Differentiating C8 radiculopathy from ulnar neuropathy

Hello. This is a very short post (because I am super busy studying)

It's on differentiating C8 radiculopathy from Ulnar neuropathy based on a question I solved the other day. How would you differentiate the two in clinical practice?

C8 radiculopathy:
- Thumb abduction weakness: abductor pollicis brevis (C8, T1)

- Triceps affected (C6, C7, C8)

- Radiculopathies are often painful.

Ulnar neuropathy:
- Hand intrinsics (C8, T1) affected:
Palmar and dorsal interossei
Lumbricals III & IV
Abductor/opponens/flexor digiti minimi

- Basically, all hand intrinsics except for the median-supplied "LOAF" muscles (lumbricals I & II, opponens/ abductor/flexor pollicis brevis)

- Triceps not affected.

- Focal neuropathies aren't painful.

Conclusion: The ulnar nerve innervates all intrinsic hand muscles, except the abductor and flexor pollicis brevis, opponens pollicis, and lateral two lumbricals, which are innervated by C8 and T1 via the median nerve which helps differentiating the ulnar neuropathy from C8 radiculopathy.

That's all!
-IkaN

Differentiating peroneal neuropathy, sciatic nerve injury and L5 radiculopathy

This post is on differentiating weak dorsiflexion of foot - I made a little algorithm on it. (I'll add images later)

If there's weakness in foot dorsiflexion, check plantar flexion and inversion.

If plantar flexion and inversion is normal: Peroneal neuropathy.

If plantar flexion and inversion is weak: Check hip movements.

If weakness at hip joint: S5 radiculopathy.

If no weakness at hip joint: Sciatic nerve compression.

You can differentiate based on sensory levels and reflexes too but this is easier.

Conclusion:
Peroneal nerve supplies the dorsiflexors and evertors of the foot. There will be no weakness in plantar flexion and inversion in peroneal nerve injury.

Hip abduction is an action of Gluteus medius and minimus muscles. These are Superior gluteal nerve innervated muscles. This nerve arises from L4, L5 and S1 roots . If there is hip abduction deficit with foot drop, it means pathology at the radicular ( root) level. 

Here's the reading material.

Common peroneal neuropathy presentation:
- Acute foot drop (difficulty dorsiflexing the foot against resistance or gravity).
- Patients describe the foot as limp; there is a tendency to trip over it unless they compensate by flexing the hip higher when walking, producing what is called a "steppage" gait.
- Patients may also complain of paresthesias and/or sensory loss over the dorsum of the foot and lateral shin.
- Examination typically reveals weakness in foot dorsiflexion and foot eversion (deep and superficial peroneal nerve-innervated, respectively), with normal inversion and plantar flexion (posterior tibial nerve).
- Sensory disturbance is confined to the dorsum of the foot, including the web space between digits 1 and 2 and the lateral shin.
- Reflexes are normal.

Sciatic nerve injury presentation:
- Weakness affecting most of the lower leg musculature, including the hamstrings.
- Hip flexion, extension, abduction and adduction, and knee extension are normal.
- Sensory loss involves the entire peroneal, tibial, and sural territories.
- In the lower leg, however, the medial calf and arch of the foot may be spared secondary to innervation by the preserved saphenous nerve (a branch of the femoral nerve). Sensation is also spared above the knee both anteriorly and posteriorly.
- The knee jerk is normal, but the ankle jerk is unobtainable.

L5 radiculopathy presentation:
- Back pain that radiates down the lateral aspect of the leg into the foot.
- On examination, strength can be reduced in foot dorsiflexion, toe extension, foot inversion, and foot eversion.
- Mild weakness in leg abduction may also be evident in severe cases due to involvement of gluteus minimus and medius. Atrophy may be subtle; it is most readily observed in extensor digitorum brevis.
- Sensory loss is confined to the lateral shin and dorsum of the foot.
- Reflexes are generally normal.

That's all!
-IkaN

Ano-Rectal anatomy: Above and below pectinate line

Here's an illustration I made :)

It shows the embryology, pathology, innervation, blood supply, venous drainage and lymphatic drainage on the rectum above and below pectinate line.

Tetrology of Fallot Causes : Mnemonic and discussion

Hello everyone !

Tetrology of Fallot refers to the tetrad of features occuring in the heart -

1. Ventricular septal defect
2. Pulmonary stenosis
3. Right Ventricular Hypertrophy
4. Overriding aorta.

Now. The factors associated with this disease include a decent bit of things.  And while I was revising I remembered I didn't remember them at all. :) :) :) :) :)

-_-

So here's a mnemonic.
CATCH NATE

CATCH = CATCH 22 Syndrome
(DiGeorge Syndrome is represented by CATCH 22 popularly).

