40. Applied Anatomy

Question 1

A 55 yo window cleaner falls from a ladder injuring right shoulder.

1. What is Diagnosis?
2. Which tendons attach to the fractured part?
3. Which nerves or vessels are most susceptible to damage in this type of injury?

Answer 1

1. Fracture/dislocation Right shoulder – anterior. Greater tuberosity/tubercle fracture.
2. Supraspinatus – greater facet attachment
   Infraspinatus – middle facet attachment
   Teres minor - inferior facet attachment
3. Axillary nerve & posterior and anterior circumflex humeral vessels (Quadrangular space)
   Radial nerve and brachial plexus

Question 2

A 19 year old student is involved in a fight where they sustain a knife injury to their left forearm.
The knife wound injures the proximal part of the anterior compartment of the forearm.
There is immediate inability to flex the hand at the wrist joint and pronate the forearm.
The hand is still pink, but less than the uninjured side.
There is altered sensation over the palm of the hand and digits.

Which muscles are most likely damaged?
Which neurovascular structures are likely to have been damaged?

Answer 2

1. Anterior/flexor compartment of forearm.
   Superficial forearm layer: pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris
   Intermediate forearm layer: flexor digitorum superficialis
   Deep forearm layer: pronator quadratus, flexor pollicis longus, flexor digitorum profundus
2. Neurovascular damage: median nerve (including anterior IO branch), ulnar artery, radial artery, ulnar nerve

Question 3

Answer 3

Question 4

Answer 4

Question 5

Cutaneous nerve supply of forearm

Answer 5

Question 6

A 45 year old typist complains of recurrent weakness in her left hand at work.
There is associated altered sensation in the little and ring fingers that causes pain at night and sometimes awakens her.
When she is examined her left hand looks much thinner than her right hand, especially over the palm on the little finger aspect.

1. Which nerve is most likely to have been damaged?
2. What is the pathway of this nerve from cubital fossa to the hand?
3. Which muscles are wasted?

Answer 6

1. Nerve damage: ulnar nerve
2. Pathway: posterior to medial epicondyle of humerus. Passes between heads of flexor carpi ulnaris and descends distally to the wrist. Palmar and dorsal branches arise proximal to wrist. Passes superficial to flexor retinaculum through Guyon’s canal t branch into deep (muscular) and superficial (cutaneous) branches.
3. Hypothenar muscle wasting: flexor digiti minimi and abductor digiti minimi (superficial), opponens digiti minimi (deep)

Question 7

What does the ulnar nerve innervate?

Answer 7

Muscles - FCU and medial half of FDP hand muscles

Cutaneous - Palmar - medial side of palm; Dorsal - skin on back of posteromedial hand and medial one and a half digits

Question 8

Answer 8

Question 9

Which muscles are the hypothenar muscles of the hand?

Answer 9

Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi

Question 10

62 year old female presents with 8/10 aching pain that travels down her right posterior thigh.
You take her history and she further describes the pain as being worse when she sits for a prolonged period of time. She also experiences pain in her lower back, and pins and needles over anterior and posterolateral leg, and over the dorsum of her right foot.
She is overweight but has no relevant medical history.

1. What is the differential diagnosis?
2. What is the most likely nerve involved to cause of the paraesthesia?

Answer 10

1. DD: sciatica presentation.
2. Causes: herniated IV disc, piriformis entrapment, spinal stenosis
   Paraesthesia: common fibular nerve distribution of cutaneous supply

Question 11

Cutaneous innervation of lower limb

Answer 11