13 Abdominal Wall

Bony Framework for the Abdominal Wall

Fig. 13.1 Bony framework of the abdomen
Anterior view. These bones are the site of attachment for the muscles and ligaments of the anterolateral abdominal wall and form a bony cage that protects certain abdominal organs.

Fig. 13.2 Ligaments of the pelvis

Fig. 13.3 Abdominal wall muscle attachment sites
Left hip bone. Muscle origins are in red, insertions in blue.

Muscles of the Anterolateral Abdominal Wall

The oblique muscles of the anterolateral abdominal wall consist of the mm. obliqui externus and internus abdominis and the m. transversus abdominis. The posterior or deep abdominal wall muscles (notably the m. psoas major) are functionally hip muscles (see p. 148).

Fig. 13.4 Muscles of the abdominal wall
Right side, anterior view.

Muscles of the Posterior Abdominal Wall & Diaphragma

Fig. 13.5 Muscles of the posterior abdominal wall

Fig. 13.6 Diaphragma in situ
The diaphragma, which separates the thorax from the abdomen, has two asymmetric domes and three apertures (for the aorta, v. cava, and oesophagus).

Abdominal Wall Muscle Facts

Fig. 13.7 Anterior abdominal wall muscles
Anterior view.

Fig. 13.8 Anterolateral abdominal wall muscles
Anterior view.

Fig. 13.9 Posterior abdominal wall muscles
Anterior view. The mm. psoas major and iliacus are together known as the m. iliopsoas.

Fig. 13.10 Anterior, anterolateral, and posterior abdominal wall muscles
Anterior view.

Regio Inguinalis & Canalis Inguinalis

The regio inguinalis (inguen) is the junction of the anterior abdominal wall and the anterior thigh. The canalis inguinalis is an important site for the passage of structures into and out of the cavitas abdominis (e.g., components of the funiculus spermaticus).

Fig. 13.11 Regio inguinalis
Right side, anterior view.

Fig. 13.12 Dissection of the regio inguinalis
Right side, anterior view.

Fig. 13.13 Opening of the canalis inguinalis
Right side, anterior view.

Funiculus Spermaticus, Scrotum & Testis

The coverings of the scrotum, testis, and funiculus spermaticus are continuations of muscular and fascial layers of the anterior abdominal wall, as are those of the canalis inguinalis.

Fig. 13.14 Scrotum and funiculus spermaticus
Anterior view. Removed: Skin over the scrotum and funiculus spermaticus.

Fig. 13.15 Funiculus spermaticus: Contents
Cross section.

Fig. 13.16 Testis and epididymis
Left lateral view.

Table 13.4 Coverings of the testis

Covering layer		Derived from
	Scrotal skin	Abdominal skin
	Tunica dartos	Stratum membranosum
	Fascia spermatica externa	Aponeurosis musculi obliqui externi abdominis
	M. cremaster and/or fascia cremasterica	M. obliquus internus abdominis
	Fascia spermatica interna	Fascia transversalis
	Lamina parietalis tunicae vaginalis testis	Peritoneum
	Lamina visceralis tunicae vaginalis testis
* The m. transversus abdominis has no contribution to the funiculus spermaticus or covering of the testis.

Anterior Abdominal Wall & Inguinal Hernias

The vagina musculi recti abdominis is created by fusion of the aponeuroses of the mm. transversus abdominis and obliqui abdominalis. The inferior edge of the lamina posterior of the vagina musculi recti abdominis is called the linea arcuata (vaginae musculi recti abdominis).

Fig. 13.17 Anterior abdominal wall and vagina musculi recti abdominis

Fig. 13.18 Inferior anterior abdominal wall: Structure and fossae
Coronal section, posterior (internal) view of left inferior portion of the anterior abdominal wall.

Clinical box 13.1

Inguinal and femoral hernias
Indirect inguinal hernias occur in younger males and may be congenital or acquired; direct inguinal hernias generally occur in older males and are always acquired. Femoral hernias are acquired and more common in females.