Aponeurosis of the Obliquus externus abdominis
Encyclopedia
The aponeurosis of the Obliquus externus abdominis is a thin but strong membranous structure, the fibers of which are directed downward and medially.
It is joined with that of the opposite muscle along the middle line, and covers the whole of the front of the abdomen; above, it is covered by and gives origin to the lower fibers of the Pectoralis major; below, its fibers are closely aggregated together, and extend obliquely across from the anterior superior iliac spine
to the pubic tubercle
and the pectineal line
.
In the middle line, it interlaces with the aponeurosis
of the opposite muscle, forming the linea alba
, which extends from the xiphoid process
to the pubic symphysis
.
That portion of the aponeurosis which extends between the anterior superior iliac spine and the pubic tubercle is a thick band, folded inward, and continuous below with the fascia lata; it is called the inguinal ligament
.
The portion which is reflected from the inguinal ligament at the pubic tubercle is attached to the pectineal line and is called the lacunar ligament
.
From the point of attachment of the latter to the pectineal line, a few fibers pass upward and medialward, behind the medial crus of the subcutaneous inguinal ring, to the linea alba; they diverge as they ascend, and form a thin triangular fibrous band which is called the reflected inguinal ligament
.
In the aponeurosis of the Obliquus externus, immediately above the crest of the pubis, is a triangular opening, the subcutaneous inguinal ring, formed by a separation of the fibers of the aponeurosis in this situation.
It is joined with that of the opposite muscle along the middle line, and covers the whole of the front of the abdomen; above, it is covered by and gives origin to the lower fibers of the Pectoralis major; below, its fibers are closely aggregated together, and extend obliquely across from the anterior superior iliac spine
Anterior superior iliac spine
The anterior superior iliac spine is an important landmark of surface anatomy. It refers to the anterior extremity of the iliac crest of the pelvis, which provides attachment for the inguinal ligament, and the sartorius muscle...
to the pubic tubercle
Pubic 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...
and 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....
.
In the middle line, it interlaces with the aponeurosis
Aponeurosis
Aponeuroses are layers of flat broad tendons. They have a shiny, whitish-silvery color, are histologically similar to tendons, and are very sparingly supplied with blood vessels and nerves. When dissected, aponeuroses are papery, and peel off by sections...
of the opposite muscle, forming the linea alba
Linea alba
The linea alba is a fibrous structure that runs down the midline of the abdomen in humans and other vertebrates. The name means white line and the linea alba is indeed white, being composed mostly of collagen connective tissue....
, which extends from the xiphoid process
Xiphoid process
The xiphoid process, or xiphisternum or metasternum, is a small cartilaginous process of the lower part of the sternum which is usually ossified in the adult human. By age 15 to 29, the xiphoid usually fuses to the body of the sternum with a fibrous joint. Unlike the synovial articulation of major...
to the pubic symphysis
Pubic symphysis
The pubic symphysis or symphysis pubis is the midline cartilaginous joint uniting the superior rami of the left and right pubic bones. It is located anterior to the urinary bladder and superior to the external genitalia; for females it is above the vulva and for males it is above the penis...
.
That portion of the aponeurosis which extends between the anterior superior iliac spine and the pubic tubercle is a thick band, folded inward, and continuous below with the fascia lata; it is called 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:...
.
The portion which is reflected from the inguinal ligament at the pubic tubercle is attached to the pectineal line and is called 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:...
.
From the point of attachment of the latter to the pectineal line, a few fibers pass upward and medialward, behind the medial crus of the subcutaneous inguinal ring, to the linea alba; they diverge as they ascend, and form a thin triangular fibrous band which is called 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....
.
In the aponeurosis of the Obliquus externus, immediately above the crest of the pubis, is a triangular opening, the subcutaneous inguinal ring, formed by a separation of the fibers of the aponeurosis in this situation.