Chapter 16: The Hand Anatomy, Function, and Pathologies

This set of vocabulary flashcards covers the anatomical structures, musculature, grip types, and common pathologies of the human hand as discussed in Chapter 16.

CMC joint of the thumb

The carpometacarpal joint of the thumb which is saddle shaped.

Biaxial joints

A classification of Metropolitan (MCP) joints which allow flexion/extension and abduction/adduction.

Uniaxial joints

A classification of Proximal Interphalangeal (PIP) and Distal Interphalangeal (DIP) joints which allow only flexion/extension.

Flexor retinaculum

A fibrous band spanning the anterior wrist that consists of the palmar carpal ligament and the transverse carpal ligament.

Palmar carpal ligament

The more proximal and superficial part of the flexor retinaculum that crosses over the flexor muscles to prevent bow-stringing of tendons.

Transverse Carpal Ligament

The deeper, distal part of the flexor retinaculum that arches over carpal bones to form a tunnel for the long finger flexor tendons and the median nerve.

Extensor retinaculum

A fibrous band on the posterior side of the wrist that holds extensor tendons close to the wrist.

Extensor Expansion Ligament (Extensor Hood)

A small triangular-shaped aponeurosis that holds extensor tendons close to the midline and serves as an attachment for extensor, lumbrical, and interossei muscles.

Extrinsic muscles

Muscles with proximal attachments proximal to the wrist that provide primary function at the thumb or fingers and assist in wrist function.

Intrinsic muscles

Muscles with proximal attachments at or distal to the carpals that allow for fine motor control and precision movement.

Flexor digitorum superficialis

An extrinsic muscle that flexes the MCP and PIP joints of fingers $2-5$ and assists in wrist flexion.

Flexor digitorum profundus

An extrinsic muscle that flexes all three joints of the fingers (MCP, PIP, DIP) and assists in wrist flexion.

Anatomical snuffbox

A depression evident with thumb extension formed by the Abductor Pollicis Longus, Extensor Pollicis Brevis, and Extensor Pollicis Longus; its floor is the scaphoid bone.

Dorsal Interossei

Intrinsic muscles responsible for finger abduction at the MCP joint.

Palmar Interossei

Intrinsic muscles responsible for finger adduction at the MCP joint.

Lumbricales

Intrinsic muscles that perform MCP flexion while extending the PIP and DIP joints.

Functional position

The optimal position of strength and precision where the wrist is slightly extended, MCP and PIP joints are slightly flexed, and the thumb is in opposition.

Power grips

Grips used when an object needs to be held forcefully, including cylindrical, modified cylindrical, spherical, and hook grips.

Precision grips

Grips used for fine movement and manipulation, including pad-to-pad, pincer, and three-jaw chuck.

Hook grip

A power grip involving the $2 ext{nd}$ through $5 ext{th}$ fingers flexed in a hooklike manner; it is the only power grip possible with a median nerve injury.

Three-Jaw Chuck

A pad-to-pad precision grip involving the thumb and two fingers (usually index and middle), similar to holding a pen.

Colles’ fracture

A transverse fracture of the distal radius with posterior displacement of the distal fragment, often caused by a FOOSH (fall on outstretched hand).

Smith’s fracture

A fracture caused by a fall on the back of the hand where the distal fragment is displaced anteriorly.

De Quervain’s disease

Tenosynovitis involving inflammation and thickening of the sheath containing the Extensor Pollicis Brevis and Abductor Pollicis Longus.

Dupuytren’s Contracture

Thickening of the palmar aponeurosis that leads to contracture of the $4 ext{th}$ and $5 ext{th}$ fingers.

Trigger finger (Stenosing contracture)

A condition involving abnormal sliding of a tendon in its sheath, causing the finger to become locked in flexion.

Swan neck deformity

A finger deformity characterized by flexion of the MCP, hyperextension of the PIP, and flexion of the DIP joints.

Mallet finger

A flexion deformity caused by the disruption of the extensor mechanism at the DIP joint.

Kienböck’s disease

Necrosis of the lunate bone following trauma.