HUMEROULNAR JOINT
(COMMONLY KNOWN AS THE ELBOW
JOINT)
BRUCE BODDEN & JANELLE JAMES
STUDENT PHYSICAL THERAPIST ASSISTANTS
Bones of the Humeroulnar Joint
and their fascinating features
Humerus (distal end articulates with ulna and radius):
• Capitulum – rounded knoblike surface on lateral aspect
• Trochlea – spool-shaped surface located medial to the
capitulum
• Radial fossa – depression just proximal to the capitulum
• Coronoid fossa – depression just proximal to the trochlea
• Olecranon fossa – large depression on posterior aspect
• Medial epicondyle – pronounced projection on medial
aspect
• Lateral epicondyle – less prominent projection on lateral
aspect
BONES OF THE ELBOW…
Ulna
Long bone on medial side of forearm – articulates with the trochlea of the
humerus
Only bone whose head is distal (at wrist joint, not elbow)
Olecranon – posterior aspect of proximal end:
Hook-shaped process that forms the bony prominence of the elbow
Fits into olecranon fossa of humerus when elbow joint is extended
Coronoid process – anterior aspect of proximal end:
smaller projection that fits into coronoid fossa of humerus when elbow joint
is flexed
Trochlear notch – depression between olecranon and coronoid process
Articulates with trochlea of humerus
Radial notch – lateral & inferior to trochlear notch
Articulates with head of radius
Ulnar tuberosity – just inferior to coronoid process
Insertion point for biceps brachii
ULNA
BONES OF THE ELBOW…
Radius
•
•
•
•
Long bone on lateral (thumb) side of forearm
Head articulates with the capitulum of the humerus
Neck – just distal to head
Radial tuberosity – just distal to neck. Also an insertion
point for biceps brachii
• Trochlea of humerus forms a hinge joint with proximal
end of ulna (elbow flexion)
•Capitulum of humerus and head of radius form a joint
that is partly like a hinge, partly ball-and-socket (more on
this in a moment)
•Head of radius forms a pivot joint with proximal end of
ulna (forearm rotation)
RADIUS
Articular capsule
• Composed of two layers
– Outer fibrous layer – thickened continuation of the
periosteum between bones
• Dense irregular connective tissue, connects bone to bone
– Inner synovial membrane – areolar connective tissue with
elastic fibers – lines the internal surface of the fibrous layer
• Cells in this layer secrete hyaluronic acid; this combines with
interstitial fluid filtered from blood plasma to create synovial fluid,
which forms a lubricating film over the articulating surfaces of the
joint
• All articulating surfaces of the bones in the elbow joint (and most freelymoving joints) are covered with a layer of hyaline articular cartilage which
provides a smooth slippery surface to reduce friction between bones.
Also helps to absorb shock.
• At the sides of the elbow joint, dense irregular connective tissue of the
fibrous layer is arranged in parallel bundles called ligaments
ARTICULAR CAPSULE
Ligaments
•
•
Collateral ligaments of the elbow joint
– Anular ligament of radius: encircles and holds the head of the radius in
the radial notch of the ulna
• Forms the proximal radioulnar joint
• Permits pronation & supination of forearm
– Radial collateral ligament: proximally, extends from lateral epicondyle of
humerus; distally, blends with anular ligament of radius
– Ulnar collateral ligament: extends from medial epicondyle of humerus to
coronoid process & olecranon of ulna. Consists of three bands:
• Anterior (cord-like, strongest)
• Posterior (fan-like, weakest)
• Oblique band (slender; deepens the socket for the trochlea of the
humerus)
Interosseous membrane – substantial sheet of dense irregular connective
tissue. Binds radius & ulna together and permits slight movement. (There is
also one of these connecting the tibia & fibula of the lower leg, but that is not
our problem  )
LIGAMENTS OF HUMEROULNAR JOINT
Bursae
• Pouches of synovial-like fluid located at friction
points around joints
– Not strictly part of synovial joints, but resemble
articular capsules because their walls consist of an
outer fibrous membrane of dense connective tissue
lined by a synovial membrane
– Subcutaneous olecranon bursa: located in the
subcutaneous connective tissue over the olecranon
– Subtendinous olecranon bursa: located between the
olecranon and the triceps tendon (just proximal to its
insertion point on the olecranon)
– Intratendinous olecranon bursa: sometimes present
in the tendon of the triceps brachii
BURSAE OF HUMEROULNAR JOINT
Olecranon bursae
SURFACE ANATOMY
• Lateral epicondyle – palpable as a bony point on the outside
of the elbow
• Medial epicondyle – palpable as a bony point on the inside of
the elbow
– (since these are part of the humerus they do not move when the
elbow flexes or the forearm rotates)
• Radial styloid process – palpable as a bony knob at the wrist,
just lateral to radial pulse point
• Ulnar styloid process – head of the ulna is palpable (& usually
visible) as a raised bony point on the medial (pinky) side of
the wrist; styloid process is just distal to that
• Olecranon – palpable & visible as the “point” of the elbow
during flexion
SURFACE ANATOMY
SURFACE ANATOMY
• Cubital fossa – the hollow on the inside of the elbow
• Medial bicipital groove – hollow on the medial side of the
upper arm between bellies of the biceps brachii (anterior) and
triceps brachii (posterior). Brachial pulse is found here.