N - NOTCH 1 Gene mutations.
A - Alagille syndrome - Associated with a very peculiar set of features - Bile duct hypoplasia. So random .
T - Trisomies 13,18,21
E - Et cetera = Maternal Diabetes , Maternal progesterone , Drugs like Retinoic acid.

Hope this helped !
Stay awesome!
~ A.P.Burkholderia

Cauda equina syndrome

Hello!

What is cauda equina syndrome (CES)?
The cauda equina syndrome is caused by an intraspinal lesion caudal to the conus that injures two or more of the 18 nerve roots constituting the cauda equina within the lumbar spinal canal.

Cauda equina syndrome causes

Motor nuclei in the brainstem : An overview

Hi everyone. Just thought of doing an overview of the various motor nuclei of cranial nerves in the brain stem.

So we can classify the motor nuclei into 3 groups -

1. Somatic motor efferent - 4
2. Branchial motor efferent - 4
3. Visceral motor efferent - 4

Now how are these classified ?

1. Somatic Motor Efferent

- In the embryological stage , there are certain precursors to muscle and skin segment groups called 'Somites'. These are processes of the paraxial mesoderm.
- Sach somite gives rise to a particular set of muscles called its myotome. 

- There 4 such important somite groups -->

A. Pre otic somites = 3.
So this is simple.
There are 3 pre otic somites giving rise to distinct groups of extraocular muscles supplied by their own cranial nerve.

Somite 1  =
Muscles -
All Extra ocular muscles except Lateral Rectus and Superior oblique.
Nerve -
Oculomotor nerve (III)
Nucleus -
Oculomotor nucleus in the Upper Midbrain.

Somite 2  =
Muscles -
Superior oblique.
Nerve -
Trochlear nerve (IV)
Nucleus -
Trochlear motor nucleus in the Lower Midbrain.

Somite 3  =
Muscles -
Lateral Rectus.
Nerve -
Abducent nerve (VI)
Nucleus -
Abducent motor nucleus in the Pons.

(I'm sure you remember the popular mnemonic - LR6 SO4)

B. Occipital somites

Muscles -
All muscles of the tongue except Palatoglossus
Nerve -
Hypoglossal I'm nerve (XII)
Nucleus -
Hypoglossal nucleus in the Medulla.

Since these nuclei represent the motor innervation to the derivatives of Somites , they're called Somatic Motor or General Somatic Efferent (GSE) Fibres. 

2. Branchial Motor Efferent - 

- In the embryological stage , there are various branchial or Pharyngeal arches that give rise to muscles , bones and cartilage supplied by a particular nerve of that arch.

- Each nucleus that supplies the muscles from such a Branchial arch is called Branchiomotor Efferent or Special Visceral Efferent. (SVE) 

- There are 4 such important arches - 

A. 1st Pharyngeal arch (mandibular arch)

Muscles -
All muscles of mastication + TT (Tensor tympani + Tensor veli Palatini) + Digastric anterior belly. ( And Meckel cartilage)
Nerve -
Mandibular branch of Trigeminal
Nucleus - 

Trigeminal motor nucleus in Pons 

B. 2nd Pharyngeal arch (hyoid arch) 

Muscles -
All muscles of facial expressions + Stapedius + Digastric posterior belly.  ( And Reichter cartilage)
Nerve -
Facial nerve (VII)
Nucleus - 

Facial motor nucleus in Pons 

C. 3rd Pharyngeal arch

Muscles -
Stylopharyngeus

(And the hyoid bone funnily.)
Nerve -
Glossopharyngeal nerve (IX)
Nucleus - 

Nucleus Ambiguus in Medulla

D. 4th and 6th Pharyngeal arches

Muscles -
- All muscles of  Soft palate ( except Tensor veli which is up in the 1st arch) by the 4th. + cricothyroid muscle of Larynx. 

- All muscles of Larynx by the 6th except cricothyroid which is by the 4th. 

(All laryngeal cartilage as well)
Nerve -
4th arch - Superior laryngeal nerve of the Vagus.(X)

6th arch - Recurrent laryngeal nerve of the Vagus (X)
Nucleus - 

Nucleus Ambiguus of Medulla 

Now there's another Motor nucleus - The Accessory nerve. It supplies Trapezius and Sternomastoid muscles but it's doubtful if it's Branchial or Somatic. 

