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m Journal cites, added 2 PMIDs, using AWB (8064)
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more on carrying angle
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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 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. |
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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]],<ref>{{cite book |
The trochlea has the [[capitulum of the humerus|capitulum]] located on its lateral side and the [[Medial epicondyle of the humerus|medial epidcondyle]] on its medial. 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]],<ref>{{cite book |
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| last = Platzer | first = Werner |
| last = Platzer | first = Werner |
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| title = Color Atlas of Human Anatomy, Vol. 1: Locomotor System |
| title = Color Atlas of Human Anatomy, Vol. 1: Locomotor System |
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| Line 25: | Line 25: | ||
}}</ref> which is regularly present in, for example, dogs. |
}}</ref> which is regularly present in, for example, dogs. |
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When viewed from in front or behind the trochlear looks roughly cylindrical, but when viewed from below its true oblique shape and the spiralling nature of its groove becomes apparent. The spiralling nature of the trochlear groove results in the varying transverse axes of the elbow joint.<ref name="Kapandji-1984-84">{{cite book |
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The trochlea has the [[capitulum of the humerus|capitulum]] located on its lateral side and the [[Medial epicondyle of the humerus|medial epidcondyle]] on its medial. |
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| last = Kapandji | first = Ibrahim Adalbert |
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| title = The Physiology of the Joints: Volume One Upper Limb |
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| publisher = Churchill Livingstone | location = New York |
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| year = 1982 | edition = 5th | page = 84 |
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}}</ref> |
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Most frequently, the groove is vertical on the anterior side but runs down laterally on the posterior side. During elbow flexion, the vertical anterior part of the trochela keep the upper arm and forearm aligned (when viewed in front). During elbow extension, however, the oblique posterior part makes contact with the trochlear notch on the ulna so that this obliquity forces the main axis of the forearm to form an small angle with that of the upper arm. This angle is known as the carrying angle and is more prominent in women than in men.<ref name="Kapandji-1984-84" /> |
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Less frequently, the anterior part is oblique too, but in the opposite direction of the posterior side. Consequently, during full elbow flexion, the hand tend to rest outside the shoulder. Very rarely, the anterior part is oblique in the opposite direction, resulting in the hand to rest on the chest during flexion.<ref name="Kapandji-1984-84" /> |
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==Function== |
==Function== |
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| Trochlea of humerus | |
|---|---|
Anterior view of distal part of left humerus
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Posterior view of distal part of left humerus
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| Details | |
| Identifiers | |
| Latin | Trochlea humeri |
| TA98 | A02.4.04.023 |
| TA2 | 1203 |
| FMA | 23370 |
| Anatomical terms of bone | |
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.
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.
The trochlea has the capitulum located on its lateral side and the medial epidcondyle on its medial. 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.
When viewed from in front or behind the trochlear looks roughly cylindrical, but when viewed from below its true oblique shape and the spiralling nature of its groove becomes apparent. The spiralling nature of the trochlear groove results in the varying transverse axes of the elbow joint.[2]
Most frequently, the groove is vertical on the anterior side but runs down laterally on the posterior side. During elbow flexion, the vertical anterior part of the trochela keep the upper arm and forearm aligned (when viewed in front). During elbow extension, however, the oblique posterior part makes contact with the trochlear notch on the ulna so that this obliquity forces the main axis of the forearm to form an small angle with that of the upper arm. This angle is known as the carrying angle and is more prominent in women than in men.[2]
Less frequently, the anterior part is oblique too, but in the opposite direction of the posterior side. Consequently, during full elbow flexion, the hand tend to rest outside the shoulder. Very rarely, the anterior part is oblique in the opposite direction, resulting in the hand to rest on the chest during flexion.[2]
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. [3]
While the ossification of the capitulum has started a year after birth, the ossification of the trochlea begins 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. [4]
{{cite journal}}: Unknown parameter |month= ignored (help)
{{cite journal}}: Unknown parameter |month= ignored (help)
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| Shoulder girdle, clavicle |
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| Scapula |
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| Humerus |
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| Forearm |
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| Hand |
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