Neural Crest Cells : Mnemonic

Hi everyone !
Here's a short mnemonic post !

Neural Crest Cells are very special cells that form at around 2-3 weeks of gestation.
They're right next to the Neural folds of the Neural tube to begin with and then eventually come to lie lateral to the tube, after which they migrate to various parts of the body giving rise to a bunch of things.

It's kind of SUPER IMPORTANT to memories what structures arise out of the Crest cells.
One of the reasons for it is that neural crest cell tumors will express certain neuroendocrine markers and that will make it easier to detect them on histopathology.
The other reason is that it's literally the most favorite embryology question - whether it's  NEET PG or Step1!

So here goes :

Mnemonic - LAMAS BABy

L - Lepto meninges (Pia + Arachnoid)
A - Adrenal Medulla
M - Melanocytes
A - ANS Ganglia
S - Schwann Cells

B - Branchial Arches
A - Aortopulmonary windows + Endocardial Cushions
B - Bronchogenic cells - Pneumocytes
Y - Yo

This will also help you understand why Melanomas , Bronchogenic Carcinoma , Schwannoma, Pheochromocytoma and even Neuroblastoma are all positive for similar markers and have similar appearances at times along with similar histopathological fetaures.

Hope this list covers them all!
Happy Studying!
Stay Awesome!

~ A.P. Burkholderia

Femoral triangle and femoral sheath contents mnemonic

Hello!

The femoral triangle is a subfascial space bounded superiorly by the inguinal ligament, medially by the adductor longus muscle, and laterally by the sartorius muscle.

Contents of the femoral triangle mnemonic:

Introduction to neuroanatomy

This video was made by our Medicowesome Student Guest Author, Salman!!!!

Urinary Bladder and Clinical Correlates

Hello everyone! This write-up attempts to organize the seemingly confusing nerve supply of the bladder and associated pathology aka the neurogenic bladder.

NERVE SUPPLY :

(beta 2 and alpha 1 are adrenergic receptors of SANS ; muscarinic type 3 is a cholinergic receptor of PANS)

• SANS inhibits micturition while PANS facilitates micturition. You don’t want to pee when you’re running a 100m sprint, an SANS-dominant activity but you can comfortably pee at rest, a PANS-dominant activity.

• Sensory fibres of pudendal nerve tell your CNS when the bladder is full. The motor fibres of pudendal nerve maintain EUS tonic contraction by default so that you’re not always peeing.

• The reflex arc, after higher centre commands, causes voluntary micturition by inhibiting the “contraction-effect” of motor fibres of pudendal nerve.

•  To oversimplify matter (so that it’s easy to understand and remember): Level 2 control inhibits reflex arc. Level 3 control facilitates reflex arc, causing micturition at will, once the bladder is full.

CLINICAL CORRELATES:

• CORTICAL BLADDER

-- Aka Incomplete Spastic OR Uninhibited bladder.

LESION	CLINICAL  FEATURE
Postcentral cortex	--  Loss of awareness of bladder fullness          --  Incontinence
Precentral cortex	--  Hesitancy = Difficulty in initiating micturition
Frontal cortex	--  Precipitancy = micturition with ‘easy’ stimulus, eg: sound of running water          -- Inappropriate micturition/ loss of social inhibition (infant-like)

Associated with:

Multiple Sclerosis

Parkinson’s disease

Stroke, among others.

• HYPERTONIC/ AUTOMATIC  BLADDER

-- UMNL/ Complete spastic type of bladder.

LESION	CLINICAL  FEATURE
Spinal cord ABOVE S2, S3 and S4.	--  Urge incontinence = patient passes low-volume urine frequently         --  Less post-voidal urine volume, so less risk of UTIs         --   More intra-vesical pressure, more risk reflux nephropathy

• HYPOTONIC/ AUTONOMOUS BLADDER

-- LMNL/ Flaccid type of bladder.

LESION	CLINICAL FEATURE
--  Spinal cord AT S2, S3, S4         --  Cauda equina/ Conus medullaris         --   Peripheral nerves	--  Overflow incontinence =  urine retention, overtime, forces IUS to mechanically open causing dribbling micturition         --  More post-voidal urine volume, more risk UTIs

2 subtypes are:

• Motor Paralytic bladder – Motor (efferent) pathway is damaged. However, patient can sense bladder fullness, resulting in prompt diagnosis. Associated with:

--  Complication of abdominal/ pelvic surgery

--  Lumbar canal stenosis

--  Lumbo-sacral meningo-myelocele

• Sensory Paralytic bladder – Sensory (afferent) pathway is damaged and hence, patient canNOT sense bladder fullness, resulting in delayed diagnosis. Associated with:

--  Diabetes mellitus

--  Syringomyelia

--  Tabes dorsalis

Medicine pearl: When we talk about bladder pathology, we only refer to PANS (lesions above/ at/ below it) as SANS lesions doNOT cause bladder pathology per se. However, bilateral lesion to L1 causes retrograde ejaculation and hence, infertility.

