[Ge. Pe.]

Estimados Foristas:


Empezaremos un tema nuevo apoyándonos en la Anatomy of the Human Body de H. GRAY.

Lo hacemos, como siempre, para despertar el interés sobre la estructuración de los organismos y su complejidad. Tenemos claro que este tema lo pueden ver en la siguiente página:

http://www.bartleby.com/107/68.html

alojada en el portal:

que permite la reproducción total o parcial del contenido de esta obra.


Tenemos la esperanza que será útil.


Para ubicarnos en los términos básicos, bajamos una introducción de WIKIPEDIA.

______________________________________________________________

Artrología - Sindesmología.

La artrología es la rama de la anatomía que se dedica al estudio de las diferentes articulaciones.

También se le conoce como sindesmología.

Una articulación o juntura es una estructura que funciona como elemento conector de diferentes piezas óseas o cartilaginosas del esqueleto. Generalmente las articulaciones entrañan la idea de movimiento, pero también funcionan como elemento de fijación firme para la unión de huesos.

Juegan un papel muy importante en los movimientos corporales, desde respirar y caminar hasta labores evolutivamente complicadas como el uso de herramientas.

Las articulaciones según su movimiento se dividen en.

• Anfiartrosis: Articulación unida por fibrocartílago, con movimientos muy limitados.
  
  
• Sinartrosis: Unidos con fibras colágeno lo cual impide en su totalidad el movimiento.
  
  
• Diartrosis: Articulación sinovial formada por superficies articulares revestidas de cartílago hialino, cápsula articular, y ligamentos de refuerzo. Poseen mucho movimiento.

Las articulaciones según su conformación se dividen en.

• Cartilaginosas: Concervan el ensamblaje oseo por medio de un cartílago y no poseen cavidad sinovial.
  
  
• Fibrosas: Mantienen unidos los huesos gracias al tejido conectivo fibroso, el cual contiene abundantes fibras de colagena, y carece de cavidad sinovial.
  
  
• Sinoviales: Los huesos que forman este tipo de articulación cuentan con una cavidad sinovial; se mantienen juntos por la acción del tejido conectivo denso y regular de una cápsula articular y con frecuencia por el trabajo de los ligamentos.

____________________________________________________

Henry Gray (1821–1865). Anatomy of the Human Body. 1918.

III. Syndesmology

Introduction

THE BONES of the skeleton are joined to one another at different parts of their surfaces, and such connections are termed Joints or Articulations. Where the joints are immovable, as in the articulations between practically all the bones of the skull, the adjacent margins of the bones are almost in contact, being separated merely by a thin layer of fibrous membrane, named the sutural ligament. In certain regions at the base of the skull this fibrous membrane is replaced by a layer of cartilage. Where slight movement combined with great strength is required, the osseous surfaces are united by tough and elastic fibrocartilages, as in the joints between the vertebral bodies, and in the interpubic articulation. In the freely movable joints the surfaces are completely separated; the bones forming the articulation are expanded for greater convenience of mutual connection, covered by cartilage and enveloped by capsules of fibrous tissue. The cells lining the interior of the fibrous capsule form an imperfect membrane—the synovial membrane—which secretes a lubricating fluid. The joints are strengthened by strong fibrous bands called ligaments, which extend between the bones forming the joint.

______________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology

Bone.—

Bone constitutes the fundamental element of all the joints. In the long bones, the extremities are the parts which form the articulations; they are generally somewhat enlarged; and consist of spongy cancellous tissue with a thin coating of compact substance. In the flat bones, the articulations usually take place at the edges; and in the short bones at various parts of their surfaces. The layer of compact bone which forms the joint surface, and to which the articular cartilage is attached, is called the articular lamella. It differs from ordinary bone tissue in that it contains no Haversian canals, and its lacunæ are larger and have no canaliculi. The vessels of the cancellous tissue, as they approach the articular lamella, turn back in loops, and do not perforate it; this layer is consequently denser and firmer than ordinary bone, and is evidently designed to form an unyielding support for the articular cartilage.

Cartilage.—

Cartilage is a non-vascular structure which is found in various parts of the body—in adult life chiefly in the joints, in the parietes of the thorax, and in various tubes, such as the trachea and bronchi, nose, and ears, which require to be kept permanently open. In the fetus, at an early period, the greater part of the skeleton is cartilaginous; as this cartilage is afterward replaced by bone, it is called temporary, in contradistinction to that which remains unossified during the whole of life, and is called permanent.

Cartilage is divided, according to its minute structure, into hyaline cartilage, white fibrocartilage, and yellow or elastic fibrocartilage.

FIG. 292




Human cartilage cells from the cricoid cartilage.

FIG. 293




Vertical section of articular cartilage.

FIG. 294




Costal cartilage from a man, aged seventy-six years, showing the development of fibrous structure in the matrix. In several portions of the specimen two or three generations of cells are seen enclosed in a parent cell wall. Highly magnified.

FIG. 295




White fibrocartilage from an intervertebral fibrocartilage.

2. Development of the Joints

The mesoderm from which the different parts of the skeleton are formed shows at first no differentiation into masses corresponding with the individual bones.

3. Classification of Joints

The articulations are divided into three classes: synarthroses or immovable, amphiarthroses or slightly movable, and diarthroses or freely movable, joints.

Synarthroses (immovable articulations).—

Synarthroses include all those articulations in which the surfaces of the bones are in almost direct contact, fastened together by intervening connective tissue or hyaline cartilage, and in which there is no appreciable motion, as in the joints between the bones of the skull, excepting those of the mandible. There are four varieties of synarthrosis: sutura, schindylesis, gomphosis, and synchondrosis.

Sutura.—

Sutura is that form of articulation where the contiguous margins of the bones are united by a thin layer of fibrous tissue; it is met with only in the skull (Fig. 296).

