अल्ना

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अल्ना क्वँय्
अपर एक्स्ट्रेमिटी.jpg
अपर एक्स्ट्रेमिटी
Carpus.png
अल्ना #२ ख
Gray's subject #52 214
MeSH अल्ना

अल्ना (एल्बो बोन) छगू लङ्ग बोन ख। थ्व प्रिज्म्याटिक आकारया जुइ व फोरआर्मया मेडियल सिथय् दै। थ्व क्वें रेडियसया प्यारालल दयाच्वनि।

आर्टिकुलेसन[सम्पादन]

अल्नाया आर्टिकुलेसन थ्व कथं दु:

Proximal and distal aspects[सम्पादन]

The ulna is broader proximally, and narrower distally.

Proximally, the ulna has a bony process, the olecranon process, a hook-like structure that fits into the olecranon fossa of the humerus. This prevents hyperextension and forms a hinge joint with the trochlea of the humerus. There is also a radial notch for the head of the radius, and the ulnar tuberosity to which muscles can attach.

Distally (near the hand), there is a styloid process.

Structure[सम्पादन]

The long, narrow medullary cavity is enclosed in a strong wall of compact tissue which is thickest along the interosseous border and dorsal surface.

At the extremities the compact layer thins.

The compact layer is continued onto the back of the olecranon as a plate of close spongy bone with lamellæ parallel.

From the inner surface of this plate and the compact layer below it trabeculæ arch forward toward the olecranon and coronoid and cross other trabeculæ, passing backward over the medullary cavity from the upper part of the shaft below the coronoid.

Below the coronoid process there is a small area of compact bone from which trabeculæ curve upward to end obliquely to the surface of the semilunar notch which is coated with a thin layer of compact bone.

The trabeculæ at the lower end have a more longitudinal direction.

Muscle attachments[सम्पादन]

Muscle Direction Attachment
Triceps brachii muscle Insertion Olecranon process (via common tendon)
Anconeus muscle Insertion Olecranon process (lateral aspect)
Brachialis muscle Insertion Coronoid process of the ulna
Pronator teres muscle Origin Coronoid process (also shares origin with medial epicondyle of the humerus)
Flexor carpi ulnaris muscle Origin Olecranon process and posterior surface of ulna (also shares origin with medial epicondyle of the humerus)
Flexor digitorum superficialis muscle Origin Coronoid process (also shares origin with medial epicondyle of the humerus and shaft of the radius)
Flexor digitorum profundus muscle Origin Coronoid process, anteromedial surface of ulna (also shares origin with the interosseous membrane)
Pronator quadratus muscle Origin Distal portion of anterior ulnar shaft
Extensor carpi ulnaris muscle Origin Posterior border of ulna (also shares origin with lateral epicondyle of the humerus)
Supinator muscle Origin Proximal ulna (also shares origin with lateral epicondyle of the humerus)
Abductor pollicis longus muscle Origin Posterior surface of ulna (also shares origin with the posterior surface of the radius bone)
Extensor pollicis longus muscle Origin Dorsal shaft of ulna (also shares origin with the dorsal shaft of the radius and the interosseous membrane)
Extensor pollicis brevis muscle Origin Dorsal shaft of ulna (also shares origin with the dorsal shaft of the radius and the interosseous membrane)
Extensor indicis muscle Origin Posterior surface of distal ulna (also shares origin with the interosseous membrane)

स्वयादिसँ[सम्पादन]

Additional images[सम्पादन]

External links[सम्पादन]


This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.