Upper Limb Forearm and elbow Flashcards
(39 cards)
1
Q
Label and describe the bone shown
A
- Top arrow = shaft of the humerus, posteriorly runs the spiral groove through which runs the radial nerve and profunda brachii artery. Humeral shaft fracture can damage these structures.
- Next arrow down = lateral supracondylater ridge
- Next arrow down = Capitulum which allows for pronation and supination
- Next arrow across = Trochlea allows for flexion and extension
- Two arrows above capitulum and trochlea = Epidcondyles
- Ulnar nerve passes posteriorly to the medial epidcondyle and can be damaged by medial epicondyle fracture.
2
Q
What are the symptoms and examination findings of medial and lateral epicondylitis?
A
Common to both medial and lateral epicondylitis:
- Elbow pain during/ after flexion or extension
- exacerbation of pain with repetitive movement or occupational activity
- decreased grip strength
Lateral epicondylitis: “tennis elbow”
- pain at lateral aspect of hte elbow
- tenderness over the common extensor tendon (lateral epicondyle)
- Pain during resisted wrist and digit extension
Medial epicondylitis: “golfers elbow”
- Pain at the medial aspect of the elbow
- tenderness approx, 5cm distal and lateral to medial epicondyle
- Increased pain with resisted forearm pronation or wrist flexion
Plus normal range of movement of elbow and normal sensation
3
Q
Label the radial parts
For each bony landmark describe any distinguishing features e.g. muscle attachments
A
Radius: (4 Arrows moving down)
- Top arrow = head is disk shaped with concave articulating surface, thicker medially forms radioulnar joint
- Neck lies between head and radial tuberosity
- Radial tuberosity is place of attachment for biceps brachii
- Radial shaft expands in diameter as it goes distal and in middle of lateral surface there is a roughening for pronator teres
- Also ridge of bone on radial shaft formed by the attachment of the interosseous membrane
- Radial styloid process palpable in anatomical snuffbox can be fractured when falling onto outstretched hand.
- middle surface of radius is ulnar notch articulates with head of ulna
- Distal surface has two facets, articulates with scaphoid and lunate carpal bones which makes up wrist joint.
4
Q
Label the regions of the ulna
For each bony landmark describe any distinguishing features (e.g. muscle attachment).
A
- Top arrow = trochlear notch -> formed by olecranon and coronoid process, wedge shaped and articulaes with trochear of humerus.
- Next arrow = coronoid process -> ridge of bone projecting anteriorly forming trochlear notch
- Next arrow = shaft
- Ulnar head –> palpable dorsally, articulates with ulnar notch of radius to form distal radioulnar joint
- Ulnar styloid process -> palpable on medial wrist
- Lateral view: Olecranon posteriorly, forms the attachment point for the triceps tendon and is palplable. Covered by a bursa to allow free movement of the skin over the structure.
- Olceranon can be broken by extension with a fall on an outstretched hand. Olecrannon fracture can also be caused by avulsion via strong triceps contraction.
5
Q
Describe the elbow joint articulations
What is the carrying angle and how is this different in women?
A
- Hinge synovial joint connecting upper arm to forearm
- Consists of trochlear notch of the ulna and the trochlea of the humerus
- Head of the radius and capitulum of the humerus
- Carrying angle is the angle between the arm at rest during anatomical position and the rest of the body
- It is wider in women to accomodate wider hips
6
Q
What nerve normally runs behind the medial epicondyle?
What normally surrounds the head of the radius?
What nerve can be damaged by neck of radius fracture?
A
- Ulnar nerve normally runs behind the medial epicondyle
- The head of the radius is normally surrounded by the annular ligament
- The radial nerve spirals laterally around the neck of the radius to form the a deeper branch called the posterior interosseous nerve.
- Fracture to the radial neck can damage the posterior interosseous nerve.
7
Q
What is the posterior interosseous nerve and what does it innervate?
Describe the course of the radial nerve
A
- The posterior interosseous nerve is a deep branch of the radial nerve
- It innervates all of the muscles of the posterior forearm.
- The radial nerve passes through the axilla, through the triangular interval, down the posterior of the humerus in the radial groove (accompanied by profunda brachii artery). It then passes to the anterior compartment between the brachialis and brachioradialis muscles.
