basic elbow Flashcards
What joints contribute to the movement of the elbow?
- humeral ulnar
- humeral radial
- proximal radial unlar
- distal radial ulnar
What is the open can closed pack position of the elbow?
- open-90 degree flexion neutral pronation and supination
2. closed full extension
How is the humeral ulnar joint classified?
- diarthrodial/saddle
- synovial
- hinge
What is the axis of motion of the humeral ulnar joint?
1.it lies slightly oblique and medial about 7-12 degrees from the vertical
What is the conjunct rotation at the humeral ulnar joint
the trochlear groove is circumscribed in a spiral so the olecranon will…
- supinate, ER glide laterally with flexion
- pronate, IR and glide medially with extension
What creates the carrying angle?
- medial surface of the trochlea is more distal than lateral creating an oblique orientation of the axis
- the groove of the trochlea is spiraled causing the ulna to project lateral in full extension
What impact does the trochlear notch have on the elbow?
- It dictates the position of the ulna relative to the humerus
- creates conjunct rotation by the orientation of the trochlear groove
- creates the carrying angle by the oblique orientation of its horizontal axis
What are the three basic shapes of the trochlea?
Type 1 goes from lateral to neutral,
type 2 lateral to lateral position,
type 3 lateral to medial position
What is the sagital plane orientation of the trochlea relative to the humerus?
45 degree
What are the attachments of the medial collateral ligament of the elbow?
- extends form medial epicondyle to the coronoid and olecranon process and is a thickening of the joint capsule
- 3 bands
- posterior- thickening of the capsule from the medial epicondyle to the posterior medial olecranon
- anterior- thickening of the anterior capsule with some additional fibers superficial the capsule and provides the primary medial stability.
- transverse- olecranon to coronoid process
What are the bands of the medial collateral ligament and when are they loaded?
- posterior-taut after about 60 degrees of flexion
- anterior- is taut in extension
- transverse
What are the most importance static stabilizers of the elbow?
- anterior band of MCL
- intact joint surface
- ulnar part of LCL
What are the articulating structures of the radial humeral joint?
- capitellum of the humerus
2. radial head
How is the radial humeral joint classified?
- diarthrodial
- synovial
- hinge
- modified saddle
What is the function of the capitotrochlear groove?
- guids movement of the radial head as the medial rim of the radius fits in it
- increases stability of the joint
What is the annular ligament of the elbow?
- strong fibroosseous ring lined with articular cartilage
- covers 4/5th of the radial head
- tapered distally creating funnel shape
- blends with the joint capsule and LCL
- attaches to the anterior and psotieor aspects of the radial notch
What are the attachments of quadrate ligament of the elbow?
attaches the inferior edge of the radial notch to the neck of the radius
What is the function of the quadrate ligament?
- re-enforces the inferior proximal radial ulnar joint capsule
- maintains radial head in oppostion with the radial notch
- limits radial head spin with pronation and supination
What are the ligaments of the proximal radial ulnar joint?
- annular
- quadrate
- oblique cord
- innerosseous membrane
What are the ligaments of the distal radial ulnar joint?
- innerosseous membrane
- articular disc of TFCC
- fibrous capsule
- anterior and posterior radial ulnar ligaments as part of the capsule that wrap around the ulnar head to the ulnar notch
What are the attachments of the oblique cord?
- ulna tuberosity
2. inferior radial notch just below biceps tubercle
How does the position of the elbow effect the movement of the forearm?
- elbow extension: ulna is fixed so the radius rotates around it with it axis through the annular ligament
- elbow flexion-radius spin in the annular ligament while the ulna move medial and anterior
How does the cubital tunnel change with elbow flexion and extension?
45% increase from full extension to full flexion
What are the attachments of the lateral colateral ligament of the elbow?
- lateral epicondyle to
2. annular ligament and olecranon process
What ligaments help support the proximal radial ulnar joint?
- annular ligament
- quadrate ligament
- oblique cord
What type of joint is the distal radial ulnar joint?
- uni-axial pivot joint
2. convex ulna and concave radius
why does a conjunct rotation occur with pronation and supination?
- occurs because there are two axis of motion for pronation and supination
- spine of the radius in the annular ligament and arcuate swing of the distal radius around the ulna
- they work like hinges on a door and if they don’t line up you don’t open the door
- the forearm is like a rectangle with the axis of motion for pro/sup traveling from corner to corner creating an conical like motion
What limits supination of the elbow?
- anterior ligament of the distal radial ulnar joint
- quadrate ligament of the proximal radial ulnar joint
- ulnar styloid process contacting radius
- tednon of ECU
- pronator tone
What is the cubital fossa
area formed by …
- line between med and lateral epicondyle
- pronator teres
- brachioradialis
What is found in the cubital fossa?
- radial nerve
- biceps tendon
- brachial artery
What limits elbow flexion and extension, normally?
- flexion normally limited by by soft tissue apposition of the biceps
- extension limited by boney contact of the olecranon in the olecranon fossa
What type of joint is the proximal radial ulnar?
trochoid joint with one degree of freedom
-functional like a ball bearing
What limits pronation?
- quadrate ligament
- radial tuberosity dropping in the supinator notch
- ulna and radius come in contact with each other
How does the anatomy of the radius and ulna facilitate greater pronation?
- the longitudnal axis of the radius shifts laterally during pronation to allow the radial tuberosity to drop in the supinator notch
- the radius and ulna are slight curved allowing for greater pronation before they contact each other
How can normal elbow movement compress the TFCC?
during pronation the radius become functionally shorter
-typing position
The distal radial ulnar joint is most stable in what position?
Neutral because the anterior and posterior radial ulnar ligaments are both under tension
What is a normal valgus angle of the elbow?
10 degrees for men and 15 degrees for women
How is the radial head shaped?
- tapered and cone like
2. oval shaped being most pronounced in the pronated position
What are the myotomes of the UE?
- dorsal scapular (C5)- retraction
- suprascapular (C56) and axillary (C56)- abduction
- upper and lower subscap (C56)- IR
- musculocutaneous (C567)- flexion and supination
- radial (5678)- extension, wrist extension, supination
- median (C56781)- Flexion with radial devation, MCP flexion, thumb opposition
- Ulnar (781)- flexion with ulnar devation and 5th digit oppostion
