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).
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Carpal tunnel and structures at the wrist The carpal tunnel is
formed anteriorly at the wrist by a deep arch formed by the carpal
bones and the flexor retinaculum.
Slide 4
Carpal arch 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.
Flexor retinaculum 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.
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Structure and relations Four tendons of the flexor digitorum
profundus Four tendons of the flexor digitorum superficialis One
tendon of the flexor pollicis longus Median nerve
Slide 8
Carpal tunnel syndrome Carpal tunnel syndrome is an entrapment
syndrome caused by pressure on the median nerve within the carpal
tunnel.
Slide 9
9 Carpal Tunnel syndrome Common in computer professionals. Due
to constant dorsiflexion of wrist while typing the keyboard
Slide 10
Palmar aponeurosis 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.
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Dupuytren Contracture of Palmar Fascia Dupuytren contracture is
a disease of the palmar fascia resulting in progressive shortening,
thickening, and fibrosis of the palmar fascia and aponeurosis.
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Compartments of palm 1. Hypothenar compartment 2. Thenar
compartment 3. Central compartment 4. Adductor compartment
5.Interosseous compartment
Slide 13
Muscles 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.
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Muscles of the Hand Thenar Muscles Abductor Pollicis
BrevisAbducts thumb Opponens Pollicis To oppose thumb Flexor
Pollicis BrevisFlexes thumb
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Muscles of the Hand Hypothenar Muscles Abductor Digit
MinimiAbducts digit 5 Flexor Digiti Minimi BrevisFlexes proximal
phalanx of digit 5 Opponens Digiti Minimibringing digit 5 into
opposition with the thumb
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Palmaris brevis Action: Improves grip
Slide 17
Thenar and hypothenar Muscles
Slide 18
Adductor pollicis Action: Adducts thumb towards middle
digit
Muscles of the Hand Short Muscles Lumbricals 1 and 2 Flex
digits at metacarpo- phalangeal joints and extends interphalangeal
joints Lumbricals 3 and 4 Flex digits at metacarpo- phalangeal
joints and extends interphalangeal joints Dorsal interossei 1-4
Abducts digits from axial line and act with lumbricals to flex
metacarpo-phalangeal joints and extends interphalangeal joints
Palmar interossei 1-3 Adducts toward axial line & assist
lumbriaclas in flexing the same joints as above
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Lumbrical muscles
Slide 23
Dorsal interossei Action of Dorsal Interossei : DAB : Abduction
Little finger and thumb have no Dorsal interossei muscle
Slide 24
Palmar interossei Action of Palmar interossei : PAD :Adduction
Middle finger and thumb have no palmar interossei muscle
Slide 25
Arteries of hand Blood supply to the hand is by the radial and
ulnar arteries, which form two interconnected vascular arches
(superficial and deep) in the palm.
Slide 26
Ulnar artery and superficial palmar arch Superficial palmar
arch: Ulnar artery+ palmar branch of radial artery
Slide 27
Radial artery and deep palmar arch Deep palmar arch: Deep
palmar branch of ulnar artery+ radial artery
Slide 28
Allen's test 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.
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Positive allen test
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Nerves The hand is supplied by the ulnar, median, and radial
nerves.
Slide 31
Ulnar nerve Immediately distal to the pisiform, ulnar nerve
divides into a deep branch, which is mainly motor and a superficial
branch, which is mainly sensory. 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
Slide 32
Slide 33
Ulnar nerve injury 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.
Slide 34
Clawing of the hand
Slide 35
Ulnar Canal Syndrome (Guyon Tunnel Syndrome) Compression of the
ulnar nerve may occur at the wrist where it passes between the
pisiform and the hook of the hamate.
Slide 36
Median nerve 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
Slide 37
Slide 38
Ape hand 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.
Slide 39
Superficial branch of the radial nerve 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.
Slide 40
Superficial branch of the radial nerve
Slide 41
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
joint B. Adduction C. Abduction D. Flexion of the distal
interphalangeal joint E. Flexion of the proximal interphalangeal
joint
Slide 42
. 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 3 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
Slide 43
3 The figure below represents cutaneous innervation of wrist
and hand. The area A in the figure represents which Nerve?
1.Superficial branch of radial nerve 2.Anterior interosseous nerve
3.Palmar branch of median nerve 4.Palmar branch of ulnar nerve
5.Lateral cutaneous nerve of fore arm