Humerus And Elbow Anatomy

Front 1

In relation to the transepicondylar axis of the humerus, is the humerus retroverted or anteverted and to what degree?

What is the normal neck shaft angle?

Back 1

Retroverted 30 degrees

Neck shaft angle: 130 degrees

Front 2

Which is more commonly involved in fractures, the anatomic or surgical neck of the humerus?

Back 2

The surgical

Front 3

From anterior to posterior, what 3 cuff muscles attach at the greater tuberosity?

Back 3

Supraspinatus, Infraspinatus, Teres Minor

Front 4

What part of the humerus articulates with the olecranon of the ulna? What articulates with the radial head?

Back 4

The trochlea of humerus articulates with the olecranon medially.
The capitellum articulates with the radial head

Front 5

Normal articular alignment of the distal humerus has what type of tilt and to what degree?

Back 5

A 7-degree valgus tilt (carrying angle)

Front 6

What is the axis of rotation for the elbow?

Back 6

Axis of rotation for the elbow is centered through the trochlea and capitellum and passes through a point anteroinferior on the medial epicondyle.

Front 7

In what position will patients hold their arm if they have an elbow effusion because it is the most comfortable?

Back 7

Capsule allows maximum distension at approximately 70 to 80 degrees of flexion

Front 8

Where does the anterior capsule attach at the elbow?

Back 8

Approximately 6 mm distal to the tip of the coronoid. The coronoid tip is an intraarticular structure that is visualized during elbow arthroscopy

Front 9

Where does the MCL of the elbow arise from, where does it insert, how many bundles does it have, and in what motion does it provide stability?

Back 9

Arises from the anteroinferior portion of the medial humeral epicondyle.
The anterior bundle (which is the most important) inserts 18mm distal to the coronoid tip.
Made up of 3 bundles: anterior, posterior, and transverse
Provides stability in valgus stress - valgus stability with the arm in pronation suggests that the anterior bundle is intact

Front 10

What parts make up the radial collateral (lateral collateral) ligament of the elbow? Where does this ligament originate?

Back 10

Annular, Radial, and Ulnar parts. Originates on the lateral humeral epicondyle near the axis of elbow rotation

Front 11

The lateral ulnar collateral ligament (LUCL) is an essential elbow stabilizer and runs between where?

Back 11

Runs from the lateral epicondyle to the ulna supinator crest

Front 12

A deficiency of the LUCL of the elbow manifests as what?

Back 12

Posterolateral rotatory instability of the elbow

Front 13

The musculocutaneous nerves comes from the ______________________ cord of the brachial plexus, pierces the __________ muscle ____________centimeters distal to the ___________. It innervates the ____________, ___________, and ___________ then gives off a branch to the elbow joint before terminating as the ________________ which is located deep to the cephalic vein

Back 13

The musculocutaneous nerves comes from the lateral cord of the brachial plexus, pierces the coracobrachialis muscle 5-8 centimeters distal to the coracoid. It innervates the coracobrachialis, brachialis, and the biceps then gives off a branch to the elbow joint before terminating as the lateral antebrachial cutaneous nerve of the forearm which is located deep to the cephalic vein

Front 14

The radial nerve comes from the __________ cord of the brachial plexus, spirals around the humerus (medial to lateral) in the ________ at a distance of approximately ________ cm from the ________. It emerges on the lateral side of the arm after piercing the _____________ approximately __________ cm above the trochlea between the _________and __________ muscles anterior to the _____________ (where it supplies the ____________ muscle)

Back 14

The radial nerve comes from the posterior cord of the brachial plexus,spirals around the humerus (medial to lateral) in the SPIRAL GROOVE at a distance of approximately 10-14 cm from the ACROMION. It emerges on the lateral side of the arm after piercing the LATERAL INTERMUSCULAR SEPTUM approximately 7.5 cm above the trochlea between the BRACHIALIS and BRACHIORADIALIS muscles anterior to the LATERAL EPICONDYLE (where it supplies the ANCONEUS muscle)

Front 15

What vessel does the median nerve run with in the arm?

Back 15

The brachial artery. The median nerve crosses the brachial artery lateral to medial during its course

Front 16

The ulnar nerve comes from what cord of the brachial plexus? Where does it run in the arm?

