SPACES OF THE HANDS
OBJECTIVES
§ By the end of this class student should able to
§ 1) to locate the different spaces of the hand on both palmar and dorsal aspects.
§ 2)To know the clinical importance of these spaces.
INTRODUCTION
§ Arrangement of the fascia and fascial septa in the hand is such that forms many spaces.
§ Spaces are of surgical importance because they may become infected and distended with pus.
Midpalmar and Thenar spaces
§ From the medial border of the palmaris aponeurosis a fibrous septum passes backward and is attached to the anterior border of the 5th metacarpal bone.
§ Medial to this septum is a fascial compartment containing the three hypothenar muscles, this compartment is unimportant clinically.
§ From the lateral border of the palmar aponeurosis, a second fibrous septum passes obliquely backward to the anterior border of the 3rd metacarpal bone.
§ Usually the septum passes between the long flexor tendons of the index and the middle fingers.
§ This second septum divides the palm into the thenar space which lies lateral to the septum and the midpalmar space which lies medial to the septum.
§ The thenar space contains the first lumbrical muscle and lies posterior to the long flexor tendons to the index finger and in front of the adductor pollicis muscle.
§ The midpalmar space contains the 2nd, 3rd, and 4th lumbrical muscles and lies posterior to the long flexor tendons to the middle, ring and little fingers. It lies in front of the interossei and the 3rd, 4th and 5th metacarpal bone.
Clinical Correlates
§ Infection of the midpalmar space may result from tenosynovitis of the middle and ring fingers or from a web infection which has spread proximally through the lumbrical canals.
§ When this happens the normal concavity of the palm is obliterated and the swelling extends to the dorsum of the hand.
§ The space can be drained by an incision in either the 3rd or 4th web depending on where the pus points.
Pulp space 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.
Clinical Correlates:
§ The infection of this space is known as whitlow.
§ If neglected a whitlow may lead to necrosis of the distal 4/5th of the terminal phalanx due to occlusion of the vessels by tension. The proximal 1/5th escapes because its artery does not traverse the fibrous septa.
Dorsal spaces
Dorsal subcutaneous space:
§ It lies immediately deep to the loose skin of the dorsum of the hand.
§ In subcutaneous infections, the pus points through the skin and can be drained at the pointing site.
Dorsal subtendinous space:
§ This space lies between the metacarpal bones and the extensor tendons which are united to one another by a thin aponeurosis.
§ In subtendinous infection, the pus points either at the webs or at the borders of the hand and can be drained accordingly.
Space of Parona
§ Forearm space of parona is a rectangular space situated deep in the lower part of the forearm just above the wrist.
§ It lies just in front of the pronator quadratus and deep to the long flexor tendons.
§ Superiorly the space extends upto the oblique origin of the flexor digitorum superficialis.
§ Inferiorly, it extends up to the flexor retinaculum and communicates with the midpalmar space; and possibly also with the thenar space.
§ The forearm space may be infected through infection in the related synovial sheaths especially of the ulnar bursa.