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Medicine year 2 semester 2 > Case 23- Anatomy 3 > Flashcards

Case 23- Anatomy 3 Flashcards

1
Q

3 major nerves in the upper limb

A
  • Median nerve- in the midline of the upper limb
  • Ulnar nerve- on the medial side of the arm (towards the little finger)
  • Radial nerve- starts posterior then moves lateral as it goes through the forearm
  • Also Musculocutaneous nerve (supplies the arm), Axillary nerve (supplies the shoulder)
  • All originate from the brachial plexus and supply all the muscles of the arm, forearm and hand
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2
Q

Median nerve course

A
  • In the arm- lies close to the brachial artery
  • In the forearm- passes between the two heads of the pronator teres (superficial and posterior head), continues deep to the flexor digitorum superficialis down the midline
  • At the wrist- passes deep to the flexor retinaculum- within the carpal tunnel. The median nerve is at risk of compression if there is swelling within the carpal tunnel
  • In the hand- emerges through the carpal tunnel to give off several branches
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3
Q

Branches of the Median nerve

A
  • Main branch- Anterior interosseous nerve (motor), this branch comes off before the median nerve passes through the carpal tunnel
  • Palmar branch (sensory)- passes into the hand superficial to the flexor retinaculum (over the top) provides sensory innervation to part of the hand. Wont be affected by carpal tunnel syndrome
  • Recurrent branch- arises in the hand. Supplies motor innervation to the Thenar (thumb) muscle.
  • Digital branches- arises in the hand to supply the digits
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4
Q

Median nerve summary

A
  • Arm= key landmarks- Brachial artery
  • Forearm= Key landmarks- Pronator teres
  • Wrist= Key landmark- under the Carpal tunnel
  • Hand= Key landmark- Thenar (thumb) muscles
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5
Q

Neurovascular bundle in the arm

A

Neurovoascular bundle in the arm of the Median nerve, Ulnar nerve and the Brachial artery. The Ulnar nerve is more medial (near the little finger)

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6
Q

Ulnar nerve course

A
  • In the arm- lies close to the brachial artery. Midway through pierces into the posterior compartment. Lies posterior to the medial epicondyle of the humerus, it is now really superficial
  • In the forearm- passes down the medial side of the forearm. At the wrist it lies medial to the ulnar artery, tucked under the flexor carpi ulnaris tendon in the wrist
  • In the hand- enters hand lateral to the pisiform with the ulnar artery. Goes over the top of the flexor retinacula to enter the hand
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7
Q

Ulnar nerve branches

A
  • In the forearm= Palmar and dorsal branches, sensory information to the hand
  • In the hand= Deep (motor) and superficial (sensory) branches
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8
Q

Ulnar nerve summary

A
  • Arm- Key landmarks: Brachial artery, Medial epicondyle
  • Forearm- Key landmarks: Flexor carpi ulnaris, Ulnar artery
  • Hand- Key landmarks: Ulnar artery
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9
Q

Radial nerve course

A
  • In the arm- Posterior, passes through the triangular interval. Continues in the radial groove. Crosses anteriorly to the lateral epicondyle. Fracture of the humerus could damage the nerve as its posterior to it
  • In the forearm- divides into a superficial and deep branch in the proximal forearm
  • Hand- only the superficial branch enter the hand, passing over the anatomical snuffbox (depression on the side of your hand formed by some tendons)
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10
Q

Branches of the radial nerve

A
  • In the arm- Posterior antebrachial cutaneous, sensory innervation to the posterior forearm
  • In the forearm- Superficial branch (sensory)- in the lateral forearm close to the radial artery. Distally it passes posteriorly to enter the hand. Provides sensation to the hand
  • In the arm- Deep branches (motor), emerges between the two heads of the supinator to become the posterior interosseous nerve. Is in the posterior compartment and provides a lot of the posterior muscles
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10
Q

Branches of the radial nerve

A
  • In the arm- Posterior antebrachial cutaneous, sensory innervation to the posterior forearm
  • In the forearm- Superficial branch (sensory)- in the lateral forearm close to the radial artery. Distally it passes posteriorly to enter the hand. Provides sensation to the hand
  • In the arm- Deep branches (motor), emerges between the two heads of the supinator to become the posterior interosseous nerve. Is in the posterior compartment and provides a lot of the posterior muscles
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11
Q

