Detailed structure of posterior abdominal wall

                 The posterior abdominal wall is a complex region of anatomy. It is the formed by the lumbar vertebral, pelvic girdle, posterior abdominal muscles and their associated fascia,major vessels, nerves and organs are located on the inner surface of the interior of the posterior abdominal wall.

Posterior Abdominal Muscles:-

                         There are five muscles in the posterior abdominal wall : 

• Iliacus 
• Psoas major 
• Psoas minor 
• Quadratus lumborum   
• Diaphragm 

                     we shall look at the attachment action and in innervation of these muscles in more detail.

Quadratus lumborum :-

                         The quadratus lumborum muscle is located laterally in the posterior abdominal wall. It is a thick muscular sheet which is quadrilateral in shape.The muscle is positioned superficially to the psoas major. 

Attachment:-

             It is originates from the iliac crest and illolumbar ligament. The fibres travel supermedially inserting onto the transverse process of L1-L4 and there inferior border of the 12th Rib.

Action :-  Extension and lateral flexion of the vertebral column. It also fixes the 12th rib inspiration, so that the contraction of the diaphragam is not wasted.

Innervation :- Anterior rami of T12-T4 nerves.

Psoas major :-

                The psoas major is located near the midline of the posterior abdominal wall, immediately lateral to the lumbar vertebral 

Attachment :- 

             Originate from the transverse processes and vertebral bodies of the T-12 T-5 It then moves inferiorly and laterally. running deep to the inguinal ligament and attaching to the lesser of the femur.

Action :- 

           Flexion of the thigh at the hip and Lateral flexion of the vertebral column.

Innervation :- 

              Anterior rami L1 to L3 nerves. 

Psoas minor :-

                The psoas minor muscles is only present in 60% of the population. It is located anterior to the psoas major.

Attachment  :- 

              Originates from the vertebral bodies of T-12 and L-1 and attache to a ridge on the superior ramus of the pubic bone known as the pectinal line.

Action :- 

         Flexion of the vertebral column.

 Innervation :- anterior any of the L1 spinal nerves.

Iliac  :- 

       The Iliac muscles is a fan shaped muscles that is situated in inferiorly on the posterior abdominal wall. It combines with the psoas major to form the iliopsoas major flexure of the thigh.

Attachement :-

                Originate from the surface of the iliac fossa and anterior inferior iliac spine. Its fibre combine with the tendon of the psoas major inserting into the leisure of the femur.

Action :-

         Election of thigh at the hip joint.

Innervation :-

               Femur nerve. 

Diaphragm :-

            The posterior aspect of the diaphragm is considered to be part of the posterior abdominal wall.

Fascia of the posterior abdominal wall

A layer of the facia lies between muscular of the posterior abdominal Wall. The fascia is continus with the transferly facia of the anteriolateral abdominal Wall. The facia is one continue sheet,it is anatomical correct to name the facia according to the structure it overless.

Deep back muscles :-

                   Between the middle and posterior layer. The posterior layer extend between the 12th ribs and the iliac crest posteriorly.Laterally the facia meets the internal oblique and transversus abdomines muscles. But not the external oblique.As it from these attachments it covers the latissimus dorsi. The anterior layer attach to the anterior espect of the transverse process of the number vertebral the 12th rib and the iliac crest. Laterally the fascia is continues with the apo- neurotic origin of the transverse abdominis muscle. Superiorly the facia thickness to become the lateral ligament which joint the iliolumbar ligaments inferiorly.