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Encyclopedia > Ulna
Ulna l. dx. - ant. view
Ulna l. dx. - ant. view
Ulna l. dx. - lat. view
Ulna l. dx. - lat. view

The ulna (Elbow Bone) [Figs. 1, 2] is a long bone, prismatic in form, placed at the medial side of the forearm, parallel with the radius. Image File history File linksMetadata Download high resolution version (400x1699, 115 KB) Ulna anterior aspect File links The following pages link to this file: Ulna Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... Image File history File linksMetadata Download high resolution version (400x1699, 115 KB) Ulna anterior aspect File links The following pages link to this file: Ulna Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... Image File history File linksMetadata Download high resolution version (400x1972, 126 KB) Ulna medial aspect File links The following pages link to this file: Ulna Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... Image File history File linksMetadata Download high resolution version (400x1972, 126 KB) Ulna medial aspect File links The following pages link to this file: Ulna Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... In geometry, a prism is a polyhedron made of two parallel copies of some polygonal base joined by faces that are rectangles or parallelograms. ... The forearm is the structure on the upper limb, between the elbow and the wrist. ... The radius and ulna of the left forearm, posterior surface. ...

Contents


Articulations

The ulna articulates with:

  • the humerus, at the elbow as a hinge joint.
  • the radius, near the elbow as a pivot joint, this allows the radius to cross over the ulna in pronation.
  • the distal radius, where it fits into the ulna notch.

The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ... Elbow redirects here. ... A joint is a nicely rolled marijuana cigarette. ... The radius and ulna of the left forearm, posterior surface. ...

Proximal and distal aspects

The femur is broader proximally, and narrower distally.


Proximally, the femur 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 humeral notch for the head of the radius, and the ulna tuberosity to which muscles can attach. In anatomy, a process (Latin: processus) is a projection or outgrowth of tissue from a larger body. ...


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


Overview of body and two extremities

It is divisible into a body and two extremities. Its upper extremity, of great thickness and strength, forms a large part of the elbow-joint; the bone diminishes in size from above downward, its lower extremity being very small, and excluded from the wrist-joint by the interposition of an articular disk.


The upper extremity

Figure 1 : Upper extremity of left ulna. Lateral aspect.

('proximal extremity') [Fig. 1] The upper extremity presents two curved processes, the olecranon and the coronoid process; and two concave, articular cavities, the semilunar and radial notches. Image File history File links Download high resolution version (251x700, 36 KB)From Grays Anatomy This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Image File history File links Download high resolution version (251x700, 36 KB)From Grays Anatomy This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...


The olecranon

('olecranon process') The olecranon is a large, thick, curved eminence, situated at the upper and back part of the ulna. It is bent forward at the summit so as to present a prominent lip which is received into the olecranon fossa of the humerus in extension of the forearm. Its base is contracted where it joins the body and the narrowest part of the upper end of the ulna. Its posterior surface, directed backward, is triangular, smooth, subcutaneous, and covered by a bursa. Its superior surface is of quadrilateral form, marked behind by a rough impression for the insertion of the triceps brachii; and in front, near the margin, by a slight transverse groove for the attachment of part of the posterior ligament of the elbow-joint. Its anterior surface is smooth, concave, and forms the upper part of the semilunar notch. Its borders present continuations of the groove on the margin of the superior surface; they serve for the attachment of ligaments: the back part of the ulnar collateral ligament medially, and the posterior ligament laterally. From the medial border a part of the flexor carpi ulnaris arises; while to the lateral border the Anconæus is attached. Triceps brachii The triceps brachii muscle is a large three-headed skeletal muscle found in humans. ... In anatomy, flexor carpi ulnaris muscle is a muscle of the human forearm that acts to flex and adduct the hand. ...


