The Structures of the Handi.e. Anatomy of the Hand

Stacey Louisa BockOccupational Therapist, Namakwa District

Only certain structures

will be discussed!

There’s TOOOO much!

TODAY 21/10/2013

• The anatomy of the hand

• Bones

• Areas

• Zones

• Arches

• Ligaments

• Muscles

• Innervation

• Test on the anatomy of the hand

• Brief overview of the infamous hand conditions

• Article: Hand Anatomy, Medscape

A hand (manus, pl. manūs)

⥤...is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs.

⥤...& are the richest source of tactile feedback, and have the greatest positioning capability of the body; thus the sense of touch is intimately associated with hands.

⥤...each hand is dominantly controlled by the opposing brain hemisphere, so that handedness, or the preferred hand choice for single-handed activities such as writing with a pencil, reflects individual brain functioning.

BONES

The human hand has 27 bones, not including the sesamoid bones which number varies

between people.

14 of which are the phalanges (proximal, intermediate and

distal) of the fingers. The metacarpals are the bones

that connects the fingers and the wrist. Each human hand

has 5 metacarpals and 8 carpal bones.

Pisiform…Triquetrum…

Lunate… …Scaphoid

Hamate ……Trapezium

… Trapezoid

… Capitate

AREASAreas of the human hand include:

The palm (Volar), which is the central region of the anterior part of the hand, located superficially to the metacarpus.

The opisthenar area (dorsal) is the corresponding area on the posterior part of the hand.

The heel of the hand is the area anteriorly to the bases of the metacarpal bones, located in the proximal part of the palm. It is the area that sustains most pressure when using the palm of the hand for support, such as in a handstand.

PALMAR DORSAL

ZONESExtensor Zones of Hand

ARCHESARCHES OF THE HAND

Red: one of the oblique archesBrown: one of the longitudinal arches of the digits

Dark green: transverse carpal archLight green: transverse metacarpal arch

LIGAMENTSThe flexor retinaculum (transverse carpal ligament, or anterior annular ligament) is a strong, fibrous band that arches over the carpus, converting the

deep groove on the front of the carpal bones into a tunnel, the carpal tunnel, through which the Flexor tendons of the digits and the median nerve pass.

The extensor retinaculum (dorsal carpal ligament, or posterior annular ligament) is an anatomical term for the thickened part of the antebrachial fascia that holds the tendons of the extensor muscles in place. It is located on the back of the forearm, just proximal to the hand. It is continuous with the palmar carpal

ligament, which is located on the anterior side of the forearm.

The palmar aponeurosis (palmar fascia) invests the muscles of the palm, and consists of central,

lateral, and medial portions.

CENTRAL PORTION

The central portion occupies the middle of the palm, is triangular in shape, and of great

strength and thickness.

MUSCLESThe muscles acting on the hand can be subdivided into two groups:

extrinsic intrinsic

The extrinsic muscle groups are the long flexors and extensors. They are called extrinsic because the muscle

belly is located on the forearm.

The intrinsic muscle groups are the thenar (thumb) and hypothenar (little

finger) muscles; the interossei muscles (four dorsally and three volarly) originating between the

metacarpal bones; and the lumbrical muscles arising from the deep flexor

(and are special because they have no bony origin) to insert on the dorsal

extensor hood mechanism.

FLEXORS

Flexor Digitorum ProfundusOrigin Anterior ulna and interosseous

membrane

Insertion By 4 tendons, each to the base of the distal phalanx of digits 2-5

Innervation Medial half: Ulnar n.Lateral half: Median n.

Action MCP, PIP and DIP flexion, wrist flexion

Flexor Digitorum SuperficialisOrigin Common flexor tendon on the

medial epicondyle of the humerus, coronoid process of the ulna and radius lateral to the bicipitaltuberosity

Insertion By 4 tendons, each to the sides of the middle phalanges of the fingers

Innervation Median n.

Action MCP and PIP flexion

Flexor Pollicis LongusOrigin Middle anterior portion of the

radius and interosseous membrane

Insertion Base of the distal phalanx of the thumb

Innervation Median n.

Action CMC, MCP and IP flexion of the thumb

STRETCH BREAK! 3 MINUTES!

EXTENSORS

Extensor DigitorumOrigin Lateral epicondyle of the humerus-

common extensor tendon

Insertion By 4 tendons, each to the base of the extensor mechanism and base of the proximal phalanx of all 4 fingers

Innervation Radial n.

Action Extensionof the fingers

Extensor IndicisOrigin Posterior surface of distal ulna and

interosseous membrane

Insertion Blends with the index tendon of the extensor digitorum

Innervation Radial n.

Action Extension of the index finger

Extensor Digiti MinimiOrigin Ulnar side of the belly of the

extensor digitorum

Insertion Joins the tendon of the extensor digitorum to the little finger

Innervation Radial n.

Action Extension of the 5th finger

Extensor Pollicus LongusOrigin Posterior surface of the ulna and

interosseous membrane

Insertion Dorsal base of the distal phalanx of the thumb

Innervation Radial n.