FIG. 296




Section across the sagittal suture.

Synchondrosis.—Where the connecting medium is cartilage the joint is termed a synchondrosis (Fig. 297).

FIG. 297




Section through occipitosphenoid synchondrosis of an infant.

Diarthroses (freely movable articulations).—

This class includes the greater number of the joints in the body. In a diarthrodial joint the contiguous bony surfaces are covered with articular cartilage, and connected by ligaments lined by synovial membrane (Fig. 299). The joint may be divided, completely or incompletely, by an articular disk or meniscus, the periphery of which is continuous with the fibrous capsule while its free surfaces are covered by synovial membrane (Fig. 300).

FIG. 299




Diagrammatic section of a diarthrodial joint.

FIG. 300




Diagrammatic section of a diarthrodial joint, with an articular disk.

4. The Kind of Movement Admitted in Joints

The movements admissible in joints may be divided into four kinds: gliding and angular movements, circumduction, and rotation. These movements are often, however, more or less combined in the various joints, so as to produce an infinite variety, and it is seldom that only one kind of motion is found in any particular joint.

_______________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology

5. Articulations of the Trunk.


a. Articulations of the Vertebral Column

These may be divided into the following groups, viz:

I. Of the Vertebral Column.
II. Of the Atlas with the Axis.
III. Of the Vertebral Column with the Cranium.
IV. Of the Mandible.
V. Of the Ribs with the Vertebræ.
VI. Of the Cartilages of the Ribs with the Sternum, and with Each Other.
VII. Of the Sternum.
VIII. Of the Vertebral Column with the Pelvis.
IX. Of the Pelvis.

Articulations of the Vertebral Column

The articulations of the vertebral column consist of

(1) a series of amphiarthrodial joints between the vertebral bodies, and

(2) a series of diathrodial joints between the vertebral arches.

1. Articulations of Vertebral Bodies (intercentral ligaments).—

The articulations between the bodies of the vertebræ are amphiarthrodial joints, and the individual vertebræ move only slightly on each other. When, however, this slight degree of movement between the pairs of bones takes place in all the joints of the vertebral column, the total range of movement is very considerable.

The ligaments of these articulations are the following:

The Anterior Longitudinal.
The Posterior Longitudinal.
The Intervertebral Fibrocartilages.

The Anterior Longitudinal Ligament (ligamentum longitudinale anterius; anterior common ligament) (Figs. 301, 312).—

The anterior longitudinal ligament is a broad and strong band of fibers, which extends along the anterior surfaces of the bodies of the vertebræ, from the axis to the sacrum.

FIG. 301




Median sagittal section of two lumbar vertebræ and their ligaments.

FIG. 312




Costovertebral articulations. Anterior view.

The Posterior Longitudinal Ligament (ligamentum longitudinale posterius; posterior common ligament) (Figs. 301, 302).—

The posterior longitudinal ligament is situated within the vertebral canal, and extends along the posterior surfaces of the bodies of the vertebræ, from the body of the axis, where it is continuous with the membrana tectoria, to the sacrum.

FIG. 301




Median sagittal section of two lumbar vertebræ and their ligaments.

FIG. 302




Posterior longitudinal ligament, in the thoracic region.

The Intervertebral Fibrocartilages (fibrocartilagines intervertebrales; intervertebral disks) (Figs. 301, 313).—

The intervertebral fibrocartilages are interposed between the adjacent surfaces of the bodies of the vertebræ, from the axis to the sacrum, and form the chief bonds of connection between the vertebræ.

FIG. 301




Median sagittal section of two lumbar vertebræ and their ligaments.

FIG. 313




Costotransverse articulation. Seen from above.

The Ligamenta Flava (ligamenta subflava, Fig. 303).—

The ligamenta flava connect the laminæ of adjacent vertebræ, from the axis to the first segment of the sacrum.

FIG. 303




Vertebral arches of three thoracic vertebræ viewed from the front.

Movements.—

The movements permitted in the vertebral column are: flexion, extension, lateral movement, circumduction, and rotation.

In flexion, or movement forward, the anterior longitudinal ligament is relaxed, and the intervertebral fibrocartilages are compressed in front; while the posterior longitudinal ligament, the ligamenta flava, and the inter- and supraspinal ligaments are stretched, as well as the posterior fibers of the intervertebral fibrocartilages. The interspaces between the laminæ are widened, and the inferior articular processes glide upward, upon the superior articular processes of the subjacent vertebræ. Flexion is the most extensive of all the movements of the vertebral column, and is freest in the lumbar region.

In extension, or movement backward, an exactly opposite disposition of the parts takes place.

This movement is limited by the anterior longitudinal ligament, and by the approximation of the spinous processes. It is freest in the cervical region.


In lateral movement, the sides of the intervertebral fibrocartilages are compressed, the extent of motion being limited by the resistance offered by the surrounding ligaments. This movement may take place in any part of the column, but is freest in the cervical and lumbar regions.

Circumduction is very limited, and is merely a succession of the preceding movements.

Rotation is produced by the twisting of the intervertebral fibrocartilages; this, although only slight between any two vertebræ, allows of a considerable extent of movement when it takes place in the whole length of the column, the front of the upper part of the column being turned to one or other side. This movement occurs to a slight extent in the cervical region, is freer in the upper part of the thoracic region, and absent in the lumbar region.

_____________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology

5b. Articulation of the Atlas with the Epistropheus or Axis

(Articulatio Atlantoepistrophica)

The articulation of the atlas with the axis is of a complicated nature, comprising no fewer than four distinct joints. There is a pivot articulation between the odontoid process of the axis and the ring formed by the anterior arch and the tranverse ligament of the atlas (see Fig. 306); here there are two joints: one between the posterior surface of the anterior arch of the atlas and the front of the odontoid process; the other between the anterior surface of the ligament and the back of the process. Between the articular processes of the two bones there is on either side an arthrodial or gliding joint. The ligaments connecting these bones are:

Two Articular Capsules.
The Posterior Atlantoaxial.
The Anterior Atlantoaxial.
The Transverse.

