Palm pdf - د. نوفل الحديثي

The palm

OBJECTIVES

…



To Describe the carpal tunnel & surrounding

structures



To define the layers of the palm



To study the muscles of the hand & their action

& nerve supply



To identify palmar arterial arches



To list the nerves which supply the hand

Carpal tunnel and structures at the wrist:

Flexor retinaculum:

- Is a thick connective tissue ligament that bridges the space between the

medial and lateral sides of carpus & converts the carpal arch into the carpal

tunnel.

-FR is attached medially to the pisiform and the hook of the hamate & laterally

to the tubercles of the scaphoid and trapezium

Structures passing in relation to FR:

-Tendons of FDS, FDP, FPL & median nerve pass through this tunnel

-FR holds the tendons & prevents bowing

-The median nerve is anterior to the tendons in the carpal tunnel.

-Free movement of the tendons in the carpal tunnel is facilitated by

synovial

sheaths

, which surround the tendons.

-All the tendons of the FDS & FDP are surrounded by a single synovial sheath

-A separate sheath surrounds the tendon of the FPL

The Carpal tunnel syndrome:

-Compression of the median

nerve as it travels through the

wrist at the carpal tunnel.

- The main symptoms are pain

& numbness in the lateral 3

fingers.

- Weak

grip

strength

may

occur and after a long period

of time the muscles at the base

of the thumb may waste away

-Sensation of thenar skin is

maintained?

Palmar aponeurosis:

-A triangular-shaped condensation of

deep fascia that covers the palm and

is anchored to the skin

-The

apex

the

triangle

continuous with the palmaris longus

tendon, fibers radiate to extensions

at the base of the digits

-The four longitudinal digital bands

are attach distally to the bases of the

proximal phalanges and become

continuous with the fibrous digital

sheaths

Functions of palmar aponeurosis:

1- Anchoring skin, eases the grip

2- Protection of deeper structures

Palmaris brevis:



Origin; palmar aponeurosis



Insertion; skin on the medial margin of the hand.



Innervation; superficial branch of the ulnar nerve.



Action; Deepens the hollow of the palm

Palmar fascial spaces:

• A medial fibrous septum extends deeply from the medial border of the PA to the 5th

metacarpal

• Lateral fibrous septum extends similarly to the 3rd metacarpal.

• These septa divide the palm into 3 fascial compartments:

1- Thenar space

containig thenar muscles

2- Hypothenar space

containing hypothenar muscles

3- Midpalmar space

located underneath the PA containing the flexor tendons, the

lumbricals with the digital vessels and nerves.

• Most fascial compartments end at the MP joints where they become

continuous with lumbrical canals

• The midpalmar space is continuous with the anterior compartment of the

forearm via the carpal tunnel

Hand muscles:

-Intrinsic muscles execute precision

movements ('precision grip') with the

fingers and thumb.

-All intrinsic muscles of the hand are

innervated by the deep branch of the

ulnar nerve except for the three thenar

and two lateral lumbrical muscles,

innervated by the median nerve.

-Spinal cord segment T1 with a

contribution

from

are

the

segments responsible for their supply

Layers… !!

Contents

Layer

Thenar & hypothenar muscles

Long flexors & lumbricals

Adductor pollicis

III

Interossei

Muscle

Origin

Insertion

Nerve

Action

Opponens

pollicis



Trapezium



metacarpal

Recurrent

branch of

median n.

Medially

rotates thumb

Flexor pollicis

brevis

Proximal phalanx

Flexes the

thumb at MPJ

Abductor

pollicis brevis



Scaphoid



Extensor hood

Abducts the

thumb at MPJ

Thumb movements

Muscle

Origin

Insertion

Nerve

Action

Opponens

digiti minimi



Hamate



Medial aspect of

metacarpal V

Deep

branch

of ulnar

Laterally rotates

metacarpal V

Flexor digiti

minimi brevis

Medial side of

proximal phalanx

Flexes LF at

MPJ

Abductor digiti

minimi



Pisiform



Lateral side of

proximal phalanx

Abducts LF at

MPJ

Fibrous digital sheaths:

-These are ligamentous tunnels that

enclose long flexor tendons as they

enter the receptive fingers

-They begin anterior to the MCPJ &

extend to the distal phalanges

-Formed by fibrous arches attached

posteriorly to the phalanges

-Prevent the tendons from bowing

when the digits are flexed.