3. Visceral Motor Efferent - General. 

- These nuclei are parasympathetic and stimulate a particular gland to secrete or a ganglion to function. 

- These are called Secretomotor or General Visceral Efferent Fibres 

Again , there are 4 of these. 

A. Ciliary ganglion 

Function mediated by - 
Sphincter pupillae - Constricts pupil 

(Mnemonic = Remember C and C - Cholinergic Constricts )
Nerve -
Oculomotor nerve
Nucleus - 

Edinger Westphal in Midbrain 

B. Pterygopalatine ganglion 

Function mediated by - 
Lacrimal glands, nasal mucosal, sinuses mucosal glands and pharynx mucosal - Secretomotor. 

Nerve -
Facial nerve  (Greater Petrosal)
Nucleus - 

Superior salivatory nucleus - Pons. 

C. Submandibular ganglion 

Function mediated by - 
Submandibular glands , sublingual glands - Secretomotor.

Nerve -
Facial nerve  (Chorda tympani)
Nucleus - 

Superior salivatory nucleus - Pons. 

D. Otic ganglion 

Function mediated by - 
Parotid gland

Nerve -
Glosspharyngeal nerve  (Lesser Petrosal)
Nucleus - 

Inferior salivatory nucleus - Pons. 

The Vagus nerve has the largest parasympathetic discharge and supplies a lot of visceral with this input in the guy as well.

Hope this helps you to re-orient yourself to neuroanatomy and grasp the roles of various brainstem structures ! 

Happy studying ! 

~ A.P.Burkholderia

High ankle and low ankle sprain mnemonic

Hello!

High ankle and low ankle sprain

Chest x-ray - Left Lung.

Hello everybody!

Let's see the image correlations of the left lung today.

The left lung has an apical lobe ,lingula and a basal lobe.

Apical lobe has 2 segments: Anterior and posterior.
Lingula : The tongue like extension and the alleged counterpart of the middle lobe has 2 parts to it : Superior and Inferior.
Basal lobe has 4 segments namely : Superior, Posterior, Medial, Lateral.

Carefully observe how the identification of these segments differs while seeing an X-ray.

Apical lobe:

Basal Lobe:

So that's it with the interpretation of lung fields on X-rays!

Hope this is helpful!

-Medha.

Chest X-ray - Right Lung!

Hello everybody!
So today let's go through the Right lung segments as seen on a Chest x-ray with the help of images.

This will help us identify the exact location of the pathology and the possible etiology for the same.

So the Right lung has 3 lobes.
Upper
Middle
Lower.

Let's start with the right UPPER LOBE.
It has 3 segments.

Now moving to the MIDDLE LOBE .
It has 2 segments Medial and Lateral.

Moving to the LOWER LOBES.

It has 5 segments.

Superior Basal

Lateral Basal

Antero Basal

Medial Basal

Posterior Basal.

(3D CT Images courtesy - CU medicine Hong Kong)

So well I hope this helps to correlate the various Bronchopulmonary segments while interpreting a Chest x-ray!

Let's Learn Together!

-Medha.

Difference between cauda equina syndrome and conus medullaris (with mnemonics)

Let's differentiate Cauda equina syndrome (CES) from conus medullaris today!
With mnemonics because they make life easier! (And because it is the IkaN style of doing things)

Ischioanal fossa (Fun Mnemonic Diagrams)

Hello Everyone,
Lets discuss Ischioanal fossa. I remember it as a Rocket!!
How to draw it?

Draw a rocket

Add 2 wings !!

Draw 2 snakes underneath the wings

                                             

Color it up.

And Label it.

That's all,

Thank you,

Chaitanya Inge

Femoral Nerve Mnemonic

Hello Everyone,
Lets discuss Femoral nerve today. Doesn't femoral nerve sound feminine? Also I am writing this post on Mothers Day, what a coincidence!

Root value: L2-L4
   (Ladies work 24 hours.)

Motor innervation:
It innervates following muscles:

• Anterior division branches innervates
•   Sartorius 
•   Illiacus
•   Pectineus 
• Posterior division branches (innervates Quadriceps femoris)
•   Rectus femoris 
•   Vastus medialis 
•   Vastus lateralis 
•   Vastus intermedius 

How to remember it? @_@
Queens hardly get time to SIP coffee  ^_^


Sensory innervation:

Anterior division branches provides sensation to anteromedial asepct of the thigh, consists of 2 branches:

• Medial cutaneous nerve of thigh 
• Intermediate cutaneous nerve

Posterior division:

• Saphenous nerve : provides sensation to anteromedial aspect of lower leg.
• Infrapatellar branches to knee :pierces the sartorius and fasica lata medial to the knee, and provides cutaneous innervation to the skin anteriorly over the patella.

