Anterior and Posterior Abdominal Walls PDF

‫‪Lectures of Anatomy for‬‬ ‫‪Physical Therapy.‬‬ ‫ا‪.‬د ‪/‬مرسي عبد الفتاح مرسي‪.‬‬ ‫أستاذ التشريح واآلجنة‪ /‬كلية الطب‪ /‬جامعة طنطا‪.‬‬ ❑ Objectives: By the end of this lecture the student will be able to: ❖Define the abdominal wall. ❖Identify the layers of the abdominal wall. ❖Descr...

‫‪Lectures of Anatomy for‬‬ ‫‪Physical Therapy.‬‬ ‫ا‪.‬د ‪/‬مرسي عبد الفتاح مرسي‪.‬‬ ‫أستاذ التشريح واآلجنة‪ /‬كلية الطب‪ /‬جامعة طنطا‪.‬‬ ❑ Objectives: By the end of this lecture the student will be able to: ❖Define the abdominal wall. ❖Identify the layers of the abdominal wall. ❖Describe the lumber vertebra. ❖Describes the anterior and posterior abdominal walls. ❖Describe the somatic nerves. ❑Abdominal wall: The abdominal wall covers a large area of the abdomen. It is bounded superiorly by the xiphoid process and costal margins, posteriorly by the vertebral column, and inferiorly by the upper parts of the pelvic bones. Its layers consist of skin, superficial fascia (subcutaneous tissue), muscles and their associated deep fascias, extraperitoneal fascia, and parietal peritoneum ❑Anterior abdominal wall: ❖ Structure of anterior abdominal wall: Skin &superficial fascia. Muscles. Extraperitoneal fascia. Parietal peritoneum. ❖ Superficial fascia: The superficial fascia of the abdominal wall (subcutaneous tissue of abdomen) is a layer of fatty connective tissue. It is usually a single layer like, and continuous with, the superficial fascia throughout other regions of the body. In the lower region of the anterior part of the abdominal wall, below the umbilicus, it forms two layers: a superficial fatty layer and a deeper membranous layer. ❖ Muscles of anterior abdominal wall: 1. External oblique muscle. 2. Internal oblique muscle. 3. Transversus abdominis muscle. 4. Rectus abdominis muscle. 5. Pyramidalis muscle. 1-External oblique muscle: It is broad thin muscular sheet Its fibers run downward, forward and medially. ❖Origin: It arises from outer surfaces of lower 8 ribs. ❖Insertion: 1. Xiphoid process. 2. Linea alba. 3. Pubic crest. 4. Pubic tubercle. 5. Anterior half of iliac crest. ❖Nerve supply: Lower 6 thoracic nerves. Iliohypogastric nerve (L 1). Ilioinguinal nerve(L 1). ❖ Action: It supports and compresses abdominal contents It assists in flexion and rotation of trunk It assists in forced expiration, micturition, defecation, parturition and vomiting ❖Aponeurosis of external oblique muscle. ❖Inguinal ligament between ant. Sup. iliac spine and pubic tubercle. 2-Internal oblique muscle. It a broad thin muscular sheet, deep to external oblique. Its fibers run upward , forwards and medially. ❖ Origin: 1. Lumbar fascia. 2. Anterior two-thirds of intermediate lip of iliac Lumbar fascia. crest 3. Lateral two-thirds of Inguinal Iliac crest inguinal ligament. ligament ❖ Insertion: Lower borders of lower 6 ribs and their costal cartilages Xiphoid process. Linea alba. Symphysis pubis. Pubic crest. Pectineal line. ❖ Nerve supply: Lower 6 thoracic nerves. Iliohypogastric nerve (L 1). Ilioinguinal nerve (L 1). ❖ Action: It compresses and supports abdominal contents. It assists in flexion and rotation of trunk. it assists in forced expiration, micturition, defecation, parturition and vomiting. 3-Transverses abdominas muscle: It a broad thin muscular sheet. It deep to internal oblique. Its fibres run horizontally forward. ❖ Origin: Deep surface of lower 6 costal cartilages (interdigitating with diaphragm). Lumbar fascia. Lumber fascia. Anterior two-thirds of iliac crest. Iliac crest Lateral third of inguinal ligament. Inguinal ligament ❖ Insertion: ▪ Xiphoid process. ▪ Linea alba. ▪ Symphysis pubis. ❖ Nerve supply: ▪ Lower 6 thoracic nerves. ▪ Iliohypogastric nerve (L 1). ▪ Ilioinguinal nerve (L 1). ❖ Action: ▪ It compress the abdominal contents. 4-Rectus abdominis: It long strap muscle, broader above. It extends along whole length of anterior abdominal wall. It lies close to midline, separated from its fellow by linea alba. It divided into segments by transverse tendinous intersections. It usually has 3 intersections: 1. At level of Xiphoid process. 2. At level of umbilicus. 