The Wrist

The hand contains 27 bones—8 carpals, 5 meta carpals, and 14 phalanges—plus ulna and variable number of sesamoid bones.

SUMMARY

The relationship between anatomic structure and movement and the forces that apply in movement are complex. To achieve efficient movement, opti mal structure is required. Musculoskeletal structure may be out of balance, causing impairment of normal movement, as a consequence of the physical stress on soft tissue that results from overtraining, other types of misuse of the body, external injuries, or internal pathologic processes. A basic understanding of normal functional anatomy is therefore a vital prerequisite for attempting to improve movement by restoring normal structure. With this understanding, a clinician can identify any

TABLE 12-16 Muscles of the Anterior Fascial Compartment of the Forearm

Muscles

Origin (Proximal Attachment)

Insertion (Distal Attachment)

Innervation

Action

Pronator teres

Humeral head: medial

Middle of lateral

Median nerve

Flexes and pronates

epicondyle of humerus

surface of radius

(C6 and C7)

forearm

Ulnar head: coronoid

process of ulna

Flexor carpi

Medial epicondyle of

Bases of second and

Median nerve

Flexes and abducts

radialis

humerus

third metacarpal bones

(C7 and C8)

hand at wrist joint

Palmaris longus

Medial epicondyle of

Flexor retinaculum

Median nerve (C7

Flexes hand

humerus

and palmar aponeurosis

and C8)

Flexor carpi

Humeral head: medial

Pisiform bone, hook

Ulnar nerve

Flexes and adducts

ulnaris

epicondyle of humerus Ulnar head: medial aspect of olecranon process and posterior border of ulna

of the hamate, base of fifth metacarpal bone

(C7 and C8)

hand at wrist joint

Flexor digitorum

Humeroulnar head: medial

Middle phalanx

Median nerve

Flexes middle

superficialis

epicondyle of humerus

of medial four

(C7-T1)

phalanx of fingers

Radial head: oblique line

fingers

and assists in

on anterior surface of

flexing proximal

shaft of radius

phalanx and hand

Flexor pollicis

Anterior surface of shaft

Distal phalanx of

Anterior interosseous

Flexes distal phalanx

longus

of radius

thumb

branch of median nerve (C8 and T1)

of thumb

Flexor digitorum

Proximal 75% of medial

Base of distal

Ulnar and median

Flexes distal phalanx

profundus

and anterior surface of

phalanges of

nerves (C8 and

of fingers; assists in

ulna and interosseous

medial four digits

T1)

flexion of middle

membrane

and proximal phalanges and wrist

Pronator

Anterior surface of shaft

Anterior surface of

Anterior interosseous

Pronates forearm

quadratus

of ulna

shaft of radius

branch of median nerve (C8 and T1)

TABLE 12-17 Muscles of the Lateral Fascial Compartment of the Forearm*

Muscles

Origin (Proximal Attachment)

Insertion (Distal Attachment)

Innervation

Extensor carpi radialis longus

Proximal two thirds of lateral supracondylar ridge of humerus Lateral supracondylar ridge of humerus

Lateral surface of distal end of radius Posterior surface of base of second metacarpal bone

Radial nerve (C5-C7)

Radial nerve (C6 and C7)

Flexes forearm at elbow joint; rotates forearm to midprone position Extends and abducts hand at wrist joint

TABLE 12-18 Muscles of the Posterior Fascial Compartment of the Forearm

Muscles

Origin (Proximal Attachment)

Insertion (Distal Attachment)

Innervation

Action

Extensor carpi radialis brevis

Extensor digitorum

Extensor digitorum minimi

Extensor carpi ulnaris

Anconeus Supinator

Abductor pollicis longus Extensor pollicis brevis

Extensor pollicis longus Extensor indicis

Lateral epicondyle of humerus

Lateral epicondyle of humerus

Lateral epicondyle of humerus

Lateral epicondyle of humerus

Lateral epicondyle of humerus

Lateral epicondyle of humerus, radial collateral and annular ligaments, supinator fossa, and crest of ulna

Posterior surface of shafts of radius and ulna Posterior surface of shaft of ulna

Posterior surface of shaft of ulna Posterior surface of shaft of ulna

Posterior surface of base of third metacarpal bone

Middle and distal phalanges of the medial four fingers

Extensor expansion of little finger

Base of fifth metacarpal bone

Lateral surface of olecranon and superior part of posterior surface of ulna

Lateral, posterior, and anterior surfaces of proximal third of radius

Base of first metacarpal bone

Base of distal phalanx of thumb

Base of distal phalanx of thumb

Extensor expansion of index finger

Deep branch of radial nerve

(C7-C8) Posterior interosseous nerve (C7-C8); a branch of radial nerve

Posterior interosseous nerve (C7-C8); a branch of radial nerve

Posterior interosseous nerve (C7-C8); a branch of radial nerve Radial nerve (C7-T1)

Deep branch of radial nerve (C5 and C6)

Deep branch of radial nerve

(C5-C7) Deep branch of radial nerve (C5-C7)

Deep branch of radial nerve

(C5-C7) Deep branch of radial nerve (C5-C7)

Extends and abducts hand at wrist joint Extends fingers and hand

Extends metacarpal phalangeal joint of little finger

Extends and adducts hand at wrist joint

Assists triceps in extending forearm, stabilizes elbow joint; abducts ulna during pronation

Supinates forearm (rotates radius to turn palm anteriorly)

Abducts and extends thumb

Extends metacarpophalangeal joints of thumb

Extends distal phalanx of thumb

Extends metacarpophalangeal joint of index finger

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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