Radial nerve summary

A
  • Arm- key landmarks, radial groove of the humerus
  • Forearm- key landmarks, superficial branch (sensory) and the deep branch (motor) which is posterior
  • Hand- key landmarks, superficial branch, anatomical snuffbox
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12
Q

Innervation of the elbow- arm muscles

A
  • Anterior compartment- Musculocutaneous nerve

* Posterior compartment- Radial nerve

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13
Q

Innervation of the wrist/finger movements- Forearm muscles

A
  • Anterior compartment- Median nerve. Except the Flexor carpi ulnaris and the medial (ulnar) half of the flexor digitorum profundus which is supplied by the ulnar nerve
  • Posterior compartment- Radial nerve (posterior interosseous)
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14
Q

Innervation of finger movements- Hand muscles:

A
  • Intrinsic hand muscles- Ulnar nerve
  • Except:
  • Thenar (thumb) muscles- median nerve (recurrent branch)
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15
Q

Median nerve

A

Course- close to the brachial artery in the arm. Runs in the midline of the forearm. Goes through the carpal tunnel
Function- supplies most of the anterior forearm muscles (except some on the ulnar side). Supplies thenar (thumb) muscles

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16
Q

Ulnar nerve

A

Course- close to the brachial artery in the arm, posterior to the medial epicondyle. Lies on the medial (ulnar) side of the forearm
Function- supplies most hand muscles (and some ulnar anterior forearm muscles)

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17
Q

Radial nerve

A

Course- Posterior in the radial groove of the hand. In the forearm there are deep (posterior) and superficial (lateral forearm) branches. Only superficial reaches the hand
Function- supplies posterior arm and forearm muscles

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18
Q

Blood supply to the upper limb- start

A
  • Subclavian artery which is a branch of the arch of the aorta
  • It becomes the axillary artery as it passes the lateral border of the 1st rib
  • The axillary artery then becomes the brachial artery as it passes the lower border of the teres major
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19
Q

Axillary artery

A
  • Its divided into three parts by its relationship to the pectoralis minor which crosses anteriorly to the artery
  • 1st part- proximal to the pectoralis minor, the 1st branch is the superior thoracic artery
  • 2nd part- posterior to the pectoralis minor. Has two branches: the Thoracoacromial artery and the Lateral thoracic artery
  • 3rd part- distal to the pectoralis major
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20
Q

The 3 divisions of the 3rd part of the axillary artery

A
  • Subscapular artery- the largest branch of the axillary artery, supplies the posterior axilla and scapular regions. It divides into two further branches: the Circumflex scapular artery and the Thoracodorsal artery
  • Anterior circumflex humeral artery
  • Posterior circumflex humeral artery
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21
Q

The divisions of the brachial artery

A

The main arterial supply to the upper limb:
• Profunda brachii artery/deep brachial artery - travels with the radial nerve in the radial groove of the humerus to supply the posterior compartment of the arm
• Radial and ulnar branches - These are the two terminal branches of the brachial artery. They continue into the forearm to supply the forearm and hand. These tend to arise just distal to the cubital fossa.
• The brachial artery gives rise to several other smaller branches which form an anastomatic supply around the elbow, supplying the muscles of the and the humerus

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22
Q

Radial artery

A

Passes along the lateral forearm, deep to brachioradialis.
• At the wrist, the radial artery lies between the tendons of brachioradialis and flexor carpi radialis
• Clinical Relevance: When taking a radial pulse, the artery can be palpated between these tendons.
• The artery passes around the lateral side of the wrist to cross the floor of the anatomical snuffbox into the hand.

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23
Q

Ulnar artery

A
  • The larger of the two terminal branches of the brachial artery
  • It passes down the medial side of the forearm, between flexor carpi ulnaris and flexor digitorum profundus.
  • It gives rise to the common interosseous artery which divides into anterior and posterior interosseous arteries (the posterior interosseous artery enters the posterior compartment)
  • In the distal forearm, the artery is often tucked under the flexor carpi ulnaris tendon, making it difficult to palpate for a pulse. In distal regions, the artery lies immediately lateral to the ulnar nerve
  • The ulnar artery enters the hand lateral to the pisiform bone, superficial to the flexor retinaculum.
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24
Q

Ulnar and radial artery in the hand

A

In the hand the radial artery contributes to the supply of the thumb and the lateral side of the index finger. The ulnar artery supplies the remaining digits and the medial side of the index finger.