Topics for further reading:

--  Age-related urine continence

--  Nocturnal enuresis

--  Barrington reflexes

Hope this helps! Let me know if anything needs clarification. Happy studying!

-- Ashish Singh.

Maxillary Artery notes

Hello Friends! This is Anisha :))

Maxillary artery is divided into three branches. Again, each branch is subdivided. 

We also have to learn their course which is very confusing and we forget it during our exam :( 

So, I came up with an easy way to learn it. I decided that I will show the course of the artery in form of a diagram ( you will get more marks! ) and write down what it supplies. 

I hope my notes will help you :)) All the best

Mnemonic for the Ascending tracts & Descending tracts in Spinal Cord

Hiiiii everyone, it’s mnemonic time again! From the title, I guess you all know what it is about… I had a hard time memorizing these tracts so I created this mnemonic to help you guys out!

he drove a honda CRV TO disneyland.

Corticospinal tract (Lateral & Anterior)

Rubrospinal tract
Vestibulospinal tract
Tectospinal tract
Olivospinal tract

**Disneyland = Descending. Hence, this mnemonic is for the descending tract
**Since it’s a descending pathway, so all the fibers will travel to spinal cord from their origins. Therefore, just add “spinal” after each word (e.g. …spinal tract)
**Don’t forget that there’s lateral and anterior for Corticospinal tract. Honda CRV from Los Angeles maybe? Hahahah :3

That Los Angeles STudent went up to stage and SCream using the PA system because he got a Freaking Cool First Grade result.

ST – SpinoThalamic tract (Lateral & Anterior)
SC – SpinoCerebellar tract (Posterior & Anterior)
FC – Fasciculus Cuneatus
FG – Fasciculus Gracilus

**Went up = Ascending. Hence, this mnemonic is for the ascending tract
**Los Angeles for STudent ; PA for SCream
**In addition, if you follow the order of FC and FG, it actually matches with the position of them from left to right in the spinal cord and mirror reflect them. (FC àFG à FG à FC)

Please comment if you have a better mnemonic! Let’s share our mnemonics ^.^

-Calvin Ong K. Y.

Arterial Supply of the Head & Neck in a Nutshell!

Helloooo everyone!!

Here’s some mnemonic I created myself for the branches of external carotid artery and the branches of facial artery. To memorize the name of the branches of external carotid artery, you just need to....

Flap Valve Mechanism of Inguinal Canal

Hello Everyone!

     Today lets understand the Flap Valve mechanism of Inguinal Canal:

That's all,

Thank you!

Chaitanya Inge

Joll's triangle in thyroidectomy

Hello friends,

This post is about the importance of Joll's triangle in thyroidectomy.

Joll's triangle is used to identify external laryngeal nerve during thyroidectomy.

Boundaries of this triangle are :
Laterally: Upper pole of thyroid gland and superior thyroid vessels.
Superiorly: Attachment of strap muscles and deep investing layer of fascia to hyoid.
Medially: Midline of neck.
Floor: Cricothyroid muscle.

This triangle contains superior laryngeal nerve which gives rise to external laryngeal nerve.

Given below is the diagram of this triangle:

Image Based MCQ on Fracture

Hello awesomites!
Yesterday we posted an Image based MCQ on Fracture of forearm bones and here's the answer for it.
Q. The X-ray of forearm in AP and Lateral views as shown in the image is diagnostic of

A. Galeazzi fracture-dislocation
B. Barton fracture
C. Monteggia fracture-dislocation
D. Colles fracture

Ans: c) Monteggia fracture-dislocation

Monteggia fracture-dislocations is defined as fracture of the ulnar shaft along with concomitant dislocation of the radial head.

Mechanism: Monteggia fracture-dislocations occur as the result of a fall onto an outstretched hand (FOOSH).

Classification: The Bado classification is used to subdivide the Fracture dislocation into four types.

Type I: anterior dislocation of radial head (Most common)
Type II: posterior dislocation of radial head
Type III: lateral dislocation of radial head
Type IV: anterior radial head dislocation as well as proximal third ulnar and radial shaft fractures

That's all!
Thanks for your active participation.

MD Mobarak Hussain (Maahii)

Question on larynx

So here is answer of our previous questions.
#Anatomy
Sensory supply of larynx, below the vocal cord-
A) Superior laryngeal nerve
B) Inferior laryngeal nerve
C) Recurrent laryngeal nerve
D)Internal laryngeal nerve

Ans is "C" Recurrent laryngeal nerve.


Things must be know.
All intrinsic muscles of larynx are supplied by recurrent laryngeal nerve except cricothyroid. Cricothyroid is supplied by external laryngeal nerve. 

