Download Forearm and Wrist Regions

Forearm and Wrist Regions
Neumann Chapter 7
REVIEW AND HIGHLIGHTS OF OSTEOLOGY & ARTHROLOGY
Radius
 dorsal radial tubercle
 radial styloid process
Ulna
 ulnar styloid process
 ulnar head
Carpals
 Proximal Row - Scaphoid, Lunate, Triquetrum, Pisiform
 Distal Row - Trapezium, Trapezoid, Capitate, Hamate
Metacarpals - 5
WRIST COMPLEX
 Primary function is to position hand
 Wrist complex not a single joint but a group of articulations making up
two operationally defined: radiocarpal and midcarpal
Radiocarpal Joint
 articulation between radius, scaphoid, lunate, triquetrum and disk (triangular fibrocartilage); ulna is
not part of articulation. Although pisiform bone is anatomically part of the proximal row of carpal
bones, functionally it is not part of the articulation.
 Biaxial condyloid joint.
 Joint enclosed by a single, relatively loose joint capsule; carpals connected by interosseous ligaments.
Midcarpal Joint
 irregular joint line between proximal and distal rows of carpals. Unlike radiocarpal joint,
midcarpal joint does not have its own distinct joint capsule but instead has a capsule which is
continuous with each intercarpal articulation. Joint surface is very irregular due to bony
configuration.
Ligaments of Wrist Complex: many ligaments – we will consider 4.
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Dorsal radiocarpal ligament
o Helps to limit wrist flexion, although not too significant
Palmar radiocarpal ligament
o Function is to limit wrist extension and provide support to lunate bone.
Radial collateral ligament
o from radius to carpals
o limits ulnar deviation
Ulnar collateral ligament
o from ulna to carpals
o limits radial deviation
Page 1
Osteokinematics at the wrist:
Motion is defined as occurring in two planes:
Sagittal plane – Flexion and Extension
Frontal plane – Ulnar and Radial deviation
Limitations of wrist movement
Ligaments limit the slide of bones at end of range and thus limit motion at the wrist. Some argue that
radial deviation is a bony end-feel.
Arthrokinematics (roll, slide, spin, convex/concave)
Radiocarpal Joint: proximal joint surface is concave; distal joint surface is convex. Rule of moving convex
surfaces. Movement at the radiocarpal joint occurs primarily as result of sliding of the proximal carpal
row in a direction opposite the direction of the distal movement. (i.e. carpals slide ulnarly with radial
deviation; slide posteriorly with wrist flexion)
To increase radiocarpal extension due to capsule/ligament tightness: perform ___________ glides
Midcarpal Joint: The surfaces are reciprocally concave/convex. In general, the carpals in the distal row
slide in the ___________ direction as movement of the hand.
CARPAL TUNNEL
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Roof - transverse carpal ligament (part of flexor retinaculum); goes from pisiform and hamate to
scaphoid and trapezium.
Floor - palmar radiocarpal ligament, palmar intercarpal ligs, & proximal carpal row.
Medial wall - pisiform and hook of hamate
Lateral wall - tuberosity of scaphoid and tubercle of trapezium.
Contents - tendons of flexor digitorum superficialis, profundus, & flexor pollicis longus and median
nerve. (9 tendons & 1 nerve)
NEUROVASCULAR
Review info (Gross) about the vessels and nerves of the anterior and posterior regions of the forearm
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Brachial artery branches into radial and ulnar arteries in the cubital fossa
Ulnar Nerve - After passing posterior to the medial epicondyle of the humerus, it enters the anterior
portion of the forearm & travels with the ulnar artery to the wrist and hand.
Median Nerve - Passes between the 2 heads of the pronator teres then travels deep to the flexor
digitorum superficialis.
Superficial & Deep branches of the Radial Nerve; the deep branch travels thru the supinator muscle
Patho-Kinesiology:
Fractures & dislocations – such as Colles' Fracture, scaphoid fracture, lunate dislocations
Nerve entrapments (forearm included in arm-elbow notes)
 Carpal Tunnel Syndrome
Page 2
MUSCULATURE
IN THE FLEXOR SIDE OF THE FOREARM
SUPERFICIAL GROUP - All have a common tendon attachment that includes the medial epicondyle.

Pronator teres

Flexor carpi radialis
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Palmaris longus: Absent in about 10-20% of individuals. Absent more often on left side

Flexor digitorum superficialis

Flexor carpi ulnaris
DEEP GROUP
None of these cross the elbow.
 Flexor digitorum profundus, Flexor pollicis longus, Pronator quadratus
WRIST FLEXORS
 Flexor carpi radialis
 Flexor carpi ulnaris
 Accessory muscle: Palmaris longus
 Aid in wrist flexion:
o Flexor digitorum superficialis, Flexor digitorum profundus, Flexor pollicis longus
IN THE EXTENSOR SIDE OF THE FOREARM
SUPERFICIAL GROUP - All have a common tendon attachment that includes the lateral epicondyle.
 Brachioradialis
 Extensor carpi radialis longus
 Extensor carpi radialis brevis
 Extensor digitorum
 Extensor digiti minimi
 Extensor carpi ulnaris
DEEP MUSCLE GROUP
 Supinator
 Abductor pollicis longus, Extensor pollicis longus, Extensor pollicis brevis, Extensor indicis
WRIST EXTENSORS
 Extensor carpi radialis longus
 Extensor carpi radialis brevis
 Extensor carpi ulnaris

Aid in wrist extension - Extensor digitorum, Extensor indicis, Extensor digiti min, Extensor pollicis longus
RADIAL DEVIATORS
 Flexor carpi radialis
 Extensor carpi radialis longus & brevis
 Aid in wrist radial deviation - Pollicis muscles
ULNAR DEVIATORS
 Flexor carpi ulnaris AND Extensor carpi ulnaris
Page 3
Compare/Contrast Internal Torque Production @ the Wrist:
All About Grip:
Tenodesis Grip:
Questions:
1. Only 1 muscle of the forearm, that acts on the wrist, actually attaches directly to the carpal bones. Most of
them exert their action on the wrist via their distal attachment to the metacarpals and phalanges. Which
muscle is the exception?
2.
What role do the wrist extensor play in producing a forceful fist/grip? How does position of the wrist
effect grip force production?
3.
Which muscle is the strongest radial deviator?
4.
Explain how the actions of the ECRL and the FCR muscles are a great example of two muscles working as
synergists for the same wrist movement (like a force couple) yet can also act as antagonists in other
movements of the wrist?
Page 4
Movement Analysis:
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