Anatomy

Question 1

What are the important structures located at the level of L1?

Answer 1

Transpyloric plane (pylorus of the stomach), fundus of the gall bladder, coeliac trunk, superior mesenteric artery, termination of spinal cord, and hilla of kidneys.

Question 2

What is the transpyloric plane?

Answer 2

Also known as Addison’s plane, it’s an upper transverse line, located halfway between the jugular notch and the upper border of the pubic symphysis. It’s where most cases cuts through the pylorus of the stomach, the tips of the ninth costal cartilages, and the lower border of the first lumbar vertebra.

Question 3

Clincher: foot drop ou unable to dorsiflex

Answer 3

Pick peroneal nerve

Question 4

What are the symptoms when the radial nerve is damaged?

Answer 4

Motor function - wrist drop

Sensory function - sensory loss is variable, but always includes the dorsal aspect of the root of the thumb. Usually leads to loss to small area between the dorsal aspect of 1st and 2nd metacarpals

Question 5

What is the name, function and resulting palsy of the CN III?

Answer 5

Oculomotor nerve

Functions: controls most of eye muscle, constriction of pupil, levator palpebrae superioris

Palsies: will have features of either ptosis and/or dilated pupil on the nerve on the same side as the affected eye

Mnemonic: letter “O” for oculomotor which with a good imagination can represent a dilated pupil

Memory tool - LR6(SO4)O3
- Lateral rectus - 6th nerve
- Superior oblique - 4th nerve
- Other - 3rd nerve

Question 6

What is the name, function and resulting palsy of the CN IV?

Answer 6

Trochlear nerve

Functions: innervates the superior oblique, causes depression (especially on adduction) and abduction of the eye

Palsies: the left trochlear nerve affects the left eye (specifically the superior oblique nerve). Diplopia on downward gaze - more noticeable on adduction. Diplopia on abduction of affected eye

As the left eye cannot depress when adducted, it moves up. The patient will have difficulty in looking down and in (intorsion is affected). This patient will have vertical diplopia (more on downgaze).

Memory tool - LR6(SO4)O3
- Lateral rectus - 6th nerve
- Superior oblique - 4th nerve
- Other - 3rd nerve

Question 7

What is the name, function and resulting palsy of the CN VI?

Answer 7

Abducens nerve.

Function: innervates the lateral rectus muscle, the main muscle involved in abduction of the eye

Palsies: if looks left and sees double, then the lesion is on the left (same side as gaze). As the left eye cannot abduct, it stays in the middle. This patient will have horizontal diplopia

Memory tool - LR6(SO4)O3
- Lateral rectus - 6th nerve
- Superior oblique - 4th nerve
- Other - 3rd nerve

Question 8

Which verteabae is located at the midpoint of the spine at the level of the iliac crest?

Answer 8

L4 is at the level of the iliac crest.

The supracristal plane is a landmark for identification of L4/5 where a lumbar puncture can be performed.

Question 9

What are typical scenarios and clinchers for upper brachial plexus injury?

Answer 9

Upper trunk palsy injuries occur when the angle between the shoulder and neck widens forcefully. This can occur when a strong force is applied to the shoulder downwards and neck flexion away from the shoulder.

Typical scenarios: forceps delivery (seen in infants), falling down on shoulder and neck (eg. falling from a ladder)

Clinchers: not being abl to bend the arm at the elbow, unable to abduct the arm, lose sensation at the lateral surface of the upper arm, radial edge of the forearm and thumb