Anatomy of the Elbow Flashcards
what 3 bones make up the elbow joint?
humerus
radius
ulna
describe the humerus?
largest bone in upper limb long bone expanded laterally (distally); flattened anteroposeriorly; slight curve forward
name the 10 bony landmarks of the humerus (relevant to the elbow)?
capitulum radial fossa coronoid fossa trochlea medial epicondyle lateral epicondyle medial supracondylar ridge lateral supracondylar ridge groove for ulnar nerve olecranon fossa
describe the capitulum?
Articulates with head of radius (meaning its lateral to trochlea)
Convex
Separated from trochlea by a shallow groove
describe the radial fossa?
small shallow depression superior to capitulum
anterolateral (lateral to coronoid fossa)
accommodates head of radius during elbow flexion
describe the coronoid fossa?
small depression found superior to trochlea of humerus
anteromedial (medial to radial fossa)
accommodates head of ulna during elbow flexion
describe the trochlea?
small pulley-shaped projection
inferomedial aspect of condyle of humerus
medial to capitulum
articulates with trochlea notch of ulna (humeroulnar joint formation)
describe the medial epicondyle of the humerus?
Subcutaneous projection found at the distal end of the medial supracondylar ridge of the humerus
More prominent than lateral epicondyle
Contains groove for ulnar nerve
Provides origin site for superficial muscles of anterior compartment of forearm (i.e. common flexor origin)
Attachment site for ulnar collateral ligament
describe the lateral epicondyle of the humerus?
projection found at distal end of lateral supracondylar ridge of humerus
less prominent than medial epicondyle
Provides origin site for superficial muscles of the posterior compartment of the forearm, supinator and anconeus (i.e common extensor origin)
Provides attachment for radial collateral ligament
describe the medial supracondylar ridge of the humerus?
Sharp, prominent margin found along medial aspect of distal end of humerus shaft
Separates anteromedial and posterior surfaces
Provides origin site for pronator teres
describe the lateral supracondylar ridge of the humerus?
Sharp, prominent margin found along lateral aspect of distal end of humerus shaft
Separates anterolateral and posterior surfaces of humerus
Provides origin site for brachioradialis and extensor carpi radialis
describe the groove for ulnar nerve?
shallow depression found on posterior surface of medial epicondyle of the humerus
describe the radius?
long bone
lateral of 2 forearm bones
shorter of 2 forearm bones
head and neck at superior end
name the 4 bony landmarks of the radius (relevant to the elbow)?
dorsal tubercle of radius
head of radius
radial tuberosity
styloid process of radius
describe the dorsal tubercle of radius?
palpable small prominence on posterior aspect of distal end of radius
roughly in line with index finger (between grooves of extensor muscle tendons)
provides attachment for extensor retinaculum and dorsal radiocarpal ligament
describe the head of the radius?
disk shaped expanded area at superior end of bone
2 articular areas:
articular circumference (articulates with radial notch
of ulna medially/ forms superior radioulnar joint
articular facet (articulates with capitulum of
humerus/ forms humeroradial joint)
describe the radial tuberosity?
oval shaped anteromedial aspect of radius at superior end (just inferior to neck)
provides insertion site for biceps brachii
describe the styloid process of radius?
blunt projection found inferomedial aspect of inferior end of bone
provides insertion site for brachioradialis muscle
attachment site for radial collateral ligament of wrist joint+ radioscaphocapiate ligament
easily palpable as sharp and large point on lateral side of wrist
overview of the ulna?
long bone
longer of 2 bones in forearm
medial of 2 bones in forearm
head is distal to the elbow, no neck
what are the 5 bony landmarks of the ulna?
coronoid process
head
olecranon process
styloid process of ulna
ulnar tuberosity
describe the coronoid process?
broad eminence anterosuperior on ulna
superior aspect contains distal portion of trochlea notch
lateral aspect contains radial notch
medial aspect contains sublime tubercle
provides origin for pronator teres, flexor digitorum profundus and the humeroulnar head of flexor digitorum superficialis
insertion site for brachialis
attachment for ulnar collateral ligament
describe the head of the ulna?
distal end of bone
round and expanded
2 articular areas
articular circumference (articulates with ulnar notch
of radius, forming distal radioulnar joint; convex and
smooth
articular facet (attaches to articular disk of distal
radioulnar joint; flat area on inferior aspect of ulnar
head
describe the olecranon process?
subcutaneous and easily palpable
posterosuperior projection at top of ulna (accommodated by olecranon fossa of humerus during elbow flexion)
anterior aspect contains trochlea notch (accommodated by trochlea of humerus during elbow flexion)
provides origin for ulnar head of flexor carpi ulnaris, insertion for anconeus and triceps brachii tendon, and attachment of ulnar collateral ligament
describe the styloid process of ulna?
