WINDSOR UNIVERSITYSCHOOL OF MEDICINE

St.Kitts

Dr. SREEKANTH THOTA

DEPARTMENT OF ANATOMY

UPPER LIMB

Hand

The hand is the region of the upper limb distal to the wrist joint.

It is subdivided into three parts:

1. Wrist 2.Metacarpus 3.Digits (five fingers

including the thumb). The hand has an anterior

surface (palm) and a dorsal surface (dorsum of hand).

HAND

The carpal tunnel is formed anteriorly at the wrist by a deep arch formed by the carpal bones and the flexor retinaculum.

Carpal tunnel and structures at the wrist

The base of the carpal arch is formed medially by the pisiform and the hook of the hamate and laterally by the tubercles of the scaphoid and trapezium.

Carpal arch

flexor retinaculum is a thick connective tissue ligament that bridges the space between the medial and lateral sides of the base of the arch and converts the carpal arch into the carpal tunnel.

Flexor retinaculum

Four tendons of the flexor digitorum profundus

Four tendons of the flexor digitorum superficialis

One tendon of the flexor pollicis longus

Median nerve

Structure and relations

Carpal tunnel syndrome is an entrapment syndrome caused by pressure on the median nerve within the carpal tunnel.

Carpal tunnel syndrome

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Carpal Tunnel syndrome

Common in computer professionals.

Due to constant dorsiflexion of wrist while typing the keyboard

The palmar aponeurosis is a triangular-shaped condensation of deep fascia that covers the palm and is anchored to the skin in distal regions.

The apex of the triangle is continuous with the palmaris longus tendon.

Palmar aponeurosis

Dupuytren contracture is a disease of the palmar fascia resulting in progressive shortening, thickening, and fibrosis of the palmar fascia and aponeurosis.

Dupuytren Contracture of Palmar Fascia

1. Hypothenar compartment

2. Thenar compartment 3. Central compartment 4. Adductor

compartment 5.Interosseous

compartment

Compartments of palm

The intrinsic muscles of the hand are located in five compartments

All of the 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, which are innervated by the median nerve.

Muscles

Muscles of the HandThenar Muscles

Abductor Pollicis Brevis Abducts thumb

Opponens Pollicis To oppose thumb

Flexor Pollicis Brevis Flexes thumb

Muscles of the HandHypothenar Muscles

Abductor Digit Minimi Abducts digit 5

Flexor Digiti Minimi Brevis Flexes proximal phalanx of digit 5

Opponens Digiti Minimi bringing digit 5 into opposition with the thumb

Palmaris brevis

Action:Improves grip

Thenar and hypothenar Muscles

Adductor pollicis

Action:Adducts thumb towards middle digit

Movements of thumb

Extension: extensor pollicis longus, extensor pollicis brevis

Flexion: flexor pollicis longus and flexor pollicis brevis

Abduction: abductor pollicis longus and abductor pollicis brevis.

Adduction: adductor pollicis Opposition: opponens pollicis.

Movements of thumb

Muscles of the Hand Short Muscles Lumbricals

1 and 2Flex digits at metacarpo-phalangeal joints and extends interphalangeal joints

Lumbricals3 and 4

Flex digits at metacarpo-phalangeal joints and extends interphalangeal joints

Dorsal interossei1-4

Abducts digits from axial line and act with lumbricals to flex metacarpo-phalangeal joints and extends interphalangeal joints

Palmar interossei1-3

Adducts toward axial line & assist lumbriaclas in flexing the same joints as above

Lumbrical muscles

Dorsal interossei

Action of Dorsal Interossei :

DAB : Abduction

Little finger and thumb have no Dorsal interossei muscle

Palmar interossei

Action of Palmar interossei :

PAD :Adduction

Middle finger and thumb have no palmar interossei muscle

Blood supply to the hand is by the radial and ulnar arteries, which form two interconnected vascular arches (superficial and deep) in the palm.

Arteries of hand

Ulnar artery and superficial palmar arch

Superficial palmar arch: Ulnar artery+ palmar branch of radial artery

Deep palmar arch: Deep palmar branch of ulnar artery+ radial artery

Radial artery and deep palmar arch

To test for adequate anastomoses between the radial and ulnar arteries, compress both the radial and ulnar arteries at the wrist, then release pressure from one or the other, and determine the filling pattern of the hand.

Allen's test

Positive allen test

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

Nerves

Immediately distal to the pisiform, ulnar nerve divides into a deep branch, which is mainly motor and a superficial branch, which is mainly sensory.

Ulnar nerve

Deep branch: supplies the hypothenar interossei, adductor pollicis, and the two medial lumbricals.

Superficial branch: supply skin on the palmar surface of the little finger and the medial half of the ring finger

The ulnar nerve is most commonly injured at two sites:

1. Elbow 2. wrist Clawing of the hand: Metacarpophalangeal joints of the fingers

are hyperextended and the interphalangeal joints are flexed.

Ulnar nerve injury

Clawing of the hand

Compression of the ulnar nerve may occur at the wrist where it passes between the pisiform and the hook of the hamate.

Ulnar Canal Syndrome (Guyon Tunnel Syndrome)

The median nerve is the most important sensory nerve in the hand because it innervates skin on the thumb, index and middle fingers, and lateral side of the ring finger.

Branches: 1. Recurrent branch: innervates the three

thenar muscles 2. Palmar digital nerves: In addition to skin,

the digital nerves supply the lateral two lumbrical muscles

Median nerve

Refers to a deformity in which thumb movements are limited to flexion and extension of the thumb in the plane of the palm.

Severance of median nerve paralyzes the thenar muscles and the thumb loses much of its usefulness.

Ape hand

The only part of the radial nerve that enters the hand is the superficial branch.

Innervates skin over the dorsolateral aspect of the palm and the dorsal aspects of the lateral three and one-half digits distally to approximately the terminal interphalangeal joints.

Superficial branch of the radial nerve

Superficial branch of the radial nerve

A 21 year old girl is brought to the emergency department with a puncture wound on the palmar side of her left index finger. Preservation of which of the following movements of her index finger will confirm the functional integrity of the flexor digitorum profundus muscle?

A.  Flexion of the metacarpophalangeal jointB. AdductionC. AbductionD. Flexion of the distal interphalangeal jointE. Flexion of the proximal interphalangeal

joint

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A 53-year-old African American man involved in a motor vehicle accident sustains a severe mid-shaft fracture of the right humerus. Vitals are Temp-100.0F, BP-120/88mm/Hg, pulse- 118/min, and RR- 14/min. Examination reveals wrist drop and no ulnar or radial pulses in the right arm. Examination reveals decreased sensation over the dorsal aspect of the lateral 3½ digits. The rest of the physical exam is otherwise unremarkable. What nerve is most likely injured given the findings in this patient?

A.Axillary nerve B.Musculocutaneous nerve C.Median nerve D.Radial nerve E.Ulnar nerve

2.

The figure below represents cutaneous innervation of wrist and hand. The area A in the figure represents which Nerve?

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1.Superficial branch of radial nerve2.Anterior interosseous nerve3.Palmar branch of median nerve4.Palmar branch of ulnar nerve5.Lateral cutaneous nerve of fore arm