This document provides an overview of the anatomy of the hand. It describes the bones (phalanges, metacarpals, and carpals), ligaments (palmar aponeurosis and extensor hoods), muscles (intrinsic muscles including thenar, hypothenar, interossei, lumbricals), neurovasculature (ulnar, median, and radial arteries and nerves), and clinical applications. The hand contains small and precise bones and muscles that allow for dexterous movement and grasping.

1. THE HAND
Dr Alimu Jalloh
Department of Anatomy
COMAHS-USL

2. Outline
Osteology
Palmar aponeurosis and extensor hoods
Intrinsic muscles of the hand
Neurovasculature of the hand
Clinical correlates

4. Osteology
• There are 3 groups of bones in the hand;
- The eight carpal bones
- The five metacarpals
- The phalanges

5. Metacarpals
- Metacarpal I is related to the thumb
- Metacarpals II-V related to the index,middle,ring and little finger
respectively
- Each metacarpal consists of a base,shaft and head

6. Phalanges
- Bones of the digits
- Each digit has a proximal, middle and distal phalanx except the thumb
which lacks a middle phalanx.
- Each phalanx has a base, shaft and head

8. Palmar aponeurosis
- Triangular condensation of deep fascia that covers the palm and
anchored to the skin in distal regions.
- Apex is continuous with the palmaris longus tendon if present or
otherwise anchored to the flexor retinaculum.
- Vessels, nerves, and long flexor tendons lie deep to the palmar
aponeurosis in the palm.

10. Fibrous digital sheaths
- Formed by fibrous arches and cruciate ligaments and attached
posteriorly to the margins of the phalanges and to the palmar
ligaments associated with the metacarpophalangeal and
interphalangeal joints
- hold the tendons to the bony plane and prevent the tendons from
bowing when the digits are flexed.

12. Extensor hoods
- Formed by the tendons of the ED and EPL
- Apex attached to the distal phalanx
- Central region attached to the middle phalanx of (index, middle, ring, and little
fingers) or proximal phalanx (thumb)
- Base wrapped around the sides of the metacarpophalangeal joint
- Free margin provides attachement sites for many intrinsic muscles of the hand
- The ability to flex the metacarpophalangeal joints, while at the same time
extending the interphalangeal joints, is entirely due to the intrinsic muscles of
the hand working through the extensor hoods.

14. Intrinsic muscles of the hand
• Originate and insert in the hand
• Function to execute precision movement with the fingers and thumb
• 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.

15. Intrinsic muscles include;
- Palmaris brevis
- Interossei
- Lumbricals
- Thenar
- Hypothenar
- Adductor pollicis

16. Palmaris brevis
- Origin - palmar aponeurosis and flexor retinaculum
- Insertion - dermis of the skin on the medial margin of the hand.
- Innervation - superficial branch of ulanr nerve
- Function - deepens the cup of the palm by pulling on skin over the
hypothenar eminence and forming a distinct ridge. This may improve
grip.

18. Dorsal interossei

19. Palmar interossei

20. Adductor pollicis

21. Thenar and hypothenar muscles

22. Lumbricals

25. Blood supply to the hand

26. Ulnar artery
Superficial palmar arch
- Palmar digital artery
- common palmar digital arteries
- proper palmar digital arteries
Deep palmar branch

28. Radial artery
Deep palmar arch
- Palmar metacarpal arteries
- Perforating branches
Dorsal carpal branch
- 3 dorsal metacarpal arteries which form digital arteries
 First dorsal metacarpal artery
 Princeps pollicis artery
Radialis indicis artery

30. NERVES
Ulnar nerve
 Deep branch - purely motor
Superficial branch
- Motor to palmaris brevis
- skin on the palmar surface of the little finger and
the medial half of the ring finger

32. Median nerve
 Recurrent branch - motor to the three thenar muscles
Palmar digital nerves
- skin on the palmar surfaces of the lateral three and one-half
digits and cutaneous regions over the dorsal aspects of the distal
phalanges (nail beds) of the same digits.
- motor to lateral two lumbricals

34. Radial nerve
 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.