Elbow and Arm Review

Question 1

Name the bony landmarks on the elbow and arm

Answer 1

• lateral epicondyle
• medial epicondyle
• capitulum
• trochlea
• head of radius
• conoid process of ulna
• radial tuberosity
• ulnar tuberosity
• olecranon process

Question 2

Describe the trochlea

Answer 2

• medial side of humerus
• meets up with ulna

Question 3

Describe the medial epicondyle

Answer 3

• looks like thumb sticking out of bone, very prominent because a lot of finger & wrist flexors originate here

Question 4

Describe the capitulum

Answer 4

• rounded, almost spherical shape along lateral side of articular surfaces of humerus
• meets up with radius

Question 5

Describe the head of radius

Answer 5

• relatively flat, slight concavity
• rounded surface if you look from above
• will spin around radial notch on ulna (probation & supination)

Question 6

Describe the radial tuberosity

Answer 6

• on proximal end of radius
• leans towards medial side
• attachment for biceps brachii

Question 7

Compare the size of the medial epicondyle and lateral epicondyle

Answer 7

Medial: very prominent
Lateral: very subtle

Question 8

What is the ulnar tuberosity an attachment for?

Answer 8

Brachialis

Question 9

Where is the conoid process located?

Answer 9

Ulna @end where it meets up with the trochlea of humerus

Question 10

Describe the olecranon process

Answer 10

• ulna scoops into back of humerus, males olecranon process
• “funny bone”
• most proximal end of ulna
• hooks into olecranon fossa on humerus

Question 11

How does the structural integrity of the elbow relate to injury?

Answer 11

• elbow has a lot of bony congruency, very stable joint
• ulna wraps around the trochlea of the humerus
• usually need someone with excessive amount of laxity/looseness through the joint or have huge amount of force coming in (especially fast & in extended elbow like Olympic lift)

Question 12

Name the joints of the elbow

Answer 12

-superior radio-ulnar joint
- humero-ulnar joint
- humero-radial joint

Question 13

Describe the superior radio-ulnar joint

Answer 13

• head of radius resting against concave notch on ulna
  -allows radius to spin through pronation and supination for rest of forearm
  *We need the radius to be held against ulna but not so much that it can’t spin = annular ligament!

Question 14

Describe the annular ligament

Answer 14

• attached to anterior & posterior margins of the radial notch on the ulna
• loops around radial head but doesn’t actually attach to it
• allows radius to spin against ulna but still be attached

Question 15

Describe the humero-ulnar joint

Answer 15

• olecranon process on back and conoid on front
• scoop around trochlea

Question 16

Describe the humero-radial joint

Answer 16

• head of radius slightly concave on superior end: meets up with capitulum

Question 17

Name the elbow ligaments

Answer 17

Radial-collateral ligament
Ulnar-collateral ligament

Question 18

Describe the radial-collateral ligament

Answer 18

• lateral side of elbow
• almost triangular in shape (it up by two bands)

Bands start @ lateral epicondyle of humerus
- 1 band moves anteriorly, 1 posteriorly
- both blend into annular ligament
- posterior band blends into part of ulna (superior crest)

** pulled apart with varus position (uncommon)

Question 19

Describe the ulnar-collateral ligament

Answer 19

• has 3 bands: all 3 start @ medial epicondyle of humerus (anterior, posterior, transverse)
• limits valgus forces (common especially in sports with rapid & powerful elbow extension like pitching and throwing)

Question 20

Describe the location of the anterior band of ulnar-collateral ligament

Answer 20

• start @ medial epicondyle of humerus
• lands on coronoid process on the front

Question 21

Describe the location of the posterior band of the ulnar-collateral ligament

Answer 21

• starts @ medial epicondyle of humerus
• blends into the olecranon process on the back

Question 22

Describe the location of the transverse band of the ulnar-collateral ligament

Answer 22

• starts @ medial epicondyle of humerus
• doesn’t cross joint at all
• completes a triangle from coronoid process>olecranon

Question 23

Describe valgus forces at elbow

Answer 23

• when elbow is in anatomic neutral (full extension), elbow has a valgus leading to it (medial side more open than lateral)
• angle between long axis of forearm and humorus = carrying angle
• whenever we do activity with forceful extension of the elbow, we get valgus traction along medial side of elbow and apply stress to medial structures
  **UCL is very developed ligament for this reason

Question 24

Name the elbow muscles

Answer 24

Biceps brachii
Brachialis
Triceps brachii

Question 25

Describe the structure of the biceps brachii

Answer 25

- 2 heads: SHORT (medial side, originating @coracoid on scapula) LONG (lateral side)

Question 26

Describe the location of the biceps brachii

Answer 26

traveling up bicipital groove between lesser & greater tuberosity - tendon goes across head of the humerus & lands on superior aspect of glenoid fossa (supraglenoid tubercle) - muscle merges into 1 belly & continues down to come past the elbow - as it passes the elbow it becomes a flexor 2 insertions: - radial tuberosity - bicipital aponeurosis (transparent CT that spreads across muscles of forearm that affect risk and hand)

Question 27

Describe the Brachialis

Answer 27

- originates from anterior aspect of humorous in the distal half - shorter than bicep, doesn't touch the shoulder - converges into 1 tendon which blends into the ulnar tuberosity

Question 28

Name the muscle actions for the biceps and brachialis

Answer 28

- biceps and brachialis are both elbow FLEXORS - Biceps brachii has capacity to cause SUPINATION OF RADIO ULNAR JOINTS

Question 29

Describe the triceps brachii

Answer 29

- 3 heads, all 3 merge into horseshoe -shaped common tendon that blends into olecranon process of ulna - long, lateral and medial head - all 3 pull on olecranon process to lock it in place in olecranon fossa on posterior side of the humerus (process of extension)

Question 30

Describe the location of long, lateral and medial head of triceps brachii

Answer 30

- long and lateral heads are very superficial - the medial head is deep to both and is best seeing if you "peel" the other two away - long head originates from infraglenoid tubercle on the scapula - lateral and medial heads originate from the posterior surface of the shaft of the humerus and land on either side of radial groove

Question 31

Describe the radial groove

Answer 31

- the radio groove is a diagonal group in which the radial nerve will travel on its way towards the radius

Question 32

Describe the function of the biceps brachii

Answer 32

- since long head is coming up over the scapula, we can have action at the shoulder: helps with extension of GH joint and a little bit of adduction - all three pull-on olecranon process to lock it in place in olecranon fossa on posterior side of the humerus (process of extension)