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25
Q

Superficial palmar arch

A
  • Formed from the ulnar artery
  • Lies superficial to the long flexor tendons and deep to the palmar aponeurosis
  • The superficial palmar branch of the radial artery anastamoses with the superficial palmar arch
  • Digital arteries arise from the superficial palmar arch.
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26
Q

Deep palmar arch

A
  • Formed from the radial artery, by passing between the two heads of adductor pollicis to access the deep plane of the palm
  • The deep palmar branch of the ulnar artery anastamoses with the deep palmar arch
  • Palmar metacarpal arteries arise from the deep palmar arch.
  • The radial artery also gives rise to dorsal carpal and dorsal metacarpal branches, the princeps pollicis artery (the major blood supply to the thumb) and the radialis indices artery
27
Q

Venous drainage of the upper limbs

A
  • Deep veins tend to travel closely to and follow the arteries
  • The two main superficial veins in the upper limb are the basilic and cephalic veins, which communicate in the cubital fossa via the median cubital vein
  • The veins in the upper limb arise from the dorsal venous network on the back of the hand, and ultimately drain into the axillary vein.
28
Q

Axillary vein

A
  • Begins at the lower margin of teres major, as a continuation of the basilic vein
  • The axillary vein becomes the subclavian vein as it crosses the lateral border of rib 1
  • Tributaries of the axillary vein tend to follow the arteries. Other tributaries include the brachial veins and the cephalic vein
29
Q

Brachial veins

A
  • The brachial veins are deep, paired veins that travel either side of the brachial artery
  • They receive tributaries from other veins that follow the branches of the brachial artery (such as the deep brachial artery)
  • These veins will join either the basilic or axillary vein.
30
Q

Basilic vein

A
  • The basilic vein is a large, superficial, cutaneous vein
  • It arises in the dorsal venous network of the hand, and continues through the forearm into the arm, lying medially throughout
  • The basilic vein becomes the axillary vein at the lower border of teres major.
31
Q

Cephalic vein

A
  • Another subcutaneous vein, the cephalic vein continues laterally from the forearm into the arm, to drain into the axillary vein
  • At the shoulder, it travels in a groove between the deltoid and pectoralis major muscles, the deltopectoral groove.
  • These two veins communicate at the elbow, via the median cubital vein which connects the cephalic and basilic vein. Clinical Relevance: This is the vein most commonly used in venepuncture.
32
Q

Lymph drainage of the upper limbs- Axillary lymph node

A
  • All lymphatics from the upper limb drain into lymph nodes in the axilla
  • Axillary lymph nodes also receive drainage from the upper back and shoulder, lower neck, chest, anterolateral abdominal wall and most of the mammary gland
33
Q

The axillary lymph nodes are divided into 5 groups

A
  1. Humeral (lateral) nodes - lie posteromedial to the axillary vein. Receive most of the lymphatic drainage from the upper limb.
  2. Pectoral (anterior) nodes - lie along the inferior margin of the pectoralis minor muscle, following the course of the lateral thoracic vessels. Receive drainage from the abdominal wall, the chest and the mammary gland
  3. Subscapular (posterior) nodes - located on the posterior axillary wall, associated with the subscapular vessels. Drain the back, shoulder and neck.
  4. The above nodes drain into the central nodes, that are embedded in axillary fat.
  5. All groups of nodes drain into the most superior group of nodes in the axilla, the apical nodes. These also receive lymphatic vessels accompanying the cephalic vein and vessels draining the superior mammary gland.
34
Q

Lymph drainage on the left and right of the upper limb

A

On the right: Efferent vessels from the apical group converge to form the subclavian trunk, which usually joins the venous system at the junction between the right subclavian vein and the right internal jugular vein in the neck.
On the left: the subclavian trunk usually joins the thoracic duct in the base of the neck.

