Description: Bone on the lateral side of the forearm (antebrachium). It pivots on its long axis and crosses the ulna during pronation

Functions:

Forearm Rotation: The radius and ulna work together to allow for pronation (palm facing down) and supination (palm facing up) of the forearm

Wrist Movement: The distal end of the radius articulates with the carpal bones to enable wrist flexion, extension, and other movements

Description: Bone on the medial side of the forearm (antebrachium). It articulates proximally with the trochlea of the humerus and the head of the radius; it articulates distally with the ulnar notch of the radius

Functions:

Elbow joint: The ulna forms the elbow joint with the humerus, enabling flexion and extension of the elbow

Pronation and supination:The ulna helps with the movement of pronation (palming downwards) and supination (palming upwards) of the forearm and hand

Muscle attachment:The ulna provides attachment points for numerous muscles involved in forearm and hand movements

Description: The bone of the arm (brachium). It articulates proximally with the scapula at the glenoid fossa; it articulates distally with the radius and ulna at the elbow joint

Functions:

Joints: It forms the glenohumeral joint (shoulder joint) with the scapula and the elbow joint with the radius and ulna.

Muscles: Numerous muscles attach to the humerus, enabling arm movement and supporting the shoulder and elbow

Support: The humerus provides structural support for the arm and is crucial for carrying weight and performing daily activities

Description: A small projection from the distal surface of the head of the ulna

Functions:

The ulnar styloid process provides attachment for the ulnar collateral ligament, which helps stabilize the wrist joint during movement and load-bearing

It also plays a role in the function of the triangular fibrocartilage complex (TFCC), a complex of cartilage and ligaments that contribute to wrist stability

Description: The distal-most projection from the lateral side of the radius. It projects lateral to the proximal row of carpal bones

Functions:

Attachment Point: The base of the radial styloid process serves as the attachment point for the tendon of the brachioradialis muscle

Ligament Attachment: The apex (tip) of the process is where the radial collateral ligament of the wrist attaches

Tendons: The lateral surface of the process has a flat groove that houses the tendons of the abductor pollicis longus and extensor pollicis brevis muscles

Description: The ligament that encircles the head of the radius

Functions: It holds the head of the radius against the ulna and cups in distal to the head to provide restraint against distal dislocation of the radius

Description: Originates on the lateral epicondyle of the humerus (upper arm bone) and attaches to the annular ligament and the radius

Functions: Stabilizes the joint and resists varus forces (forces pushing the elbow inwards).

Description: A thickening of connective tissue fibers at the proximal end of the interosseous membrane. It connects the proximal end of the shaft of the radius to the proximal end of the shaft of the ulna

Functions: Help to stabilize the forearm and limit supination (rotating the forearm so the palm faces upward)

Description: A thickening of connective tissue fibers at the proximal end of the interosseous membrane. It connects the proximal end of the shaft of the radius to the proximal end of the shaft of the ulna

Functions: Help to stabilize the forearm and limit supination (rotating the forearm so the palm faces upward)

Description: A strong ligament spanning the medial side of the elbow joint. Tt connects the medial epicondyle of the humerus with the ulna, it reinforces the medial side of the elbow articular capsule

Functions: Stabilize the elbow particularly during valgus (outward) stress on the elbow, which is common in throwing and other overhead activities