Forearm & Hand Anatomy: Bones, Joints, and Ligaments

Vocabulary practice flashcards focusing on the bones, bony landmarks, joints, ligaments, bursae, and clinical surface landmarks of the forearm, elbow, wrist, and hand.

Humeroulnar Joint

A hinge articulation formed between the trochlea of the humerus and the trochlear notch of the ulna, permitting flexion and extension of the elbow.

Proximal Radioulnar Joint

A pivot joint formed by the articulation of the articular circumference of the radial head with the radial notch of the ulna, allowing forearm pronation and supination.

Humeroradial Joint

An articulation between the capitulum of the humerus and the articular facet on the head of the radius; structurally classified as a ball-and-socket joint but functionally acting as part of the elbow hinge system.

Ulnar Collateral Ligament (UCL)

A major stabilizing ligament on the medial elbow extending from the medial epicondyle to the ulna, consisting of anterior, posterior, and transverse bands that protect against valgus stress.

Radial Collateral Ligament (RCL)

A stabilizing ligament originating at the lateral epicondyle of the humerus that blends directly into the annular ligament to resist varus stress at the elbow.

Annular Ligament

A fibrous collar that encircles the head of the radius and attaches to the anterior and posterior margins of the ulnar radial notch, securing the radius while permitting rotational pronation and supination.

Quadrate Ligament

A short fibrous band extending from the inferior border of the radial notch of the ulna to the neck of the radius, contributing rotational stability to the proximal radioulnar joint.

Subcutaneous Olecranon Bursa

A synovial fluid-filled sac situated between the skin and the olecranon process of the ulna that reduces friction during elbow motion.

Subtendinous Triceps Bursa

A bursa situated deep to the triceps brachii tendon immediately proximal to its insertion on the olecranon, reducing mechanical friction against the bone.

Radiocarpal Joint

An ellipsoid joint formed by the distal articular surface of the radius articulating with the scaphoid and lunate carpal bones; bears approximately $80\%$ of mechanical load during wrist movements and permits flexion, extension, abduction, and adduction.

Ulnocarpal Articulation

A complex synovial articulation where the head of the ulna articulates with the triangular fibrocartilage complex (TFCC) connecting to the lunate and triquetrum bones; carries $18\text{--}20\%$ of axial load in a neutral position.

Distal Radioulnar Joint

A synovial pivot joint formed by the ulnar notch of the radius and the articular circumference of the ulnar head, responsible for forearm pronation and supination and stabilized by the TFCC and radioulnar ligaments.

Scaphoid

A proximal-row carpal bone that articulates proximally with the radius and distally with the trapezium and trapezoid; features a palpable anterior tubercle that forms part of the lateral wall of the carpal tunnel.

Lunate

A crescent-shaped proximal carpal bone lying between the scaphoid and triquetrum that articulates proximally with the radius and TFCC and distally with the capitate.

Triquetrum

A pyramidal carpal bone positioned medial to the lunate that articulates with the lunate, the pisiform anteriorly, and the hamate distally.

Pisiform

A small sesamoid bone resting on the palmar surface of the triquetrum; serves as the insertion site for the flexor carpi ulnaris, origin for the abductor digiti minimi, and attachment for the pisohamate and pisometacarpal ligaments.

Trapezium

The lateral-most carpal bone of the distal row located beneath the thumb; articulates with the 1st and 2nd metacarpals and features a distinct tubercle and a groove for the flexor carpi radialis tendon.

Trapezoid

A small distal-row carpal bone situated medial to the trapezium that articulates with the 2nd metacarpal, scaphoid, and capitate.

Capitate

The largest carpal bone, centrally positioned in the distal row with a proximal head and distal base; articulates with the 3rd metacarpal, lunate, scaphoid, trapezoid, and hamate.

Hamate

The medial-most distal carpal bone articulating with the 4th and 5th metacarpals, capitate, and triquetrum; characterized by an anterior hook-like projection.

Hook of the Hamate

A curved palmar bony projection that provides an attachment site for the pisohamate ligament, flexor digiti minimi brevis, and opponens digiti minimi muscles.

Dorsal Radial Tubercle (Lister's Tubercle)

A bony prominence located on the dorsal surface of the distal radius that acts as a pulley and anatomical landmark separating the extensor tendon compartments.

Sublime Tubercle

A bony prominence located on the medial aspect of the coronoid process of the ulna that provides the attachment for the anterior bundle of the ulnar collateral ligament.

Supinator Crest

A prominent longitudinal bony ridge on the proximal ulna below the radial notch that serves as an attachment site for the supinator muscle.

Midcarpal Joint

A composite S-shaped joint articulation situated between the proximal and distal rows of carpal bones, functioning in concert with intercarpal ligaments to assist wrist motion.

First Carpometacarpal (CMC I) Joint

A specialized saddle joint formed between the trapezium and the base of the first metacarpal, allowing flexion, extension, abduction, adduction, and opposition of the thumb.

Metacarpophalangeal (MCP) Joints

Condyloid joints formed between the rounded heads of the metacarpals and the shallow bases of the proximal phalanges, permitting flexion, extension, abduction, and adduction.

Deep Transverse Metacarpal Ligaments

Short, strong fibrous bands connecting the palmar plates of metacarpophalangeal joints II through V, maintaining transverse arch alignment of the hand.

Interphalangeal (IP) Joints

Uniaxial hinge joints connecting adjacent phalanges within the digits (PIP and DIP in fingers II–V; a single IP joint in the thumb), supported by collateral ligaments and palmar plates to allow flexion and extension.

Palmar Radiocarpal Ligament

A strong anterior ligament complex comprising radioscaphocapitate (RSC), radioscapholunate (RSL), and radiolunate (short and long) fiber bands that reinforces the anterior aspect of the wrist joint capsule.

Tinel's Sign (at the Elbow)

A neurological assessment finding where gentle tapping over the ulnar nerve within the cubital tunnel reproduces paresthesia or tingling into the 5th digit and medial hand.

Active Flexion Test

A clinical diagnostic maneuver in which sustained active elbow flexion provokes or increases medial elbow pain and ulnar nerve paresthesia, indicative of cubital tunnel syndrome.