35
Q

Forearm muscles (flexors/extensors)

A

Anterior- flexors

Posterior- extensors

36
Q

Anterior forearm- Flexor compartment

A
  • Role- flexion at the wrist, flexion of the digits, Pronation of the forearm
  • 3 layers of muscle- superficial, intermediate, deep
37
Q

Anterior forearm compartment- superficial layer muscles

A
  • Common origin- medial epicondyle of the humerus
  • Muscles- Flexor carpi ulnaris, Flexor carpi radialis. Muscles on the medial/lateral side of the forearm also abduct/adduct at the wrist
  • Pronator teres muscle
  • Palmaris longus
  • From lateral to medial Pass, Fail, Pass, Fail
38
Q

Anterior Forearm muscles- Flexor carpi ulnaris

A
  • Action- flexor of wrist, adduction of wrist
  • Inserts- Carpals
  • Location- medial (little finger)
39
Q

Anterior Forearm muscles- Flexor carpi radialis

A
  • Action- flexor of wrist, abduction of wrist
  • Inserts- Carpals
  • Location- lateral (thumb)
40
Q

Anterior Forearm muscles- Pronator teres muscle

A
  • Pronation= movement and rotation of the radius (moves the arm from the palm facing up to the palm facing down)
  • Inserts on the midshaft radius
  • 2 heads= Humeral head from the medial epicondyle (superficial) and the Ulnar head from the coronoid process (deeper)
  • The fibres run diagnonally
41
Q

Anterior Forearm muscle- Palmaris longus

A
  • Attaches to the Palmar aponeurosis, a large flat tendon in the hand which protects the nerves and blood vessels
  • Long thin tendon
  • Absent in 15% of the population
42
Q

Anterior compartment Intermediate layer muscles forearm

A

Flexor Digitorum superficialis:
• Two heads: Humero-ulnar head (medial epicondyle), Radial head (runs along the oblique line of the radius)
• The two attachment points come together to form the belly of the muscle
• Forms 4 tendons attached to the middle phalanges of the 4 digits
• Which joints does it flex- PIP (Proximal interphalangeal joint), MCP (Metacorpopharyngeal), wrist.
• The Flexor digitorum superficialis tendons run through the carpal tunnel underneath the Flexor retinaculum, only muscle in the superficial/intermediate layer to do so.

43
Q

Anterior forearm- Deep layer muscles

A
  • Flexor Digitorum Profundus
  • Pronator quadratus
  • Flexor pollicis longus
  • Deeper forearm muscles tend to originate from the radius/ulna/interosseous membrane in both the anterior and posterior compartment
44
Q

Anterior forearm- Flexor Digitorum Profundus

A
  • Originates from the ulna/interosseous membrane. The interosseous membrane runs between the forearm bones
  • Splits into 4 tendons which attach to the 4 distal phalanges
  • Control of the distal phalanges
  • Flexes the DIP, PIP, MCP and wrist
  • The Flexor digitorum superficialis tendon has to split to get around the Flexor Digitorum Profundus
45
Q

Anterior forearm- Pronator quadratus

A
  • Pronation= movement of the radius
  • Originates on the ulna, inserts on the radius
  • Pulls the radius over the ulnar to do Pronation
46
Q

Anterior forearm- Flexor pollicis longus

A
  • Originates from the Radius/interosseous membrane
  • Attaches to the Distal phalanx of the thumb, flexor of the thumb
  • Runs through the Carpal tunnel
47
Q

Muscles in the carpal tunnel

A

Flexor pollicis longus, Flexor digitorum superficialis, Flexor digitorum profundus

48
Q

Anterior forearm innervation

A
  • All supplied by the median nerve
  • Except the Flexor carpi ulnaris and the Medial (ulnar) half of the flexor digitorum profundus which is supplied by the Ulnar nerve
49
Q

Anterior forearm innervation- Median nerve

A
  • Near brachial artery in the arm
  • Passes between the two heads of the pronator teres (humeral and ulnar)
  • Continues deep to the flexor digitorum superficialis
  • Deep to the flexor retinaculum- through the carpal tunnel, this is vulnerable to compression if there is agitation or swelling. The Palmar cutaneous branch goes over the top of the flexor retinaculum so would not be affected
  • Branches: Anterior interosseous nerve (motor) which is the main branch and supplies the anterior forearm muscles. Also gives off the Palmar branch (sensory) to the hand. The Palmar branch is superficial to the flexor retinaculum
50
Q

Forearm innervation- Ulnar nerve

A
  • Near brachial artery in arm, then passes posterior to medial epicondyle
  • Passes down medial side of forearm, in the plane between FCU (Flexor Carpi ulnaris) and FDP (Flexor digitorum Profundus). Runs on the superficial surface of Flexor digitorum Profundus
  • At the wrist lies medial to the ulnar artery, tucked under flexor carpi ulnaris tendon which protects it
  • Passes superficial to the Flexor retinaculum, doesn’t go through the carpal tunnel
  • Branches: Palmar and dorsal branches – sensory to hand
51
Q