Back 16

The medial cord. Passes medial to the brachial artery in the arm and then runs behind the medial epicondyle of the humerus, where it is superficial

Front 17

What structures form the cubital fossa? (3)

Back 17

Distal humerus proximally, the brachioradialis laterally, and the pronator teres medially

Front 18

The brachial artery originates at the lower border of the tendon of the _________ and continues to the elbow, where it bifurcates into the _______ and ________ arteries. It lies medial in the arm, curving laterally to enter the ________________

Back 18

The brachial artery originates at the lower border of the tendon of the TERES MAJOR and continues to the elbow, where it bifurcates into the RADIAL and ULNAR arteries. It lies medial in the arm, curving laterally to enter the CUBITAL FOSSA

Front 19

What are the principal branches of the brachial artery?

Back 19

▪ Deep brachial (also known as the profunda, this artery accompanies the radial nerve posteriorly in the triangular interval)
▪ Superior and inferior ulnar collateral arteries
▪ The nutrient and muscular branches
▪ The supratrochlear artery (the least flexible branch)

Front 20

What is the interval for the proximal approach to the anterior humerus and what structures are at risk?

Back 20

Deltoid (axillary nerve) and pectoralis major (medial and lateral pectoral nerves).
Risk: the anterior circumflex humeral vessels may need to be ligated

Front 21

What is the interval for a distal anterior approach to the humerus?

Back 21

Distal approach: between the biceps (musculocutaneous) and brachialis (musculocutaneous/radial) laterally, or the brachialis can be split because of its dual innervation.

The radial and axillary nerves could be at risk mostly due to traction

Front 22

What is the interval for the posterior approach to the humerus? Describe the superficial and deep approaches.

Back 22

None, it is triceps splitting (radial nerve).

Superficial approach: Dissect between the lateral and long heads of the triceps.

Deep approach: Split the medial head of the triceps.

Front 23

What structure would be at risk with proximal extension of the posterior approach to the humerus?

What structure is at risk if a subperiosteal dissection is not performed meticulously?

Back 23

The Radial nerve: limits proximal extension of approach
Identify and protect the radial nerve as it passes from medial to lateral in the proximal part of the exposure.

Ulnar nerve: jeopardized unless subperiosteal dissection of the humerus is performed meticulously

Front 24

In the posterior approach to the elbow, how is predrilling of the olecranon osteotomy best performed?

Back 24

With a chevron cut 2cm distal to the tip

Front 25

What is the interval for the proximal medial approach to the elbow? What is at risk?

Back 25

between the brachialis (musculocutaneous nerve) and the triceps (radial nerve) proximally. Incise the anterior third of the flexor pronator mass to reach the anterior elbow capsule

Risks: The ulnar and medial antebrachial cutaneous nerves are in the field and must be protected

Front 26

What is the interval for the distal medial approach to the elbow?

Back 26

Between the brachialis (musculocutaneous) and pronator teres (median nerve) distally.

Risks: The ulnar and medial antebrachial cutaneous nerves are in the field and must be protected

Front 27

What is the interval for the lateral or posterolateral (Kocher's) approach to the elbow? How would you protect the PIN from injury?

Back 27

Interval: between the anconeus (radial nerve) and the origin of the main extensor (extensor carpi ulnaris, posterior interosseous nerve [PIN]).

Dissection: Pronate the arm to move the PIN anteriorly and radially, and approach the radial head through the proximal supinator fibers

Front 28

What is the interval to proximally extend the lateral approach to the elbow?
Why should you place a retractor under the brachialis anteriorly?

Back 28

Interval: along lateral intercondylar ridge, between triceps and extensor carpi radialis longus (ECRL) (brachioradialis nerve)
Dissection: Subperiosteally expose the anterior humerus and lateral column.
Risks: retractor placed under brachialis anteriorly to protect radial nerve, distally limited by PIN

Front 29

What are the 3 portals for elbow arthroscopy and what structures are at risk when placing them?

Back 29

1. Anterolateral portal (risk for injury to the radial nerve)
2. Anteromedial portal (risk for injury to the medial antebrachial cutaneous and median nerves)
3. Posterolateral portals

Front 30

What is the origin, insertion, action, and innervation of the following muscle?
Coracobrachialis

Back 30

Origin: Coracoid process
Insertion: Medial mid-humerus
Action: Flexion, adduction of the arm
Innervation: Musculocutaneous (C5-C7)

Front 31

What is the origin, insertion, action, and innervation of the following muscle?
Brachialis

Back 31

Origin: Distal half of anterior surface of humerus
Insertion: Coronoid process and tuberosity of ulna
Action: Flexes forearm
Innervation: Musculocutaneous (C5-C6), Radial Nerve (C5-C7)

Front 32

What is the origin, insertion, action, and innervation of the following muscle?
Biceps brachii

Back 32

Origin: Coracoid (short); Supraglenoid tubercle (long)
Insertion: Radial tuberosity
Action: Supination, flexion of forearm
Innervation: Musculocutaneous (C5-C6)