The coronoid process

('processus coronoideus') The coronoid process is a triangular eminence projecting forward from the upper and front part of the ulna. Its base is continuous with the body of the bone, and of considerable strength. Its apex is pointed, slightly curved upward, and in flexion of the forearm is received into the coronoid fossa of the humerus. Its upper surface is smooth, concave, and forms the lower part of the semilunar notch. Its antero-inferior surface is concave, and marked by a rough impression for the insertion of the brachialis. At the junction of this surface with the front of the body is a rough eminence, the tuberosity of the ulna, which gives insertion to a part of the brachialis; to the lateral border of this tuberosity the oblique cord is attached. Its lateral surface presents a narrow, oblong, articular depression, the radial notch. Its medial surface, by its prominent, free margin, serves for the attachment of part of the ulnar collateral ligament. At the front part of this surface is a small rounded eminence for the origin of one head of the Flexor digitorum sublimis; behind the eminence is a depression for part of the origin of the flexor digitorum profundus; descending from the eminence is a ridge which gives origin to one head of the pronator teres. Frequently, the flexor pollicis longus arises from the lower part of the coronoid process by a rounded bundle of muscular fibers. Brachialis is a flexor muscle in the upper arm. ... The flexor digitorum profundis is a muscle in the forearm that flexes the fingers. ... The Pronator teres muscle is a muscle of the human body, in the forearm. ... The Flexor pollicis longus muscle is a muscle of the human body. ...


The semilunar notch

('incisura semilunaris; greater sigmoid cavity') The semilunar notch is a large depression, formed by the olecranon and the coronoid process, and serving for articulation with the trochlea of the humerus. About the middle of either side of this notch is an indentation, which contracts it somewhat, and indicates the junction of the olecranon and the coronoid process. The notch is concave from above downward, and divided into a medial and a lateral portion by a smooth ridge running from the summit of the olecranon to the tip of the coronoid process. The medial portion is the larger, and is slightly concave transversely; the lateral is convex above, slightly concave below.


The radial notch

('incisura radialis; lesser sigmoid cavity') The radial notch is a narrow, oblong, articular depression on the lateral side of the coronoid process; it receives the circumferential articular surface of the head of the radius. It is concave from before backward, and its prominent extremities serve for the attachment of the annular ligament. The radius and ulna of the left forearm, posterior surface. ...


The body or shaft

Figure 2 : Bones of left forearm. Anterior aspect.
Figure 2 : Bones of left forearm. Anterior aspect.
Figure 3 : Bones of left forearm. Posterior aspect.
Figure 3 : Bones of left forearm. Posterior aspect.

('corpus ulnæ') The body at its upper part is prismatic in form, and curved so as to be convex behind and lateralward; its central part is straight; its lower part is rounded, smooth, and bent a little lateralward. It tapers gradually from above downward, and has three borders and three surfaces. Image File history File links Download high resolution version (700x1245, 71 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (700x1245, 71 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (717x1254, 103 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (717x1254, 103 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...


Borders

The volar border (margo volaris; anterior border) begins above at the prominent medial angle of the coronoid process, and ends below in front of the styloid process. Its upper part, well-defined, and its middle portion, smooth and rounded, give origin to the flexor digitorum profundus; its lower fourth serves for the origin of the pronator quadratus. This border separates the volar from the medial surface. The flexor digitorum profundis is a muscle in the forearm that flexes the fingers. ... Pronator quadratus is a square shaped muscle on the distal forearm that acts to pronate (turn so the palm faces downwards) the hand. ...


The dorsal border (margo dorsalis; posterior border) begins above at the apex of the triangular subcutaneous surface at the back part of the olecranon, and ends below at the back of the styloid process; it is well-marked in the upper three-fourths, and gives attachment to an aponeurosis which affords a common origin to the flexor carpi ulnaris, the extensor carpi ulnaris, and the flexor digitorum profundus; its lower fourth is smooth and rounded. This border separates the medial from the dorsal surface. In anatomy, flexor carpi ulnaris muscle is a muscle of the human forearm that acts to flex and adduct the hand. ... Extensor carpi ulnaris is a muscle, located in the forearm of humans that acts to extend and adduct the wrist. ... The flexor digitorum profundis is a muscle in the forearm that flexes the fingers. ...


The interosseous crest (crista interossea; external or interosseous border) begins above by the union of two lines, which converge from the extremities of the radial notch and enclose between them a triangular space for the origin of part of the Supinator; it ends below at the head of the ulna. Its upper part is sharp, its lower fourth smooth and rounded. This crest gives attachment to the interosseous membrane, and separates the volar from the dorsal surface.


