RAD 101 Unit 6 Anatomy of the Forearm, Elbow, and Distal Humerus

Forearm in anatomical position

Radius is lateral, and ulna is medial.

Bones articulate at the proximal and distal radioulnar joints, which allow

rotation (pronation and supination) of the hand

Radius

shorter than ulna

Ulna

Two radioulnar joints

distal and proximal radioulnar joints

Ulnar notch

Head of the ulna fits into what joint

distal radioulnar joint

Radial notch

Head of the radius fits into

notch to form the proximal radioulnar joint.

Only the distal radius is directly involved

in the wrist joint.

When pronating the hand

it is the radius that rotates, the ulna remains stationary.

Proximal ulna primarily forms

the elbow joint

Head of the ulna is distal while

the head of the radius is proximal.

Olecranon process

posterior and easily palpated. It is the "point" on the posterior elbow

Coronoid process

anterior

Medial margin of coronoid process opposite radial notch

Coronoid tubercle (medial)

Head of radius

Neck of radius

Radial tuberosity

Body of the ulna

Head of ulna

Ulna styloid process

Radius styloid process

Trochlear notch of ulna

articulates with the distal humerus

AP Elbow

Humerus body

Radial fossa

The radial head fits into fossa during complete elbow flexion

Coronoid fossa

the coronoid process fits into fossa during complete elbow flexion

Lateral epicondyle

projection above capitulum

Medial epicondyle

larger and above the trochlea

Capitulum

articulates with the head of the radius

Humeral condyle

distal end of the humerus

Trochlea

has 2 outer margins and a depressed center referred to as the trochlear sulcus

Articulates with the ulna

Trochlear Sulcus (Groove)

Olecranon fossa

olecranon process fits into fossa during complete flexion

Lateral elbow

Three Concentric Arcs

Trochlear sulcus- smallest and will appear darker or more radiolucent.

Edges of capitulum and trochlea

Trochlear notch is largest

Anterior fat pad

shaped like a tear drop. Located anterior to distal humerus

Trauma will cause it to be elevated, more visible, and distorted in shape.

Posterior fat pad

D

located within the olecranon fossa, shaped like a sail

If visible suggests a joint effusion which displaced the fat pad

Supinator fat stripe

E

located anterior to proximal radius

If visible may indicate radial head or neck fractur

Monteggia fracture

fracture of the proximal half of the ulna, along with dislocation of the radial head, may result from defending against blows with a raised forearm