upper extremity - the elbow Flashcards
what are the bones involved in the elbow?
humerus, ulna, & radius
where is the radius located when in anatomical position?
lateral (same side as thumb)
where is the ulna located when in anatomical position?
medial (same side as pinky finger)
what are the 3 synovial joints in the same articular cavity/capsule in the elbow?
- humeroulnar joint
- humeroradial joint
- proximal radioulnar joint
what kind of synovial joint is the humeroulnar joint?
hinge/trochlear joint
what kind of synovial joint is the humeroradial joint?
hybrid ball-and-socket joint
what kind of synovial joint is the proximal radioulnar joint?
troichoid joint
movements allowed by the humeroulnar joint
flexion/extension
movements allowed by the humeroradial joint
flexion/extension;
pronation/supination
movements allowed by the proximal radioulnar joint
pronation/supination
what two distinct articular surfaces does the distal humerus have?
- trochlea articulating with the trochlear notch of the ulna
- capitulum (head) articulating with the head of the radius
important anterior bony landmark for mid-to-distal humerus
medial: trochlea, coronoid fossa, medial epicondyles & supracondylar ridges
lateral: capitulum, radial fossa, lateral epicondyles & supracondylar ridges
origin of brachialis muscle
important posterior bony landmark for mid-to-distal humerus
olecranon fossa; medial & lateral epicondyles & supracondylar ridges;
origin of medial & lateral heads of triceps & anconeus muscles
what is the purpose of the medial & lateral epicondyles & supracondylar ridges?
serves as attachment sites for multiple forearm muscles
important bony landmarks of the radius
head; radial tuberosity; styloid process; superior aspect; ulnar notch
important bony landmarks of the ulna
olecranon process; radial notch; trochlear notch; coronoid process; ulnar tuberosity; styloid process; head
what happens during flexion of the humeroulnar joint?
the coronoid process of the ulna enters the coroing fossa of the humerus
what happens during extension of the humeroulnar joint?
the olecranon process of the ulna enters the olecranon fossa of the humerus
how is the humeroulnar joint’s bony congruency?
strong (joint is very stable)
how is the humeroulnar joint so stable?
it is enhanced by strong surrounding capsule and ligaments
where is the humeroulnar joint located?
located between the trochlear notch of the ulna & the trochlea of the humerus
where is the humeroradial joint located?
located between the fovea of the radial head & the capitulum of the humerus
how is the humeroradial joint’s bony congruency?
poor
why is the humeroradial joint’s bony congruency so poor?
this is due to the joint being stabilized by surrounding capsule, ligaments, & muscles
what dictates the movements at the humeroradial joint?
the humeroulnar joint & radioulnar joint (proximal & distal)
what happens during flexion/extension at the humeroradial joint?
this joint moves with the ulna
what happens during pronation/supination at the humeroradial joint?
this joint rotates along the longitudinal axis
where is the proximal radioulnar joint located?
located between the head of the radius & the radial notch of the ulna
movements allowed by the proximal radioulnar joint
pronation/supination with distal radioulnar joint
what holds the head of the radius in the proximal radioulnar joint?
held in the radial notch by the annular ligament & quadrate ligament
what allows for motion in the annular ligament to the proximal radioulnar joint?
deep surface lined with hyalin & fibrocartilage
where is the distal radioulnar joint located?
located between the head of the ulna & the ulnar notch on the radius
how is the radioulnar joint’s bony congruency?
poor
what holds the distal radioulnar joint?
capsule, ligaments, & articular disc located between head of ulna & carpal bones
what cartilage is found at the distal radioulnar joint?
triangular fibrocartilage complex (TFCC)
what kind of cartilage is the triangular fibrocartilage complex?
fibrocartilage
purpose of the triangular fibrocartilage complex
maintains head of ulna snuggly against ulnar notch of radius;
added stability for ulnocarpal joint
physical property of triangular fibrocartilage complex
edge of disc are continuous with radioulnar capsular ligaments
ligaments found at the elbow
medial collateral ligament (anterior & posterior fibers); radial collateral ligament; lateral (ulnar) collateral ligament; annular ligament; quadrate ligament
motions increasing tension at the medial collateral ligament (anterior fibers)
valgus & extension
motions increasing tension at the medial collateral ligament (posterior fibers)
valgus & flexion
motions increasing tension at the radial collateral ligament
varus
motions increasing tension at the lateral (ulnar) collateral ligament
varus, flexion, & external rotation of elbow complex
motions increasing tension at the annular ligament
distraction of radius
motions increasing tension at the quadrate ligament
pronation/supination & distraction of radius
range of motion at the elbow during flexion
active: 120°
passive: 140°
range of motion at the elbow during extension
0° to -5° (hyperextension)
range of motion at the elbow during pronation/supination
80°-90°
what are the types of muscles of the elbow complex?
elbow flexors/extensors & forearm supinators/pronators
what muscles are elbow flexors?
biceps brachii;
brachialis;
brachioradialis;
pronator teres
what muscles are elbow extensors?
triceps brachii & anconeus
what muscles are forearm supinators?
supinator & biceps brachii
what muscles are forearm pronators?
pronator teres & pronator quadratus
origins of biceps brachii
long head: supraglenoid tubercle (scapula)
short head: coracoid process (scapula)
insertions of biceps brachii
radial tuberosity & bicipital aponeurosis
actions of biceps brachii
shoulder flexion & abduction;
elbow flexion & supination
origin of brachialis
distal half of anterior portion of humerus
insertion of brachialis
coronoid process
action of brachialis
elbow flexion
origin of brachioradialis
lateral supracondylar ridge of humerus
insertion of brachioradialis
styloid process of radius
action of brachioradialis
elbow flexion when elbow is in neutral position
origins of pronator teres
medial epicondyle & coronoid process of ulna
insertion of pronator teres
proximal third of radius on lateral surface
action of pronator teres
elbow flexion & forearm pronation
origins of triceps brachii
long head: infraglenoid tubercle (scapula)
lateral head: proximal half of posterior humerus
medial head: distal 2/3 of posterior humerus
insertion of triceps brachii
olecranon process (ulna)
actions of triceps brachii
extension in elbow & shoulder
what assists during shoulder extension in the triceps brachii?
long head of the triceps brachii
origin of anconeus
lateral epicondyle (humerus)
insertion of anconeus
olecranon process (ulna)
action of anconeus
assists triceps brachii in elbow extension
origins of supinator
lateral epicondyle (humerus) & supinator crest (ulna)
insertions of supinator
lateral, posterior & anterior aspects of proximal third of radius
action of supinator
forearm supination
origin of pronator quadratus
distal 1/4 of anterior aspect of ulna
insertion of pronator quadratus
distal 1/4 of anterior aspect of radius
action of pronator quadratus
forearm pronation
what is the purpose of the interosseus membrane?
improves stability between radius & ulna;
provides greater surface area for muscle attachment of forearm, hand & finger muscles
what increases stability between the radius & ulna?
interosseus membrane;
oblique cord;
distal oblique fibers;
hiatuses
what is a hiatus?
opening in soft tissue for blood vessels & nerves
what is little league elbow?
occurs when repetitive overhand throwing without adequate rest that results in injuries ranging from soreness to fractures to ripped ligaments