U4: Bones & Joints of Elbow and Forearm

label the features (ant/distal humerus)

1. A - radial fossa

2. B - coronoid fossa

3. C - medial epicondyle

4. D - trochlea

5. E - capitulum

what is the radial fossa

a small, anterior depression

• found above capitulum

• which recieves radial head

what is the coronoid fossa

a small, anterior depression

• found above trochlea

• which receives coronoid process of the ulna

what is the medial epicondyle (of the humerus)

a large medial projection

• on the distal humerus

• acts as an attachment site for the MCL/UCL

what is the capitulum

a rounded, lateral articular surface

• of the distal humerus

• which articulates with the radial head

what is the trochlea

a medial articular surface

• of the distal humerus

• which articulates with the trochlear notch of the ulna

label the features (post/distal humerus)

1. A - olecranon fossa

2. B - lateral epicondyle

what is the olecranon fossa

a large, posterior depression

• of the distal humerus

• which receives olecranon process of the ulna

what is the lateral epicondyle (of the humerus)

smaler, lateral projection

• on the distal humerus

• acts as an attachment site for the LCL/RCL

what is the radius

lateral forearm bone which

• articulates w/ the wrist

• rotates around the ulna (during pronation/supination)

• connected to the ulna via IM

• small → big

what is the ulna

medial forearm bone which

• articulates w/ humerus = humeral-ulnar joint (elbow)

• connected to the radius via IM

• big → small

label the features (ant/proximal radius + ulna)

1. A - radial notch of ulna

2. B - coronoid process

3. C - ulnar tuberosity

4. D - radial tuberosity

5. E - radial neck

6. F - radial head

what is the radial notch (of the ulna)

small, lateral depression

• on the proximal ulna

• which articulates with the radial head = superior radial-ulnar joint

what is the coronoid process (of the ulna)

anterior projection

• on the proximal ulna

• which stabilizes the elbow joint

what is the ulnar tuberosity

rough projection

• found inferior to the coronoid process

• on the proximal ulna

• acts as an attachment site for the brachialis

what is the radial tuberosity

rough projection

• on the medial, proximal radius

• acts as an attachment site for the biceps brachii

what is the radial head

proximal end of the radius

• which articulates w/ the capitulum (humerus) + radial notch (ulna)

• allows for pronation/supination (forms the superior radio-ulnar joint)

label the features (ant/distal radius + ulna)

1. A - radial styloid process

2. B - ulnar head

3. C - ulnar styloid process

what is the ulnar head

rounded, distal end

• of the ulna

• which articulates w/ the radius = inferior radio-ulnar joint

• allows for pronation/supination

label the features (post/proximal radius + ulna)

1. A - olecranon process

2. B - radial notch of ulna

3. C - radial head

4. D - radial neck

what is the olecranon process

large, posterior projection

• of the proximal ulna

• forms the tip of the elbow

• acts as an attachment site for the triceps brachii

• fits into the olecranon fossa

label the features (post/distal radius + ulna)

1. A - ulnar notch of radius

2. B - ulnar styloid process

3. C - dorsal radial tuberosity

4. D - radial styloid process

what is the ulnar notch of radius

medial depression

• on the distal radius

• which articulates w/ the ulnar head

• forms the inferior radio-ulnar joint = pronation/supination

what is the dorsal radial tuberosity

posteiror projection

• on the distal radius

• acts as a pulley for tendon to go around

label the features (lateral/proximal of ulna)

1. A - olecranon process

2. B - trochlear notch

3. C - radial notch of ulna

4. D - coronoid process

what is the humero-ulnar joint

a hinge joint

• found between the trochlea (humerus) / trochlear notch (ulna)

• very stable due to its high congruency

movements permitted by the humero-ulnar joint

1. flexion/extension (hu)

what is the humero-radial joint

a pivot joint

• found between the capitulum (humerus) / radial head (radius)

movements permitted by the humero-radial joint

1. flexion / extension

what is the superior radio-ulnar joint

a pivot joint

• found between the radial head (radius) / radial notch of the ulna

• which is stabilized by the anular ligament

what is the inferior radio-ulnar joint

a pivot joint

• found between the ulnar head (ulna) / ulnar notch of radius

movements permitted by the superior/inferior radio-ulnar joint

1. pronation/supination

what is the MCL/UCL

on the medial side of the elbow

• between the medial epicondyle (humerus) / medial olecranon process (ulna)

• resists valgus stress (push laterally)

what is the LCL/RCL

on the lateral side of the elbow

• between the lateral epicondyle (humerus) / lateral olecranon process (ulna)

• resists varus stress (push medially)

what is the anular ligament

ring-shaped ligament

• which attaches on either side of the radial notch of ulna

• helps hold the radial head in place

• holds the superior radio-ulnar joint together

what is the palmar radio-ulnar ligament

ligament..

• on the anterior (palmar) side

• connects the ulnar notch of radius / ulnar head

• stabilizes the inferior radio-ulnar joint (keeps them from spreading apart)

what is the dorsal radio-ulnar ligament

ligament..

• on the posterior (dorsal) side

• connects the ulnar notch of radius / ulnar head

• stabilizes the inferior radio-ulnar joint (keeps them from spreading apart)