FIG. 306




Articulation between odontoid process and atlas.

The Anterior Atlantoaxial Ligament (Fig. 304).—

This ligament is a strong membrane, fixed, above, to the lower border of the anterior arch of the atlas

FIG. 304




Anterior atlantoöccipital membrane and atlantoaxial ligament.

The Posterior Atlantoaxial Ligament (Fig. 305).—

This ligament is a broad, thin membrane attached, above, to the lower border of the posterior arch of the atlas

FIG. 305




Posterior atlantoöccipital membrane and atlantoaxial ligament.

The Transverse Ligament of the Atlas (ligamentum transversum atlantis) (Fig. 306, 307, 308).—

The transverse ligament of the atlas is a thick, strong band, which arches across the ring of the atlas, and retains the odontoid process in contact with the anterior arch. It is concave in front, convex behind, broader and thicker in the middle than at the ends, and firmly attached on either side to a small tubercle on the medial surface of the lateral mass of the atlas.

FIG. 307




Membrana tectoria, transverse, and alar ligaments.

FIG. 308




Median sagittal section through the occipital bone and first three cervical vertebræ. (Spalteholz.)

5c. Articulations of the Vertebral Column with the Cranium

The ligaments connecting the vertebral column with the cranium may be divided into two sets: those uniting the atlas with the occipital bone, and those connecting the axis with the occipital bone.

Articulation of the Atlas with the Occipital Bone (articulatio atlantoöccipitalis).—

The articulation between the atlas and the occipital bone consists of a pair of condyloid joints. The ligaments connecting the bones are:

Two Articular Capsules.
The Posterior Atlantoöccipital membrane.
The Anterior Atlantoöccipital membrane.
Two Lateral Atlantoöccipital.


The Anterior Atlantoöccipital Membrane (membrana atlantoöccipitalis anterior; anterior atlantoöccipital ligament) (Fig. 304).


Ligaments Connecting the Axis with the Occipital Bone.—

The Membrana Tectoria. Two Alar. The Apical Odontoid.


The Membrana Tectoria (occipitoaxial ligament) (Figs. 307, 308).—The membrana tectoria is situated within the vertebral canal.


The Alar Ligaments (ligamenta alaria; odontoid ligaments) (Fig. 307).

The alar ligaments are strong, rounded cords, which arise one on either side of the upper part of the odontoid process, and, passing obliquely upward and lateralward, are inserted into the rough depressions on the medial sides of the condyles of the occipital bone.

The apical odontoid ligament (Fig. 308).

_________________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology



5d. Articulation of the Mandible

(Articulatio Mandibularis; Temporomandibular Articulation)

This is a ginglymo-arthrodial joint; the parts entering into its formation on either side are: the anterior part of the mandibular fossa of the temporal bone and the articular tubercle above; and the condyle of the mandible below.

The ligaments of the joint are the following:

The Articular Capsule.
The Sphenomandibular.
The Temporomandibular.
The Articular Disk.
The Stylomandibular.


The Articular Capsule (capsula articularis; capsular ligament).—The articular capsule is a thin, loose envelope, attached above to the circumference of the mandibular fossa and the articular tubercle immediately in front; below, to the neck of the condyle of the mandible.


The Temporomandibular Ligament (ligamentum temporomandibulare; external lateral ligament) (Fig. 309).—The temporomandibular ligament consists of two short, narrow fasciculi, one in front of the other, attached, above, to the lateral surface of the zygomatic arch and to the tubercle on its lower border; below, to the lateral surface and posterior border of the neck of the mandible.

FIG. 309




Articulation of the mandible. Lateral aspect.

The Sphenomandibular Ligament (ligamentum sphenomandibulare; internal lateral ligament) (Fig. 310).—The sphenomandibular ligament is a flat, thin band which is attached above to the spina angularis of the sphenoid bone, and, becoming broader as it descends, is fixed to the lingula of the mandibular foramen.


The Stylomandibular Ligament (ligamentum stylomandibulare); stylomaxillary ligament (Fig. 310).—The stylomandibular ligament is a specialized band of the cervical fascia, which extends from near the apex of the styloid process of the temporal bone to the angle and posterior border of the ramus of the mandible, between the Masseter and Pterygoideus internus.

FIG. 310




Articulation of the mandible. Medial aspect.

The Articular Disk (discus articularis; interarticular fibrocartilage; articular meniscus) (Fig. 311).—The articular disk is a thin, oval plate, placed between the condyle of the mandible and the mandibular fossa. Its upper surface is concavo-convex from before backward, to accommodate itself to the form of the mandibular fossa and the articular tubercle. Its under surface, in contact with the condyle, is concave. Its circumference is connected to the articular capsule; and in front to the tendon of the Pterygoideus externus.

FIG. 311




Sagittal section of the articulation of the mandible.

5e. Costovertebral Articulations

(Articulationes Costovertebrales)

The articulations of the ribs with the vertebral column may be divided into two sets, one connecting the heads of the ribs with the bodies of the vertebræ, another uniting the necks and tubercles of the ribs with the transverse processes.


1. Articulations of the Heads of the Ribs (articulationes capitulorum; costocentral articulations) (Fig. 312).—These constitute a series of gliding or arthrodial joints, and are formed by the articulation of the heads of the typical ribs with the facets on the contiguous margins of the bodies of the thoracic vertebræ and with the intervertebral fibrocartilages between them; the first, tenth, eleventh, and twelfth ribs each articulate with a single vertebra. The ligaments of the joints are:

The Articular Capsule. The Radiate. The Interarticular.

FIG. 312




Costovertebral articulations. Anterior view.

