The trochlea and capitulum are the rounded, smooth, knuckle-like surfaces at the anterior and distal end of the humerus. The elbow flexes and extends around these structures. Two outcroppings of bone flank the trochlea and capitulum.
What is the purpose of the trochlea in the humerus?
The trochlea forms the articular surface of the medial column of the elbow and is responsible for allowing ulnohumeral flexion and extension. Fractures of the humeral trochlea can result in elbow stiffness, instability, and post-traumatic arthritis.
Are the capitulum and trochlea condyles?
A large central condyle which has two articular components – the capitulum is the lateral articular component and articulates with the radius, and the trochlea is the medial component which articulates with the ulna. Learn more about the anatomy of the elbow joint in this tutorial.
What articulates with the trochlea of the humerus?
The upper end of the ulna presents a large C-shaped notch—the semilunar, or trochlear, notch—which articulates with the trochlea of the humerus (upper arm bone) to form the elbow joint.
Where is Capitellum?
The capitellum, also referred to as the capitulum, is the lateral part of the humeral condyle that articulates with the radial head.
What is the function of the capitulum?
capitulum: At the distal head of the humerus, it articulates with the radius of the forearm. trochlea: At the distal head of the humerus, it articulates with the ulna of the forearm. anatomical neck: A constriction adjacent to the humeral head that increases the range of movement possible at the shoulder joint.
What is flange of trochlea?
Medial flange of trochlea is 6 mm deeper than lateral flange. Superior articular surface of coronoid process of ulna is oblique to the long axis of ulna. These two factors produces normal valgus angulation between arm and forearm. Carring angle disappears in full flexion and during pronation.
What does the trochlea do?
The tendon then reaches laterally and posteriorly prior to its insertion point on the posterior half of the eye. This “pulley” system afforded by the trochlea makes the superior oblique unique among the extraocular muscles and allows for its muscular functions of depression, abduction, and intorsion of the eye.
Where is Trochlear notch?
The trochlear notch (/ˈtrɒklɪər/), also known as semilunar notch and greater sigmoid cavity, is a large depression in the upper extremity of the ulna that fits the trochlea of the humerus (the bone directly above the ulna in the arm) as part of the elbow joint. It is formed by the olecranon and the coronoid process.
Is the capitulum part of the trochlea?
The trochlea has the capitulum located on its lateral side and the medial epicondyle on its medial. It is directly inferior to the coronoid fossa anteriorly and to the olecranon fossa posteriorly.
Is the capitulum anterior or posterior?
Immediately lateral to the trochlea is the capitulum (“small head”), a knob-like structure located on the anterior surface of the distal humerus. The capitulum articulates with the radius bone of the forearm. Just above these bony areas are two small depressions.
What articulates with the capitulum?
The capitulum laterally articulates with the radius; the trochlea, a spool-shaped surface, articulates with the ulna.
What bone articulates with humerus?
humerus, long bone of the upper limb or forelimb of land vertebrates that forms the shoulder joint above, where it articulates with a lateral depression of the shoulder blade (glenoid cavity of scapula), and the elbow joint below, where it articulates with projections of the ulna and the radius.
How do you remember capitulum and trochlea?
The mnemonic of the order of appearance of the individual ossification centers is C-R-I-T-O-E: Capitellum, Radial head, Internal (medial) epicondyle, Trochlea, Olecranon, External (lateral) epicondyle.
Is the trochlea and condyle?
Although not generally termed condyles, the trochlea and capitulum of the humerus act as condyles in the elbow, and the femur head acts as a condyle in the hip joint.
What do you mean by capitulum?
1 : a rounded protuberance of an anatomical part (such as a bone) 2 : a racemose inflorescence (as of the sunflower) with the axis shortened and dilated to form a rounded or flattened cluster of sessile flowers — see inflorescence illustration.
What is capitulum in biology?
capitulum An inflorescence that consists of closely packed flowers or florets which have no stalks and arise on a flattened axis, all at the same level. The capitulum is surrounded or subtended by an involucre of bracts giving it the appearance of a single flower. Capitula are typical of the Compositae.
What is a capitellum fracture?
Fracture of the capitellum is an intra-articular fracture of the elbow, analogous to the Hoffa fracture of the knee. It is a rare fracture which represents an injury to the lateral column of the distal humerus. The mechanism of injury is usually an axial loading through the radial head [3].
Is the capitulum medial or lateral?
The capitulum is on the lateral side, the trochlea is medial. On the posterior surface, above the trochlea is a large dent, called the olecranon fossa. The proximal end of the ulna fits into this fossa when the elbow is extended.
How do you palpate capitulum?
Which forearm bone articulates with the capitulum?
the radius bone The capitulum articulates with the radius bone of the forearm. Just above these bony areas are two small depressions. These spaces accommodate the forearm bones when the elbow is fully bent (flexed).
Is the trochlea convex?
The medial portion of the articular surface of distal humerus is named the trochlea, and 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.
What fossa is above trochlea of humerus?
The two depressions—the olecranon fossa, behind and above the trochlea, and the coronoid fossa,…
What is trochlea in anatomy?
Medical Definition of trochlea : an anatomical structure resembling a pulley: as. a : the articular surface on the medial condyle of the humerus that articulates with the ulna. b : the fibrous ring in the inner upper part of the orbit through which the tendon of the superior oblique muscle of the eye passes.
Why is it called the trochlea?
The superior oblique muscle ends in a tendon that passes through a fibrous loop, the trochlea, located anteriorly on the medial aspect of the orbit. Trochlea means “pulley” in Latin; the fourth nerve is named after this structure.
What is the trochlea made of?
The trochlea of superior oblique is a pulley-like structure in the eye. The tendon of the superior oblique muscle passes through it. Situated on the superior nasal aspect of the frontal bone, it is the only cartilage found in the normal orbit. The word trochlea comes from the Greek word for pulley.
What does trochlear notch do?
The articulation of the humeral trochlea and the trochlear notch of the ulna is the major facilitator of flexion and extension about the elbow. The radiocapitellar articulation supports motion in both the flexion and extension of the elbow in addition to supination and pronation of the forearm.
What is Trochlear fossa?
: a depression in the antero-medial aspect of each orbital plate of the frontal bone that forms a point of attachment for the corresponding superior oblique muscle.
What is the trochlear notch in anatomy?
Medical Definition of trochlear notch : the deep depression in the proximal end of the ulna by which the ulna articulates with the trochlea of the humerus at the elbow. — called also semilunar notch, sigmoid notch.
Graduated from ENSAT (national agronomic school of Toulouse) in plant sciences in 2018, I pursued a CIFRE doctorate under contract with Sun’Agri and INRAE in Avignon between 2019 and 2022. My thesis aimed to study dynamic agrivoltaic systems, in my case in arboriculture. I love to write and share science related Stuff Here on my Website. I am currently continuing at Sun’Agri as an R&D engineer.