Action Extension of the IP, MCP and CMC of the thumb

Extensor Pollicus BrevisOrigin Posterior aspect of the radius and

interosseous membrane

Insertion Dorsal base of the proximal phalanx of the thumb

Innervation Radial n.

Action Extension of the MCP & CMC joints of the thumb

ABDuctor Pollicis LongusOrigin Posterior surface of the radius, ulna

and interosseous membrane

Insertion Base of the 1stmetacarpal

Innervation Radial n.

Action ABD and extension of the CMC of the thumb

“ANATOMIC SNUFF BOX”

Extensor Pollicis Longus

Extensor Pollicis Brevis

ABDuctor PollicisLongus

INNERVATIONCUTANEOUS INNERVATION OF THE UPPER LIMB

The hand is innervated by the radial, median, and ulnar nerves.

All muscles of the hand are innervated by the brachial plexus (C5–T1) and can be classified by innervation:

Radial Median Ulnar

Extensors: carpi radialis longus and brevis, digitorum, digiti minimi, carpi ulnaris, pollicis longus and brevis, and indicis.

Other: abductor pollicis longus.

.

Flexors: carpi radialis, pollicis longus, digitorum profundus (half), superficialis, and pollicis brevis (superficial head).

Other: palmaris longus. abductor pollicis brevis, opponens pollicis, and first and second lumbricals.

Flexor carpi ulnaris, flexor digitorum profundus (half), palmaris brevis, flexor digiti minimi, abductor digiti minimi, opponens digiti minimi, adductor pollicis, flexor pollicis brevis (deep head), palmar and dorsal interossei, and third and fourth lumbricals.

MY NAME ISWHAAAAT??!!

ARCHES OF THE HAND

Red: one of the oblique archesBrown: one of the longitudinal arches of the digits

Dark green: transverse carpal archLight green: transverse metacarpal arch

THE INFAMOUS HAND CONDITIONS

General clinical picture:The typical picture of an RA hand is as follows:

Synovitis on the dorsum of the wrist. The wrist may be in radial deviation. In some cases volar subluxation may also be present. In RA seen in black South Africans, wrist involvement may be the only manifestation.The MP joints are in ulnar deviation and flexion. This may be combined with volar subluxation. At the PIP joint level, boutonnière and swanneck deformities may be present in the same hand.

DIP joints are seldom involved. There may be swelling and crepitations of the flexor tendons, which may cause carpal tunnel syndrome or triggering Shoulder involvement includes swelling, stiffness and pain.

Arthritis

Dupuytren's contracture…is another disorder of the fingers that is

due to thickening of the underlying skin tissues of the palm. The disorder results in a deformed finger which appears thin and has small bumps on the surface. Dupuytren's contracture does run in families, but is also associated with diabetes, smoking, seizure recurrence and other vascular disorders.

Ganglion cysts are soft

globular structures that occur on the back of the hand usually near the junction of the wrist joint. These small swellings are usually painless when small but can affect hand motion when they become

large. The cysts contain a jelly like substance and usually do disappear on their own. If the ganglion cyst is not bothersome, it should be left alone. Just removing the fluid from the cyst is not curative because fluid will come back in less than a week.

CARPAL TUNNEL SYNDROME

Carpal tunnel syndrome is a

common disorder of the hand. This disorder results from compression of an important nerve in the wrist. Disorders like diabetes mellitus, thyroid or rheumatoid arthritis can narrow the tunnel and cause impingement of the nerve. Carpal tunnel syndrome also occurs in people who overuse their hand or perform repetitive actions like using a computer key board, a cashiers machine or a musical instrument. When the nerve is compressed, it can result in disabling symptoms like numbness, tingling, or pain in the middle three fingers.

DE QUERVAINS’S DISEASE

Clinical signs and symptomsAPL and EPL are stuck in the tunnel(s) at the radial side of the distal radiusThis area may be very prominent, swollen and tender because of the synovitisThumb flexion together with wrist ulnar deviation, and thumb abduction is painfulPercussion over the tunnel can be excruciatingly painful

AssessmentFinkelstein test: Thumb flexion (gripping thumb with other fingers) together with wrist ulnar deviation. (see illustration below) -This is extremely painful and unbearable for patient –almost unable to do

This condition occurs frequently in patients with osteo arthritis. It is described as stenosingtenosynovitis (inflammation) of the tendon sheaths of the Abductor pollicis longus and

Extensor pollicis brevis (APL & EPB) tendons, which is often caused by excessive unusual

repetitive movements of the thumb. This is also described as inflammation within the tendon

sheaths causing narrowing of the lumens (The space where the tendon is gliding through)

TRIGGER FINGER

Trigger finger is a common

disorder which occurs when the sheath through which tendons pass, become swollen or irritated. Initially, the finger may catch during movement but symptoms like pain, swelling and a snap may occur with time.

The finger often gets locked in one position and it may be difficult to straighten or bend the finger. Trigger finger has been found to be associated with diabetes, gout and rheumatoid arthritis.

NERVE PALSY

THANK YOU!!!

Any questions, concerns, comments,

rude remarks??