Synovial Membranes.—

There are two synovial membranes in each of the articulations where an interarticular ligament exists, one above and one below this structure; but only one in those joints where there are single cavities.


2. Costotransverse Articulations (articulationes costotransversariæ) (Fig. 313).—The articular portion of the tubercle of the rib forms with the articular surface on the adjacent transverse process an arthrodial joint.

In the eleventh and twelfth ribs this articulation is wanting.

The ligaments of the joint are:

The Articular Capsule.
The Posterior Costotransverse.
The Anterior Costotransverse.
The Ligament of the Neck of the Rib.
The Ligament of the Tubercle of the Rib.

FIG. 313




Costotransverse articulation. Seen from above.

FIG. 314




Section of the costotransverse joints from the third to the ninth inclusive. Constrast the concave facets on the upper with the flattened facets on the lower transverse processes.

1F. Sternocostal Articulations

(Articulationes Sternocotales; Costosternal Articulations) (Fig. 315)

The articulations of the cartilages of the true ribs with the sternum are arthrodial joints, with the exception of the first, in which the cartilage is directly united with the sternum, and which is, therefore, a synarthrodial articulation.

The ligaments connecting them are:

The Articular Capsules.
The Interarticular Sternocostal.
The Radiate Sternocostal.
The Costoxiphoid.

FIG. 315




Sternocostal and interchondral articulations. Anterior view.

______________________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology




5g. Articulation of the Manubrium and Body of the Sternum

The manubrium is united to the body of the sternum either by an amphiarthrodial joint—a piece of fibrocartilage connecting the segments—or by a diarthrodial joint, in which the articular surface of each bone is clothed with a lamina of cartilage. In the latter case, the cartilage covering the body is continued without interruption on to the cartilages of the facets for the second ribs.


Vertebrosternal Ribs (Figs. 316, 317).—

The first rib differs from the others of this group in that its attachment to the sternum is a rigid one; this is counterbalanced to some extent by the fact that its head possesses no interarticular ligament, and is therefore more movable.

FIG. 316




Lateral view of first and seventh ribs in position, showing the movements of the sternum and ribs in A, ordinary expiration; B, quiet inspiration; C, deep inspiration.

FIG. 317




Diagram showing the axes of movement (A B and C D) of a vertebrosternal rib. The interrupted lines indicate the position of the rib in inspiration.

Vertebrochondral Ribs (Fig. 318).—

The seventh rib is included with this group, as it conforms more closely to their type. While the movements of these ribs assist in enlarging the thorax for respiratory purposes, they are also concerned in increasing the upper abdominal space for viscera displaced by the action of the diaphragm.

FIG. 318




Diagram showing the axis of movement (A B) of a vertebrochondral rib. The interrupted lines indicate the position of the rib in inspiration.

5h. Articulation of the Vertebral Column with the Pelvis The Iliolumbar Ligament

The ligaments connecting the fifth lumbar vertebra with the sacrum are similar to those which join the movable segments of the vertebral column with each other—viz. 1. The continuation downward of the anterior and posterior longitudinal ligaments. 2. The intervertebral fibrocartilage, connecting the body of the fifth lumbar to that of the first sacral vertebra and forming an amphiarthrodial joint. 3. Ligamenta flava, uniting the laminæ of the fifth lumbar vertebra with those of the first sacral. 4. Capsules connecting the articular processes and forming a double arthrodia. 5. Inter- and supraspinal ligaments.

On either side an additional ligament, the iliolumbar, connects the pelvis with the vertebral column.


The Iliolumbar Ligament (ligamentum iliolumbale) (Fig. 319).—The iliolumbar ligament is attached above to the lower and front part of the transverse process of the fifth lumbar vertebra. It radiates as it passes lateralward and is attached by two main bands to the pelvis.

FIG. 319




Articulations of pelvis. Anterior view. (Quain.)

5i. Articulations of the Pelvis

The ligaments connecting the bones of the pelvis with each other may be divided into four groups:

1. Those connecting the sacrum and ilium.
2. Those passing between the sacrum and ischium.
3. Those uniting the sacrum and coccyx.
4. Those between the two public bones.


The Anterior Sacroiliac Ligament (ligamentum sacroiliacum anterius) (Fig. 319).

FIG. 319




Articulations of pelvis. Anterior view. (Quain.)

The Posterior Sacroiliac Ligament (ligamentum sacroiliacum posterius) (Fig. 320).—The posterior sacroiliac ligament is situated in a deep depression between the sacrum and ilium behind; it is strong and forms the chief bond of union between the bones.

FIG. 320




Articulatios of pelvis. Posterior view. (Quain.)

The Interpubic Fibrocartilaginous Lamina (lamina fibrocartilaginea interpubica; interpubic disk).— connects the opposed surfaces of the pubic bones.

FIG. 321




Symphysis pubis exposed by a coronal section.

Mechanism of the Pelvis.—

The pelvic girdle supports and protects the contained viscera and affords surfaces for the attachments of the trunk and lower limb muscles. Its most important mechanical function, however, is to transmit the weight of the trunk and upper limbs to the lower extremities.


If a series of coronal sections of the sacroiliac joints be made, it will be found possible to divide the articular portion of the sacrum into three segments: anterior, middle, and posterior. In the anterior segment (Fig. 322),

FIG. 322




Coronal section of anterior sacral segment.

which involves the first sacral vertebra, the articular surfaces show slight sinuosities and are almost parallel to one another; the distance between their dorsal margins is, however, slightly greater than that between their ventral margins. This segment therefore presents a slight wedge shape with the truncated apex downward. The middle segment (Fig. 323) is a narrow band across the centers of the articulations.

FIG. 323




Coronal section of middle sacra segment.

