major plexuses and peripheral nerves Flashcards
draw the spinal cord demonstrating the spinal nerve diverging into the anterior and posterior rami, draw the additional divergence of the anterior rami and which constitutes to limb formation
see diagram
draw the brachial plexus
include the radial, axillary, ulnar, median and muculocutaneous nerves
decribe the cervical plexus
it includes CN12, and C1-5, the most notable feature is that the phrenic nerve which innervates the diaphragm arises from this plexuses and diverges from C3,4,5
what are the motor and sensory functions of the axillary
deltoid (shoulder abduction), shoulder chevron
the musculocutaneous nerve
flexes the forarm (biceps), and provides sensation to the lateral forearm
the radial nerve
extension below shoulder (triceps), supination. provides sensation to the posterior forearm
the median nerve is the thenar nerve and innevates which muscles and provides sensation where
LLOAF, and 3.5 of the palmar surface of the hand, and the tips of the three fingers and thumb on the dorsal surface
ulnar nerve
covers 1.5 from the little finger in both palmar and dorsal surfaces of the hand, it is referred to as the hypothenar nerve and innervates all intrinsic hand muscles besides LLOAF and the flexor carpi ulnaris
thumb movements are mediated by
RUM
opposition and abduction, extension and adduction
the lumbar plexus
is from T12 to L5 and is within the psoas major
Interested in getting laid on fridays?
iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, obturator and femoral
the sacral plexus
occurs from L4-S4
includes the sciatic nerve (the hamstring nerve), which has the common peroneal and tibial nerve
the pudendal nerve also arises from this plexus and innervates the urogential area
the femoral nerve
flexes the hip and extends the knee and provides sensation to the anterior thigh and medial shin
the lateral femoral cutaneous
has no motor function yet provides sensation to the anterolateral thigh
the obturator
adducts the thigh and has sensation along the medial thigh
the sciatic nerve
has no sensory input but flexes the knee
the tibial and common peroneal
are opposites of each other
the tibial is posterior (plantar) and the common peroneal is anterior and lateral (dorsum)
the tibial allows plantarflexion, toe flexion, and inversion
the common peroneal allows foot eversion and forsiflexion and toe extension
the brachial plexus is the most prone to damage of all plexuses decribe some common plexopathies
- brachial neuritis - idiopathic condition common in males
- klumpke’s palsy - trauma or traction of arm and shoulder during childbirth or following motor vehicle accident
- apical lung tumour (non small cell) - causing pancoast syndrome, which may produce Horners syndrome and voice hoarseness if invaded the laryngeal nerve
- thoracic outlet syndrome - compression of the brachial plexus by the clavicle and first rib, or by the scalenes, or by subclavian artery occulusion causing ischaemia and neuropathy
- radiation plexitis
decribe the common presentation of mononeuropathies
usually caused by entrapment, they present with pain which later develops into muscle weakness and atrophy
decribe some of the common features of median nerve palsy
presentation will be that of a preachers hand with thenar wasting and atrophy
usual causes are carpal tunnel syndrome
the causes/aetiology:
MEDIAN TRAP - myxodema, odema, diabetes, idiopathic, acromegaly (men), neoplasm, trauma, rheumatoid, amyloidosis, preganancy
treated surgically by ligating the flexor retinaculum
common causes of ulnar nerve palsies
patients present with a claw hand or a benedictian hand
common causes include entrapment caused from a former fracture of elbow, this nerve travels in the cubital tunnel of the elbow and has a tardy presentation of neuropathy
in the wrist - compression in Guyons canal - common in bike riders
radial nerve palsies
present with a wrist drop and wasting of the interossei
the usual causes are a saturday night pasly or from trauma
sensory loss in the anterolateral thigh is caused by
compression of the lateral femoral cutaneous nerve and is known as meralgia parasthetica and common causes include pregnancy and obesity, pregnancy
femoral nerve palsies can be caused by
femoral angiography, haematoma, direct injury or a false aneurysm
a foot drop can be seen in
an L4,5 radiculopathy or can even be caused by direct injury to common peroneal nerve as it is very superficial over fibula head on the lateral aspect of the leg