Surfaces

The volar surface (facies volaris; anterior surface), much broader above than below, is concave in its upper three-fourths, and gives origin to the flexor digitorum profundus; its lower fourth, also concave, is covered by the pronator quadratus. The lower fourth is separated from the remaining portion by a ridge, directed obliquely downward and medialward, which marks the extent of origin of the pronator quadratus. At the junction of the upper with the middle third of the bone is the nutrient canal, directed obliquely upward. The flexor digitorum profundis is a muscle in the forearm that flexes the fingers. ... Pronator quadratus is a square shaped muscle on the distal forearm that acts to pronate (turn so the palm faces downwards) the hand. ...


The dorsal surface (facies dorsalis; posterior surface) directed backward and lateralward, is broad and concave above; convex and somewhat narrower in the middle; narrow, smooth, and rounded below. On its upper part is an oblique ridge, which runs from the dorsal end of the radial notch, downward to the dorsal border; the triangular surface above this ridge receives the insertion of the Anconæus, while the upper part of the ridge affords attachment to the supinator. Below this the surface is subdivided by a longitudinal ridge, sometimes called the perpendicular line, into two parts: the medial part is smooth, and covered by the extensor carpi ulnaris; the lateral portion, wider and rougher, gives origin from above downward to the Supinator, the abductor pollicis longus, the extensor pollicis longus, and the extensor indicis proprius. The Supinator muscle is a muscle of the human body. ... Extensor carpi ulnaris is a muscle, located in the forearm of humans that acts to extend and adduct the wrist. ... The Abductor pollicis longus muscle is a muscle of the human body. ... The Extensor pollicis longus muscle is a muscle of the human body. ...


The medial surface (facies medialis; internal surface) is broad and concave above, narrow and convex below. Its upper three-fourths give origin to the Flexor digitorum profundus; its lower fourth is subcutaneous.


The lower extremity

Figure 4 : Plan of ossification of the ulna. From three centers.
Figure 4 : Plan of ossification of the ulna. From three centers.
Figure 5 : Epiphysial lines of ulna in a young adult. Lateral aspect. The lines of attachment of the articular capsules are in blue.
Figure 5 : Epiphysial lines of ulna in a young adult. Lateral aspect. The lines of attachment of the articular capsules are in blue.

('distal extremity') The lower extremity of the ulna is small, and presents two eminences; the lateral and larger is a rounded, articular eminence, termed the head of the ulna; the medial, narrower and more projecting, is a non-articular eminence, the styloid process. The head presents an articular surface, part of which, of an oval or semilunar form, is directed downward, and articulates with the upper surface of the triangular articular disk which separates it from the wrist-joint; the remaining portion, directed lateralward, is narrow, convex, and received into the ulnar notch of the radius. The styloid process projects from the medial and back part of the bone; it descends a little lower than the head, and its rounded end affords attachment to the ulnar collateral ligament of the wrist-joint. The head is separated from the styloid process by a depression for the attachment of the apex of the triangular articular disk, and behind, by a shallow groove for the tendon of the extensor carpi ulnaris. Image File history File links Gray215. ... Image File history File links Gray215. ... Image File history File links Gray216. ... Image File history File links Gray216. ... Extensor carpi ulnaris is a muscle, located in the forearm of humans that acts to extend and adduct the wrist. ...


Structure

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.


Ossification

(Figs. 215, 216) The ulna is ossified from three centers: one each for the body, the inferior extremity, and the top of the olecranon. Ossification begins near the middle of the body, about the eighth week of fetal life, and soon extends through the greater part of the bone. At birth the ends are cartilaginous. About the fourth year, a center appears in the middle of the head, and soon extends into the styloid process. About the tenth year, a center appears in the olecranon near its extremity, the chief part of this process being formed by an upward extension of the body. The upper epiphysis joins the body about the sixteenth, the lower about the twentieth year. For other uses of the word bone, see bone (disambiguation). ...


See also

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
Grays illustration of a human femur, a typically recognized bone. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... Henry Grays Anatomy of the Human Body, commonly known as Grays Anatomy, is an anatomy textbook widely regarded as a classic work on human anatomy. ...