Front 33

What is the origin, insertion, action, and innervation of the following muscle?
Triceps brachii

Back 33

Origin: Long head: infraglenoid tubercle of scapula; Lateral head: posterior surface of humerus, superior to radial groove; Medial head: posterior surface of humerus, inferior to radial groove

Insertion: Olecranon
Action: Elbow extension
Innervation: Radial (C6-C8)

Front 34

What is the origin, insertion, action, and innervation of the following muscle?
Brachioradialis

Back 34

Origin: Proximal 2/3 of lateral supracondyle ridge of humerus
Insertion: Lateral surface of distal end of radius
Action: Flexes forearm
Innervation: Radial Nerve (C5-C7)

Front 35

What are the sites of compression of the median nerve?

Back 35

Supracondylar process of humerus & ligament of Struthers
Lacertus fibrosis (bicipital aponeurosis)
Pronator teres
Arch of flexor digitorum superficialis

Front 36

What are the possible compression sites of the AIN

Back 36

Deep head of pronator teres
Flexor digitorum superficialis
Aberrant vessels
Accessory muscles (i.e., Gantzer's muscles, which is an accessory head of the FPL)

Front 37

What are the possible sites of compression of the ulnar nerve?

Back 37

1. Arcade of Struthers
2. Medial intermuscular septum
3. Medial epicondyle
4. Cubital tunnel
5. Proximal edge of FCU (Osborne fascia)
6. Deep flexor pronator aponeurosis

Front 38

What is the arcade of struthers?

Back 38

A thin aponeurotic band extending from medial head of triceps to the medial intermuscular septum; it lies approximately 8 cm proximal to the medial epicondyle

Front 39

What is the ligament of struthers?

Back 39

Struthers' ligament is a ligament that extends between the shaft of the humerus and the medial epicondyle of the humerus. It is not a constant ligament and can be acquired or congenital. Its clinical significance arises from the fact that the median nerve, passes in the space between the ligament and the humerus and can be compressed

Front 40

What are the possible compression sites of the PIN?

Back 40

1. Fibrous bands
2. Recurrent leash of Henry
3. Extensor carpi radialis brevis
4. Arcade of Frohse (proximal edge of superficial head of supinator)
5. Supinator distal margin

Front 41

Back 41

Front 42

A fracture at the surgical neck of the humerus could injure what neurovascular structures?

Back 42

The axillary nerve and posterior humeral circumflex artery as they pass through the quadrangular space

Front 43

What neurovascular structures could a fracture of the humeral shaft damage?

Back 43

Radial nerve and deep brachial artery

Front 44

A supracondylar fracture is common in children and occurs when the child falls on the outstretched hand with the elbow in what position? What neurovascular structure is at risk?

Back 44

Elbow in extension. The median nerve is at risk

Front 45

Where does the following cutaneous nerve arise from and what does it innervate?
Supraclavicular nerve

Back 45

Arises from the cervical plexus (C3,C4) and innervates teh skin over the upper pectoral, deltoid, and outer trapezius area

Front 46

Where does the following cutaneous nerve arise from and what does it innervate?
Medial brachial cutaneous nerve

Back 46

Arises from the medial cord and innervates the medial side of the arm

Front 47

Where does the following cutaneous nerve arise from and what does it innervate?
Medial antebrachial cutaneous nerve

Back 47

From the medial cord and innervates the medial side of the forearm

Front 48

Where does the following cutaneous nerve arise from and what does it innervate?
Lateral brachial cutaneous

Back 48

From the axillary nerve and innervates the lateral side of the arm

Front 49

Where does the following cutaneous nerve arise from and what does it innervate?
Lateral antebrachial cutaneous

Back 49

Arises from the musculocutaneous nerve and innervates the lateral side of the forearm

Front 50

Where does the following cutaneous nerve arise from and what does it innervate?
Posterior brachial and antebrachial cutaneous nerves

Back 50

Arise from the radial nerve and innervate the posterior sides of the arm and forearm

Front 51

Where does the following cutaneous nerve arise from and what does it innervate?
Intercostobrachial nerve

Back 51

The lateral cutaneous branch of the second intercostal nerve and emerges from the second intercostal space by piercing the intercostal and serratus anterior muscles. May communicate with the medial brachial cutaneous nerve

Front 52

Describe the path of the radial nerve

Back 52

From the posterior cord of the brachial plexus, passes anterior to the insertion of the latissimus dorsi then dives into the triceps on the posterior surface of the humerus crossing into the radial groove approximately 10-14 cm distal to the acromion. The nerve crosses the midline about 15 cm from the distal articular surface of the elbow and pierces the lateral intermuscular septum ~ 12 cm from the lateral epicondyle. 1-3 cm distal to the lateral epicondyle, deep to the brachioradialis, the radial nerve splits into the PIN and SBRN.

