In this article, we shall be looking at the anatomy of the intrinsic muscles of the hand. The thenar muscles are three short muscles located at the base of the thumb. The muscle bellies produce a bulge, known as the thenar eminence.
Your thenar eminence is the soft fleshy area at the base of your thumb. The four muscles found here make your thumb opposable. That is, they allow your thumb to grip and hold small objects like a pencil, sewing needle, or spoon.
Learning Objectives. Carpal tunnel syndrome CTS is the most common of all entrapment neuropathies. Just proximal to the wrist, the Palmar Cutaneous Sensory branch leave the median nerve to run subcutaneously to supply sensation over the thenar eminence.
A cursory review of this area is included in the Upper Extremity Examination. What follows is a description of commonly occurring pain syndromes and pathologic processes involving this region. Presentation and Anatomy: The median nerve travels through a narrow space when it crosses the wrist en route to the hand.
They are innervated by median nerve, except FPB which also provided by ulnar nerve. Together the muscle group primarily acts to oppose the thumb. The four muscles are:.
The thenar eminence refers to the bulge that can be seen at the base of your thumb. Its function is very important to what makes human thumbs opposable. The opponens pollicis works to move the thumb away from the other fingers of the hand.
These are four in number, and they form a fleshy mass at the radial border the palm, covered by the thenar portion of the palmar fascia, and called the thenar eminence or ball of the thumb. They are the abductor pollicis, the opponens pollicis, the flexor brevis pollicis, and the adductor pollicis. The abductor pollicis - named from its action upon the thumb - is a small thi triangular sheet.
Its unique opposability allows us to grasp, hold, squeeze manipulate; its enormous strength gives power to our grip; and its unmatched sensitivity matched by an colossal portion of the brain dedicated to its sensations helps us feel the most minute differences in texture, size or pressure. Thumbs are good at so many things that they are commonly overused, causing tissue and joint irritation, pain, and eventual damage. For example, the increasing use of small-device keyboards means that thumbs are more active than ever in awkward, repetitive movement patterns that are needed to type out texts, posts, and tweets.
Thenar muscles are part of the intrinsic muscles of hand that contributes to the finer movements of the thumb including the opposition. Their insertions are primarily on the base of the proximal phalanx of thumb, except for the opponens, which inserts on the first metacarpal. Blood Supply : Superficial palmar branches of Radial arterywhich arises from the radial artery at the level of the radial styloid.