- Then anteriorly over the lateral epicondyle though the cubital fossa.
- then terminates into two branches, the deep branch (posterior interosseous nerve) which is MOTOR to the posterior forearm.
- and the superficial branch which is sensory and descends anterorlaterally over the forearm, travels with the radial artery. Passes over the anatomical snuffbox to innervate the dorsal surface of the lateral three and half digits.
8
Q
What are the functions of the ulnar nerve?
What are the symptoms of ulnar nerve damage at the level of the medial epicondyle?
What is the cubital tunnel?
A
- Ulnar nerve innervates the intrinsic muscles of the hand (apart from thenar muscles and two lateral lumbricals) and two muscles in the forearm:
- flexor carpi ulnaris
- Medial portion of flexor digitorum profundus (to 4th and 5th digits).
- Ulnar nerve does sensory to anterior and posterior surfaces of the medial one and a half fingers and associated palm area.
- The cubital tunnel us a space in the dorsal medial elbow that allows the passage of the ulnar nerve. Bordered medially by medial epicondyle, laterally by olcercranon process of ulna.
- Ulnar nerve can become stretched here causing cubital tunnel syndrome
- Presents with:
- numbness/ tingling in the 4th and 5th digits.
- abduction and adduction of fingers cannot occur (paralysis of interossei)
- paralysis of 4th and 5th digits
- adduction of thumb impaired -> Froment’s sign -> patient unable to hold piece of paper between thumb and index finger as paper pulled away.
- Wasting of hypothenar eminaence
9
Q
What surrounds the elbow joint?
where are its weak spots and what does this allow?
A
- Fibrous capsule surrounds the elbow joint, it is weaker anteriorly and posteriorly to permit flexion and extension.
10
Q
Describe the ligaments of the elbow
A
- Joint capsule of elbow stregthened by ligaments medially and laterally
- Radial collateral ligament found on the lateral side of the joint extends from the lateral epicondyle and blends with the annular ligaments of the radius.
- Annular ligament covers the head of the radius and comes from the proximal radioulnar joint
- The ulnar collateral ligament originates from the medial epidocondyle and attaches to the coronoid process and olecranon of the ulna.
11
Q
What force does the lateral collateral ligament of the elbow resist?
What force does the medial collateral ligament of the elbow resist?
A
- Lateral collateral ligament of elbow = radial collateral ligament, resists excess adduction forces / varus forces.
- Medial collateral ligament of elbow = ulnar collateral ligament, resists excess abduction and valgus forces.
12
Q
What is the anconeus triangle?
what are its borders?
Clinical relevance?
A
- Anconeus triangle is a region in the elbow for safe injection or aspiration
- Formed by:
- inferior point of triangle = radial head
- upper point = lateral epicondyle
- upper point = olecranon
13
Q
What joint permits pronation and supination?
What muscles are involved in these movements?
what are their innervations?
A
- Radioulnar joints permit pronation and supination
- Pronation –> pronator teres and pronator quadratus
- Supination –> supinator muscle, biceps brachii
- Supination = most powerful movement controlled by biceps and supinator
- Pronator teres and quadratus -> median nerve therefore pronation controlled by median nerve
- Supinator and biceps brachii –> supinator (radial) and biceps brachii (musculocutaneous).
14
Q
Label the image
What type of joint exists at each articulation between the radius and ulna?
A
- Proximal radioulnar joint –> synovial pivot joint formed between radius and ulna that allows pronation and supination. Annular ligament encircles the radial head which forms the synovial pivot joint.
- Interosseous membrane forms a fibrous joint between the radius and ulna.
- Distal radioulnar joint –> synovial pivot joint
- Articular disk -> between the ulna and the proxumal carpal bones of the wrist. (Wrist formed by articulation of the radius with the carpal bones -> radiocarpal joint).
15
Q
Compartments of the forearm:
What are the two compartments?
What is the main function of each compartment?
what is the main innervation of each compartment?
A
- Anterior compartment –> flexion and pronation, mostly median nerve except flexor carpi ulnaris and the medial half of flexor digitorum profundus (Ulnar nerve).
- Posterior compartment –> extensors, supinator and thumb abductor, all innervated by Radial nerve (or its posterior interosseous branch).
