The document describes the anatomy of the palm of the hand. It discusses the skin, nerves, muscles and fascia of the palm. The palmaris brevis muscle covers and protects the base of the hypothenar eminence. The deep fascia forms the flexor retinaculum and palmar aponeurosis. The flexor retinaculum converts the front of the wrist into the carpal tunnel. The palmar aponeurosis divides into bands that attach to the skin and flexor tendon sheaths. The document also outlines the small muscles of the hand including the thenar, hypothenar and interossei muscles.

1. Anatomy of the palm of the hand
Dr. Mohammed Mahmoud Mosaed

2. Skin of the palm
• The skin of the palm of the hand is
thick and hairless.
• The skin shows many flexure
creases at the sites of skin
movement
• Sweat glands are present in large
numbers.
• The sensory nerve supply to the
skin of the palm
• The palmar cutaneous branch of
the median nerve supplies the
lateral part (2/3rd ) of the palm.
• The palmar cutaneous branch of
the ulnar nerve supplies the medial
part (1/3rd) of the palm.

3. The palmaris brevis muscle
• Origin: arises from the flexor
retinaculum and palmar
aponeurosis.
• Insertion: into the skin of the
palm.
• Nerve supply: the superficial
branch of the ulnar nerve.
• Action: Its function is to
corrugate the skin at the base
of the hypothenar eminence
and so improve the grip of the
palm in holding a rounded
object.

4. Deep Fascia
• The deep fascia of the wrist and
palm is thickened to form;
• The flexor retinaculum
• The palmar aponeurosis

5. Flexor Retinaculum
• The flexor retinaculum is a thickening of deep fascia that
holds the long flexor tendons in position at the wrist.
• It stretches across the front of the wrist and converts the
concave anterior surface of the hand into an osteofascial
tunnel, the carpal tunnel, for the passage of the median
nerve and the flexor tendons of the thumb and fingers.
• It is attached:
• Medially to the pisiform bone and the hook of the hamate
• Laterally to the tubercle of the scaphoid and the trapezium
• The upper border of the retinaculum corresponds to the
distal transverse skin crease in front of the wrist and is
continuous with the deep fascia of the forearm.
• The lower border is attached to the palmar aponeurosis

7. • The structures pass deep to the flexor retinaculum From medial to
lateral:
• Tendons of flexor digitorum superficialis and flexor digitorum
profundus with their common synovial sheath.
• Median nerve
• Flexor pollicis longus tendon surrounded by a synovial sheath
• Flexor carpi radialis tendon going through a split in the flexor
retinaculum, the tendon is surrounded by a synovial sheath.
• The structures pass superficial to the flexor retinaculum
• Ulnar nerve.
• Ulnar artery.
• Tendon of palmaris longus.
• Palmar cutaneous branch of ulnar nerve.
• Palmar cutaneous nerve of median nerve.

9. The Palmar Aponeurosis
• The palmar aponeurosis is triangular thickening of the
deep fascia in the central area of the palm of the hand.
• The apex of the palmar aponeurosis receives the insertion
of the palmaris longus tendon.
• The base of the aponeurosis divides at the bases of the
fingers into four slips.
• Each slip divides into two bands, one passing superficially
to the skin and the other passing deeply to fuse with the
fibrous flexor sheath and the deep transverse ligaments.
• The function of the palmar aponeurosis is to give firm
attachment to the overlying skin and so improve the grip
and to protect the underlying tendons.

11. Fibrous Sheaths of the Flexor Tendon
• It is a strong fibrous sheath
attached to the sides of the
phalanges from the head of the
metacarpal to the base of the
distal phalanx.
• The sheath and the bones form a
blind tunnel in which the flexor
tendons of the finger lie.
• In the thumb, the sheath contains
the tendon of the flexor pollicis
longus.
• In the four medial fingers, the
sheath is occupied by the tendons
of the flexor digitorum
superficialis and profundus.
• The fibrous sheath is thick over
the phalanges but thin and lax
over the joints

13. Synovial Flexor Sheaths
• In the hand, the tendons of the flexor
digitorum superficialis and profundus
muscles has a common synovial
sheath (ulnar bursa). The medial part
of this common sheath continous
with the tendons of the little finger.
The lateral part of the sheath stops
abruptly on the middle of the palm
• The flexor pollicis longus tendon has
its own synovial sheath (radial bursa)
that passes into the thumb.
• These sheaths allow the long tendons
to move smoothly, with a minimum
of friction, beneath the flexor
retinaculum and the fibrous flexor
sheaths.

