Palmar Aponeurosis

Original Editor - Shanshika Maddumage

Top Contributors - Shanshika Maddumage

Description

Palmar aponeurosis is the central part of the deep fascia of the palm which is a highly specialized thickened structure with little mobility [1]. It is triangular in shape and it covers the underlying neurovascular and tendon structures. Mainly it covers the superficial palmar arch, long flexor tendons, the terminal part of the median nerve and the superficial branch of the ulnar nerve [2]. Pylogenetically the palmar aponeurosis is considered as the degenerated tendon of palmaris longus [3].
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Attachments

Apex

Apex lies proximally and blends with the the flexor retinaculum and is continuous with the tendon of the palmaris longus [2].

Base

From the distal border of the flexor retinaculum it fans out distally towards the bases of the fingers.

It divides into superficial and deep strata.

Superficial strata is attached to the dermis.

Deep strata again divides into four slips (one for each finger) opposite the heads of the metacarpals of the medial four digits. These slips divide into two parts which are continuous with the fibrous flexor sheaths. Extensions from these slips pass to the deep transverse metacarpal ligament, capsule of the metacarpophalangeal joints and the sides of the base of the proximal phalanx. Digital vessels and tendons of the lumbricals pass through the intervals between these four slips. When the fingers are forcefully extended, soft tissue of the palm can be seen bulging out through the intervals between the four slips just proximal to the interdigital webs [2] [3].

Function

  • Gives firm attachment to the skin of the palm to improve grip
  • Protects underlying tendons, vessels and nerves [2][3]

Clinical relevance

Thickening and contraction due to inflammation of the ulnar side of the aponeurosis leads to Dupuytren's contracture. As a result proximal and distal phalanx of the fingers (Usually the third and fourth digits) become flexed. Terminal phalanx remains unaffected.[2]

References

  1. Strickland JW, Hand Function in the Child (Second Edition), 2006. Available from: https://www.sciencedirect.com/topics/neuroscience/palmar-aponeurosis (Last accessed 23.11.2020)
  2. 2.0 2.1 2.2 2.3 2.4 Chaurasia BD. BD Chaurasia's Human Anatomy. CBS Publishers & Distributors PVt Ltd.; 2010. p112-13.
  3. 3.0 3.1 3.2 Sinnatamby CS. Last's Anatomy, International Edition: Regional and Applied. Elsevier Health Sciences; 2011 Apr 19.