Its dorsal width is distinctly greater than its ventral, so that the segment is more definitely wedge-shaped, the truncated apex being again directed downward. Each articular surface presents in the center a marked concavity from above downward, and into this a corresponding convexity of the iliac articular surface fits, forming an interlocking mechanism. In the posterior segment (Fig. 324) the ventral width is greater than the dorsal, so that the wedge form is the reverse of those of the other segments—i. e., the truncated apex is directed upward. The articular surfaces are only slightly concave.

FIG. 324




Coronal section of posterior sacral segment.

_________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology




6. Articulations of the Upper Extremity. a. Sternoclavicular Articulation

The articulations of the Upper Extremity may be arranged as follows:

I. Sternoclavicular.
VI. Wrist.
II. Acromioclavicular.
VII. Intercarpal.
III. Shoulder.
VIII. Carpometacarpal.
IV. Elbow.
IX. Intermetacarpal.
V. Radioulnar.
X. Metacarpophalangeal.
XI. Articulations of the Digits.


Sternoclavicular Articulation (Articulatio Sternoclavicularis) (Fig. 325)


The sternoclavicular articulation is a double arthrodial joint. The parts entering into its formation are the sternal end of the clavicle, the upper and lateral part of the manubrium sterni, and the cartilage of the first rib. The articular surface of the clavicle is much larger than that of the sternum, and is invested with a layer of cartilage, which is considerably thicker than that on the latter bone.

The ligaments of this joint are:

The Articular Capsule.
The Interclavicular.
The Anterior Sternoclavicular.
The Costoclavicular.
The Posterior Sternoclavicular.
The Articular Disk.

FIG. 325




Sternoclavicular articulation. Anterior view.

6b. Acromioclavicular Articulation

Coracoacromial, Superior and Inferior Transverse. (Articulatio Acromioclavicularis; Scapuloclavicular Articulation) (Fig. 326)


The acromioclavicular articulation is an arthrodial joint between the acromial end of the clavicle and the medial margin of the acromion of the scapula. Its ligaments are:

The Articular Capsule.
The Articular Disk.
The Superior Acromioclavicular.
The Coracoclavicular {Trapezoid and Conoid.
The Inferior Acromioclavicular.

6c. Humeral Articulation or Shoulder-joint

(Articulatio Humeri) (Fig. 326)

The left shoulder and acromioclavicular joints, and the proper ligaments of the scapula.

FIG. 326





The Articular Capsule (capsula articularis; capsular ligament) (Fig. 327).—

The articular capsule completely encircles the joint, being attached, above, to the circumference of the glenoid cavity beyond the glenoidal labrum; below, to the anatomical neck of the humerus, approaching nearer to the articular cartilage above than in the rest of its extent.

FIG. 327




Capsule of shoulder-joint (distended). Anterior aspect.

Synovial Membrane.—

The synovial membrane is reflected from the margin of the glenoid cavity over the labrum; it is then reflected over the inner surface of the capsule, and covers the lower part and sides of the anatomical neck of the humerus as far as the articular cartilage on the head of the bone.

FIG. 328




Glenoid fossa of right side.

Movements.—

The shoulder-joint is capable of every variety of movement, flexion, extension, abduction, adduction, circumduction, and rotation.

6d. Elbow-joint

(Articulatio Cubiti) (Figs. 329, 330)

The elbow-joint is a ginglymus or hinge-joint. The trochlea of the humerus is received into the semilunar notch of the ulna, and the capitulum of the humerus articulates with the fovea on the head of the radius. The articular surfaces are connected together by a capsule, which is thickened medially and laterally, and, to a less extent, in front and behind. These thickened portions are usually described as distinct ligaments under the following names:

The Anterior.
The Posterior.
The Ulnar Collateral.
The Radial Collateral.

FIG. 329




Left elbow-joint, showing anterior and ulnar collateral ligaments.

FIG. 330




Left elbow-joint, showing posterior and radial collateral ligaments.

Synovial Membrane (Figs. 331, 332).—

The synovial membrane is very extensive. It extends from the margin of the articular surface of the humerus, and lines the coronoid, radial and olecranon fossæ on that bone; it is reflected over the deep surface of the capsule and forms a pouch between the radial notch, the deep surface of the annular ligament, and the circumference of the head of the radius. Projecting between the radius and ulna into the cavity is a crescentic fold of synovial membrane, suggesting the division of the joint into two; one the humeroradial, the other the humeroulnar.

FIG. 331





Capsule of elbow-joint (distended). Anterior aspect.

FIG. 332





Capsule of elbow-joint (distended). Posterior aspect.




___________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology



6e. Radioulnar Articulation

(Articulatio Radioulnaris)

The articulation of the radius with the ulna is effected by ligaments which connect together the extremities as well as the bodies of these bones. The ligaments may, consequently, be subdivided into three sets: 1, those of the proximal radioulnar articulation; 2, the middle radioulnar ligaments; 3, those of the distal radioulnar articulation.


The Annular Ligament (ligamentum annulare radii; orbicular ligament) (Fig. 333).—

This ligament is a strong band of fibers, which encircles the head of the radius, and retains it in contact with the radial notch of the ulna. It forms about four-fifths of the osseo-fibrous ring, and is attached to the anterior and posterior margins of the radial notch; a few of its lower fibers are continued around below the cavity and form at this level a complete fibrous ring.

FIG. 333





Annular ligament of radius, from above. The head of the radius has been sawn off and the bone dislodged from the ligament.

Distal Radioulnar Articulation (articulatio radioulnaris distalis; inferior radioulnar joint).—

This is a pivot-joint formed between the head of the ulna and the ulnar notch on the lower end of the radius. The articular surfaces are connected together by the following ligaments:

The Volar Radioulnar.
The Dorsal Radioulnar.
The Articular Disk.


The Volar Radioulnar Ligament (anterior radioulnar ligament) (Fig. 334).—This ligament is a narrow band of fibers extending from the anterior margin of the ulnar notch of the radius to the front of the head of the ulna.

