Anatomical Description of Wrist Joint and Hand Skeleton

1. WRIST JOINT & HAND
Dr. Mushfiqul Hoque
Lecturer
Dhaka National Medical College

2. Wrist Joint

3. Wrist Joint
Type of joint:
Wrist joint is a synovial joint of the ellipsoid variety
Lower end of radius and articular disc of inferior radioulnar joint
proximally
three lateral bones of proximal row of carpus, i.e. scaphoid, lunate and
triquetral distally.
The pisiform does not play a role in the radiocarpal articulation. It is a
sesamoid bone acting as a pulley for flexor carpi ulnaris.

4. Wrist Joint
Articular Surfaces
Upper:
1. Inferior surface of the lower
end of the radius
2. Articular disc of the inferior
radioulnar joint
Lower:
1. Scaphoid
2. Lunate
3. Triquetral bones.

5. Wrist Joint
Ligaments:
1. Articular Capsule
2. Palmar radiocarpal ligament
3. Palmar ulnocarpal ligament
4. Dorsal radiocarpal ligament
5. Radial collateral ligament
6. Ulnar collateral ligament

6. Wrist Joint
• Blood supply: Anterior and posterior carpal arches
• Nerve supply: Anterior and posterior interosseous nerves

7. Wrist Joint
• Movements:
Flexion (Flexor carpi radialis, Flexor carpi ulnaris, Palmaris longus)
Extension (Extensor carpi radialis longus, Extensor carpi radialis
brevis, Extensor carpi ulnaris)
Abduction (Radial Deviation) (Flexor carpi radialis, Extensor carpi radialis
longus and extensor carpi radialis brevis, Abductor pollicis longus and
extensor pollicis brevis)
Adduction (ulnar Deviation) (Flexor carpi ulnaris, Extensor carpi ulnaris)
circumduction

8. Hand

11. Bones of the Hand
There are 3 groups of bones in the
skeleton of the hand:
1. Carpal bones at the wrists
2. Metacarpal bones at the palm
3. Phalangeal bones in the digits

12. Bones of the Hand
Carpal bones:
• Short bones
• 8 in number
• Arranged in proximal and distal rows
• Proximal row: (From lateral
to medial) scaphoid, lunate,
triquetral, pisiform
• Distal row: (from lateral to medial)
trapezium, trapezoid, capitate,
hamate

13. Bones of the Hand
Metacarpal bones:
• Miniature long bones
• 5 in number
• Numbered from lateral to medial
• Each metacarpal possesses a
diaphysis and a single epiphysis
• The epiphysis of all metacarpal
directed towards the head except
the first where it is located towards
the base

14. Bones of the Hand
Phalangeal bones:
• Total number 14
• 3 for each finger, 2 for the thumb
• Referred to as proximal middle and
distal
• Possesses one diaphysis
• Single epiphysis directed towards the
base
• Miniature long bones

15. Joints of the Hand
1. Intercarpal joints: Plane type of synovial joint
2. Carpometacarpal joints of thumb: Saddle type of synovial joint
3. Other carpometacarpal joints: Plane type of synovial joints
4. Intermetacarpal joints: Plane type of synovial joints
5. Metacarpophalangeal joints: ellipsoid type of synovial joints
6. Interphalangeal joints: Hinge type of synovial joints

16. Hand
The human hand is designed:
• For grasping,
• For precise movements,
• For serving as a tactile organ.

17. Steps of dissection
1. A horizontal incision at the distal crease
of front of the wrist.
2. Make a vertical incision from the centre
of the above incision through the palm
to the centre of the middle finger.
3. Make one horizontal incision along the
distal palmar crease.
4. Make an oblique incision starting 3 cm
distal to incision no. 2 and extend it till
the tip of the distal phalanx of the
thumb.

18. Steps of dissection
Thus the skin of the palm gets
divided into 3 areas. Reflect the skin
of lateral and medial flaps on their
respective sides. The skin of the
intermediate flap is reflected distally
towards the distal palmar crease.
Further the skin of middle finger is to
be reflected on either side.

19. Palm of the Hand
Layers:
1. Skin
2. Superficial fascia
3. Deep fascia
4. Muscles, tendons, nerves and vessels

20. Palm of the Hand
The skin of the palm is:
• Thick for protection of underlying tissues.
• Immobile because of its firm attachment to the underlying palmar
aponeurosis.
• Creased.
All of these characters increase the efficiency of the grip.
The skin is supplied by spinal nerves C6, C7, C8 through the median and
ulnar nerve.

22. Palm of the Hand
The deep fascia is specialised to
form:
1. The flexor retinaculum at the
wrist.
2. The palmar aponeurosis in the
palm.
3. The fibrous flexor sheaths in
the fingers.
All three form a continuous
structure which holds the tendons
in position and thus increase the
efficiency of the grip

23. Flexor Retinaculum
Flexor (Latin to hold back)
retinaculum is a strong
fibrous band which bridges
the anterior concavity of the
carpus and converts it into a
tunnel, the carpal tunnel

24. Attachment of the flexor retinaculum
Medially, to
1. The pisiform bone.
2. To the hook of the hamate.
Laterally, to
1. The tubercle of the scaphoid, and
2. The crest of the trapezium.

