Clinical Anatomy Considerations of the Upper Limbs Flashcards
Where does the axillary nerve pass?
Passes under the head of the humerus to become the radial nerve
What forms the quadrangular space?
Humerus, teres minor and major, and the long head of triceps brachii (on posterior of patient’s axilla)
What are the functions of teres minor and deltoid?
Teres minor = lateral rotation of arm
Deltoid = abduction of arm
What is the cutaneous innervation of the lateral upper arm (badge patch area)?
Superior lateral cutaneous nerve of the arm
How can C5 dysfunction be ruled out?
By function of the suprascapular nerve
What innervates triceps brachii?
The radial nerve
Where does the radial nerve pass?
Courses around the radial groove of the humerus (with the profundal brachii artery), passes to posterior compartment of the arm
What are the sensory and motor branches of the radial nerve?
Sensory = superficial branch Motor = posterior interosseous nerve
Where does the main branch of the radial nerve supply?
Triceps brachii, brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, supinator
Where does the posterior interosseous nerve supply?
All other muscles of the posterior forearm not supplied by the main branch of the radial nerve
What may cause wrist drop?
Damage to the radial nerve (e.g in a distal humeral fracture)
Where does the median nerve pass?
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
What are the structures within the cubital fossa?
Biceps brachii tendon, median nerve and brachial artery
Where does the anterior interosseous nerve supply?
Muscles of deep layer of anterior forearm = flexor digitorum profundus (lateral half), flexor pollicis longus, pronator quadratus
What are some examples of conditions caused by median nerve palsy?
Hand of Benediction, ape hand, abnormal “ok” sign
What are some features of flexor digitorum superficialis (FDS)?
Controls digits 2-5
Inserts on intermediate phalanx
Flexes PIPs
Innervated by median nerve
What are some features of flexor digitorum profundus (FDP)?
Controls digits 2 Medial half innervated by ulnar nerve Lateral half innervated by anterior interosseous nerve Inserts on distal phalanx Flexes DIPs
What are some features of flexor pollicis longus (FPL)?
Inserts on distal phalanx of thumb#
Flexes thumb
Innervated by anterior interosseous nerve
What muscles make up the thenar eminence?
Flexor pollicis brevis, abductor pollicis brevis, opponens pollicis
What nerve innervates the thenar eminence?
Recurrent branch of the median nerve
Where are the origins and the insertions of the four lumbricals?
Origin = FDP tendon Insertion = dorsal digital expansion
What is the innervation of the lumbricals?
Medial two = ulnar nerve
Lateral two = median nerve
What are the functions of the lumbricals?
Flex the MCP
Extend the PIPs and DIPs
What may occur due to carpal tunnel syndrome?
Potential wasting of the thenar eminence and the lateral two lumbricals
Ape hand deformity
Which branch of the median nerve is spared form carpal tunnel syndrome?
Palmar cutaneous branch = doesn’t pass through carpal tunnel
What occurs due to approximal lesion to the median nerve?
Hand of Benediction deformity
All motor symptoms of carpal tunnel compression plus the muscles of anterior forearm supplied by the median nerve
Where does the ulnar nerve pass?
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
Where does the deep branch of the ulnar nerve give motor supply to?
Hypothenar muscles = abductor digiti minimi, flexor digiti minimi, opponens digiti minimi
Adductor pollicis, interossei, medial two lumbricals
Where do the branches of the ulnar nerve in the forearm give motor supply to?
Flexor carpi ulnaris and flexor digitorum profundus (medial half)
Where does the ulnar nerve give sensory innervation to?
Skin of medial palm, little finger and medial half of fourth digit
What will a proximal ulnar nerve problem cause?
Patient only able to use FDS = only slight flexion of the fourth and fifth digits
What will a distal ulnar nerve problem cause?
Patient will have function of FDS and FDP = flexion at DIPs and PIPs plus extension at MCP (due to unopposed action of extensor digitorum)