FIG. 334




Ligaments of wrist. Anterior view

The Dorsal Radioulnar Ligament (posterior radioulnar ligament) (Fig. 335).—This ligament extends between corresponding surfaces on the dorsal aspect of the articulation.

FIG. 335




Ligaments of wrist. Posterior view.

The Articular Disk (discus articularis; triangular fibrocartilage) (Fig. 336).—The articular disk is triangular in shape, and is placed transversely beneath the head of the ulna, binding the lower ends of the ulna and radius firmly together. Its periphery is thicker than its center, which is occasionally perforated. It is attached by its apex to a depression between the styloid process and the head of the ulna; and by its base, which is thin, to the prominent edge of the radius, which separates the ulnar notch from the carpal articular surface. Its margins are united to the ligaments of the wrist-joint. Its upper surface, smooth and concave, articulates with the head of the ulna, forming an arthrodial joint; its under surface, also concave and smooth, forms part of the wrist-joint and articulates with the triangular bone and medial part of the lunate. Both surfaces are clothed by synovial membrane; the upper, by that of the distal radioulnar articulation, the under, by that of the wrist.

FIG. 336




Vertical section through the articulations at the wrist, showing the synovial cavities.

Movements.—

The movements in the distal radioulnar articulation consist of rotation of the lower end of the radius around an axis which passes through the center of the head of the ulna. When the radius rotates forward, pronation of the forearm and hand is the result; and when backward, supination.

1F. Radiocarpal Articulation or Wrist-joint

(Articulatio Radiocarpea) (Figs. 334, 335)


The wrist-joint is a condyloid articulation. The parts forming it are the lower end of the radius and under surface of the articular disk above; and the navicular, lunate, and triangular bones below. The articular surface of the radius and the under surface of the articular disk form together a transversely elliptical concave surface, the receiving cavity. The superior articular surfaces of the navicular, lunate, and triangular form a smooth convex surface, the condyle, which is received into the concavity. The joint is surrounded by a capsule, strengthened by the following ligaments:

The Volar Radiocarpal.
The Ulnar Collateral.
The Dorsal Radiocarpal.
The Radial Collateral.

FIG. 334




Ligaments of wrist. Anterior view

FIG. 335




Ligaments of wrist. Posterior view.

6g. Intercarpal Articulations

(Articulationes Intercarpeæ; Articulations of the Carpus)

These articulations may be subdivided into three sets:

1. The Articulations of the Proximal Row of Carpal Bones.
2. The Articulations of the Distal Row of Carpal Bones.
3. The Articulations of the Two Rows with each Other.

FIG. 334




Ligaments of wrist. Anterior view

FIG. 336




Vertical section through the articulations at the wrist, showing the synovial cavities.

6h. Carpometacarpal Articulations

(Articulationes Carpometacarpeæ)

Carpometacarpal Articulation of the Thumb (articulatio carpometacarpea pollicis).—This is a joint of reciprocal reception between the first metacarpal and the greater multangular; it enjoys great freedom of movement on account of the configuration of its articular surfaces, which are saddle-shaped. The joint is surrounded by a capsule, which is thick but loose, and passes from the circumference of the base of the metacarpal bone to the rough edge bounding the articular surface of the greater multangular; it is thickest laterally and dorsally, and is lined by synovial membrane.

6i. Intermetacarpal Articulations

(Articulationes Intermetacarpeæ; Articulations of the Metacarpal Bones with Each Other)

The bases of the second, third, fourth and fifth metacarpal bones articulate with one another by small surfaces covered with cartilage, and are connected together by dorsal, volar, and interosseous ligaments.

The dorsal (ligamenta basium oss. metacarp. dorsalia) and volar ligaments (ligamenta basium oss. metacarp. volaria; palmar ligaments) pass transversely from one bone to another on the dorsal and volar surfaces. The interosseous ligaments (ligamenta basium oss. metacarp. interossea) connect their contiguous surfaces, just distal to their collateral articular facets.

The synovial membrane for these joints is continuous with that of the carpometacarpal articulations.

6j. Metacarpophalangeal Articulations

(Articulationes Metacarpophalangeæ; Metacarpophalangeal Joints) (Figs. 337, 338)

The Transverse Metacarpal Ligament (ligamentum capitulorum [oss. metacarpalium] transversum) (Fig. 337).—This ligament is a narrow fibrous band, which runs across the volar surfaces of the heads of the second, third, fourth and fifth metacarpal bones, connecting them together. It is blended with the volar (glenoid) ligaments of the metacarpophalangeal articulations. Its volar surface is concave where the Flexor tendons pass over it; behind it the tendons of the Interossei pass to their insertions.

6k. Articulations of the Digits

(Articulationes Digitorum Manus; Interphalangeal Joints) (Figs. 337, 338)

The interphalangeal articulations are hinge-joints; each has a volar and two collateral ligaments. The arrangement of these ligaments is similar to those in the metacarpophalangeal articulations. The Extensor tendons supply the place of posterior ligaments.

FIG. 337




Metacarpophalangeal articulation and articulations of digit. Volar aspect.

FIG. 338





Metacarpophalangeal articulation and articulations of digit. Ulnar aspect.

________________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology

7. Articulations of the Lower Extremity. a. Coxal Articulation or Hip-joint

The articulations of the Lower Extremity comprise the following:
I. Hip.
V. Intertarsal.
II. Knee.
VI. Tarsometatarsal.
III. Tibiofibular.
VII. Intermetatarsal.
IV. Ankle.
VIII. Metatarsophalangeal.
IX. Articulations of the Digits.

