Abdominal wall 腹壁 山东大学医学院解剖教研室 李振华

Boundaries of the abdomen Superiorly－ xiphoid process, lower border of costal arch, 11th and 12th ribs, vertebra T12 Inferiorly－superior border of pubic symphysis, pubic crest, pubic tubercle, fold of inguinal canal, anterior superior iliac spine, iliac crest, spinous process of L5

The abdominal regions 腹部分区 ——Nine regions Epigastric region 腹上区 R. hypochondriac region 右季肋区 L. hypochondriac region 左季肋区 R. lateral regions 右外区 L. lateral regions 左外侧区 R. inguinal region右腹股沟区 Umbilical region 脐区 L. inguinal region 左腹股沟区 Pubic region 耻区

The abdominal regions 腹部分区 ——Four quadrants Left and right upper quadrants Left and right lower quadrants

Landmarks of abdomen Pubic symphysis Pubic tubercle Iliac crest Umbiicus Linea semilunaris Transpyloric plane

Anterolateral abdominal wall Layers ( from superficial to deep) Skin Superficial fascia Anterolateral muscles Transverse fascia 腹横筋膜 Extraperitoneal fascia 腹膜下筋膜 Parietal peritoneum 壁腹膜

Anterolateral abdominal wall Superficial fascia －divisions below umbilicus Fatty layer (Camper’s fascia) continuous with the superficial fascia over the rest of the body. Membranous layer (Scarpa’s fascia) passes over the inguinal ligament to fuse the deep fascia of the thigh (fascia lata) approximately one fingerbreadth below the inguinal ligament. In the midline, it is not attached to the pubis but instead from a tubular sheath for the penis (clitoris). In the perineum, it is attaches on each side to the margins of the pubic arch and is know as Colles’ fascia.

Superficial vessels and cutaneous nerves Arteries Superficial epigastric a. Superficial iliac circumflex a. Veins Thoracoepigastric v. Superficial epigastric v. Cutaneous nerves Anterior and lateral cutaneous n. of lower six thoracic Iliohypogastric n. (first lumb nerves)

Superficial vessels and cutaneous nerves Lymph drainge Superficial lymph vessels above the level of the umbilicus grain upward into the pectoral Ln. The vessels below this level drain downward into the superficial inguinal Ln.

Muscles of abdomen

Muscles of abdomen Anterolateral group Obliquus externus abdominis 腹外斜肌 Obliquus internus abdominis 腹内斜肌 Transversus abdominis 腹横肌 Rectus abdominis 腹直肌

Muscles of abdomen Posterior group Quadratus lumborum 腰方肌 Psoas major 腰大肌

Obliquus externus absominis 腹外斜肌 General direction of fibers: downward, forward and medially (run down and inward)

Obliquus externus absominis 腹外斜肌 Structures Inguinal ligament 腹股沟韧带 Lacunar ligament 腔隙韧带 Superficial inguinal ring 腹股沟管浅环 －triangular-shaped defect in aponeurosis of obliquus externus abdominis above pubic tubercle

Superficial inguinal ring

Obliquus internus abdominis 腹内斜肌 Deep to obliquus externus abdominis General direction of fibres: upwards, forwards and medially

Transversus abdominis 腹横肌 Deep to obliquus internus General direction of fibers: run horizontally forward.

Transversus abdominis 腹横肌 Inguinal falx 腹股沟镰 Obliquus internus abdominis has a lower, free border that arches over spermatic cord Inserted with transversus abdominis fiber into medial part of pecten of pubis Cremaster 提睾肌 Dirived from the lower fibers of the obliquus internus abdominis and transversus abdominis Around the spermatic cord and testis

Rectus abdominis 腹直肌 Position: lie on to either of midline Origin: pubic crest and symphysis Insertion: xiphoid and 5th-7th costal cartilages Tendinous intersections 腱划 3-4 linea semiluaris 半月线

Similar functions for above four pairs of muscles Support and compress the abdominal viscera Increase intra-abdominal pressure, aid in expulsive efforts-vomiting, coughing, sneezing, defecation, urination and childbirth. Depress ribs, assist in (the act of force(4)expiration. Flex, lateral flex, and rotate vertebral column

Sheath of rectus abdominis 腹直肌鞘 Anterior layer Formed by fusion of aponeurosis of obliquus externus abdominis and anterior leaf of aponeurosis of obliquus internus abdominis

Sheath of rectus abdominis 腹直肌鞘 Posterior layer Formed by fusion of posterion leaf of aponeurosis of obliquus internus abdominis and aponeurosis of transversus abdominis Absent in about 4-5cm below the umbilicus, where aponeuroses of all three muscles form anterior layer the lower free border named arcuate line 弓状线 Below this line rectus abdominis in contact with transverse fascia

Muscles of abdomen Linea alba 白线 －tendinous raphe between right and left recti from xiphoid to pubic symphysis

Deep vessels of abdomen Arteries Superior and inferior epigastric arteris Lower posterior intercostal aa. Subcostal a. Deep iliac circumflex a. Four lumbar a.