3. Halfway between these two. The intersections are strongly attached to anterior wall of rectus sheath. Enclosed between aponeurosis of external oblique, internal oblique and transversus abdominis (rectus sheath). ❖ Origin:(Two heads): Xiphoid process 1. From front of symphysis pubis. 5th,6th,7th costal cartilages 2. From the pubic crest. ❖ Insertion: 5th, 6th and 7th costal cartilages. Xiphoid process. ❖ Nerve supply: ▪ Lower 6 thoracic nerves (T7- T12 ❖ Action: ✓ It compress the abdominal contents. ✓ It flex the vertebral column. Symphysis pubis and ✓ It accessory muscle of pubic crest expiration. 5-Pyramidalis: ▪ It often absent. ▪ It lies in front of rectus abdominis. ❖ Origin: ▪ From the anterior surface of pubis. ❖ Insertion: ▪ Into the linea alba. ❖ Nerve supply: ▪ From the subcostal nerve (T12). ❖ Action: ▪ It tenses the linea alba. ❑ Rectus sheath: The rectus abdominis and pyramidalis muscles are surrounded with aponeurosis (the rectus sheath) formed from external ,internal oblique, and transversus abdominis muscles. The rectus sheath completely encloses the upper three-quarters of the rectus abdominis and covers the anterior surface of the lower one- quarter of the muscle. No sheath covers the posterior surface of the lower quarter of the rectus abdominis muscle so the muscle at this point is in direct contact with the transversalis fascia. ❑ Innervation of the anterior abdominal wall: The skin and muscles of the anterolateral abdominal wall are supplied by T7 to T12 and L1 spinal nerves. The anterior rami of these spinal nerves pass around the body, from posterior to anterior, in an inferomedial direction. They give off a lateral cutaneous branch and end as an anterior cutaneous branch. The intercostal nerves (T7 to T11) leave their intercostal spaces, passing deep to the costal cartilages, and continue onto the anterolateral abdominal wall between the internal oblique and transversus abdominis muscles. When reaching the lateral edge of the rectus sheath, they enter the rectus sheath and pass posterior to the lateral aspect of the rectus abdominis muscle. When approaching the midline, an anterior cutaneous branch passes through the rectus abdominis muscle and the anterior wall of the rectus sheath to supply the skin. Spinal nerve T12 (the subcostal nerve) follows a similar course as the intercostals. Iliohypogastric nerve and ilio-inguinal nerve are branches from lumber plexus (L1) which follow similar courses initially but deviate from this pattern near their destination. Course of lower 6 intercostal nerve and Iliohypogastric and ilioinguinal nerves in the anterior abdominal wall ❑ Posterior abdominal wall: It consists of bones and muscles 1- Bones Lumbar vertebrae and the sacrum They projecting into the midline of the posterior abdominal area are the bodies of the five lumbar vertebrae. The prominence of these structures in this region is due to the secondary curvature (a forward convexity) of the lumbar part of the vertebral column. The lumbar vertebrae can be distinguished from cervical and thoracic vertebrae due to their size. ❖Lumbar vertebrae: Typical vertebrae (1- 4). Atypical vertebra (5). ❑Typical lumbar vertebrae: ❖ The body is large, and kidney shaped to bear the greater part of the body weight. ❖ The pedicles are strong and directed backward. ❖The laminae are thick. ❖The vertebral canal is triangular. ❖The transverse processes are long and slender. ❖ The spinous processes are short, flat, quadrangular and project backward. ❖ The articular surfaces of the superior articular processes face medially, and those of the inferior articular processes face laterally. ❖ The lumber vertebrae have the mammillary process which is connected in the lumbar region with the back part of the superior articular process and the accessory process which is situated at the back part of the base of the transverse process. Note: The lumbar vertebrae have no facets for articulation with ribs and no foramina in the transverse processes.  Typical lumber vertebra Body is kidney shape. Vertebral canal is triangle. Transverse process. Pedicle. Accessory process. Sup. articular facet is Mamillary process. directed backward and Spine medially.  Lumber vertebrae (posterior view). Mamillary process. Superior. articular facet. Spine is rectangular Accessory process. and horizontal.  