Superior pubic ramus
Encyclopedia
The superior pubic ramus is a part of the pubic bone which forms a portion of the obturator foramen
.
It extends from the body to the median plane where it articulates with its fellow of the opposite side. It is conveniently described in two portions, viz., a medial flattened part and a narrow lateral prismoid portion.
take origin.
The posterior surface, convex from above downward, concave from side to side, is smooth, and forms part of the anterior wall of the pelvis. It gives origin to the Levator ani
and Obturator internus, and attachment to the puboprostatic ligament
s and to a few muscular fibers prolonged from the bladder.
(pubic spine), which projects forward; the inferior crus of the subcutaneous inguinal ring (external abdominal ring), and the inguinal ligament
(Poupart’s ligament) are attached to it.
Passing upward and laterally from the pubic tubercle is a well-defined ridge, forming a part of the pectineal line
which marks the brim of the lesser pelvis
: to it are attached a portion of the inguinal falx (conjoined tendon of Obliquus internus and Transversus), the lacunar ligament
(Gimbernat’s ligament), and the reflected inguinal ligament
(triangular fascia).
Medial to the pubic tubercle is the crest, which extends from this process to the medial end of the bone. It affords attachment to the inguinal falx, and to the Rectus abdominis and Pyramidalis
.
The point of junction of the crest with the medial border of the bone is called the angle; to it, as well as to the symphysis
, the superior crus of the subcutaneous inguinal ring is attached.
The medial border is articular; it is oval, and is marked by eight or nine transverse ridges, or a series of nipple-like processes arranged in rows, separated by grooves; they serve for the attachment of a thin layer of cartilage, which intervenes between it and the interpubic fibrocartilaginous lamina.
The lateral border presents a sharp margin, the obturator crest, which forms part of the circumference of the obturator foramen
and affords attachment to the obturator membrane
.
Obturator foramen
The obturator foramen is the hole created by the ischium and pubis bones of the pelvis through which nerves and muscles pass.- General structure :...
.
It extends from the body to the median plane where it articulates with its fellow of the opposite side. It is conveniently described in two portions, viz., a medial flattened part and a narrow lateral prismoid portion.
Medial portion
The Medial Portion of the superior ramus, formerly described as the body of the pubis, is somewhat quadrilateral in shape, and presents for examination two surfaces and three borders.Surfaces
The anterior surface is rough, directed downward and outward, and serves for the origin of various muscles. The Adductor longus arises from the upper and medial angle, immediately below the crest; lower down, the Obturator externus, the Adductor brevis, and the upper part of the GracilisGracilis muscle
The gracilis is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.-Origin and insertion:...
take origin.
The posterior surface, convex from above downward, concave from side to side, is smooth, and forms part of the anterior wall of the pelvis. It gives origin to the Levator ani
Levator ani
The levator ani is a broad, thin muscle, situated on the side of the pelvis.It is attached to the inner surface of the side of the lesser pelvis, and unites with its fellow of the opposite side to form the greater part of the floor of the pelvic cavity....
and Obturator internus, and attachment to the puboprostatic ligament
Puboprostatic ligament
The Puboprostatic ligament is a thickening of the superior fascia of the pelvic diaphragm in the male that extends laterally from the prostate to the tendinous arch of the pelvic fascia and continues forward and medially from the tendinous arch to the pubis....
s and to a few muscular fibers prolonged from the bladder.
Borders
The upper border presents a prominent tubercle, the pubic tuberclePubic tubercle
The pubic tubercle is a prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of the pubis...
(pubic spine), which projects forward; the inferior crus of the subcutaneous inguinal ring (external abdominal ring), and the inguinal ligament
Inguinal ligament
The inguinal ligament is a band running from the pubic tubercle to the anterior superior iliac spine. Its anatomy is very important for operating on hernia patients.-Anatomy:...
(Poupart’s ligament) are attached to it.
Passing upward and laterally from the pubic tubercle is a well-defined ridge, forming a part of the pectineal line
Pectineal line
On the posterior surface of the femur, the intermediate ridge or pectineal line is continued to the base of the lesser trochanter and gives attachment to the pectineus muscle....
which marks the brim of the lesser pelvis
Lesser pelvis
The lesser pelvis is that part of the space enclosed by the skeleton of the pelvis which is situated between the pelvic inlet and the pelvic floor. Some authors call this cavity the pelvic cavity...
