The medial epicondyle of the humerus is an
epicondyle
An epicondyle () is a rounded eminence on a bone that lies upon a condyle ('' epi-'', "upon" + ''condyle'', from a root meaning "knuckle" or "rounded articular area"). There are various epicondyles in the human skeleton, each named by its anatomic ...
of the
humerus
The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...
bone of the upper arm in humans. It is larger and more prominent than the
lateral epicondyle and is directed slightly more posteriorly in the
anatomical position. In birds, where the arm is somewhat rotated compared to other
tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...
s, it is called the ventral epicondyle of the humerus. In
comparative anatomy
Comparative anatomy is the study of similarities and differences in the anatomy of different species. It is closely related to evolutionary biology and phylogeny (the evolution of species).
The science began in the classical era, continuing in t ...
, the more neutral term entepicondyle is used.
The medial epicondyle gives attachment to the
ulnar collateral ligament of elbow joint
The ulnar collateral ligament (UCL) or internal lateral ligament is a thick triangular ligament at the medial aspect of the elbow uniting the distal aspect of the humerus to the proximal aspect of the ulna.
Structure
It consists of two portio ...
, to the
pronator teres, and to a common tendon of origin (the
common flexor tendon
The common flexor tendon is a tendon that attaches to the medial epicondyle of the humerus (lower part of the bone of the upper arm that is near the elbow joint).
It serves as the upper attachment point for the superficial muscles of the fron ...
) of some of the flexor muscles of the
forearm
The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...
: the
flexor carpi radialis
In anatomy, flexor carpi radialis is a muscle of the human forearm that acts to flex and (radially) abduct the hand. The Latin ''carpus'' means wrist; hence flexor carpi is a flexor of the wrist.
Origin and insertion
The flexor carpi radialis is ...
, the
flexor carpi ulnaris
The flexor carpi ulnaris (FCU) is a muscle of the forearm that flexes and adducts at the wrist joint.
Structure Origin
The flexor carpi ulnaris has two heads; a humeral head and ulnar head. The humeral head originates from the medial epicondyle of ...
, the
flexor digitorum superficialis
Flexor digitorum superficialis (''flexor digitorum sublimis'') is an extrinsic flexor muscle of the fingers at the proximal interphalangeal joints.
It is in the anterior compartment of the forearm. It is sometimes considered to be the deepest pa ...
, and the
palmaris longus
The palmaris longus is a muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much long ...
. The medial epicondyle is located on the distal end of the humerus. Additionally, the medial epicondyle is inferior to the
medial supracondylar ridge. It is also proximal to the
olecranon fossa
The olecranon fossa is a deep triangular depression on the posterior side of the humerus, superior to the trochlea. It provides space for the olecranon of the ulna during extension of the forearm.
Structure
The olecranon fossa is located on ...
.
The medial epicondyle protects the
ulnar nerve, which runs in a groove on the back of this epicondyle. The ulnar nerve is vulnerable because it passes close to the surface along the back of the bone. Striking the medial epicondyle causes a tingling sensation in the ulnar nerve. This response is known as striking the "funny bone". The name funny bone could be from a play on the words humorous and humerus, the bone on which the medial epicondyle is located, although according to the
Oxford English Dictionary
The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces the historical development of the English language, providing a com ...
, it may refer to "the peculiar sensation experienced when it is struck".
are common when falling onto an outstretched hand.
Fractures
Medial epicondyle fractures are common elbow injuries in children. There is considerable controversy about their treatment, with uncertainty about whether surgery to restore the natural position of the bone is better than healing in a cast.
Additional images
File:HumerusFront.png, Left humerus. Anterior view.
File:Gray414.png, Front of the left forearm. Superficial muscles.
File:Gray419.png, Posterior surface of the forearm. Deep muscles.
File:Slide1bgbg.JPG, Elbow joint. Deep dissection. Posterior view.
File:Slide2bgbg.JPG, Elbow joint. Deep dissection. Posterior view.
File:Slide3bgbg.JPG, Elbow joint. Deep dissection. Posterior view.
References
External links
*
Slim Golf Blog - Treating & Preventing Golfer's Elbow* ()
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Upper limb anatomy
Humerus