Clinical Anatomy Considerations of the Upper Limbs

Question 1

Where does the axillary nerve pass?

Answer 1

Passes under the head of the humerus to become the radial nerve

Question 2

What forms the quadrangular space?

Answer 2

Humerus, teres minor and major, and the long head of triceps brachii (on posterior of patient’s axilla)

Question 3

What are the functions of teres minor and deltoid?

Answer 3

Teres minor = lateral rotation of arm

Deltoid = abduction of arm

Question 4

What is the cutaneous innervation of the lateral upper arm (badge patch area)?

Answer 4

Superior lateral cutaneous nerve of the arm

Question 5

How can C5 dysfunction be ruled out?

Answer 5

By function of the suprascapular nerve

Question 6

What innervates triceps brachii?

Answer 6

The radial nerve

Question 7

Where does the radial nerve pass?

Answer 7

Courses around the radial groove of the humerus (with the profundal brachii artery), passes to posterior compartment of the arm

Question 8

What are the sensory and motor branches of the radial nerve?

Answer 8

Sensory = superficial branch 
Motor = posterior interosseous nerve

Question 9

Where does the main branch of the radial nerve supply?

Answer 9

Triceps brachii, brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, supinator

Question 10

Where does the posterior interosseous nerve supply?

Answer 10

All other muscles of the posterior forearm not supplied by the main branch of the radial nerve

Question 11

What may cause wrist drop?

Answer 11

Damage to the radial nerve (e.g in a distal humeral fracture)

Question 12

Where does the median nerve pass?

Answer 12

Runs medially in the arm and passes anterior to the elbow joint, pierces two heads of pronator teres, runs between intermediate and deep layers of anterior compartment of forearm

Question 13

What are the structures within the cubital fossa?

Answer 13

Biceps brachii tendon, median nerve and brachial artery

Question 14

Where does the anterior interosseous nerve supply?

Answer 14

Muscles of deep layer of anterior forearm = flexor digitorum profundus (lateral half), flexor pollicis longus, pronator quadratus

Question 15

What are some examples of conditions caused by median nerve palsy?

Answer 15

Hand of Benediction, ape hand, abnormal “ok” sign

Question 16

What are some features of flexor digitorum superficialis (FDS)?

Answer 16

Controls digits 2-5
Inserts on intermediate phalanx
Flexes PIPs
Innervated by median nerve

Question 17

What are some features of flexor digitorum profundus (FDP)?

Answer 17

Controls digits 2
Medial half innervated by ulnar nerve
Lateral half innervated by anterior interosseous nerve
Inserts on distal phalanx
Flexes DIPs

Question 18

What are some features of flexor pollicis longus (FPL)?

Answer 18

Inserts on distal phalanx of thumb#
Flexes thumb
Innervated by anterior interosseous nerve

Question 19

What muscles make up the thenar eminence?

Answer 19

Flexor pollicis brevis, abductor pollicis brevis, opponens pollicis

Question 20

What nerve innervates the thenar eminence?

Answer 20

Recurrent branch of the median nerve

Question 21

Where are the origins and the insertions of the four lumbricals?

Answer 21

Origin = FDP tendon
Insertion = dorsal digital expansion

Question 22

What is the innervation of the lumbricals?

Answer 22

Medial two = ulnar nerve

Lateral two = median nerve

Question 23

What are the functions of the lumbricals?

Answer 23

Flex the MCP

Extend the PIPs and DIPs

Question 24

What may occur due to carpal tunnel syndrome?

Answer 24

Potential wasting of the thenar eminence and the lateral two lumbricals
Ape hand deformity

Question 25

Which branch of the median nerve is spared form carpal tunnel syndrome?

Answer 25

Palmar cutaneous branch = doesn't pass through carpal tunnel

Question 26

What occurs due to approximal lesion to the median nerve?

Answer 26

Hand of Benediction deformity | All motor symptoms of carpal tunnel compression plus the muscles of anterior forearm supplied by the median nerve

Question 27

Where does the ulnar nerve pass?

Answer 27

Median in arm with the median nerve before coursing posteriorly, runs posteriorly between the medial epicondyle and olecranon process in cubital tunnel, passes into hand alongside ulnar artery and vein

Question 28

Where does the deep branch of the ulnar nerve give motor supply to?

Answer 28

Hypothenar muscles = abductor digiti minimi, flexor digiti minimi, opponens digiti minimi Adductor pollicis, interossei, medial two lumbricals

Question 29

Where do the branches of the ulnar nerve in the forearm give motor supply to?

Answer 29

Flexor carpi ulnaris and flexor digitorum profundus (medial half)

Question 30

Where does the ulnar nerve give sensory innervation to?

Answer 30

Skin of medial palm, little finger and medial half of fourth digit

Question 31

What will a proximal ulnar nerve problem cause?

Answer 31

Patient only able to use FDS = only slight flexion of the fourth and fifth digits

Question 32

What will a distal ulnar nerve problem cause?

Answer 32

Patient will have function of FDS and FDP = flexion at DIPs and PIPs plus extension at MCP (due to unopposed action of extensor digitorum)