Forearm
What is nursemaid's elbow
A distraction injury that commonly occurs in children when their arm is pulled on.
What is the resting posture, "carrying angle" ?
Angle between longitudinal axes of the humerus and ulna Male: 5-11 degrees Female: 10-16 degrees
Ulnar collateral ligament (MCL)
Anterior band: medial epicondyle to coronoid process Posterior band: medial epicondyle to olecranon process Oblique/transverse band: coronoid to olecranon process
Radial collateral ligament (LCL)
Attach: lateral epicondyle to coronoid process and annular ligament
Elbow joint capsule (attachments)
Attaches: humerus, ulna, and indirectly to radius via annular ligament
What is a common way to injure LCL?
Backhand sports, lead arm in golf (varus loading)
If a magic fairy made your coronoid fossa more shallow and coronoid process larger, what would that limit?
Flexion ROM
Elbow ROM
Flexion: 130-150 degrees Limited by: soft tissue or coronoid process (ulna) in coronoid fossa (humerus) Hyperextension: 0-10 degrees Limited by: olecranon process in olecranon fossa or soft tissue stretch anteriorly
Joints of Elbow
Humeroulnar (trochlea of humerus and trochlear notch of ulna) (synovial hinge) Humeroradial (capitulum of humerus and head of radius) (synovial, pivot)
What is the oblique cord?
Ligament from ulna tuberosity to inferior radial tuberosity Protects against: inferior displacement of the radius and excessive supination
Why have an interosseous membrane instead of one bone?
Lighter
What does the interosseous membrane resist?
Limits supination Slack in pronation Fibers run from ulna up to radius which helps prevent superior displacement of the radius during a fall on hand
Describe where the elbow joint capsule is loose/tight and it's effect on motion?
Loose ant/post; allowing sagittal plane movement Tight med/lat; limit frontal plane movement
Ligaments of distal radioulnar joint
Palmar radioulnar ligament Attaches: palmar/medial/distal radius to palmar base of style process of ulna Limits: supination Dorsal radioulnar ligament Attaches: dorsal/medial/distal radius to dorsal base of ulna styloid process Limits: pronation
Why is the annular ligament relevant in regards to proximal radioulnar joint?
Proximal radioulnar joint has poor bony fit (only 20% coverage). Therefore, the annular ligament encircles 80% circumference of the radius, going from anterior to posterior radial notch of ulna.
What are the radioulnar joints and types?
Proximal: synovial/pivot (between head of radius and radial notch on ulna) Middle: fibrous/interosseous membrane (medial radius to lateral ulna) Distal: synovial/pivot (head of ulna and ulnar notch of radius)
Joints of Forearm
Radioulnar (proximal, middle, distal)
What is a common way to injure MCL?
Tennis, throwing sports, baseball (valgus loading)
