Lec 10 Forearm and Elbow Flashcards
Anconeus
MA: Abduct ulna during pronation, stabilize elbow joint, assist triceps with extension
PA: Lateral epicondyle of humerus
DA: Lateral olecranon
N: Radial C7, C8, T1
Supinator
has a superficial and deep layer, deep layer starts on posterior ulna
MA: Supinate the forearm (proximal radioulnar joint)
PA: lateral epicondyle of humerus, radial collateral and anular ligaments, supinator fossa, crest of ulna
DA: lateral, posterior, and anterior surfaces of proximal third of radias
N: PIN of radial nerve C7 and C8
Pronator teres
MA: pronate the forearm (radioulnar joint) (assitst to flex elbow but not really)
PA: common flexor tendon (medial epicondyle of humerus) and coronoid process
DA: lateral surface of radius
N: Median N C6 and C7
Flexor Carpi Radialis
MA: flex the wrist and radial deviation (abduct at wrist)
PA: common flexor tendon (medial epicondyle)
DA: Bases of the 2nd and 3rd Metacarples
N: Median Nerve C6 *C7
Palmaris Longus
MA: Flex the wrist and tense the palmar aponeurosis
PA: common flexor tendon (medial epicondyle)
DA: Flexor retinaculum and palmar aponeurosis
N: Median N C7 and C8 (bc goes down to palm
Flexor Carpi Ulnaris
MA: Flex the wrist, ulnar deviation
PA:
- humeral head: common flexor tendon
- ulnar head: posterior ulna
DA: pisiform, hook of hamate, base of 5th metacarpal
N: Ulnar N C7 and *C8
*Special because its the 1/4 muscle that comes from medial epicondyle that is not innervated by median nerve
Pronator Quadratus
MA: pronate the arm, deep fibers binds the radius and ulna together
PA: distal ulna
DA: distal radius
N: Medial AIN N C8 and T1
What makes up the condyle of the humerus?
Capitellum (lateral)
Trochlea (medial and bigger)
Anterior vs Posterior fossa of humerus (3!)
Anterior is coronoid fossa AND RADIAL FOSSA (lateral)
Posterior is olecranon fossa
Lateral and medial intermuscular spetum
Possibly just to check if we know lateral vs medial humerus
connective tissue structures that extend from the humeral shaft to the surrounding muscles and serve to divide the arm into compartments
Parts of the radius
Head
Neck
Radial tuberosity
Where is the radial tuberosity?
Proximal radius on MEDIAL side
use to help you oriented
Know where to locate the olecranon, tochlear notch, radial notch, supinator crest, coronoid process
What three joints make up the elbow? How many degrees of freedom does the elbow joint have?
3 distinct joints share a common synovial cavity (humeroulnar joint, proximal radioulnar joint, humeroradial
DF: 2
flexion/extension
pronation/supination
Carrying angle
norm 5-15 lateral angle of forearm
only present in supinated position, may be because the trochlea protrudes more distally
Variations of carrying angle
cubitus valgus > 15 degrees
cubitus varus < 5 degrees “gunstock deformity”
Name the two primary elbow ligaments
Collateral ligaments - RCL and UCL
Annular ligament of radius
Where are the RCL and UCL located and what movements do they prevent?
RCL on radial side from humerus to radius,
UCL on ulnar side, has THREE divisions
prevent adduction and abduction of elbow
(so think ligaments on side, prevent side to side motions)
**What are the three divisions of the UCL?
Anterior band - cord like
Posterior band - fan like
Oblique band
Where is the annular ligament of radius?
Wraps around head of radius, connects to ulna
blends in with RCL
What ligament is repaired during tommy john surgery?
UCL
can be due to a rupture after constant stretching
can be fixed with an autogradft from palmaris longus or plantaris
can make a synthetic ligaments (new)
drill holes
Describe the elbow joint capsule
Encapsulates all three articulations
its fairly loose, thin and weak on the anterior / posterior aspect which allows more flexion and extension movements
stronger medially and laterally (ligaments) to prevent side to side mvoements
FOOSH common injuries
Fall on outstretched hand
Monteggia and Galleazzi
**Monteggia
ulnar fracture with radial head dislocation
**Galleazzi
radial fracture with distal radioulnar joint dislocation
Gazelle Running in the Distance
What is significant about the elbow vascular supply?
Anastomotic network of vessels derived from collateral and recurrent (going UP) branches of the brachial, profunda brachii, radial and ulnar arteries
Who is the ulnar artery’s parent structure?
Bracial artery splits into radial and ulnar artery
Who innervates the elbow flexors and extensors?
Flexors - Musculocutaneous N
Extensors - Radial N
Where are bursa located?
3 on back of elbow
Humeroulnar joint - articulation and movements
DF: 1, flexion/extension
Trochlear notch of olecranon process with olecranon fossa
Trochlear notch and trochlear ridge alignment help guide movements of the joint
trochlear ridge - refers to the prominent edges or raised portions on either side of the trochlea. It helps to define the space for the ulna as it articulates with the trochlea
Humeroradial joint articulations and movements
Capitulum and radial head
1DF flex/extension
Proximal radioulnar joint articulation and movements
radial head and radial notch of ulna
synovial pivot
DF: pronation/supination
(forearm rotation)
Cubital Fossa borders
Medial - pronator teres
Lateral - brachioradialis
Superior - kinda the brachialis, epicondyles are good landmark
floor - supinator and maybe brachialis
Cubital fossa contents
TAN
T - Biceps tendon
A - brachial artery
N - Median Nerve
**TAN is LATERAL TO MEDIAL
RADIAL Nerve runs on outside of cubital fossa?
Median cubital vein
joins basilic vein and cephalic vein
venopuncture
Myotomes for elbow flexion and extension
flexion c6 extension c7
radioulnar complex
proximal and distal synovial joints
interosseus membrane
Pronation radius movements
radius functionally shortens
flips over at wrist
What are the functions of the interosseous membrane?
holds radius and ulna together
increases surface area for attachments
collagen fibers transfer axial forces from distal radius to proximal ulna (absorbs shock when you fall)
Oblique cord
Know where it is!!
interosseous membrane
below radial notch of ulna to radial tuberosity
limits distal (inferior) motion of radius “pulled elbow”
Quadrate ligament
radial notch of ulna to neck of radius
Distal radioulnar joint
rounded head of ulna articulates with ulnar notch of radius
synovial pivot
articular disc that helps with pronation/supination and keeps separation between joint and wrist
L shaped joint cavity
TFCC
triangular disc
Triangular fibre cartilage complex
binds the ends of the radius and ulna
connects the anterior and posterior radioulnar ligaments
disc attaches to ulnar styloid process
Separates distal radioulnar joint from radiocarpal joint
KNOW WHERE THE SKIN INNERVATION IS FOR THE 5 TERMINAL BRANCHES
FDS
MA: Flex digits 2-5 at proximal phalanx (MCP), and middle phalanx (PIP joints)
PA: humeroulnar head: medial epicondyle and coronoid process of ulna, radial head: anterior radius
DA: shafts of middle phalanx of digits 2-5
N: Median N C7, C8, T1
Flexor Digitorum Profundus
MA: Flex digits 2-5 at MCP, PIP & DIP
PA: proximal ulna and interosseous membrane
DA: medial part: digits 4&5, lateral part: digits 1&2
N: lateral: Median AIN C8 T1, medial: ulnar C8, T1
Flexor Pollicis Longus
MA: flexes phalanges of thumb
PA: anterior radius and interosseous membrane
DA: base of distal phalanx of 1st digit
N: Median AIN C8 T1