: to it are attached a portion of the inguinal falx (conjoined tendon of Obliquus internus and Transversus), the lacunar ligament
Lacunar ligament
The lacunar ligament is a ligament in the inguinal region that connects the inguinal ligament to the pectineal ligament near the point where they both insert on the pubic tubercle.-Anatomy:...
(Gimbernat’s ligament), and the reflected inguinal ligament
Reflected inguinal ligament
The reflected inguinal ligament is a layer of tendinous fibers of a triangular shape, formed by an expansion from the lacunar ligament and the inferior crus of the subcutaneous inguinal ring....
(triangular fascia).
Medial to the pubic tubercle is the crest, which extends from this process to the medial end of the bone. It affords attachment to the inguinal falx, and to the Rectus abdominis and Pyramidalis
Pyramidalis muscle
The pyramidalis is a small and triangular muscle, anterior to the Rectus abdominis, and contained in the rectus sheath.-Attachments and actions:...
.
The point of junction of the crest with the medial border of the bone is called the angle; to it, as well as to the symphysis
Symphysis
A symphysis is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint.1.A symphysis is an amphiarthrosis, a slightly movable joint.2.A growing together of parts or structures...
, the superior crus of the subcutaneous inguinal ring is attached.
The medial border is articular; it is oval, and is marked by eight or nine transverse ridges, or a series of nipple-like processes arranged in rows, separated by grooves; they serve for the attachment of a thin layer of cartilage, which intervenes between it and the interpubic fibrocartilaginous lamina.
The lateral border presents a sharp margin, the obturator crest, which forms part of the circumference of the obturator foramen
Obturator foramen
The obturator foramen is the hole created by the ischium and pubis bones of the pelvis through which nerves and muscles pass.- General structure :...
and affords attachment to the obturator membrane
Obturator membrane
The obturator membrane is a thin fibrous sheet, which almost completely closes the obturator foramen.Its fibers are arranged in interlacing bundles mainly transverse in direction; the uppermost bundle is attached to the obturator tubercles and completes the obturator canal for the passage of the...
.
Lateral portion
The Lateral Portion of the ascending ramus has three surfaces: superior, inferior, and posterior.Surfaces
- The superior surface presents a continuation of the pectineal linePectineal lineOn the posterior surface of the femur, the intermediate ridge or pectineal line is continued to the base of the lesser trochanter and gives attachment to the pectineus muscle....
, already mentioned as commencing at the pubic tuberclePubic tubercleThe pubic tubercle is a prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of the pubis...
. In front of this line, the surface of bone is triangular in form, wider laterally than medially, and is covered by the Pectineus. The surface is bounded, laterally, by a rough eminence, the iliopectineal eminenceIliopectineal eminenceMedial to the anterior inferior iliac spine is a broad, shallow groove, over which the iliacus and psoas major muscles pass. This groove is bounded medially by an eminence, the iliopubic eminence , which marks the point of union of the ilium and pubis.It constitutes a lateral border of the pelvic...
, which serves to indicate the point of junction of the iliumIlium (bone)The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium.The name comes from the Latin ,...
and pubisPubis (bone)In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....
, and below by a prominent ridge which extends from the acetabular notchAcetabular notchThe acetabulum presents below a deep notch, the acetabular notch, which is continuous with a circular non-articular depression, the acetabular fossa, at the bottom of the cavity: this depression is perforated by numerous apertures, and lodges a mass of fat....
to the pubic tubercle.
- The inferior surface forms the upper boundary of the obturator foramenObturator foramenThe obturator foramen is the hole created by the ischium and pubis bones of the pelvis through which nerves and muscles pass.- General structure :...
, and presents, laterally, a broad and deep, oblique groove, for the passage of the obturator vessels and nerve; and medially, a sharp margin, the obturator crestObturator crestThe anterior border of superior pubic ramus presents a sharp margin, the obturator crest, which forms part of the circumference of the obturator foramen superiorly and affords attachment to the obturator membrane....
, forming part of the circumference of the obturator foramen, and giving attachment to the obturator membraneObturator membraneThe obturator membrane is a thin fibrous sheet, which almost completely closes the obturator foramen.Its fibers are arranged in interlacing bundles mainly transverse in direction; the uppermost bundle is attached to the obturator tubercles and completes the obturator canal for the passage of the...
.
- The posterior surface constitutes part of the anterior boundary of the lesser pelvisLesser pelvisThe lesser pelvis is that part of the space enclosed by the skeleton of the pelvis which is situated between the pelvic inlet and the pelvic floor. Some authors call this cavity the pelvic cavity...
. It is smooth, convex from above downward, and affords origin to some fibers of the Obturator internus.