14. Insertion of the Long Flexor Tendons
• Each tendon of the flexor digitorum superficialis perforated
opposite the proximal phalanx to pass the tendon of flexor
digitorum profundus.
• The superficialis tendon inserted into the middle phalanx.
• The tendon of the flexor digitorum profundus, inserted into
the anterior surface of the base of the distal phalanx

15. Vincula
• It is a folds of synovial membrane carry blood vessels to the
tendons at certain defined points. These folds (vincula tendinum)
are of two kinds;
• Vincula brevia, of which there are two in each finger, are
attached to the deep surfaces of the tendons near to their
insertions.
• Vincula longa usually two are attached to each superficial tendon
and one to each deep tendon

17. Small muscles of the hand
• The small muscles of the hand
include:
• four short muscles of the thumb.
• three short muscles of the little
finger.
• four lumbrical muscles.
• eight interossei muscles.

18. Short muscles of the thumb
The short muscles of the thumb are:
• the abductor pollicis brevis
• the flexor pollicis brevis
• the opponens pollicis
• the adductor pollicis.
The first three of these muscles form the
thenar eminence.

19. Abductor pollicis brevis
Origin: distal border of flexor retinaculum and the tubercle of
scaphoid and trapezium
Insertion: lateral aspect of base of proximal phalanx of the
thumb.
Action: Abduction of thumb
Nerve supply: median nerve.
Flexor pollicis brevis
Origin: Flexor retinaculum
Insertion: into the lateral side of the base of proximal phalanx of
thumb.
Action: powerfully flexes the thumb.
Nerve supply: median nerve
Opponens pollicis
Origin: Flexor retinaculum
Insertion: Shaft of metacarpal bone of thumb
Nerve supply: Median nerve.
Action: Pulls thumb medially and forward across palm
Adductor pollicis
Origin: Oblique head; second and third metacarpal bones
transverse head; third metacarpal bone
Insertion: Base of proximal phalanx of thumb
Nerve supply: Deep branch of ulnar nerve
Action: Adduction of thumb

21. Movements of the thumb
• Anatomical position of the thumb
• The thumd become at a right angle with the palm of the
hand and with the other fingers
• Movements: The following movements are possible:
• Flexion: Flexor pollicis longus and brevis and opponens
pollicis
• Extension: Extensor pollicis longus and brevis
• Flexion and extension occur at the metacarpophalangeal
joint
• Abduction: Abductor pollicis longus and brevis
• Adduction: Adductor pollicis
• Rotation (opposition): The thumb is rotated medially by the
opponens pollicis.
• These movements occur at the carpometacarpal joint of the
thumb

23. Short muscles of the little's finger
Abductor digiti minimi
• Origin: Pisiform bone
• Insertion: Base of proximal phalanx of little finger
• Nerve supply: Deep branch of ulnar nerve
• Action: Abducts little finger
Flexor digiti minimi
• Origin: Flexor retinaculum
• Insertion: Base of proximal phalanx of little finger
• Nerve supply: Deep branch of ulnar nerve
• Action: Flexes little finger
Opponens digiti minimi
• Origin: Flexor retinaculum
• Insertion: Medial border fifth metacarpal bone
• Nerve supply: Deep branch of ulnar nerve
• Action: Pulls fifth metacarpal forward as in cupping the palm

26. Interossei muscles
Palmar interossei (4 in number)
• Origin: First arises from base of first
metacarpal, the remaining three arise
from anterior surface of shafts of
second, fourth, and fifth metacarpals
• Insertion: Proximal phalanges of thumb
and index, ring, and little fingers.
• They also are inserted into the extensor
expansions of the index, ring and little
fingers.
• Nerve supply: deep branch of ulnar
nerve
• Action: Adduction of the index, ring
and little fingers.
• Flexion of their metacarpophalangeal
joints.
• Extension of their interphalangeal
joints.

27. Interossei muscles
Dorsal interossei
• Origin: Contiguous sides of shafts
of metacarpal bones
• Insertion: Proximal phalanges of
index, middle, and ring fingers and
their dorsal extensor expansion
• Nerve supply: Deep branch of
ulnar nerve
• Action: Abduction of the fingers
from center of third finger;
• Flex metacarpophalangeal joints
and extend interphalangeal joints

28. Lumbrical muscles
• 4 in number
• Origin: Tendons of flexor
digitorum profundus
• Insertion: Extensor
expansion of medial four
fingers
• Nerve supply: First and
second, (i.e., lateral two)
median nerve; third and
fourth deep branch of ulnar
nerve C8; T1
• Action: Flex
metacarpophalangeal joints
and extend interphalangeal
joints of fingers except
thumb