16
Q
Label the image
A
Top layer starting medial to lateral :
- flexor digitorum superficialis
- Flexor carpi ulnaris
- brachioradialis
Deeper layer medial to lateral:
- Flexor carpi ulnaris
- flexor digitorum profundus
- Flexor pollicis longus
Medial blue arrows point to ulnar artery and ulnar nerve
Lateral blue arrows to median nerve and radial artery
17
Q
Label and describe the actions and innervations of the muscles of the top layer of anterior forearm.
A
- Superficial muscles in anterior compartment are flexor carpi ulnaris, palmaris longus, flexor carpi radialis and pronator teres.
- All originate from common tendon which arises from the medial epicondyle of humerus.
From left to right:
- Pronator teres -> from medial epicondyle and coronoid process of ulna, attaches laterally to midshaft of radius –> pronation of forearm. (Median N)
- Flexor carpi radialis -> originates medial epicondyle attaches to base of metacarpals 1 and 2. Flexion and adduction of the wrist.
- Palmaris longus –> from medial epicondyle, attaches to flexor retinaculum. Flexion of wrist. (Median N)
- Flexor carpi ulnaris –> from medial epicondyle and ulna, attaches rto pisiform. Flexion and adduction of wrist. (Ulnar N).
18
Q
Describe the muscle/s in the anterior forearm: layer 2
A
- Only muscle in intermediate compartment = Flexor digitorum superficialis
- Good landmark -> median nerve and ulnar artery pass between its two heads
- Origins: one from medial epidondyle of humerus, other from radius.
- Splits into 4 tendons at wrist, travel in carpal tunnel under the transverse carpal ligament and attaches to middle phalanges of 4 fingers.
- Flexes metacarpophalangeal joints and PIP joints of 4 fingers, flexes at wrist.
- Innervation median nerve.
19
Q
Describe the muscles of the deep compartment of the forearm (layer 3)
Actions/ innervations.
Label the image.
A
-
Blue: Flexor digitorum profundus:
- origin from ulna, interosseous membrane
- splits into 4 tendons travels via carpal tunnel
- attaches to distal phalanges of 4 fingers
- Action only muscle that can flex at the distal interphalangeal joints. Also flexes at PIP and metacarpophalangeal joint and wrist.
- Innervation: digits 2 & 3 -> median nerve. Digits 4 & 5 -> ulnar nerve
-
Red: flexor pollicis longus
- muscle lies lateral to FDP.
- Origin from radius and interosseous membrane
- attaches to base of distal phalanx of thumb
- flexes the interphalangeal joint and metacarpophalangeal joint of the thumb
- innervation: median nerve
-
Green: Pronator quadratus
- square shaped muscle deep to FDP and FPL
- origin from ulna to radius
- pronates forearm
- median nerve
20
Q
What is the golden rule for innervation of the anterior compartment of the forearm?
A
Everything is innervated by the median nerve except:
Flexor carpi ulnaris
Flexor digitorum profundus to fingers 4 and 5
21
Q
What sensory loss would be associated with median nerve damage?
A
- Median nerve responsible for cutaneous innervation of part of the hand:
- Palmar cutaneous branch –> innervates lateral aspect of the palm
- Digital cutaneous branch –> innervates palmar surface and fingertips of the lateral three and half digits.
22
Q
How to the tendons of FDP travel to the distal interphalangeal joint?
A
- Tendons of FDP pass through the FDS and both are held down by a pulley system.
23
Q
Describe the muscles in the superficial layer of the posterior compartment of the arm:
Common origin
Label image shown
Actions / Innervations
A
- Common extensor origin = lateral epicondyle, all muscles in posterior compartment innervated by radial nerve.
