Flexor, Elbow Joint, Hand Flashcards
What 3 muscles flex the wrist?
1) Flexor carpi radialis
2) Flexor carpi ulnaris
3) Palmaris longus
What 3 muscles flex the digits?
1) Flexor digitorum superficialis
2) Flexor digitorum profundus
3) Flexor pollicis longus
What muscle flexes the DIP joints?
Flexor digitorum profundus
What muscle flexes the PIP joints?
Flexor digitorum superficialis
What 2 muscles flex the MCP joints?
1) Flexor digitorum superficialis
2) Flexor digitorum profundus
What muscle flexes the thumb joint?
Flexor pollicis longus
What muscle is the strongest flexor of the elbow (in the absence of supination)?
Brachialis
NOT biceps brachii
What is the common origin point for the flexor muscles?
Medial epicondyle
What nerve allows for abduction + adduction of the fingers?
Ulnar nerve
What is the stabilizing bone of the forearm?
Ulna
Name the fossae of the distal humerus
1) Radial fossa
2) Coronoid fossa
3) Olecranon fossa
Name the two articular surfaces of the distal humerus
1) Capitulum
2) Trochlea
Name the two proximal projections of the ulna
1) Olecranon
2) Coronoid process
What part of the ulna articulates with the radius?
1) Radial notch articulates w/ head of radius on proximal ulnar end
2) Head of ulna articulates w/ ulnar notch at distal radial end
What are the bony projections at the distal end of the radius & ulna?
Ulnar & radial styloid processes
Name the articular surfaces of the proximal ulna with the humerus
1) Trochlear notch
2) Olecranon
3) Coronoid process
Does the ulna articulate with the carpal bones?
No
Name the proximal row of carpal bones
(Lateral to medial) Scaphoid Lunate Triquetrum Pisiform
“So Long To Pinky”
Name the distal row of carpal bones
(medial to lateral) Hamate Capitate Trapezoid Trapezium
“Here Comes The Thumb”
*trapezi-UM rhymes with thUMB
What nerve is injured with fracture of the surgical neck of the humerus?
Axillary nerve
What nerve is injured with fracture of the mid humeral shaft?
Radial nerve
What nerve is injured with fracture of the distal humerus?
Median nerve
What nerve is injured with fracture of the medial epicondyle?
Ulnar nerve
Colles fracture
- Complete fracture of distal 2 cm of radius
- Most common fracture of the forearm
- Ulnar styloid process often is avulsed
- Typically occurs when people try to break fall with arm
Which carpal bone is susceptible to avascular necrosis and why?
- Scaphoid bone
- Poor blood supply in that area
What nerve can be injured if hamate bone is fractured?
Ulnar nerve (+ possibly artery)
What test assesses status of ulnar nerve?
ABduction/ADduction of fingers
Name parts of proximal end of radius
- Articular fossa
- Articular circumference
- Radial tuberosity
What ligament holds the proximal radioulnar joint together?
Annular ligament (of radius)
Where are the posterior interosseous vessels located?
- Pass through gap between oblique cord and upper end of the interosseous membrane
Oblique cord
- Flat band running obliquely to interosseous membrane
- Slope proximally from just below radial tuberosity superiorly to side of ulnar tuberosity
What two strong ligaments hold the elbow joint together?
1) Radial collateral ligament
2) Ulnar collateral ligament
Attachments of radial collateral ligament
1) Lateral epicondyle
2) Annular ligament of radius
Attachments of ulnar collateral ligament
1) Medial epicondyle
2) Coronoid process + olecranon of ulna
*3 bands
Strongest = anterior (cord-like)
Weakest = posterior (fan-like)
Oblique band - deepens socket for trochlea of humerus
Triangular fibrocartilage complex (TFCC)
- Load-bearing structure between lunate, triquetrum, & ulnar head
- Main uniting structure of distal radius + ulna
- Acts as stabilizer for distal ulna
- Consists of: articular disc, meniscus homologue, ulnocarpal ligament, dorsal & volar radioulnar ligament and extensor carpi ulnaris sheath
Complete fracture
- Cortex to cortex
- Longer to heal
Incomplete fracture
- Cortex one side, not to cortex of other
- Faster to heal
- More commonly seen in Peds due to plasticity of bones
Closed fracture
No skin break
Open (compound) fracture
Skin break
Spiral fracture
- Anterior + posterior component
- Implies rotational force causing fracture
Comminuted fracture
- Multiple fracture lines in one area
- Longer recovery time
Segmental fracture
- Multiple fracture lines with free floating bone segment in between
- Longer recovery time due to blood supply being cut off on both ends (delay osteogenesis)
Stress fracture
Fracture in which bone is “torn” off instead of ligament tearing
Avulsion fracture
Ligament torn off and pulled off piece of bone
Greenstick fracture
- Bone bends & cracks instead of breaking completely
- Think ‘green’ wood
- Intact appearing side likely has microtrabecular fracture
Supination
- Turning palm up
* Think of holding Soup
Pronation
- Turning palm down
* Think of Pouring soup
What muscles supinate the forearm?
- Supinator (resistance absent)
- Biceps brachii (resistance present)
Helped by:
- EPL
- ERCL
What muscles pronate the forearm?
- Pronator quadratus (primary)
- Pronator teres (secondary)
Helped by:
- FCR
- Palmaris longus
- Brachioradialis (when in mid-pronated position)
How to describe alignment of fractures
Always describe the distal fracture fragment
8 ways to describe alignment of fractures
1) Lateral displacement
2) Medial displacement
3) Medial angulation
4) Lateral angulation
5) Internal rotation
6) External rotation
7) Overriding with foreshortening (shortening w/ overlapping)
8) Distraction (pulled apart)
Transverse fracture
Straight across
Oblique fracture
Angled
Damage to intra-articular bones means certain damage to what?
