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 The standard anatomical position, or standard anatomical model, is the scientifically agreed upon reference position for anatomical location terms. Standard anatomical positions are used to standardise the position of appendages of animals with ...

. In birds, where the arm is somewhat rotated compared to other

tetrapod Tetrapods (; ) are four-limb (anatomy), limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant taxon, extant and extinct amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (p ...

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 ...

, 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 port ...

, to the

pronator teres The pronator teres is a muscle (located mainly in the forearm) that, along with the pronator quadratus, serves to pronate the forearm (turning it so that the palm faces posteriorly when from the anatomical position). It has two attachments, to ...

, and to a common tendon of origin (the common flexor tendon) 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, the flexor carpi ulnaris, 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 medial epicondyle is located on the distal end of the humerus. Additionally, the medial epicondyle is inferior to the

medial supracondylar ridge The inferior third of the medial border of the humerus is raised into a slight ridge, the medial supracondylar ridge (or medial supracondylar line), which becomes very prominent below; it presents an anterior lip for the origins of the Brachialis ...

. 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 In human anatomy, the ulnar nerve is a nerve that runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is c ...

, 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".

Medial epicondyle fracture of the humerus A medial epicondyle fracture is an avulsion injury to the medial epicondyle of the humerus; the prominence of bone on the inside of the elbow. Medial epicondyle fractures account for 10% elbow fractures in children. 25% of injuries are associated ...

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
* () {{Authority control Upper limb anatomy Humerus