-
From Anconeus: (working way to right of picture)
- originates at lateral epicondyle and attaches to the posterior and lateral part of the olecranon
- extends and stabilises elbow joint
- aducts ulna during pronation of forearm
-
Extensor carpi ulnaris:
- origin from lateral epicondyle to base of metacarpal V
- extension and adduction of wrist
-
Extensor Digiti minimi:
- Origin lateral epicondyle attaches to extensor digitorum tendon, into extensor hood of little finger
- extends little finger, extension of the wrist
-
Extensor digitorum:
- originates from lateral epicondyle, splits into 4, inserts into extensor hood of each finger
- extends medial 4 fingers at MCP and IP joints
-
Extensor carpi radialis brevis and longus:
- ECRL origin from supracondylar ridge whereas ECRB from lateral epicondyle
- tendons insert onto metacarpals 2 and 3
- extend and abduct wrist
24
Q
Describe the muscles in the deep compartment of the posterior forearm:
Name/ Action/ Innervation
Label them on the image
A
- 5 muscles in deep compartment of posterior forearm: All innervated by Radial nerve
- Supinator
- abductor pollicus longus
- extensor pollicis brevis
- extensor pollicis longus
- extensor indicis
-
Supinator:
- 2 heads, origin from lateral epicondyle and ulna
- inserts onto posterior radius
- supinates forearm
-
Abuductor pollicis longus:
- originates interosseous membrane and ulna/ radius
- inserts lateral side of metacarpal 1
- abducts thumb
- Extensor pollicis brevis: lateral border anatomical snuffbox
- medial and deep to abductor pollicus longus
- originates posterior radius and interosseous membrane
- inserts base of proximal phalanx of thumb
- extends metacarpophalangeal and carpometacarpal joints
-
Extensor pollicis longus: medial border anatomical snuffbox
- originates posterior ulna and interosseous membrane
- inserts distal phalanx of thumb
- extends all joints of thumb: carpometacarpal, metacaropohalangeal and interphalangeal.
-
Extensor indicis
- originates posterior ulna and interosseous membrane
- attaches to base of 2nd proximal phalanx
- extends index finger only to PIP joint
25
What is the golden rule of the posterior forearm innervation?
* Everything is posterior interosseous nerve (branch of radial nerve) supplied
26
What sensory loss is associated with radial nerve damage?
* 4 branches of the radial nerve that provide cutaneous innervation to the skin of the upper limb
* Three branches arise in the upper arm:
* lower lateral cutaneous nerve of arm
* posterior cutaneous nerve of arm
* posterior cutaneous nerve of the forearm
* 4th branch = superficial branch terminal division of radial nerve
* innervates the dorsal surface of hte lateral three and a half digits and area of the back of the hand
27
Describe the extensor compartments of the wrist
* There are six extensor compartments that cross the wrist and contain specific posterior forearm tendons covered in common synovial sheaths
* These are tight compartments so can become worn and get tenosynovitis
* i: extensor pollicis brevis, abductor pollicis longus
* ii: extensor carpi radialis longus, extensor carpi radialis brevis
* iii: extensor pollicis longus
* iv: extensor digitorum, extensor indicis
* v: extensor digiti minimi
* vi: extensor carpi ulnaris
28
Clinical conditions associated with extensor compartments
* **Compartment 1** --\> abductor pollicis longus and extensor pollicis brevis inflammation --\> **De Quervains tenosynovitis** and **pain** on outside of the wrist
* **Compartment 3** --\> **Extensor pollicus longus** can wear on the **dorsal radial tubercle** and **rupture**
* Compartment 6 --\> **Extensor carpi ulnaris** can wear on the **ulnar styloid process and rupture**
29
# Fill the blanks:
What muscle is this?
What is its action?
What roots does tapping its tendon test?
What border does it form of what anatomical region?
* Brachioradialis is a flexor muscle but situated in the posterior compartment of the arm (innervated by the radial nerve)
* It forms the lateral border of the cubital fossa
* Tapping the brachioradialis tendon at the wrist tests C5/C6 reflex
* Action: Flexes the elbow, moves the forearm to midpronation /supination.
* Origin: from lateral supracondylar ridge of humeru, attaches to distal end of radius before radial styloid process
30
Cubital fossa:
Borders
Floor and roof
Clinical relevance
* **Superior border = inter- epicondylar line,** imaginary line between the epicondyles
* **Lateral border =** medial border of **brachioradialis**
* **Medial border -** lateral border of **pronator teres**
* **Floor --\> brachialis** proximally and **supinator** distally
* **Roof --\> Skin, fascia, bicipital aponeurosis (note bicipital aponeurosis protects the median nerve and brachial artery from clinicians).**
* **Biceps tendon** runs centrally through the fossa, useful landmark of **brachial artery** and **median nerve** which sit medially to it.