Front 53

Describe the path of the superficial branch of the radial nerve

How far from the radial styloid does the SBRN become subQ?

Where can this be compressed and what are the typical symptoms?

Back 53

The SBRN continues along the lateral border of the brachioradialis (deep to it) and becomes subcutaneous at its middle 1/3 innervating the skin on the radial aspect of the forearm & the dorsal aspect of the radial 3 and 1/2 digits.

Becomes subQ ~9 cm proximal to the radial styloid

Compression can occur between brachioradialis and ECRL where it emerges between. Typical symptoms: numbness and dysaesthesia over the dorsal and lateral aspect of the hand (Tinnel's for dx) -- This is called Wartenberg's syndrome

Front 54

Describe the path of the PIN

Back 54

After branching from the radial nerve 1-3 cm distal to the lateral epicondyle deep to the brachioradialis, the PIN continues down the forearm, diving into the supinator and providing branches to the extensors of the wrist and hand in the following order:
1) Supinator
2) Brachioradialis
3) ECRL
4) ECRB
5) Supinator
6) EDC
7) ECU
8) EDM
9) APL
10) EPB
11) EPL
12) EIP

Front 55

What is the terminal branch of the posterior interosseous nerve?

Back 55

This is a sensory branch to the dorsal wrist capsule and lies in the radial aspect of the floor of the fourth dorsal compartment

Neurectomy procedures have been performed 3-4 cm proximal to the DRUJ to tx chronic wrist pain

Front 56

Where is the first possible site of PIN entrapment?

Back 56

Distal to its origin, the PIN passes deep to fibrous bands that are confluent with the brachialis, brachioradialis, ECRB, and the superficial head of the supinator. These form the roof of the radial tunnel and may compress the PIN against the deep head of the supinator which forms the floor of the radial tunnel along with the capsule of the radiocapitellar joint

Front 57

What is the 2nd structure with the radial tunnel that can compress the radial nerve?

Back 57

The leash of Henry which is made up of recurrent vessels of the radial artery at the level of the radial neck

Front 58

What is the 3rd structure along the path of the PIN that may lead to compression?

Back 58

At the point in which the PIN encounters the ECRB, it can be compressed

Front 59

Where is the 4th and final location the PIN can be compressed?

Back 59

The arcade of Frohse, found beneath the sharp proximal edge of the supinator

Front 60

How would you reproduce pain caused by radial tunnel syndrome?
What is the main symptom of compression of the PIN?

Back 60

Provoked by resisted supination and repetitive forearm pronation or wrist flexion

Because the PIN is mainly a motor nerve, weakness is the main symptom of compression

Front 61

Why is full strength of extension at the wrist maintained with radial tunnel syndrome?

Back 61

The mobile wad is spared because it is innervated proximal to the radial tunnel

Front 62

What is the order of innervation of the radial nerve muscles?

Back 62

Triceps, brachialis, brachioradialis, ECRL, ECRB, anconeus, (PIN): Supinator, EDC, ECU, EDQ, APL, EPB , EPL, EI

Front 63

List the ossification center, ossification age, and fusion age for the ossification centers of the Humerus

Back 63

CENTER OSSIFIES FUSES
Body (primary) 8 wk (fetal) Blends @ 6 yr unites _ @ 20 yr
Head 1 yr
Greater tuberosity 3 yr
Lesser tuberosity 5 yr
Capitulum 2 yr Blends unites w/ body at 16-18
Med epicondyles 5 yr
Trochlea 9 yr
Lat epicondyles 13 yr

Front 64

Describe the course of the median nerve

Back 64

Formed by contributions from the medial and lateral cords of the brachial plexus with contributions from the full plexus (C5-T1). The median nerve does not provide motor or sensory innervation until reaching the elbow.

The nerve courses down the arm within the lateral intermuscular septum with the brachial artery (lateral to the artery), deep to the short head of the biceps. At the midbrachium, it crosses to the medial side of the brachial artery and descends to the antecubital fossa where it lies deep to the bicipital aponeurosis and medial to the antecubital vein

Distal to the elbow, it is found between the FDS and FDP. It emerges from this relationship prior to entering the carpal tunnel and is found medial to the FCR and lateral to the palmaris longus.

