biomechanics in simple version

1. HAND COMPLEX
BY K . SANJAIDAS, PHYSIOTHERAPIST
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

2. THE HAND COMPLEX
INTRODUCTION
CARPOMETACARPAL JOINTS OF THE FINGERS
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

3. INTRODUCTION
The hand consists of five digits: four fingers and a thumb (Fig. 9-14).
Each digit has a CMC joint and a metacarpophalangeal (MP) joint.
The fingers each have two IP joints, the proximal (PIP) and distal (DIP), and the
thumb has only one.
There are 19 bones and 19 joints distal to the carpals that make up the hand
complex.
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

4. HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

5. HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

6. CARPOMETACARPAL JOINTS OF THE
FINGERS
The CMC joints of the fingers are composed of the articulations
between the distal carpal row and the bases of the second through fifth
metacarpal joints (see Fig. 9-1).
The distal carpal row also, of course, is part of the midcarpal joint.
The proximal portion of the four metacarpals of the fingers articulate
with the distal carpals to form the second through fifth CMC joints (see
Fig. 9-14).
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

7. HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

8. HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

9. The second metacarpal articulates primarily with the trapezoid and
secondarily with the trapezium and capitate.
The third metacarpal articulates primarily with the capitate, and
The fourth metacarpal articulates with the capitate and hamate.
Last, the fifth metacarpal articulates with the hamate.
Each of the metacarpals also articulates at its base with the contiguous
metacarpal or metacarpals, with the exception of the second metacarpal,
which articulates at its base with the third but not the first metacarpal.
All finger CMC joints are supported by strong transverse and weaker
longitudinal ligaments volarly and dorsally.
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

10. The DEEP TRANSVERSE METACARPAL LIGAMENT spans the heads of the
second through fourth metacarpals volarly.
The deep transverse metacarpal ligament tethers together the metacarpal
heads and effectively prevents the attached metacarpals from any more than
minimal abduction at the CMC joints.
Although the transverse metacarpal ligament contributes directly to CMC
stability, it also is structurally part of the MP joints of the fingers.
The ligamentous structure is primarily responsible for controlling the total
ROM available at each CMC joint, although some differences in articulations
also exist.
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

11. One attribute of the distal carpals that affects CMC and hand function but not
wrist function is the volar concavity, or proximal transverse (carpal) arch,
formed by the trapezoid, trapezium, capitate, and hamate (Fig. 9-15).
The carpal arch persists even when the hand is fully opened and is created not
only by the curved shape of the carpals but also by the ligaments that
maintain the concavity.
The ligaments that maintain the arch are the TCL and the transversely oriented
intercarpal ligaments.
The TCL is the portion of the flexor retinaculum that attaches to the pisiform
and hook of the hamate medially and to the scaphoid and trapezium laterally;
the more proximal portion of the flexor retinaculum is continuous with the
fascia overlying the forearm muscles.
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

12. HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

13. The TCL and intercarpal ligaments that link the four distal carpals maintain the
relatively fixed concavity that will contribute to the arches of the palm.
These structures also form the CARPAL TUNNEL.
The carpal tunnel contains the median nerve and nine flexor tendons: the
extrinsic finger and thumb flexors (see Fig. 9-12B).
A number of intrinsic hand muscles attach to the TCL and bones of the distal
carpal row.
These may also contribute to maintaining the carpal arch.
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

14. HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST

15. THANKYOU
HAND COMPLEX BY SANJAIDAS, PHYSIOTHERAPIST