• Biceps tendon – palpable (& usually visible, with elbow
flexion) just proximal to the cubital fossa.
• Triceps tendon – palpable (& often visible) as a ridge on
posterior of upper arm, extending proximally from the
olecranon
• Carrying angle – at full extension, the arm is not a straight
line. In anatomical position, the long axis of the ulna makes
an angle of ~170o with the long axis of the humerus.
– More pronounced in women (~165o) than men (~170o)
SURFACE ANATOMY
MUSCLES OF THE ELBOW AND FOREARM
MUSCLES OF THE HUMEROULNAR
JOINT
MUSCLES CONT…
MUSCLES CONT…
MUSCLES CONT…
MUSCLES CONT…
MUSCLES CONT…
MUSCLES CONT…
Nerves
• Radial nerve: originates from posterior cord of brachial plexus
– Roots: C5-8, T1
– Motor innervation: triceps brachii and extensors of the hand & wrist
– Sensory innervation: most of the back of the hand
• Ulnar nerve: originates from medial cord of brachial plexus
– Roots: C8 – T1
– Motor innervation: muscles in the forearm that move the hand & wrist (mostly
flexors)
– Sensory innervation: 5th finger, medial half of 4th finger
• Median nerve: originates from lateral & medial cords of brachial plexus
– Roots: C5-8, T1
– Motor innervation: pronator teres, pronator quadratus, flexors of hand & wrist
– Sensory innervation: parts of palm, some fingertips
• Musculocutaneous nerve: originates from lateral cord of brachial plexus
– Roots: C5-7
– Motor innervation: biceps brachii, brachialis, coracobrachialis
– Sensory innervation: lateral forearm
NERVES
Arteries
• Brachial artery: continuation of subclavian artery
( axillary artery  brachial artery)
– Supplies blood to nearly all structures of the arm, incl.
the humerus
– At the cubital fossa, divides to form the radial and
ulnar arteries
• Deep brachial artery (profunda brachii): arises
from brachial artery in upper arm
– Supplies posterior compartment of upper arm
• Radial artery: arises from brachial artery at
cubital fossa (smaller of the two branches)
• Ulnar artery: arises from brachial artery at cubital
fossa (larger branch)
Arteries, cont’d
• Common interosseous artery: arises from
ulnar artery in cubital fossa. Gives rise to
– Anterior interosseous artery
– Posterior interosseous artery
• Interosseous recurrent artery: arises from posterior
interosseous, between radius & ulna
• Superficial palmar arch: direct continuation of
ulnar artery
– Lies across palm at level of distal border of
extended thumb
ARTERIES/VEINS
ARTERIES CONT…
Veins
• Dorsal venous arch: network of veins that drains the dorsal
surface of the fingers & hands. Veins come together to form
the basilic and cephalic veins.
• Basilic vein: travels up the medial side of the arm and joins
the brachial vein to become the axillary vein in the mid-arm
region
• Cephalic vein: travels up the lateral side of the arm and joins
the axillary vein in the pectoral region
• Median cubital vein: crosses cubital fossa between basilica &
cephalic veins
• Median antebrachial vein: drains the venous network of the
palmar side of the hand. Ascends the front of the ulnar side
of the forearm and ends in the median cubital vein.
• Brachial vein: begins at cubital fossa at the joining of the ulnar
& radial veins. Runs parallel to the brachial artery, but deeper.
Joins the basilic vein in the axillary region to become the
axillary vein.
VEINS
TENNIS ELBOW
TENNIS ELBOW CONT…
• Tennis elbow is caused by either abrupt
or subtle injury of the muscle and tendon
area around the outside of the elbow.
Tennis elbow specifically involves the
area where the muscles and tendons of
the forearm attach to the outside bony
area (called the lateral epicondyle) of the
elbow. Your doctor may call this
condition lateral epicondylitis.
CAUSES
• microscopic and macroscopic tears between
the common extensor tendon and the
periosteum of the lateral humeral epicondyle.
An operation conducted in this study showed
that 28 out of 39 patients showed tearing at
the tendon cuff. Radial nerve was significantly
involved in tennis elbow: constriction of the
radial nerve by adhesions to the capsule of the
radiohumeral joint and the short extensor
muscle of the wrist.
TREATMENT
• Tennis elbow usually is successfully
treated by medical means -- such as
physical therapy, forearm bracing to
rest the tendons, topical antiinflammatory gels, topical cortisone
gels, and cortisone injections. It only
rarely requires surgery.