subcutaneous, cylindrical projection found posteromedially on inferior end of ulna
provides attachment for ulnar collateral ligament of wrist joint
easily palpable
describe the ulnar tuberosity?
large rough elevated area on anterior side of ulna
inferior to coronoid process
provides attachment for brachialis
what 3 joints make up the elbow joint, an what do they all share?
humeroulnar
humeroradial
superior radioulnar joint
fibrous capsule of the ‘elbow joint’
describe the humeroulnar joint+ the movements it can do?
flexion/extension
trochlea (humerus) + trochlea notch (ulna)
stability from medial/lateral collateral ligaments
describe the humeroradial joint+ the movements it can do?
flexion/extension
pronation/supination
capitulum (humerus) + articular facet (radius)
resembles a ball-in-socket joint
stability from anular ligament
describe the superior radioulnar joint+ the movements it can do?
pronation/supination
pivot joint
head of radius + radial notch of ulna
held in place by anular/quadrate ligaments
describe the inferior radioulnar joint?
pronation/supination
pivot joint
convex head of ulna + ulnar notch of radius
radius pivots around the fixed ulna
stability from dorsal and palmer radioulnar ligaments
name the 4 muscles flexing the elbow joint?
biceps brachii
brachialis
brachioradialis
pronator teres
describe the biceps brachii?
origin:
long head =cylindrical tendon at supraglenoid tubercle of scapula within shoulder joint capsule
short head= short flat tendon from apex of coracoid process (anterosuperior to origin of coracobrachialis)
insertion: long and short bellies converge and travel inferiorly to form a single tendon that inserts onto radial tuberosity
action: elbow flexion, shoulder flexion, supinates forearm
superficial to brachialis, and can be palpated with elbow flexed 90degrees and feel origin/insertion sites
describe the brachialis?
lies beneath biceps brachii
travels inferiorly
flat fusiform muscle
origin: anterior aspect of distal half of humerus
insertion: coronoid process/ulnar tuberosity
action: flexes elbow joint
belly can be palpated either side of that of biceps brachii/ distal tendon by applying pressure at coronoid process
describe the brachioradialis?
runs via long tendon all the way to the wrist, and may be fused in upper part to brachialis
origin: superior 2/3 of lateral supracondylar ridge of humerus
insertion: lateral aspect of distal part of radius
action: flexes elbow joint, pronation/supination
can be palpated if elbow flexed 90degrees and resisting pronation, felt along top of forearm; tendon proximal to radial styloid process
what 2 muscles extend the elbow joint?
triceps brachii
anconeus
describe the triceps brachii?
3 heads- medial, long, lateral
origin:
long= infraglenoid tubercle of scapula
medial= inferior to radial nerve groove of humerus
lateral= superior to radial nerve groove of humerus
insertion: all 3 heads converge to single tendon inserting on superior aspect of olecranon (ulna)
action: extends elbow joint
can be palpated with elbow flexed 90degrees, hand on table and pushing down
long= high up on posterior humerus
medial head= just above olecranon
lateral= upper lateral part, near biceps brachii
describe the anconeus?
small triangular muscle behind elbow
origin: posterior aspect of lateral epicondyle of humerus
insertion: posterolateral aspect of olecranon
action: extends elbow joint
can be palpated between lateral epicondyle of humerus and upper part of ulna during supination
what 3 muscles supinate the forearm?
supinator
biceps brachii
brachioradialis
describe the supinator?
travels inferolaterally over elbow joint, spirals over superior 1/3 of radius then inferomedially to insertion
origin: 2 heads
lateral epicondyle of humerus
supinator crest/fossa of ulna
insertion: anterior, posterior and lateral aspects of superior 1/3 of ulna
action: supination of forearm at RU joints
can be palpated with arm fully extended and half pronated; contracts upper 1/3 of radius resisting supination
what 3 muscles pronate the forearm?
pronator teres
pronator quadratus
brachioradialis
describe the pronator teres?
most lateral of superficial muscles in flexor compartment; inferolaterally across ulna to radius
origin: 2 heads
humeral: medial supracondylar ridge (common flexor tendon)
ulnar: medial aspect of coronoid process (ulna)
insertion: middle 1/3 anterolateral aspect of radius via flat tendon
action: pronates forearm at RU joints/ elbow flexion
hard to palpate
describe the pronator quadratus?
square muscle
origin: anterior aspect of distal 1/4 of ulna
insertion: anterior aspect of distal 1/4 of radius
action: pronates forearm at RU joints
difficult to palpate, but can be sometimes felt resisting pronation