Coxal Articulation or Hip-joint (Articulatio Coxæ)

This articulation is an enarthrodial or ball-and-socket joint, formed by the reception of the head of the femur into the cup-shaped cavity of the acetabulum. The articular cartilage on the head of the femur, thicker at the center than at the circumference, covers the entire surface with the exception of the fovea capitis femoris, to which the ligamentum teres is attached; that on the acetabulum forms an incomplete marginal ring, the lunate surface. Within the lunate surface there is a circular depression devoid of cartilage, occupied in the fresh state by a mass of fat, covered by synovial membrane. The ligaments of the joint are:

The Articular Capsule.
The Pubocapsular.
The Iliofemoral.
The Ligamentum Teres Femoris.
The Ischiocapsular.
The Glenoidal Labrum.
The Transverse Acetabular



The Articular Capsule (capsula articularis; capsular ligament) (Figs. 339, 340).—The articular capsule is strong and dense.


The Iliofemoral Ligament (ligamentum iliofemorale; Y-ligament; ligament of Bigelow) (Fig. 339).—The iliofemoral ligament is a band of great strength which lies in front of the joint; it is intimately connected with the capsule, and serves to strengthen it in this situation.

FIG. 339




Right hip-joint from the front. (Spalteholz.)

FIG. 340




The hip-joint from behind. (Quain.)

The Ligamentum Teres Femoris (Fig. 341).

FIG. 341




Left hip-joint, opened by removing the floor of the acetabulum from within the pelvis.

FIG. 342




Hip-joint, front view. The capsular ligament has been largely removed.

Synovial Membrane (Fig. 343).—The synovial membrane is very extensive.

FIG. 343




Capsule of hip-joint (distended). Posterior aspect.

FIG. 344




Structures surrounding right hip-joint.

______________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology




7b. The Knee-joint

(Articulatio Genu)

The knee-joint was formerly described as a ginglymus or hinge-joint, but is really of a much more complicated character. It must be regarded as consisting of three articulations in one: two condyloid joints, one between each condyle of the femur and the corresponding meniscus and condyle of the tibia; and a third between the patella and the femur, partly arthrodial, but not completely so, since the articular surfaces are not mutually adapted to each other, so that the movement is not a simple gliding one. This view of the construction of the knee-joint receives confirmation from the study of the articulation in some of the lower mammals, where, corresponding to these three subdivisions, three synovial cavities are sometimes found, either entirely distinct or only connected together by small communications. This view is further rendered probable by the existence in the middle of the joint of the two cruciate ligaments, which must be regarded as the collateral ligaments of the medial and lateral joints. The existence of the patellar fold of synovial membrane would further indicate a tendency to separation of the synovial cavity into two minor sacs, one corresponding to the lateral and the other to the medial joint.

The bones are connected together by the following ligaments:

The Articular Capsule.
The Anterior Cruciate.
The Ligamentum Patellæ.
The Posterior Cruciate.
The Oblique Popliteal.
The Medial and Lateral Menisci.
The Tibial Collateral.
The Transverse.
The Fibular Collateral.
The Coronary.



The Articular Capsule (capsula articularis; capsular ligament) (Fig. 345).—The articular capsule consists of a thin, but strong, fibrous membrane which is strengthened in almost its entire extent by bands inseparably connected with it.


The Ligamentum Patellæ (anterior ligament) (Fig. 345).—The ligamentum patellæ is the central portion of the common tendon of the Quadriceps femoris, which is continued from the patella to the tuberosity of the tibia.


The Tibial Collateral Ligament (ligamentum collaterale tibiale; internal lateral ligament) (Fig. 345).—The tibial collateral is a broad, flat, membranous band, situated nearer to the back than to the front of the joint. It is attached, above, to the medial condyle of the femur immediately below the adductor tubercle; below, to the medial condyle and medial surface of the body of the tibia.

FIG. 345




Right knee-joint. Anterior view.

The Oblique Popliteal Ligament (ligamentum popliteum obliquum; posterior ligament) (Fig. 346).—This ligament is a broad, flat, fibrous band, formed of fasciculi separated from one another by apertures for the passage of vessels and nerves.

FIG. 346




Right knee-joint. Posterior view.

The Anterior Cruciate Ligament (ligamentum cruciatum anterius; external crucial ligament) (Fig. 347) is attached to the depression in front of the intercondyloid eminence of the tibia, being blended with the anterior extremity of the lateral meniscus; it passes upward, backward, and lateralward, and is fixed into the medial and back part of the lateral condyle of the femur.

FIG. 347




Right knee-joint, from the front, showing interior ligaments.

The Fibular Collateral Ligament (ligamentum collaterale fibulare; external lateral or long external lateral ligament) (Fig. 348).—The fibular collateral is a strong, rounded, fibrous cord, attached, above, to the back part of the lateral condyle of the femur, immediately above the groove for the tendon of the Popliteus; below, to the lateral side of the head of the fibula, in front of the styloid process.

FIG. 348




Left knee-joint from behind, showing interior ligaments.

The Menisci (semilunar fibrocartilages) (Fig. 349).—The menisci are two crescentic lamellæ, which serve to deepen the surfaces of the head of the tibia for articulation with the condyles of the femur.

FIG. 349




Head of right tibia seen from above, showing menisci and attachments of ligaments.

Synovial Membrane.—The synovial membrane of the knee-joint is the largest and most extensive in the body. Commencing at the upper border of the patella, it forms a large cul-de-sac beneath the Quadriceps femoris (Figs. 350, 351) on the lower part of the front of the femur, and frequently communicates with a bursa interposed between the tendon and the front of the femur.

FIG. 350




Sagittal section of right knee-joint.

FIG. 351





Capsule of right knee-joint (distended). Lateral aspect.

FIG. 352





Capsule of right knee-joint (distended). Posterior aspect.

FIG. 353





Posterior surface of the right patella, showing diagrammatically the areas of contact with the femur in different positions of the knee.