Front 65

Describe the course of the musculocutaneous nerve

Back 65

Dives into coracobrachialis at ~5-8 cm distal to the coracoid and travels between the biceps and brachialis innervating the coracobrachialis, long and short heads of the biceps, and half of the brachialis (other half by radial nerve). It terminates as the lateral antebrachial cutaneous nerve providing sensation to the lateral volar surface of teh forearm

Front 66

List the order of innervation for the muscles of the median nerve

Back 66

1. Pronator teres (proximal to the elbow)
2. FCR
3. FDS
4. Palmaris Longus
5.APB
6. 2 lateral lumbricals
7. FPB

Front 67

Where does the palmar cutaneous branch from the median nerve branch?

Back 67

This branch provides sensation to the thenar skin of the palm and most commonly branches 4-5 cm proximal to the wrist on the ulnar side of the FCR. The palmar cutaneous nerve then branches into a radial and ulnar branch. The ulnar branch often penetrates the transverse carpal ligament and is at risk with a radially-placed incision during a carpal tunnel release

Front 68

What are the 2 proximal entrapment syndromes of the median nerve?

Back 68

Pronator syndrome and anterior interosseous syndrome

Front 69

What are the 4 structures that can cause compression leading to pronator syndrome?

Back 69

The ligament of struthers - a ligament about 5cm proximal to the medial epicondyle that extends between the shaft of the humerus and the medial epicondyle of the humerus

Lacertus fibrosis

Muscle belly of the pronator teres

Proximal edge of the FDS

Front 70

What are the symptoms of pronator syndrome?

Back 70

Pain in the proximal volar forearm with associated weakness and numbness of the radial digits

Front 71

What is the provocate movememnt for dx of median nerve compression @ the ligament of struthers?

Back 71

Symptoms reproduced by resisted elbow flexion

Front 72

What is the provocate movememnt for dx of median nerve compression @ the lacertus fibrosis?

Back 72

Resisted elbow flexion with a pronated wrist
or
Resisted supination

Front 73

What is the provocate movememnt for dx of median nerve compression @ the proximal edge of th fdse

Back 73

Resisted pronation with forearm stabilized on a table

Front 74

What symptomatology is different with AIN vs median nerve compression?

Back 74

AIN compression will lack sensory symptoms in the fingers. There may be weakness at the FPL and FDP but with AIN syndrome the thenar muscles should be spared

Front 75

Describe the course of the ulnar nerve

Back 75

Terminal branch from the medial cord with contributions from C8-T1. The ulnar nerve courses medial to the brachial artery anterior to the long head of the triceps. At the level of the attachment of the coracobrachialis to teh humerus (~10 cm proximal to medial epicondyle) it pierces the medial intermuscular septum and enters the posterior compartment and passes under the ARCADE of Struthers approximately 8cm proximal to the medial epicondyle. As the nerve passes posterior to the medial epicondyle through the cubital tunnel, it is covered by Osborne's ligament lateral and the head of the FCU posteromedially. Upon exiting through the cubital tunnel, it courses between the 2 heads of the FCU and enters the anterior compartment of the forearm and runs anterior to the FDP. In the middle of the forearm, approximately 12 cm distal to the medial epicondyle, the ulnar nerve becomes superficial and travels with the ulnar artery. ~ 5cm proximal to the pisiform a dorsal sensory branch is released and the ulnar nerve continues and turns medially at the pisiform to run through Guyon's canal where the nerve splits into motor and sensory branches...(the rest is for hand)

Front 76

Which is more commonly present, the arcade of struthers or the ligament of struthers?

Back 76

The arcade of Struthers is present in 70% of the population while the ligament of struthers is present in only 1% of the population

Arcade: ulnar nerve compression
Ligament: median nerve compression

Front 77

What 2 structures form the cubital tunnel?

Back 77

Osborne's ligament laterally
Head of the FCU posteromedially

Front 78

What does the first branch of the ulnar nerve provide?

Back 78

Sensory innervation to the elbow capsule

Front 79

What are the 3 locations in the arm/elbow that the ulnar nerve can be compressed?

Back 79

Medial intermuscular septum, arcade of struthers, cubital tunnel

Front 80

What is the most common site for ulnar nerve compression?

Back 80

The cubital tunnel

Front 81

What is Froment's sign?

Back 81

Used to detect compression of ulnar nerve (e.g. cubital tunnel). Ask patient to grasp piece of paper butween thumb and radial border of index metacarpal. If the patient has weakness in the adductor, they will attempt to recruit the FPL (innervated by AIN) to hold onto paper

Front 82

What are the attachments of the medial intermuscular septum?

Back 82

Medial lip of the intertubercular sulcus to the medial epicondyle

Front 83

What are the attachments of the lateral intermuscular septum?

Back 83

Lateral lip of the intertubercular sulcus to the lateral epicondyle