Overview of the upper limb Flashcards
can you live without a shoulder or elbow
shoulder not that important
the shoulder forms…
• Shoulder forms foundation from which the upper limb can move
describe the movements that the shoulder allows
- the large range of movement in the shoulder allows the hand to be positioned in a wide area
- they anchor the arm to the trunk
- forms a mobile pectoral girdle this allows a wider range of movement that is possible for the limb
- clavicle and scapula can move to get extra movement
what do we depend on the elbow for
washing, dressing, eating and drinking
is the elbow very stable yes or no
- Very stable joint
what is the hand used for
- Holds objects (dexterity and grasp)
- Touches objects (sense organ)
- Communication
where do the muscles that move the fingers originate In
- Partially in the hand – intrinsic – used for fine movement
- Partially in forearm -extrinsic – for power
what are the two types of grip
power grip and precisions grips
what grips make up power grips
• Cylindrical grip, spherical grip, hook grip, lateral prehension
describe the position of the power grip
• All fingers flex around object, thumb curled round to press against acts as safety bar to hold those fingers closed, or meet fingers
- can allow you to hold an object in the palm of the hand
what do the hypothenar muscles do in the power grip
• Hypothenar muscles stabilise medial side of palm against handle.
what do the wrist extensors do in the power grip
• Wrist extensors active - provide stable base - this gives the tendons a good working range
which grip is more primitive, the power grip or precision grip
• the power grip is Most primitive (present in new born babies
- precision grips take longer to be able to perform as they are more complicated as they require a combination of movements - it develops at around 9 months
what power grip is the thumb not involved in
• Thumb isn’t aways involved when you are carrying the handle of a bag this is called a hook grip
describe the precision grip
- Object held between tip of thumb and 1,2, or 3 fingers
what re the muscles that are involved in the precision grip
- Intrinsic muscles involved, co-operate with long flexors and extensor muscles
- Flexions and extension – combination of movements, therefore it takes time to develop and be able to perform these types of movements
what grip is non prehensile
Hook grip is non prehensile whereas every other movement is prehensile
the radial nerve is the ..
- This is the biggest terminal branch of the brachia’s plexus
what does the radial nerve innervate
- It innervates all the extensor muscles of the upper limb
- It also innervates anything in the posterior compartment
where does the radial nerve run
- Runs between the medial and lateral head of triceps, it runs between the insertion points next to the humerus this is the spiral group – this is also the radial group
- It then goes into the anterior part of the elbow and back into the posterior part of the forearm
what is another word for spiral group
radial group
what is the most common cause of radial nerve damage
- Most common region where the radial nerve gets injured is a midshaft humerus fracture – goes along the point where the radial nerve goes along the bone
what is a clinical presentation of radial nerve damage
wrist drop
what is cause of wrist drop
- compression or damage to the radial nerve
• No extension of wrist and digits - unopposed action of FDS and FDP
• Only weak flexion at DIP joint from intrinsic muscles of hand
• Sometimes they can extend the elbow, depends on where the radial nerve comes up the triceps – may not completely lose extension of the elbow - not able to form a power grip as this needs an extended grip
what is the cause of Saturday nigh palsy
- Radial nerve in armpit or upper arm is compressed or stretched
- Usually as a result of falling asleep with arm hanging\
- This can give you wrist drop
is Saturday nigh palsy permanent or not
• This is not permenanet and will once the compression has eased and the blood supply is better it will regrow and sensory innervtion will come back
what is the cause of radial nerve palsy in newborns
- Secondary to prolonged pressure on inferior arm by pelvic brim
- Wrist drop
- Inability to extend thumb and MCP of all digits
- Weak extension of the elbow
when is radial nerve palsy in newborns reversed
- After about 2 weeks to 2 months they gain back innervation again
what does the median nerve innervate
- Innervates the antieror plexus and goes to the thenar muscles at the base of the thumb
where does the median nerve run
- This is in the anterior compartment
- Doesn’t do anything in the arm
- Runs with brachial artery
- Goes into the forearm
where can you injure the median nerve
- Can injure it at the elbow where it becomes superficial – supercondyle fracture to the humerus, humerus and proximal region has moved into the humerus – stretch or lacterate the medial nerve high
- Everything distal to that point is lost
what happens if you have high median nerve damage
- Loss of flexion of MCP digits 2-3
- Loss of flexion of PIP in digits 1-3
- Loss of DIP flexion digits 2-3
- Weak PIP flexion of digits 4-5
- Can flex DIP of digits 4-5
- Because ulnar nerve innervates medial FDP and FCU – can still flex fingers 4 and 5 – little finger and ring finger
what is the hand caused when it has damage to the median nerve
hand of benediction
how can you test for damage to the median nerve
- ask the patient to make a fist
- then you can see which area of the hand is being effected
- then you get the hand of benedicition – thumb index finger and middle finger do not move
what causes low median nerve damage
carpal tunnel syndrome
how symptoms are caused with low median nerve damage
- progressive loss of co-ordination and strength in thumb
- causes compression to the median nerve all the long flexor muscles can still work,
- can make a thirst but the thumb doesn’t work very much, loose ability to oppose the thumb
what is the most common site of nerve lesions to the upper limb
– medial epicondyle of humerus therefore it effects the ulnar nerve
what does damage to the ulnar nerve cause
claw hand
what muscles are effected in the ulnar nerve damage
– flexor carpi ulnaris, – medial half of FDP, – medial two lumbricals, – all interossei (palmar and dorsal) – adductor pollicis
what does the ulnar nerve innervate in the hand
– all the instrinsic muscles of the hand except the thenar muscles innervated by the ulnar nerve
what is more severe in an ulnar nerve injury a high lesion or low lesion
low lesion
describe what happens with a high lesion in an ulnar nerve injury
both intrinsic hand and FDP weak so clawing milder
describe what happens with a low lesion in an ulnar nerve injury
only intrinsic muscles weak means clawing is more severe
what happens in cubital tunnel syndrome
- Cubital tunnel syndrome – high all muscle lost
what happens in guyot’s anal syndrome
- Guyon’s anal syndrome – low – FDP pulls digit 4 and 5 in flexion
what are the presentations of ulnar nerve lesions
- Muscle atrophy of the intrsic muscles of hand
- Most obvious in 1st dorsal interosseus web, thenar not effected
- Even in long term the thenar muscle is still there
- Loose intrinsic muscles for precisois grip
- Muscle atrophy of FCU and medial FDP
how do you test motor control of the hand
- Test extension and the power of exntesion in the wrist
- Median nerver – making a this and what the thumb does – opposition and flexion of the thumb
- Ulnar – abduction and adduction – ask them to hold a piece of paper between two fingers or ask them to spread fingers apparat and resist you pushing them in