By ojas gite

Injury to spinal accessory nerve

Hello friends,

This post is about damage to spinal accessory nerve.

We know that this nerve in the neck first supplies sternocleidomastoid,then lies on levator scapulae to supply trapezius.

On excision biopsy for matted cervical lymph nodes,we may damage that part of nerve which is lying on levator scapulae.So, this may lead to paralysis of trapezius.

To find this:

Ask the patient to shruggle his shoulder,

To do overhead abduction of arm, and

See for winging of scapula at rest.

On paralysis, there will be difficulty in shruggling his shoulders , difficulty in overhead abduction of arm and winging of scapula at rest.

Winging of scapula is also seen in paralysis of serratus anterior but prominent on movement like pushing the wall, whereas in paralysis of trapezius, it's seen at rest.

Thanks for reading!

Madhuri Reddy (Madhu)

Branches of subclavian artery mnemonic

Hello friends,

Today let's memorise the branches of subclavian artery.

The mnemonic is  VITamin 'C ' and 'D'

Here VIT corresponds to branches arising from first part. 

'C' from second part. 

'D' from third part  of subclavian artery.

So from first part:

V - Vertebral

 I - Internal thoracic artery

T - Thyrocervical trunk or Thyroscapulocervical trunk( this makes our task easy to memorize branches of this trunk)

Thyroscapulocervical - Gives  rise to 3 arteries:

Thyro -- Inferior thyroid artery

Scapulo -- suprascapular artery

Cervical - superficial cervical artery.

From second part:

C - Costocervical trunk which gives rise to superior intercostal artery and deep cervical artery.

From third part:

D - Dorsal scapular artery.

Sometimes, instead of superficial cervical and dorsal scapular arteries arising as 2 separate arteries, there is a single branch which arises from 1 st part of subclavian artery that is Transverse cervical artery.

This artery divides into superficial ascending branch and deep descending branch as shown in the flow chart below.

Thanks for reading and do correct me if there is anything wrong.

Madhuri Reddy (Madhu)

Fact of the Day : Pantaloon Hernia

So this is just a very interesting fun fact.

When a person has a Direct Inguinal Hernia along with an Indirect Inguinal hernia , the person is said to have a Dual / Pantaloon/ Romberg / Saddle bag hernia.

Tried a lot to find out why the name is 'Pantaloon'. Pantaloon = Saggy pants or a Foolish old man. So take your pick !

That's all!
Happy studying!
Stay Awesome.
~ A.P.Burkholderia

Torn meniscus and inability to extend the knee

Doubt: Why does torn meniscus present with inability to extend the knee? I don't understand the anatomy correlation.

If there is complete tear, the meniscus (a piece of it) gets dislodged. It gets stuck in the knee joint.

This causes:
Inability to extend the knee.
Pain on extension of the knee.

Why is it called "bucket handle"?

A bucket handle meniscus tear represents a complete tear of the mensicus support or the ligament that holds the meniscus in place. This allows the meniscus to flop over like the handle on a bucket.  When the meniscus flips over it becomes stuck in the middle of the knee joint, you lose the ability to fully straighten the knee then you have a “locked knee”.

Explained by Dr. Mustufa Poonawala

The meaning of valgus (with doubt + mnemonic)

Meaning of valgus: A deformity involving oblique displacement of part of a limb away from the midline.

Doubt: Why is genu valgum knock knees? The knees (genu) are displaced towards the midline!

Answer: It's not the knees we consider during the deformity... It's the relationship of distal part with the proximal part at a joint.

Mnemonic: L in vaLgum is for Lateral displacement.

(Conversely, varuM is medial displacement.)

That's all!
Hate the inaccurate naming.
-IkaN

CerebelloPontine Angle Syndrome

13th and 14th Cranial Nerves.

13th and 14th cranial nerves

Hilton's law

Hilton's law.

The nerve which supplies a muscle of a joint, will also supply the joint and the overlying skin.
Conversely, any nerve that is innervating a joint will also supply the muscles of the joint and the overlying skin.

In humans, we find only 2 exceptions to this general rule:

1) Buccal branch of Mandibular nerve as we all know, pierces the Buccinator muscle. But it doesn't supply the muscle. The innervation of Buccinator is by the Buccal branch of Facial nerve.
2) Sciatic nerve in the Gluteal region....is very closely related to the Pyriformis muscle.... And may occasionally send a fibre that pierces the muscle. But it doesn't supply it. Pyriformis is supplied directly by the sacral plexus(the nerve to pyriformis).

Mithil Jagannath.
Medicowesome 2017.

CMS neurology form 2: Question on numbness, tingling and decreased grip strength

Disclaimer: This is an CMS neurology form 2 question for step 2 CK. If you are planning to take USMLE step 2 CK in the future, I would recommend that you DO NOT read this post because it will bias your assessments.