Hello #medstudenttwitter, I was alerted to tweets expressing concern about spinal cord anatomy on step 1, so here’s a new #EndNeurophobia #tweetorial on

THE SPINAL CORD

#meded #Neurology
cc @MedTweetorials @DxRxEdu @CPSolvers @Tracey1milligan

But first, a moment of silence for
#GeorgeFloyd
#AhmaudArbery
#BreonnaTaylor
and other lives lost to racism, structural violence, police brutality .
.

.

.

.

.

.

Grateful for all the #EndNeurophobia has received but hope you check out the rest of my feed, which seeks to amplify voices I’m learning from in the path to being an antiracist ally. Want to learn more?

Follow some folks I follow
check out @thepraxispod
read #BlackInTheIvory

This tweetorial inspired by a tweet showing a complex overwhelming set of tracts in the spinal cord for step 1 review

Good news, you really just need to know 3 tracts for clinical neurology (and most step 1 ?s)!

1. Corticospinal tracts (CSTs): upper motor neurons descending form brain

2. Dorsal columns (DCs): carry vibration/proprioception from periphery to brain

3. Spinothalamic (anterolateral) tracts (STTs): carry pain/temperature from periphery to brain

CSTs (motor): posterior/lateral

DCs (vib/prop): posterior

STTs (pain/temp): anterior/lateral

CSTs: crossed on way down, so motor deficits are
IPSILATERAL below level of lesion

DCs: cross in lower medullay, so vib/proprio deficits are IPSILATERAL below level of lesion

STTs: *cross immediately* in spinal cord so pain/temp deficits *CONTRALATERAL* below level of lesion

** NOTE **
*STTs (pain/temp) are the exception, deficits = CONTRALATERAL*

CSTs (motor) /DCs (vib/prop) deficits = ipsilateral

Other important anatomic point=lamination

CSTs and STTs–upper extremities medial/lower extremities lateral

DCs–uppers lateral (fasciculus cuneatus)/lowers medial (fasciculus gracilis)

See mnemonic=2 bodies feet to feet on top, 4 diving hands first into spinal canal on sides

If you understand

- functions of these 3 tracts
- where they cross (STTs in cord, others in lower medulla)
- lamination (DCs feet to feet medial; CSTs/STTs hands medial)

then you can understand the 4 common spinal cord syndromes!

BROWN SEQUARD=half of cord:
*contralateral* pain/temperature
ipsilateral weakness and vib/prop loss
cause=usually penetrating trauma

ANTERIOR CORD=CSTs and STTs only=bilateral weakness/pain/temp
Dorsal columns (vib/prop) spared
cause=ant spinal artery infarct usually 2/2 AAA

SYRINX/Central cord syndrome
Affects crossing fibers of STTs at cervical level=upper extremity fibers so loss of pain/temperature in hands with sparing motor/vib/prop

Subacute combined degeneration: DCs & SCTs= vib/prop/weakness with spared pain/temperature
Cause=B12 deficiency

Now that we have localization, just add time course = DDx:

HYPERACUTE (minutes to hours) myelopathy:

Trauma

Structural disease of the spine: acute central disc prolapse acute vertebral collapse

Vascular: stroke, epidural hemorrhage, or spinal cord hemorrhage (hematomyelia)

ACUTE TO SUBACUTE-onset (hours to days) myelopathy

Infxn: viral myelitis, epidural abscess, schistosomiasis

Inflamm: transverse myelitis, flare of multiple sclerosis, flare of neuromyelitis optica, lupus, Sjögren’s syndrome, sarcoidosis

SUBACUTE to CHRONIC-onset (days to months) myelopathy

Structural disease =cervical spondylosis

Tumor: primary or metastatic

Infections: tuberculosis of the spine

Vascular causes: spinal dural arteriovenous
fistula

Metabolic causes: vitamin B12 deficiency or copper deficiency

CHRONIC-onset (months to years) myelopathy:

Infections: human T-cell lymphocytic virus 1 (HTLV-1) and AIDS vacuolar myelopathy

Neurodegenerative myelopathies: hereditary spastic para- plegia, spinocerebellar ataxia, adre- nomyeloneuropathy

Radiation-induced myelopathy

Hope that helps! #EndNeurophobia

Want to see this all animated!? Login into your school library's subscription to AccessMedicine and go to Ch 5, videos https://accessmedicine.mhmedical.com/MultimediaPlayer.aspx?MultimediaID=17882409