Wrapping fingers around an object

Fine control via reciprocal muscle activation

Horizontal

Synovial membrane folds supplying blood to FDS and FDP tendons

Dorsal carpal major ligaments

Types of precision handling

Wrist flexors’ work capacity is over twice that of wrist extensors. Radial deviators have slightly higher work capacity than ulnar deviators

Both lunate and scaphoid flex, while triquetrum and distal carpal row extend

Ruptured lateral band

Full extension restricts further deviation, while the greatest ROM occurs in a neutral wrist position

How many bones and joints in hand complex

Saddle joint

Key muscles of CMC jt

Involves the entire hand for forceful grasping

Greater finger spread

Full radial deviation maximized stability

How many anatomical bands

Radial deviation

Ruptured central slip

Sccapholunate ligament positions the scaphoid and lunate together

Extensor tunnel lateral to medial

Fibrocartilage enhancing joint stability, limits hyperextension, supports longitudinal arch

IP joint degrees of freedom

Ulnar deviation

Move objects using proximal hand joints

MCP key structures

Order of independent extension

Increased contact pressures can lead to degenerative changes at the radioscaphlod joint

Runs length of fingers

Encases flexor pollicis longus tendon

Fingers without thumb

Occurs when lunate-triquetrum ligament is disrupted

Ulnar deviation

As the wrist moves from full extension to flexion, the scaphoid’s role varies while ligaments maintain the proximal carpal row’s integrity. Increasd dorsal contact during extension suggests complex interactions between the concave proximal carpal surface and hand motion

Wrist extension can flex fingers passively in paralyzed individuals

MCP articulation

Tightens in flexion

More flexible

Proximal surfaces moving as a unit on the radius and triangular fibrocartilage, with taut ligaments

Tips of thumb and finger contact, requiring full joint flexion

Solution is to passive extend to “unlock” the finger

Holding thin objects between adjacent fingers

How many cruciform pulleys?

Flexes MCP, PIP, and DIP jts

Flexes PIP jts and assists MCP flexion

Maximum stability occurs in

In flexion/extension of wrist, the _____ exhibits the greatest motion while ______ shows the least

Opposing pads of thumb and index finger

Fine manipulation using fibgers and thumb without palm movement

Plane joints, almost immobile

Prevents direct tendon to tendon contact and lessens the friction and allows smooth motion

Key for thumb opposition and grip

IP joint articulation

MCP hyperextension with IP flexion

lunate assumes an extebded posture; scaphoid subluxates

1st CMC joint articulation

Formed by the metacarpal bones

Caused by EDC contracyion, unopposed by intrinsic muscles

Encloses FDP and FDS tendons, reducing friction

Active extensuon begins at the distal carpal row, gliding over fixed proximal bones

Tightens in hyperextension

DIP Normal flexion ROM

Stabilizes the radiocarpal joint and aids scaphoid stability during movement

CMC articulations

Ensure tendon functionality despite limited direct vascularization

Injury to ligaments: Damage to scaphoid and lunate ligaments disrupts stabilization. Hamate collapses into flexion on the distal radius

Carpal tunnel

Tendon trapped under annular pulley; locking finger in flexed position

Types of power grips

Held in neutral or slighr extension to balance forces from finger flexors

Thumb pad presses against the side of a finger

Transitipn from full extension to full flexion

Finger flexion and extension

Wrist extension RC and midcarpal degrees

Fine placement of an object between fingers and thumb

Essential for grip

May progress to scapholunate advanced collapse (SLAC wrist)

Obliquely oriented

Radial deviation

PIP Normal flexion ROM

Supports grip and provides sensory feedback

1st CMC joint type

MCP joint type

Connect EDC tendons for passive extension of adjacent fingers

Grasping or holding objects using the hand, with the thumb often playing a key role

Optimal grip strength

Nodules form on flexor tendons due to repetitive trauma

Minimize friction, ensure smooth tendon gliding

Full flexion results in

IP joint type

Mechanical locking of the finger flexor tendons

Formed by carpal bones; contribute to palm’s concavity

ROM is greatest in

More prone to degeneration

Wrist flexion RC and midcarpal degrees

Finger abduction and adduction