Posterior forearm- extensor compartment

A
  • Extension at the wrists, extension of the digits, supination of the forearm
  • 2 layers of the muscle- Superficial and Deep
52
Q

Common muscle origins

A
  • Anterior superficial layer- medial epicondyle

* Posterior superficial layer- lateral epicondyle

53
Q

Posterior forearm- superficial layer muscles

A
  • Common origin- lateral epicondyle of the humerus
  • Extensor carpi radialis (longus and brevis)
  • Extensor carpi ulnaris
  • Anconeus
  • Extensor digitorum- inserts on extensor hoods
  • Extensor digiti minimi- little finger, inserts on the extensor hood
  • Brachioradialis- Flexor
54
Q

Posterior forearm- Extensor carpi radialis (longus and brevis)

A
  • 2 muscles, a short and long version
  • Action- extensor of the wrist, adduction of wrist
  • Inserts- Meta-carpals II and III
  • Location- lateral (thumb)
  • The Extensor carpi radialis longus inserts just above the lateral epicondyle of the humerus
55
Q

Posterior forearm- Extensor carpi ulnaris

A
  • Action- extensor of wrist, abduction of wrist
  • Inserts- Metacarpal V
  • Location- medial (little finger)
56
Q

Posterior forearm- Anconeus

A

Assists with pronation and extension

57
Q

Posterior forearm- Extensor digitorum and Extensor digiti minimi

A
  • Responsible for moving the digits.
  • The Extensor digitorum goes to the four digits.
  • The Extensor digiti minimi is on the medial side, it runs between the Extensor digitorum and the Extensor carpi ulnaris, it extend the little finger. Both insert on the extensor hoods.
58
Q

Extensor hoods (Dorsal Digital Expansions)

A
  • Many of the muscles inserting on the posterior aspects of the digits attach to the extensor hood which is also known as the Dorsal Digital expansions.
  • This is a brad flat tendon which extends along the length of the digit
  • Its an expansions of the tendons of extensor muscles
  • Attachments for muscles that extend the digits
  • Attachments for intrinsic hand muscles
59
Q

Posterior forearm- Brachioradialis

A

Doesn’t fit the pattern of the other posterior superficial muscles. It originates from the lateral supraepicondylar ridge in the humerus and is a flexor at the elbow which is most effective in mid-pronation. An intruder. Inserts on the radius. Positioned very laterally

60
Q

Posterior forearm- Deep layer

A
  • Common origin: Posterior radius/ Ulna/ Interosseous membrane
  • Muscles moving the thumb are in the deep layer
  • Supinator
  • Extensor indices
  • Extensor pollicis longus and brevis
  • Abductor pollicis longus
61
Q

Posterior forearm- Supinator

A
  • Originates from the lateral epicondyle/ proximal ulna
  • 2 heads- superficial (lateral epicondyle) and deep (ulna)
  • Inserts on the radius
  • Action= Supination, the radius moves back to its parallel positions. The palm moves from facing down to facing up
62
Q

Pronation and supination of the forearm

A
  • Pronation- Pronator teres, Pronator quadratus. Pulling the radius so it crosses the Ulnar
  • Supination- Biceps brachii, Supinator. The anconeus helps a bit
63
Q

Posterior forearm- Extensor indices

A

• Origin- posterior radius/interosseus membrane
• Inserts on the extensor hood of the index finger
In both the anterior and posterior compartment, muscles moving the thumb are found in the deep layer

64
Q

Posterior forearm- Extensor pollicis longus/brevis and the Abductor pollicis longus

A
  • Extensor pollicis longus origin: Posterior ulna/interosseous membrane
  • Extensor pollicis brevis origin: Posterior radius (distal to abductor pollicis longus)/interosseous membrane
  • Both insert: Distal phalanx thumb
  • Abductor pollicis longus: From radius/ulna and interosseous membrane. Inserts on metacarpal I
  • Both act on the thumb, the Extensor pollicis extends the thumb and Abductor pollicis abducts the thumb. The abductor attaches more to the side of the thumb, the extensors are more on the back of the thumb
65
Q

Posterior forearm innervation

A

All radial nerve:
• In the radial groove in the arm, then passes anterior to the lateral epicondyle. Enters the forearm very anteriorly
• Divides into a superficial and deep branch in the proximal forearm, deep to the brachioradialis

Medicine year 2 semester 2 (47 decks)

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