Kienbock’s

Avascular necrosis of the lunate

Panner’s

Avascular necrosis of the capitellum. Also known as Little Leaguer elbow

Preiser’s

Avascular necrosis of the scaphoid

Gamekeeper thumb

Chronic instability of the thumb MP joint secondary to rupture of the ulnar collateral ligament (UCL). Often incorrectly used to describe and acute rupture of the thumb MCP joint UCL.

Galeazzi fracture

Fracture of the distal shaft of the radius with disruption of the distal radioulnar joint (DRUJ).

Jersey finger

Traumatic avulsion of the terminal FDP tendon, resulting in inability to actively flex the DIP joint.

Monteggia fracture

Fracture of the proximal ulna (not olecranon) in association with a radial head dislocation.

Rolando fracture

A comminuted, intra-articular fracture of the base of the thumb metacarpal.

Salter-Harris classification

Classification system used to describe physeal fractures in the skeletally immature population, delineating the fracture’s involvement of the metaphysis, epiphysis, and physis.

Seymour fracture

A physeal fracture of the distal phalanx. There is an associated nail bed injury and the nail matrix may become interposed within the physis, preventing reduction of the fracture segments. The nail plate is displaced dorsal to the eponychial fold that suggests the presence of this easily missed open frion.

Check ligaments

The proximal extensions of the PIP joint volar plate. When a flexion contracture develops at the PIP joint, these may be termed as “check-rein” ligaments as they tighten and contribute to the contracture.

DIP

Distal interphalangeal joint.

Kienbock’s

Avascular necrosis of the lunate

Panner’s

Avascular necrosis of the capitellum. Also known as Little Leaguer elbow

Preiser’s

Avascular necrosis of the scaphoid

Eponychium

Thin membrane that extends onto the dorsum of the nail and gives the nail its “shine.”

Germinal matrix

The proximal portion of the nail matrix. This is the area where nail growth is initiated.

Lunula

The white crescent visible through the nail plate. Its distal extent marks the beginning of the sterile matrix.

Paronychium

Skin lateral to the nail plate.

Perionychium

Nail bed complex.

Nail fold

The depression into which the nail fits proximally. The ventral floor is composed of the germinal matrix.

Nail plate

The hard portion of the nail complex (the nail itself).

Sterile matrix

The distal portion of the nail matrix. This area is responsible for nail adherence.

Central slip

The portion of the extensor tendon that inserts on the base of the middle phalanx and is responsible for the extrinsic component of PIP joint extens plate

Thickening of the volar joint capsule with proximal extension at the level of the MCP, PIP, and DIP joints; it prevents dorsal subluxation and hyperextension. The proximal extensions known as the check ligaments at the PIP joint.

Basal joint

Carpometacarpal joint of the thumb. Also referred to as the CMC joint.

Distal palmar flexion crease

Volar flexion crease, which marks the cutaneous level of the MCP joints.

Juncturae tendinum

The tendinous connections between the EDC tendons to the individual digits. When a tendon laceration occurs proximal to the juncturae, the MCP can still be actively extended through the adjacent tendon connection via the juncturae albeit with pain and some weakness.

TFCC

Triangular fibrocartilage complex. This is the soft tissue stabilizing structure of the DRUJ. It is comprised of the dorsal and volar distal radioulnar ligaments, a central disc with attachments to the fovea and the ulnar styloid, the meniscal homolog, ulno-carpal ligaments, and the sheath of the ECU tendon.

Bouchard nodes

The proximal part of the extensor apparatus which centralizes the extensor tendon over the MCP. It attaches to the extensor tendon and wraps around the base of the proximal phalanx, inserting on the volar plate. It contributes to proximal phalanx extension at the MCP joint by “lifting” the proximal phalanx when the extrinsic extensor tendon contracts.

Transverse retinacular lig

Structure at the level of the PIP joint (similar to the sagittal band at the MCP joint), which attaches to the extensor tendon and the volar plate and functions to prevent dorsal shift of the lateral bands when the digit is extended. Attenuation contributes to Swan neck deformity.

Triangular ligament