___________________________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology



7c. Articulations between the Tibia and Fibula

The articulations between the tibia and fibula are effected by ligaments which connect the extremities and bodies of the bones. The ligaments may consequently be subdivided into three sets:
(1) those of the Tibiofibular articulation;

(2) the interosseous membrane;

(3) those of the Tibiofibular syndesmosis.



The Anterior Ligament (anterior superior ligament).—The anterior ligament of the head of the fibula (Fig. 347) consists of two or three broad and flat bands, which pass obliquely upward from the front of the head of the fibula to the front of the lateral condyle of the tibia.


The Posterior Ligament (posterior superior ligament).—The posterior ligament of the head of the fibula (Fig. 348) is a single thick and broad band, which passes obliquely upward from the back of the head of the fibula to the back of the lateral condyle of the tibia. It is covered by the tendon of the Popliteus.

FIG. 347




Right knee-joint, from the front, showing interior ligaments.

FIG. 348




Left knee-joint from behind, showing interior ligaments.

The Anterior Ligament (ligamentum malleoli lateralis anterius; anterior inferior ligament).—The anterior ligament of the lateral malleolus (Fig. 355) is a flat, triangular band of fibers, broader below than above, which extends obliquely downward and lateralward between the adjacent margins of the tibia and fibula, on the front aspect of the syndesmosis. It is in relation, in front, with the Peronæus tertius, the aponeurosis of the leg, and the integument; behind, with the interosseous ligament; and lies in contact with the cartilage covering the talus.


The Posterior Ligament (ligamentum malleoli lateralis posterius; posterior inferior ligament).—The posterior ligament of the lateral malleolus (Fig. 355), smaller than the preceding, is disposed in a similar manner on the posterior surface of the syndesmosis.

FIG. 355




The ligaments of the foot from the lateral aspect. (Quain.)

The Interosseous Ligament.—The interosseous ligament consists of numerous short, strong, fibrous bands, which pass between the contiguous rough surfaces of the tibia and fibula, and constitute the chief bond of union between the bones. It is continuous, above, with the interosseous membrane (Fig. 356).

FIG. 356




Capsule of left talocrura articulation (distended). Lateral aspect.

7d. Talocrural Articulation or Ankle-joint


(Articulatio Talocruralis; Tibiotarsal Articulation)

FIG. 354–





Ligaments of the medial aspect of the foot. (Quain.)

____________________________________________________

[Ge. Pe.]

Completando, ampliando, resumiendo, definiendo, repitiendo conceptos...


______________________________________________________


Henry Gray (1821–1865). Anatomy of the Human Body. 1918.


III. Syndesmology

7e. Intertarsal Articulations

(Articulationes Intertarseæ; Articulations of the Tarsus)

Talocalcaneal Articulation (articulatio talocalcanea; articulation of the calcaneus and astragalus; calcaneo-astragaloid articulation).—The articulations between the calcaneus and talus are two in number—anterior and posterior. Of these, the anterior forms part of the talocalcaneonavicular joint, and will be described with that articulation. The posterior or talocalcaneal articulation is formed between the posterior calcaneal facet on the inferior surface of the talus, and the posterior facet on the superior surface of the calcaneus. It is an arthrodial joint, and the two bones are connected by an articular capsule and by anterior, posterior, lateral, medial, and interosseous talocalcaneal ligaments.

1F. Tarsometatarsal Articulations

(Articulationes Tarsometatarseæ)

These are arthrodial joints. The bones entering into their formation are the first, second, and third cuneiforms, and the cuboid, which articulate with the bases of the metatarsal bones. The first metatarsal bone articulates with the first cuneiform; the second is deeply wedged in between the first and third cuneiforms articulating by its base with the second cuneiform; the third articulates with the third cuneiform; the fourth, with the cuboid and third cuneiform; and the fifth, with the cuboid. The bones are connected by dorsal, plantar, and interosseous ligaments.

FIG. 357




Coronal section through right talocrural and talocalcaneal joints.

FIG. 358




Ligaments of the sole of the foot, with the tendons of the Peronæus longus, Tibialis posterior and Tibialis anterior muscles. (Quain.)

7g. Intermetatarsal Articulations

(Articulationes Intermetatarseæ)

The base of the first metatarsal is not connected with that of the second by any ligaments; in this respect the great toe resembles the thumb.

The bases of the other four metatarsals are connected by the dorsal, plantar, and interosseous ligaments.

FIG. 360




Oblique section of left intertarsal and tarsometatarsal articulations, showing the synovial cavities.

7h. Metatarsophalangeal Articulations

(Articulationes Metatarsophalangeæ)

The metatarsophalangeal articulations are of the condyloid kind, formed by the reception of the rounded heads of the metatarsal bones in shallow cavities on the ends of the first phalanges.

The ligaments are the plantar and two collateral.

7i. Articulations of the Digits

(Articulationes Digitorum Pedis; Articulations of the Phalanges)

The interphalangeal articulations are ginglymoid joints, and each has a plantar and two collateral ligaments.

The arrangement of these ligaments is similar to that in the metatarsophalangeal articulations: the Extensor tendons supply the places of dorsal ligaments.

7j. Arches of the Foot

In order to allow it to support the weight of the body in the erect posture with the least expenditure of material, the foot is constructed of a series of arches formed by the tarsal and metatarsal bones, and strengthened by the ligaments and tendons of the foot.

The main arches are the antero-posterior arches, which may, for descriptive purposes, be regarded as divisible into two types—a medial and a lateral. The medial arch (Fig. 290) is made up by the calcaneus, the talus, the navicular, the three cuneiforms, and the first, second, and third metatarsals.

FIG. 290




Skeleton of foot. Medial aspect.

The lateral arch (Fig. 291) is composed of the calcaneus, the cuboid, and the fourth and fifth metatarsals.

FIG. 291




Skeleton of foot. Lateral aspect.

____________________________________________

Tema completo.


_____________________________________________________________