25. Relations of the flexor retinaculum
The structures passing superficial to the
flexor retinaculum are:
1. The palmar cutaneous branch of the
median nerve.
2. The tendon of the palmaris longus.
3. The palmar cutaneous branch of the
ulnar nerve.
4. The ulnar vessels.
5. The ulnar nerve. The thenar and
hypothenar muscles arise from the
retinaculum

26. Relations of the flexor retinaculum
The structures passing deep to the flexor retinaculum
are:
1. The median nerve.
2. Four tendons of the flexor digitorum superficialis.
3. Four tendons of the flexor digitorum profundus.
4. The tendon of the flexor pollicis longus.
5. The ulnar bursa.
6. The radial bursa.
7. The tendon of the flexor carpi radialis lies between
the retinaculum and its deep slip, in the groove on
the trapezium

27. Palmar Aponeurosis
• This term is often used for the entire deep fascia of the palm.
However, it is better to restrict this term to the central part of the
deep fascia of the palm which covers the superficial palmar arch, the
long flexor tendons, the terminal part of the median nerve, and the
superficial branch of the ulnar nerve

28. Palmar Aponeurosis
• Palmar aponeurosis is triangular
in shape. The apex which is
proximal, blends with the flexor
retinaculum and is continuous
with the tendon of the palmaris
longus. The base is directed
distally.

29. Palmar Aponeurosis
Functions:
Palmar aponeurosis fixes the skin
of the palm and thus improves the
grip. It also protects the underlying
tendons, vessels and nerves.

30. Fibrous Flexor Sheaths of the Fingers
• The fibrous flexor
sheaths are made up of
the deep fascia of the
fingers. The fascia is
thick and arched. It is
attached to the sides of
the phalanges and
across the base of the
distal phalanx.
Proximally, it is
continuous with a slip
of the palmar
aponeurosis.

31. Fibrous Flexor Sheaths of the Fingers
• A blind osseofascial tunnel
is formed which contains
the long flexor tendons
enclosed in the digital
synovial sheath. The fibrous
sheath is thick opposite the
phalanges and thin opposite
the joints to permit flexion.
The sheath holds the
tendons in position during
flexion of the digits.

32. Intrinsic muscles of Hand
• The intrinsic muscles of the hand serve the function of adjusting the
hand during gripping and also for carrying out fine skilled
movements. The origin and insertion of these muscles is within the
territory of the hand. There are 20 muscles in the hand.
• The muscles are divided into 4 layers

33. Intrinsic muscles of Hand
1st layer of muscles
a. Three muscles of thenar eminence
i. Abductor pollicis brevis
ii. Flexor pollicis brevis
iii. Opponens pollicis.
b. One adductor of thumb:
i. Adductor pollicis.

34. Intrinsic muscles of Hand
Second layer of muscles
Four Hypothenar muscles
i. Palmaris brevis
ii. Abductor digiti minimi
iii. Flexor digiti minimi
iv. Opponens digiti minimi

35. 3rd Layer: Lumbricals

36. 4th Layer: Palmar and Dorsal Interossei

39. Nerves of Hand
1. Ulnar nerve
2. Median nerve

40. Nerves of Hand
Ulnar nerve:
Main nerve of hand.
Ulnar nerve lies superficial to
flexor retinaculum, covered only
by the superficial slip of the
retinaculum. It terminates by
dividing into a superficial and a
deep branch.

41. Nerves of Hand
Median nerve:
• The median nerve is
important because of its role
in controlling the movements
of the thumb which are
crucial in the mechanism of
gripping by the hand.

42. Nerves of Hand
Median nerve:
• Median nerve lies deep to
flexor retinaculum in the
carpal tunnel and enters the
palm. Soon it terminates by
dividing into muscular and
cutaneous branches.

44. Spaces of Hand
The arrangement of fasciae and the fascial septa in the hand is such
that many spaces are formed. These spaces are of surgical importance
because they may become infected and distended with pus. The
important spaces are as follows.

45. Spaces of Hand
The important spaces are as follows:
A. Palmar spaces
1. Pulp space of the fingers
2. Mid palmar space
3. Thenar space
B. Dorsal spaces
1. Dorsal subcutaneous space
2. Dorsal subaponeurotic space
C. The forearm space of Parona.

46. Pulp spaces of the fingers
The tips of the fingers and thumb
contain subcutaneous fat arranged
in tight compartments formed by
fibrous septa which pass from the
skin to the periosteum of the
terminal phalanx. Infection of this
space is known as whitlow. The
rising tension in the space gives
rise to severe throbbing pain.

48. Synovial Sheaths in the Hand
Many of the tendons entering the
hand are surrounded by synovial
sheaths. The extent of these
sheaths is of surgical importance
as they can be infected
These are:
1. Digital synovial sheaths
2. Ulnar bursa
3. Radial bursa

49. Synovial Sheaths in the Hand
1. Ulnar bursa:
Infection of this bursa is usually
secondary to the infection of the little
finger, and this in turn may spread to
the forearm space of the Parona. It
results in an hourglass swelling. Pricking
in the little finger might cause spread of
infection in the ulnar bursa because the
synovial sheath of little finger is
connected with ulnar bursa.

50. END OF CLASS
QUESTIONS?