Human Bones
VERTEBRAL COLUMN: vertebrae (cervical - atlas - axis | thoracic | lumbar) | sacrum | coccyx

THORAX: sternum | rib A typical adult human skeleton consists of the following 206 bones. ... The vertebral column seen from the side Different regions (curvatures) of the vertebral column The vertebral column (backbone or spine) is a column of vertebrae situated in the dorsal aspect of the abdomen. ... A diagram of a thoracic vertebra. ... A cervical vertebra Cervical vertebrae (Vertebrae cervicales) are the smallest of the true vertebrae, and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process. ... First cervical vertebra, or Atlas In anatomy, the Atlas (C1) is the topmost (first) cervical vertebra of the spine. ... In anatomy, the second cervical vertebra (C2) of the spine is named the axis or epistropheus. ... A typical thoracic vertebra The thoracic vertebrae (vertebrae thoracales) compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. ... Categories: Anatomy stubs | Anatomy ... Sacrum, pelvic surface The sacrum (os sacrum) is a large, triangular bone at the base of the vertebral column and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. ... The coccyx is formed of four fused vertebrae. ... Diagram of a tsetse fly, showing the head, thorax and abdomen The thorax is a division of an animals body that lies between the head and the abdomen. ... Figure 1 : Anterior surface of sternum and costa cartilages. ... The human rib cage. ...


cranial bones of SKULL: occipital | parietal | frontal | temporal | sphenoid | ethmoid A hippopotamus skull A skull, or cranium, is a bony structure of Craniates which serves as the general framework for a head. ... The occipital bone [Fig. ... The parietal bones (os parietale) are bones in the human skull and form, by their union, the sides and roof of the cranium. ... The frontal bone (os frontale, TA: A02. ... The temporal bones (os temporales) are situated at the sides and base of the skull. ... Figure 1 : Sphenoid bone, upper surface. ... Your skull is in your back (this is obviously not true, I was just testing the website to see if it really works) The ethmoid bone (os ethmoidale) is a bone in the skull that separates the nasal cavity from the brain. ...


facial bones of SKULL nasal | maxilla | lacrimal | zygomatic | palatine | inferior nasal conchae | vomer | mandible | hyoid A hippopotamus skull A skull, or cranium, is a bony structure of Craniates which serves as the general framework for a head. ... The Nasal Bones (Ossa Faciei & Ossa Nasalia) are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, the bridge of the nose. ... The maxillae are the largest bones of the face, except for the mandible, and form, by their union, the whole of the upper jaw. ... The lacrimal bone (Os Lacrimale), the smallest and most fragile bone of the face, is situated at the front part of the medial wall of the orbit . ... The zygomatic bone (also known as the zygoma; Os Zygomaticum; Malar Bone) is a paired bone of the human skull. ... The palatine bone is a bone situated at the back part of the nasal cavity between the maxilla and the pterygoid process of the sphenoid. ... The inferior nasal concha (Concha Nasalis Inferior; Inferior Turbinated Bone) extends horizontally along the lateral wall of the nasal cavity [Fig. ... The vomer bone is one of the unpaired facial bones of the skull. ... The mandible (inferior maxillary bone) (together with the maxilla) is the largest and strongest bone of the face. ... The hyoid bone (Os Hyoideum; Lingual Bone) is a bone in the human neck, not articulated to any other bone; it is supported by the muscles of the neck and in turn supports the root of the tongue. ...


UPPER EXTREMITY: clavicle | scapula | humerus | ulna | radius Left clavicle - from above Left clavicle - from below Collarbone (a bone) redirects here. ... Left scapula - front view () Left scapula - rear view () In anatomy, the scapula, or shoulder blade, is the bone that connects the humerus (arm bone) with the clavicle (collar bone). ... The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ... The radius and ulna of the left forearm, posterior surface. ...


carpus (scaphoid | lunate bone | triquetral | pisiform | trapezium | trapezoid | capitate | hamate) | metacarpals | phalanges (prox | int | dist) In Greek mythology, Carpus fruit was a son of Chloris and Boreas. ... The scaphoid bone of the wrist is found on the thumb side of the hand, within the anatomical snuffbox. ... The lunate bone (os lunatum; semilunar bone) is a bone in the human hand that may be distinguished by its deep concavity and crescentic outline. ... The triquetral bone (also called triquetral, os triquetrum, cuneiform bone, pyramidal bone, cubital bone, os pyramidale, os triangulare, three-cornered bone, and triangular bone) is a type of carpal bone. ... The left pisiform bone. ... The trapezium is a bone in the human hand. ... In human anatomy, the trapezoid bone (lesser multangular bone; os multangulum minus) is a bone in the hands. ... The capitate bone (os capitatum; os magnum) is a bone in the human hand. ... The hamate bone (os hamatum; unciform bone) is a bone in the human hand that may be readily distinguished by its wedge-shaped form, and the hook-like process which projects from its volar surface. ... The metacarpus is the intermediate part of the hand skeleton that is located between the fingers distally and the carpus which forms the connection to the forearm. ... Proximal phalanges are bones found in the limbs of most vertebrates. ... Intermediate phalanges are bones found in the limbs of most vertebrates. ... Distal phalanges are bones found in the limbs of most vertebrate skeletons. ...


