar wrist causing wrist drop-Loss of sensation to lateral and posterior arm, posterior forearm and to lateral 3 nd half digits, bar nail bed, and their associated dorsum
How is the radial nerve commonly injured in the radial groove?
-Fracture of shaft of humerus
What nerve roots contribute to the median nerve?
-C6, C7, C8 and T1
What are the motor functions of the median nerve?
-Innervates the muscles in the anterior forearm (except flexi carpi ulnaris and the medial half of flexi digitorum profundus)-Innervates the thenar eminence (recurrent branch) and the lateral two lumbricals of the hand (palmar digital branch)
What are the sensory functions of the median nerve?
-Palmer lateral 3andhalf digits (except an area over thenar eminiance) and the nailbeds of the lateral 3andhalf digits
What is tinels sign?
-A test for carpal tunnel syndrome where the nerve is tapped within the carpal tunnel to elicit pain
What is phalen’s manoeuvre?
-A test for carpal tunnel syndrome where the wrist is helf in flexion for 60 seconds to elicit numbness/pain in median distribution
What are possible treatments of carpal tunnel syndrome?
-A splint to hold the wrist in dorsiflexion overnight to relieve pain-Corticosteroids injections-Surgical decompression in severe cases
How is the median nerve commonly damaged at the elbow?
-Supracondylar fracture of the humerus
What nerve roots contribute to the ulnar nerve?
-C8 and T1
What is the motor function of the ulnar nerve?
-Innervates FCU, and medial half of FDP-Innervates hypothenar, adductor pollicis, interossei and medial two lumbricals
What is the sensory function of the ulnar nerve?
-Innervates the skin anteriorly and posteriorly of medial 1andhalf digits, and their associated palmar and dorsum areas
What makes the lateral border of the cubital fossa?
-Medial border of brachioradiales
What forms the medial border of the cubital fossa?
-The lateral border of pronator teres
What makes the superior border of the cubital fossa?
-An imaginary line between the two epicondyles
What forms the floor of the cubital fossa?
-Brachialis-Supinator
What forms the roof of the cubital fossa?
-Skin, fascia and bicipital aponeurosis
What are the contents of the cubital fossa?
-Radial nerve (not strictly but within the vicinity)-Tendon of biceps brachii-Brachial artery-Median nerve(Really Need Beer To Be At My Nicest)
What is Volkmann’s ischaemic contracture?
-Uncontrolled flexion of the hand as the flexor muscles become shirt and fibrotic due to ischaemia
What is filum terminale?
-The slender tapering terminal of the spinal cord
What is the conus medullaris?
-The conical end of the spinal cord, at the level of the first lumbar vertebrae
Why, and where, does the spinal cord vary in its thickness?
-Thicker in its cervical and lumbar segments as it has excessive neural tissue for the upper and lower limb, respectively
Why is overlap functionally beneficial?
-Reduces the probability of skin patches without sensory nerve supply when there is damage to a single spinal nerve.
Describe the dermatomes of the anterior upper limb
-C4 - over the tip of the shoulder-C5- Radial third of upper arm to mid forearm-C6- The thumb and the middle forearm and arm-C7-2nd, 3rd and 4th digit and accompanying palm to a V-C8- 5th digit, accompanying palm to just over wrist-T1- Ulnar forearm to mid upperarm-T2- Axilla
Describe the dermatomes of the anterior lower limb
-L1 - groin-L2- superior half of thigh-L3- Inferior half of thigh-L4 - Medial half leg-L5-Lateral half of leg and first three digits of foot with associated dorsum-S1- lateral two digits ans associated dorsum-S2/3 - Penis