How to remember it? @_@

MISs is Insensitive to pain. ^_^

Wish you Happy Mothers Day : )

That's all

Thank you,

Chaitanya Inge

Authors' diary: Cerebellar tumor location and associated symptoms

Hello!

In 2013, I wrote this anatomy mnemonic on parts of the cerebellum and their functions.

I was tested this fact in a question today and I got it right. Yaay! :D

The question asked about a tumor, expected to know the most common location of the tumor and then expected you to know the symptoms caused due to it's location. Ooooh!

Anyway, lemme summarize what you should know:

Medulloblastomas usually occur in the vermis and spare the cerebellar hemispheres - They are more likely to cause truncal ataxia.

Pilocytic astrocytomas occur in the cerebellar hemispheres - They are more likely to cause intention tremors.

Added by VM:
An ependymoma can also cause truncal ataxia just like medulloblastoma. Ependymoma can be differentiated by it's location, again. Being more common on the floor of fourth ventricle, it will irritate area postrema and cause vomiting. It can also cause CN 7, CN 10 and CN 12 palsies. 

It's funny how in your preclinical years, all you ask is, "WHY DO I HAVE TO LEARN THIS?" 
And in your clinical years, you are always like - I wish I took my first and second year seriously! :P

-IkaN

Abdominal Aorta Mnemonic

Hello Everyone,
Lets discuss abdominal aorta.
Its a game of odd numbers. Following branches are present:

• 3 Anterior
• 3 Lateral visceral
• 3 Terminal
• 5 Lateral Abdominal

3 Anterior branches single include:

• Coeliac Trunk (T12)
• Superior Mesenteric Artery (L1)
• Inferior Mesenteric Artery (L3)

3 paired lateral Visceral:

•  Middle Suprarenal(L1)
• Renal (between L1 and L2)
• Gonadal (L2)

5 paired lateral abdominal

• 4 Lumbar arteries (respectively at L1 L2 L3 L4)
• Inferior phrenic (T12)

3 Terminal

• 2 Common Illiac (L4)
• Median Sacral (L4)

How to remember it? @_@
Counter Strike Is MR GLIC's Mastery. ^_^

Fun Facts:

• There are 3 suprarenal arteries ( again a odd number). The superior branch is derived from the inferior phrenic artery, the middle branch originates directly from the aorta, and the inferior branch comes off the renal artery.

• The fifth lumbar arteries on either side arise from the median sacral artery. 

     Click Here to see a beautiful flowchart submitted to us.

That's all,

Thank you 

Chaitanya Inge

Medulla (Fun Mnemonic Diagrams)

Hello Everyone,
Today lets discuss sections of medulla. I remember them as three sisters!

The basics: Lesions of Spinal Cord

Here is a basics video on Spinal cord with mnemonics for first year med students by Chaitanya Inge. Enjoy :)

Fact of the day: Shoulder dislocation

An anterior shoulder dislocation is usually caused by a blow to the abducted, externally rotated, and extended arm (eg, blocking a basketball shot).

Violent muscle contractions following a seizure or electrocution represent the most common causes of posterior shoulder dislocation.

Anterior Abdominal Wall : Mnemonics

Hi everyone. So I've just started Surgery and it makes me go back to Anatomy. A lot.
Here are some helpful Mnemonics on the Anterior abdominal wall

The External Oblique muscle is the SIR of  all muscles.
It's the SIR of all muscles.
Hence , This SIR forms the Superficial Inguinal Ring.
Because it's the SIR , it forms the Sir of all ligaments too - the Inguinal Ligament.

The Fascia Transversalis is a scary thing. Whenever I see it , I get DAR. ( Dar is the Hindi word for Fear)
So I get DIR when I look at it. :P
And hence the Deep Inguinal Ring is in the Fascia Transversalis.
Since this is such a scary muscle , the important artery Inferior Epigastric Pierces this muscle. Making it more DIR-avna.

Finally,
How should one remember the direction of the External and Internal oblique muscles ?
Hands in your pocket is External Oblique.
So medially and downwards.

Hands on the Tits is Internal Oblique.
So medially and upwards.

