#tables #OSCE
see: [Dunn - nerve injuries](x-devonthink-item://E3002D7E-66F6-451C-A354-CE31B962FB84)
See also: [[peripheral nerve disorders]], [[Dermatomes]]
## Neurovascular structures and injury risks table
| structure | exam | causes |
| ---------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| radial artery | pulse compared with other side | |
| brachial artery | hand perfusion, cap refill<br>- beware spasm or intimal shear in [[Supracondylar humerus fractures]] | - [[Supracondylar humerus fractures\|supracondylar fracture]]<br>- [[Elbow dislocation]] (8% of cases) |
| radial nerve | *sensation* - dorsum of hand 1st web space<br>*motor* - dorsiflex wrist, extend fingers | - displaced humeral shaft injury. <br>- [[Monteggia fracture-dislocation]] |
| median nerve | *sensation* - 1st and second distal finger radial side, thenar eminence<br>*motor* - opposition, flexion interphalangeal thumb | - supracondylar fracture<br>- elbow dislocation<br>- [[Smith fracture]] |
| anterior interosseous nerve | cannot make OK sign<br>- branch of median nerve<br>- ==no sensory component== | [[Supracondylar humerus fractures]] (may only have AIN injury and ∴ no sensory loss, just this motor finding |
| ulnar nerve | *sensation* - 4th and 5th distal finger ulnar side, hypothenar eminence<br>*motor* - ABduction, ADDuction fingers<br>medial 2 lumbricals | - elbow dislocation<br>- supracondylar fracture<br>- [[paediatric elbow#lateral condyle fracture\|lateral condyle fracture]]<br>- [[Galeazzi fracture dislocation]] |
| posterior interosseous nerve | - branch of radial nerve<br>- finger extension | [[Monteggia fracture-dislocation]] |
| popliteal artery | Weak distal pulses, pallor, pain | - [[knee dislocation]]<br>- complex [[tibial plateau fracture]]<br>- supracondylar femoral fracture |
| common peroneal nerve | foot drop, reduced sensation of 1st web space and great toe (deep peroneal), paraesthesia to dorsum of feet | - proximal fibula fractures<br>- [[knee dislocation]]<br>- [[tibial plateau fracture]] |
| deep peroneal nerve | - sensation in first web space and extension of first toe<br><br>- dorsal foot pain radiation to 1st webspace<br>- positive tinel's sign (tapping nerve elicits pins and needles) | - [[Lis Franc injury]] |
| Tibial nerve | weakness of posterior compartment of leg muscles, weakness of intrinsic foot muscles on plantar flexion. paresthesia of skin to sole of feet | - [[knee dislocation]]<br>- distal femoral shaft fracture if comminuted / angulated |
| femoral artery | | - [[Femur fractures#Femoral shaft fractures\|femoral shaft fracture]] if penetrating or compound fracture |
| Sciatic nerve | - loss of knee flexion<br>- foot drop<br>- anaesthesia below knee<br>- sparking of medial side of leg and foot | [[Hip dislocation]] |
| infraorbital nerve | - branch of maxillary nerve (CN V2) | associated with [[eye trauma#orbital blowout fracture\|orbital blowout fracture]] |
## Anatomy
### Upper limb
![[Pasted image 20240515174653.png]]
![[Pasted image 20250622120428.png]]
![[Pasted image 20250622120455.png]]
![[Pasted image 20250622120519.png]]
![[Pasted image 20250622120654.png]]
> [!caption] Neuro innervation of the arm and wrist. **A**) Radial , **B)** Median, **C)** Ulnar. see [[#quick upper limb peripheral nerve exam]]
### Lower limb
![[Pasted image 20240820144207.png]]
![[Pasted image 20240820144300.png]]
## quick upper limb peripheral nerve exam
*radial nerve*
motor - thumbs up, wrist extension
sensory - sensation 1st dorsal web space
*median nerve*
motor - OK sign (anterior interosseus n), palmar abduction of thumb (thenar muscle)
sensory - sensation in tips of 2nd and 3rd fingers
*ulnar nerve*
motor - fingers crossed sign, abduct fingers against resistance
sensory - sensation in 5th finger
**More comprehensive:**
Radial nerve (C5-8)
- wrist extension, weak elbow extension (if high lesion), snuffbox sensation
- crutches --> wrist splint
Median nerve (C6-T1)
- Pen touch (abductor pollicis brevis)
- OK sign (AION branch)
- sensory loss to lateral palmar 3.5 fingers (incl. thumb)
Ulnar nerve (C8-T1)
- reduced finger abduction, Froment's sign (adductor policis)
- sensory loss to medial 1.5 fingers (palmar & dorsal)
axillary nerve (C5-6)
- deltoid - reduced shoulder abduction after 15 degrees (supraspinatus initiates shoulder abduction)
- regimental badge area
musculocutaneous nerve (C5-6)
- reduced flexion of the arm at the elbow, reduced supination
- sensory loss to lateral surface of forearm
## Lower limb peripheral nerve exam
Femoral nerve (L2-4)
- weak hip flexion & knee extension, absent knee jerk
- sensation medial aspect of thigh + medial lower leg (saphenous)
obturator nerve (L2-4)
- weak hip adduction, loss of sensation to medial thigh
lateral cutaneous nerve of thigh
- loss of sensation of lateral thigh
- inguinal ligament entrapment, upper thigh dysesthesia / numbness
Sciatic nerve (L4-S2)
- foot drop (unable to dorsiflex), weak knee flexion, absent ankle & plantar jerk
- loss of sensation below knee (except saphenous on medial side)
- buttock injury, hip dislocation --> physio
Common peroneal nerve (L4-S1)
- foot drop, loss of eversion
- loss of sensation to dorsum of foot + lateral shin
- Able to invert foot
- proximal fibula injury --> ankle splint
Deep peroneal nerve
- weakness of toe extension
- First dorsal webspace numbness
Tibial nerve (L4-S3)
- weakness of ankle plantarflexion, flexion of toes, inversion of foot
- sensory loss to whole sole of foot (3 branches)
saphenous nerve
- loss of sensation to medial calf + arch of foot