-Within each tunnel, the tendons are

surrounded by a synovial sheath

-Fibrous sheaths are weak at the site

of IPJ

The lumbricals (4 muscles):

Origin;

Lateral aspect of tendons of FDP

Insertion;

Extensor hoods of medial 4

fingers

Nerve;

like mother tendons

Action:

-Flexion MPJ (direct action)

-Extension IPJ (via the extensor hoods)

Adductor pollicis:

Origin;

Oblique

head;

capitate

metacarpals 2 & 3 (base)

Straight head; metacarpal 3 (shaft)

Insertion

; Proximal phalanx thumb

(medial aspect)

Nerve

; deep branch ulnar n.

Action

: thumb adduction

Muscle

Origin

Insertion

Nerve

Action

Dorsal interossei

(4)

Adjacent sides
of metacarpals

(2 heads)

Extensor hood

2,3 & 4

Deep branch

of ulnar nerve

DAB

Palmar interossei

(3)

Sides of

metacarpals

(single head)

Extensor

hoods 2,4 & 5

PAD

The interossei:

Arteries of the hand:

• Superficial (mainly ulnar) &

deep (mainly radial) palmar

arches form at the proximal

& distal borders of a

stretched thumb

• From these arches blood is

distributed to the fingers &

dorsum of the hand

Superficial palmar arch:

Formation:

Ulnar a. + palmar branch of radial a.

Location:

Superficial to long flexor tendons

Branches:

palmar digital branch to the little finger

common palmar digital branches to the medial

three webs, each of the three will divide into

proper

palmar digital branches to adjacent fingers

Radial artery in the hand:

- After passing in the floor of the

snuffbox, radial artery enters the

palm between the 2 heads of the

dorsal interosseous muscle

- It

gives

branches

before

continuing

the

adductor

pollicis muscle as the deep

palmar arch with the deep branch

of ulnar artery

- Branches:

1- Radialis indicis: radial border of

index

2- Princeps pollicis: to the thumb

Deep palmar arch:

Formation:

Radial a. + deep branch of ulnar a.

Location:

Deep to long flexor tendons

Branches:

palmar metacarpal branches

which join the three common palmar

digital branches of the superficial arch

2- Perforating branches anastomose

with dorsal metacarpal arteries

Ascending

branches

the

anastomosis around the wrist

Nerves of the hand:

Ulnar nerve:

-Before reaching the hand it gives a

dorsal cutaneous branch to the medial

skin of the dorsum & medial 1 &

fingers

-Enters the hand lateral to the pisiform

& divides into:

1- Superficial branch;

for palmaris

brevis & skin of medial 1

1/2

fingers

(palmar aspect)

Deep

branch;

passes

the

concavity

deep

arterial

arch,

supplies hand muscles except the

thenar & lumbricals 1 & 2

Median nerve:

After leaving the carpal tunnel, median nerve enters the hand & gives:

1- The recurrent branch;

given near the distal margin of the flexor retinaculum,

it curves around the margin of the retinaculum enters the thenar muscles

2- Three palmar digital nerves;

for the palmar aspect of lateral 31/2 fingers +

dorsal skin of nailbed

* Palmar branch of median nerve which supplies the skin covering the thenar

muscles is given before the nerve enters the CT so it is not affected by CTS

Claw hand (Ulnar nerve paralysis)

Paralysed lumbricals 4 & 5

Loss of flexion of MCPJ & extension of IPJ

Extension of MCPJ & flexion of IPJ

Benediction hand (Median nerve paralysis)

Paralysed long flexors except tendons 4 & 5 of FDP

Flexion of fingers 4 & 5 & failure of flexion in fingers 2 & 3

This happens only when the patient is asked to flex his fingers

Claw

Benediction