LOWER EXTREMITY: pelvis (ilium, ischium, pubis, acetabulum) | femur (greater trochanter - lesser trochanter - linea aspera) | patella | fibula | tibia Human male pelvis, viewed from front Human female pelvis, viewed from front The pelvis is the bony structure located at the base of the spine (properly known as the caudal end). ... The ilium is a bone that is part of the pelvis. ... The ischium forms the lower and back part of the hip bone. ... The pubis, the anterior part of the hip bone, is divisible into a body, a superior and an inferior ramus. ... Categories: Anatomy stubs | Skeletal system ... If you were looking for an organization, see FEMA. The femur or thigh bone is the longest, most voluminous and strongest bone of the human body. ... Bones of the Hip In anatomy, the hip is the bony projection of the femur, known as the greater trochanter, and the overlying muscle and fat. ... The Lesser Trochanter (small trochanter) of the femur is a conical eminence, which varies in size in different subjects; it projects from the lower and back part of the base of the neck. ... The linea aspera is a ridge of roughened surface on the posterior aspect of the femur, to which are attached muscles and intermusclular septa. ... Left patella - anterior aspect Left patella - posterior aspect The patella or kneecap is a thick, triangular bone which articulates with the femur and covers and protects the front of the knee joint. ... Figure 1 : Lower extremity of right fibula. ... Figure 1 : Upper surface of right tibia. ...


tarsus (calcaneus | talus | navicular | cuneiform | cuboid ) | metatarsals | phalanges (prox | int | dist) FIG. 268– Bones of the right foot. ... The calcaneus is the large bone making up the heel of the human foot. ... FIG. 270– Left talus, from above. ... The navicular bone (also called the navicular or scaphoid) is a small boat-shaped human bone of the tarsus. ... There are three cuneiform bones in the human foot: the medial cuneiform, the intermediate cuneiform and the lateral cuneiform. ... The cuboid bone is one of seven Tarsal bones. ... The metatarsus consists of the five long bones of the foot, which are numbered from the medial side (ossa metatarsalia I.-V.); each presents for examination a body and two extremities. ... Proximal phalanges are bones found in the limbs of most vertebrates. ... Intermediate phalanges are bones found in the limbs of most vertebrates. ... Distal phalanges are bones found in the limbs of most vertebrate skeletons. ...


OSSICLES: malleus | incus | stapes The ossicles (also called auditory ossicles) are the three smallest bones in the human body. ... The malleus is hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum. ... The incus is the anvil-shaped small bone or ossicle in the middle ear. ... stapes The stapes or stirrup is the stirrup-shaped small bone or ossicle in the middle ear which attaches the incus to the fenestra ovalis, the oval window which is adjacent to the vestibule of the inner ear. ...


  Results from FactBites:
 
Ulna - definition of Ulna in Encyclopedia (1704 words)
The ulna (along with the radius) is one of the two bones in the forearm.
The ulna is broader proximally, and narrower distally.
The ulna articulates with the humerus and radius.
Ulna - Wikipedia, the free encyclopedia (1692 words)
Its antero-inferior surface is concave, and marked by a rough impression for the insertion of the brachialis.
At the junction of this surface with the front of the body is a rough eminence, the tuberosity of the ulna, which gives insertion to a part of the brachialis; to the lateral border of this tuberosity the oblique cord is attached.
The head presents an articular surface, part of which, of an oval or semilunar form, is directed downward, and articulates with the upper surface of the triangular articular disk which separates it from the wrist-joint; the remaining portion, directed lateralward, is narrow, convex, and received into the ulnar notch of the radius.
  More results at FactBites »

 
 

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