Palmar branch of the median nerve

It pierces the palmar carpal ligament, and divides into a lateral and a medial branch;

• The lateral branch supplies the skin over the ball of the thumb, and communicates with the volar branch of the lateral antebrachial cutaneous nerve.
• The medial branch supplies the skin of the palm and communicates with the palmar cutaneous branch of the ulnar.

Unlike most of the median nerve innervation of the hand, the palmar branch travels superficial to the Flexor retinaculum of the hand. Therefore, this portion of the median nerve usually remains functioning during carpal tunnel syndrome.^[1]

• 
  Diagram of segmental distribution of the cutaneous nerves of the right upper extremity.

This article incorporates text in the public domain from page 938 of the 20th edition of Gray's Anatomy (1918)

• http://nervesurgery.wustl.edu/NerveImages/Anatomy%20and%20Physiology/AP-Median-Nerve---IMG_3299.jpg