* Clinical relevance:
* brachial pulse and blood pressure
* venepuncture -\> median cubital vein located superficially in roof of cubital fossa, connects basilic and cephalic veins and can be accessed easily.
31
Contents of cubital fossa
* Radial nerve passes underneath the brachioradialis muscle and divides into its deep and superficial branches
* Biceps tendon runs through the cubital fossa attaching to radial tuberosity
* Brachial artery runs medial to biceps tendon, bifurcates into radial and ulnar arteries at the apex of cubital fossa
* Median nerve runs medial to brachial artery and leaves the cubital fossa between the two heads of the pronator teres
32
Describe the superficial veins of the cubital fossa
* **Basilic vein** --\> "inner vein", runs medially
* **Cephalic vein** --\> "head" therefore runs towards head, laterally
* Basilic and cephalic vein joined by **medial cubital vein**
* Basilic moves deep into the arm at the border of teres major, combines with brachial veins to become axillary vein
* Cephalic vein travels between deltoid and pectoralis major and enters axillar region to empty into axillary vein
33
# Fill the blanks
What vein is often safest for phlebotomy or cannulation?
Cubital vein often saftest for phlebotomy
Cutaenous nerves travel near the superficial veins of the arm
Medial basilic, connecting is the median cubital vein, laterally is the cephalic vein
34
Describe the nerves of the forearm
Their courses through the forearm and points of compression/ anatomical relations
* Median and radial nerves pass anterior to the elbow, the ulnar nerve passes posterior to the elbow
* **Ulnar nerve** passes through the **cubital tunnel** and **posterior to the medial epicondyle** and then enters the forearm, possible point of compression
* Then runs into the hand under the cover of the **FCU** and **lateral** to the **pisiform bone** -\> potential point of compression
* **Median nerve** runs **medial to the biceps brachii tendon** in the cubital fossa, innervates majority of the flexors in the forearm. Sits lateral or just under **palmaris longus** at the wrist
* **Radial nerve** runs **lateral to biceps tendon,** gives off **deep posterior interosseous branch** that passes close to the **radial neck**
35
Describe the arterial supply to the forearm
* Radial and ulnar arteries are formed by the bifurcation of the brachial artery in the cubital fossa
* Radial artery supplies posterolateral aspect of forearm, contributes to anastomotic networks suorround elbow joint and carpal bones
* Radial artery palpate immediately lateral to prominent tendon of flexor carpi radialis
* Ulnar artery supplies anteromedial aspect of the forearm and contributes to anastomotic network around elbow joint
* Also gives rise to common interosseous artery that splits into anterior and posteriro interosseous arteries which supply deep structures in the forearm
* Radial and ulnar arteries anastomose in the hand forming two arches, superficial and deep palmar arch
36
Describe arterial supply to the hand
* Arterial supply to the hand is rich to ensure arterial supply even under high resistance to flow (e.g. grasping action), formed by ulnar and radial arteries
* **Superficial palmar arch:**
* anterior to flexor tendons in the hand and deep to palmar aponeurosis
* gives rise to digital arteries supplying 4 fingers
* **Deep palmar arch:**
* Located deep to flexor tendons of the hand, contributes to blood supply to the digits and wrist joint.
37
What would happen to the hand it the radial artery was blocked proximal to the wrist?
If the radial artery is blocked proximal to the wrist, blood supply to the hand should still be functional as long as the palmar arches are intact.
You can harvest the radial artery for CABG as long as the palmar arteries join up with each other.
Allens test -\> branches of ulnar and radial artery are compressed then released and pattern of filling in the hand is observed and assessed. Plays screen method to assess circulation of the hand before harvest of radial artery for CABG.
38
Where does the radial artery sit in the wrist?
Clinical uses of radial artery?
* Radial artery sits lateral to the FCR at the anterior wrist
* Can be cannulated for ABG
* Harvested for CABG
* anastomosed to cephalic vein for dialysis port
39
Where does the ulnar artery sit in the wrist?
* Ulnar artery sits under or lateral to the flexor carpi ulnaris at the anterior wrist
* It bends as the wrist is extended and flexed and gives many branches to the skin