Cartilage –> early DJD
Epiphyseal plate
- Growth plate
- Becomes scar in adults
3 causes for pathologic fractures
1) Tumor (benign, malignant)
2) Stress fractures (insufficiency, fatigue)
3) Metabolic bone disease (osteomalacia, renal osteodystrophy, etc.)
What are the hallmarks of bone formation?
Calcium + phosphate
Normal appearance of elbow joint on XR
- Anterior humeral line lines up w/ capitellum
- Midline of radius lines up w/ capitellum
Sail sign
- Dark sails (fat pads) seen around distal humerus
- Should NEVER see posterior fat pad
- Indicates radial head fracture until proven otherwise
Most common elbow fracture in adults
Radial head fracture
Most common elbow fracture in peds
Distal humerus/supra-epicondylar fracture
Interosseous membrane
Strong connective membrane connecting radius + ulna
What muscles does the ulnar nerve innervate in the forearm?
1) Flexor carpi ulnaris
2) Flexor digitorum profundus (pinky + medial half of digit 4)
What muscles does the median nerve innervate in the forearm?
1) Flexor carpi radialis
2) Palmaris longus
3) Pronator teres
4) Pronator quadratus
5) Flexor digitorum superficialis
6) Flexor digitorum profundus (except last 1.5 fingers)
7)
How many muscles does the anterior compartment of the forearm have?
8
Name the superficial forearm muscles of the anterior compartment.
1st layer:
1) Pronator teres
2) Flexor carpi radialis
3) Palmaris longus
4) Flexor carpi ulnaris
2nd layer:
5) Flexor digitorum superficialis
Name the deep forearm muscles of the anterior compartment.
3rd layer:
6) Flexor digitorum profundus
7) Flexor pollicus longus
4th layer:
8) Pronator quadratus
Flexor carpi ulnaris (origin + insertion)
Origin:
- Medial epicondyle of humerus
- Olecranon
Insertion:
- Pisiform bone
- Hook of hamate
- 5th metacarpal bone
Flexor carpi ulnaris (function + innervation)
Function:
Flexor + ulnar adductor of wrist
Innervation:
- Ulnar nerve (C8) (C7)
Pronator teres (origin + insertion)
Origin:
- Humeral head: Medial epicondyle of humerus
- Ulnar head: Coronoid process of ulna
Insertion:
- Middle of lateral surface of radius
Pronator teres (function + innervation)
Function:
- Pronate + flex forearm
Innervation:
- Median nerve (C7) (C6)
Flexor digitorum superficialis (origin + insertion)
Origin:
- Humero-ulnar head: Medial epicondyle + coronoid process
- Radial head: Oblique line of radius
Insertion:
- Shafts of middle phalanges of digits 2-5
Flexor digitorum superficialis (function + innervation)
Function:
- Flex PIP joints (1st)
- Flex MCP + wrist joints (2nd)
- Assist flexion of elbow + wrist
Innervation:
- Median nerve (C7-T1)
Flexor digitorum profundus (origin + insertion)
Origin:
- Proximal 3/4 of medial + anterior surface of ulna & IOM
Insertion:
- Bases of distal phalanges of digits 2-5
Flexor digitorum profundus (function + innervation)
Function:
- Flex DIP joints (1st)
- While still acting, rolls fingers + wrist into flexion
Innervation:
- Lateral (radial) part : Median nerve (C8) (T1)
- Medial (ulnar) part: Ulnar nerve (C8) (T1)
Pronator quadratus (origin + insertion)
Origin:
- Distal 1/4 of anterior surface of ulna
Insertion:
- Distal 1/4 of anterior surface of radius
Pronator quadratus (function + innervation)
Function:
- Pronate forearm
Innervation:
- Anterior interosseus nerve from median nerve (C8,T1)
Name the branches of the forearm arteries
- Brachial artery ends in distal cubital fossa
- Splits into radial + ulnar
- Each give off anterior + posterior recurrent branches
- Ulnar gives off common interosseous artery which branches into anterior + posterior
- Ulnar + radial arteries anastomose to form superficial + deep palmar arches
Palmaris longus (origin + insertion)
Origin:
- Medial epicondyle of humerus
Insertion:
- Palmar aponeurosis
- Distal half of flexor reticulum
Palmaris longus (function + innervation)
Function:
- Flex hand (at wrist)
- Tense palmar aponeurosis
Innervation:
- Median nerve (C7, C6)
Flexor carpi radialis (origin + insertion)
Origin:
- Medial epicondyle of humerus
Insertion:
- Base of 2nd (3rd) metacarpal
Flexor carpi radialis (function + innervation)
Function:
- Flex + abduct wrist
Innervation:
- Median nerve (C7) (C6)
Flexor pollicis longus (origin + insertion)
Origin:
- Anterior surface of radius & adjacent IOM
Insertion:
- Base of distal phalanx of thumb
Flexor pollicis longus (function + innervation)
Function:
- Flex MCP & IP joints of thumb
- Flex wrist joint, CMC joint
Innervation:
- Anterior interosseous nerve, from median nerve (C8) (T1)
What major branch does the median nerve give off?
Anterior interosseous nerve
What muscle does the median nerve pass between to enter the forearm?
Heads of the pronator teres
What are the 4 muscles of the thumb?
1) Flexor pollicis brevis
2)