Hope these help you !
Happy Studying !
Stay aweosme.

~ A.P.Burkholderia

Mnemonic for Sulci And Gyri of the cerebrum

Hello everyone,
  Memorising sulci and gyri of the cerebrum consists of two parts:

1. Memorising the names of the sulci and gyri
2. Memorising the locations

Today I will help you with the first part. Please bear with me, it will be a lengthy one.
Lets start with Superolateral surface
We have 4 regions on superolateral surface. They are

1. Frontal 
2. Parietal
3. Temporal
4. Occipital

Trick for superolateral surface revolves around 3 letters, they are: PSI

Frontal

Sulci- PSI      Gyri- PSIM
Sulci:

1. Precentral 
2. Superior frontal
3. Inferior frontal

Gyri

1. Precentral
2. Superior Frontal
3. Inferior frontal
4. Middle frontal 

Temporal
Sulci:SI  Gyri: SMI
  Names of Sulci are:

1. Superior Temporal
2. Inferior Temoral

Gyri

1. Superior Temporal
2. Middle Temporal
3. Inferior Temporal

Parietal
Sulci: PI Gyri: PSI

Sulci

1. Postcentral
2. Intraparietal

Gyri

1. Post central 
2. Superior Parietal
3. Inferior Parietal

For occipital. Remember a simple mnemonic : Sulci- SaLLTy C    Gyri- Gisa.

Sulci
SaLLTy C

1. Superior and Inferior Polar
2. Lunate
3. Lateral Occipital
4. Transverse Occipital
5. Calcarine

And the gyri

GISA

1. Gyrus descendens
2. Inferior Occipital
3. Superior Occipital
4. Arcus parieto-occipitalis.

So that completes the superolateral surface.

Now moving on to Medial Surface

  Here's the mnemonic CAPS. Men wear CAPs.  

Now  it goes like this Sulci- CCCAPPS. Gyri- Men wear CCaPPPPs

Sulci 

1. Calcarine
2. Callosal 
3. Cingulate
4. Anterior parolfactory
5. Posterior Parolfactory
6. Parieto-Occipital
7. Suprasplenial or subparietal

Gyri

1. Median frontal
2. Cuneus
3. Cingulate
4. Paraterminal
5. Paraolfactory
6. Paracentral
7. Precuneus

Finally moving to the Inferior Surface

 Here's the mnemonic

     when Cars HOORns  PeoPle LAugh LoudLy on boys playing GaMMes on streets!

Sulci (red coloured in mnemonic)

1. Collateral
2. H shaped orbital sulci
3. Olfactory
4. Occipitotemporal
5. Rhinal

Gyri(purpled coloured in mnemonic

1. Parahippocampal
2. Posterior Orbital
3. Lateral orbital
4. Anterior Orbital
5. Lingual
6. Lateral Occipitotemporal
7. Gyrus rectus
8. Median Occipitotemporal
9. Medial Orbital

Lets hope it will make memorising these things a bit easier.

That's all,
Thankyou,
Chaitanya Inge

Blood Supply And Nerve Supply of the Scalp

 Hello Everyone!
                Today we will discuss blood supply and nerve supply of the scalp. Just too many nerves and arteries out there. But there is a way out.

     First let us talk about nerves.

Nerve Supply:

1.  Sensory
2. Motor

Sensory:

Here's the trick

 In front of the auricle we have 4 nerves, and all are branches of trigeminal nerve.They are:

1. Supratrochlear (Opthalmic division)
2. Supraorbital  (Opthalmic division)
3. Zygomaticotemporal (Maxillary division)
4. Auriculotemporal (Mandibular division)

The remaining 4 are located behind the auricle. They are very simple to remember:

GaLeO Go To

1. Great Auricular(C2,C3)
2. Lesser Occipital(C2)
3. Greater Occipital(C2)
4. Third Occipital(C3)

Motor Supply:

In front of auricle: Temporal branch of facial nerve

Behind the auricle: Posterior auricular branch of facial nerve

Nerve supply of the Scalp 

Coming to the  Blood Supply:

1. Arterial supply:
1. Supratrochlear
2. Supraorbital
3. Superficial Temporal
4. Posterior Auricular
5. Occipital

1. Venous Drainage: Common, thats simple. Names corresponds to arteries.
• But there's a twist. The superficial temporal along with maxillary vein wants to drain in external as well as internal jugular. So they form retro mandibular vein whose course is pretty clear in diagram.

Blood Supply of the Scalp

That's all,

-Chaitanya Inge