Lumber vertebrae (lateral view) Intervertebral foramen. Spine is horizontal and rectangular. Intervertebral disc. the lumber vertebra is convex forwards. Inferior articular facet is directed forwards and lat. ❖Intervertebral discs in the lumbar region: Annulus fibrosis. Thicker than in other regions of the vertebral column. Wedge shaped. It consists of annulus fibrosis and nucleus pulposis Responsible for normal posterior concavity in the Nucleus pulposis. curvature of the vertebral column in the lumbar region (lordosis). ❑ 5th lumbar vertebra: ❖The transverse process: Massive, continuous with the whole length of the pedicle and encroaches on the body. ❖The body: The largest of all vertebrae. ❖The spine: Small and has a rounded tip. ❖ Muscles of posterior abdominal wall: 1. Psoas major. 2. Psoas minor. 3. Quadratus lumborum. 4. Transversus abdominis (origin). 5. Diaphragm. Note: Iliacus lies in false pelvis. ❑ Psoas major: ❖ Origin: ▪ 12th thoracic to 5th lumbar vertebrae (Roots of transverse processes, sides of vertebral bodies and intervertebral discs) ❖ Insertion: ▪ Lesser trochanter of the femur. ❖ Nerve supply: ▪ Branches of lumbar plexus (L2- 4). ❖ Action: ▪ Flexion and medial rotation of the thigh. ▪ Flexion of the trunk, if the thigh is fixed. ❑ Psoas minor: May be absent in 40% of subjects. T12 Long slender muscle. L1 ❖ Origin: 1. Sides of 12th thoracic. 2. 1st lumbar vertebrae. 3. The disc in between T12 and L 1. ❖ Insertion: Iliopectineal (Iliopubic) eminence of hip bone. ❖ Nerve supply: Branch from 1st lumbar nerve. ❖ Action: Weak flexion of lumbar vertebral column Iliopubic eminence ❑ Iliacus: ❖ Origin: Upper 2/3 of iliac fossa of hip bone. Inner lip of iliac crest. Iliolumber ligament. ❖ Insertion: Joins tendon of psoas major to form iliopsoas muscle. Lesser trochanter of the femur. ❖ Nerve supply: Femoral nerve (within abdomen). ❖ Action: Flexion and medial rotation of the thigh. Flexion of the trunk, if the thigh is fixed. ❑Quadratus lumborum: Flat, quadrilateral-shaped muscle. Alongside of vertebral column. Lateral to psoas major. ❖ Origin: 1. Iliolumbar ligament. 2. Adjoining part of iliac crest. 3. Tips of transverse processes of lower lumbar vertebrae. ❖ Insertion: 1. Lower border of 12th rib. 2. Transverse processes of upper 4 lumbar vertebrae. ❖ Nerve supply: Lumbar plexus (T12 and L1, 2, 3, 4). ❖ Action: Fixes or depresses the 12th rib during respiration. Laterally flexes vertebral column to the same side. ❑ Nerves of posterior abdominal wall: ❖ Lumbar plexus: ▪ Formation of lumbar plexus: Anterior rami of upper 4 lumbar nerves It also receives a contribution from the T12 (subcostal) nerve. Inside the psoas major muscle. Receive grey rami communicants from the sympathetic trunk. ❑ Formation and branches T12 of lumber plexus: 1-Subcostal T12. 2-Iliohypogastric L1. L1 3-Ilioinguinal L1. 4-Genitofemoral L1,2. 5-Lateral cutaneous nerve of L2 the thigh L2,3. 6-Femoral nerve L2,3,4. dorsal division. L3 7-Obturator nerve L2,3,4. ventral division. 8-Accessory obturator nerve L3,4. L4 9-Lumbosaral trunkL4,5. L5 ❑ Lumber plexus inside the Sympathetic chain substances of psoas major muscle and its connections Psoas major with sympathetic plexus: 1 1. Subcostal nerve. 2. Iliohypogastric nerve. 2 3. Ilioinguinal nerve. 4. Lateral cutaneous nerve of the thigh. 3 5. Femoral nerve. 6. Obturator nerve. 4 6 7 7. Lumbosacral trunk. 5  MCQ Q1:Which of the following is consider the nerve supply to pyramidalis muscle? a. T7-T11 b. T12 c. L1 d. L1,2 Q2:Regarding muscles of anterior abdominal wall which of the following is false? a. External oblique b. Internal oblique c. Rectus abdominus d. Psoas major Q3: Regarding lumber plexus which of the following is not branch from it? a. Iliogastric nerve b. Ilioinguinal nerve c. Lateral cutaneous nerve of the thigh d. Subcostal nerve Q4: Which of the following is true regarding lumber vertebra? a. Its body is heart shape b. Its vertebral canal is rounded c. Its pedicle is strong and directed backward d. Its lamina is thin Q5: Rectus abdominis muscle is arising from which of the following bones? a. Symphysis pubis and pubic crest b. Outer lip of iliac crest c. Lower 8 ribs d. Superior pubic ramus Thanks, with the best wishes. Prof.Dr/Morsy Abdelfattah.