Chapter 16: Hand

Joints of the hand

Carpometacarpal, metacarpophalangeal, interphalangeal

Joint motions the occur at the Carpometacarpal joint of the thumb

Flexion/extension, abduction/adduction, opposition/reposition

Joint motions that occur at the metacarpophalangeal joints

Flexion/extension, abduction/adduction

Joint motions that occur at the interphalangeal joints

Flexion/extension

Bones of the hand

Five metacarpals, five proximal phalanges, four middle phalanges, five distal phalanges

Intrinsic muscles

Have both their origin and insertion within the wrist and hand. Responsible for fine motor control and precision movement

Extrinsic muscles

Have their origin proximal to the wrist and their insertion within the hand. These muscles produce wrist movements as well as hand movements

Prehension

Positioning the thumb and fingers to grasp, seize, hold, or manipulate objects.

Power grips

Used to hold objects firmly. Minimal or no movement occurs between the hand and the object being held

Precision

Holding an object in a manner that allows precision movements for manipulation

Types of power grips

Cylindrical, spherical, hook

Cylindrical grip

Consists of all four fingers flexed around an object in one direction and the thumb in opposition. (Gripping handle of a hammer)

Spherical grip

All four fingers and thumb abducted around an object. (holding a doorknob/ball)

Hook grip

All four fingers flexing around an object and does not include the thumb. (Holding the handle of a suitcase)

Types of precision grips

Pincer/tip-to-tip, tripod, pad to pad, pad to side, side to side, lumbrical grip

Pad-to-pad

Placement of the pad of the thumb in contact with the pad of one to two fingers

Side to side

Holding something between the sides of two fingers

Lumbrical grip

Flexing the MCPs, extending the PIP and DIP, thumb as an opposing force on top. (Holding a dinner plate)

Pad-to-side grip

Pad of thumb pressing on object against the radial side of the index finger. (Holding a key)

Tripod

Involves the thumb and two fingers. (Holding a pen/pencil)

Tip to tip/pincer

Tip of the thumb in contact with the tip of one finger. (Used to pick up small objects like a coin)

Swan neck deformity

Typical deformation of someone with rheumatoid arthritis. characterized by flexion of the MCP joint, hyperextension of the PIP joint, and flexion of the DIP joint

Boutonniere deformity

Typical deformation of someone with rheumatoid arthritis. Extension of the MCP joint, flexion of the PIP joint, and extension of the DIP joint.

Mallet finger

Loss of extensor digitorum and extensor digiti minimi muscle action as a result of disruption of the extensor mechanism of the DIP joint

Gamekeepers thumb

Sprain of the ulnar collateral ligament

Carpal tunnel syndrome

Pain, numbness, and weakness in the hand caused by compression of the median nerve within the carpal tunnel

DeQuervain’s disease

Tenosynovitis narrowing or inflammation within the sheaths of tendons

Dupuytren's contracture

Contracture of the palmar aponeurosis and is accompanied by nodular thickening

Trigger finger

Development of nodules on the tendonous sheaths of finger flexors. finger gets stuck

Skiers thumb

Acute tear of the ulnar collateral ligament of the thumb. Most injuries occur as a result of falling on an outstretched arm

Flexor digitorum superficialis

origin medial epicondyle of the humerus, insertion lateral and medial sides of the middle phalanx on all four fingers

Flexor digitorum profundus

origin proximal part of the ulna, insertion on the anterior side of the distal phalanx of all four fingers