Trochlea of humerus
| Bone: Trochlea of humerus | |
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| Anterior view of distal part of left humerus | |
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| Posterior view of distal part of left humerus | |
| Latin | Trochlea humeri |
| Gray's | subject #51 212 |
In the human arm, the humeral trochlea is the medial portion of the articular surface of the elbow joint which articulates with the trochlear notch on the ulna in the forearm.
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[edit] Structure
It presents a deep depression between two well-marked borders; it is convex from before backward, concave from side to side, and occupies the anterior, lower, and posterior parts of the extremity.
It is directly inferior to the coronoid fossa anteriorly and to the olecranon fossa posteriorly. In humans, these two fossae, the most prominent in the humerus, are occasionally transformed into a hole, the supratrochlear foramen,[1] which is regularly present in, for example, dogs.
The trochlea has the capitulum located on its lateral side and the medial epidcondyle on its medial.
[edit] Function
The elbow is a hinge joint with a rotatory component where the trochlea forms the convex, proximal surface which articulates with the concave, distal surface on the ulna, the trochlear notch. While the trochlea together with its associated fossae almost covers a 360° angle, the trochlear notch on the ulna forms a 190° arc and the gap in between allows flexion and extension at the elbow. Maximum elbow flexion and extension is made possible because the two fossae accommodates to coronoid and olecranon processes. [2]
[edit] Ossification
While the ossification of the capitulum has started a year after birth, the ossification of the trochlea begin at 8–9 years of age; that of the head of radius and the medial epicondyle at 4–5 years and that of the lateral condyle at 10 years. [3]
[edit] References
- ^ Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. p. 114. ISBN 3-13-533305-1.
- ^ Wells, Jason; Ablove, Robert H. (May 2008). "Coronoid Fractures of the Elbow". Clin Med Res. (Anatomy of the Elbow) 6 (1): 40–44. doi:10.3121/cmr.2008.753. PMC 2442031. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2442031.
- ^ Brubacher, Jacob W.; Dodd, Seth D. (December 2008). "Pediatric supracondylar fractures of the distal humerus". Curr Rev Musculoskelet Med. 1 (3-4): 190–196. doi:10.1007/s12178-008-9027-2. PMC 2682409. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2682409.
[edit] External links
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