Deep nerves of abdomen Lower five intercostals nerves Subcostal nerve Run between obliquus internus and tranversus abdominis.

Deep nerves of abdomen Iliohypogastric n. 髂腹下神经 Arises from lumbar plexus Passes forward in the interval between obliquus internus and tranversus abdominis Pieces obliquus internus abdominis 2.5 cm medial to anterior superior iliac spine Pieces aponeurosis of obliquus externus abdominisabout 2.5 cm above superficial inguinal ring

Deep nerves of abdomen Ilioinguinal n. 髂腹股沟神经 Arises from lumbar plexus Runs parallel with iliohypogastric n. at a lower level Enters inguinal canal and exits through superficial inguinal ring Supplies the transversus abdominis, obliquus internus, and obliquuse externus abdiminis. It also supplies the skin just above the symphysis pubis and the scrotum or greater lip of pudendum.

Deep nerves of abdomen Genitofemoral n. 生殖股神经 Arises from lumbar plexus Emerges through superficial inguinal ring and supplies the cremaster muscle

Inguinal region 腹股沟区 Boundaries Inguinal ligament Lateral margin of rectus abdominis A horizontal line stretching from anterior iliac spine to lateral margin of rectus abdominis

Inguinal canal 腹股沟管 Position: oblique passage, 4cm long, located 1.5cm above medial half of inguinal ligament

Boundaries of inguinal canal Anterior wall Aponeurosis of obliquus externus abdominis Obliquus internus abdominis (lateral third of wall) Posterior wall Transverse fascia Inguinal flax medially Roof－arching fibers of obliquus internus and transversus abdominis Floor－inguinal ligament

Boundaries of inguinal canal Two openings Superficial inguinal ring 腹股沟管浅环 －a triangular-shaped defect in the aponeurosis of the obliquus externus abdominis and lies immediately above and medial to the pubic tubercle

Boundaries of inguinal canal Two openings Deep inguinal ring 腹股沟管深环 －an oval opening in transverse fascia and lies approximately 1.5cm above midpoint of inguinal ligament

Mechanics of the inguinal canal The inguinal canal is a site of potential weakness in both sexes. On coughing and straining (as in micturition, defecation, and parturition), the arching lowers fibers of the obliquus internus and transversus abdominis contract and flatten the arch. In turn, this lowers the roof of the canal toward the floor and virtually closes the canal.

Structures passing through the inguinal canal In males Spermatic cord 精索 Ilioinguinal nerve 髂腹股沟神经 In females Round ligament of uterus 子宫圆韧带

Descent of testes Seven-week embryo showing the testis before its descent from the dorsal abdominal wall

Descent of testes Fetus at 28 week the testis passing through the inguinal canal

Descent of testes Newborn

Inguinal Triangle (of Hesselbach) 腹股沟三角 Boundaries Medially: Lateral border of rectus abdominis Laterally: Inferior epigastric artery Inferiorly: Inguinal ligament

Indirect inguinal hernia and direct inguinal hernia

Anterior abdominal wall Transverse fascia 腹横筋膜 Extraperitoneal fascia 腹膜外筋膜 Parietal peritoneum 壁腹膜

Landmarks and surface anatomy Xiphoid process Costal arch Anterior superior iliac spine Iliac crest Superior border of pubic symphysis Pubic tubercle

Landmarks and surface anatomy Linea alba Rectus abdominis Tendinous intersections Linea semilunaris Umbilicus: at the level of L3 ~ L4 Inguinal ligament

Layer ? Median or midline incision Subcostal incision Muscle-splitting incision Left paramedian incision Transverse incision Suprapubic incision

★You must identify follow structures！ Obliquus externus abdominis Inguinal ligament Superficial inguinal ring Obliquus internus abdominis Transversus abdominis Inguinal falx Rectus abdominis Tendinous intersections Sheath of rectus abdominis arcuate line inferior epigastric artery Posterior intercostal a. Intercostals nerve Iliohypogastric n. Ilioinguinal n. Spermatic cord