Gross Anatomy 1 - Abdominal Hypaxial Structures PDF - Summer 2024

Gross Anatomy 1 Dr. Melissa Kehl Module 5 Abdominal Hypaxial Structures Courtesy of Dr. Terri Clark  Learning Objectives Discuss the origin, insertion, and muscle fiber orientation of each abdominal...

Gross Anatomy 1 Dr. Melissa Kehl Module 5 Abdominal Hypaxial Structures Courtesy of Dr. Terri Clark  Learning Objectives Discuss the origin, insertion, and muscle fiber orientation of each abdominal muscle. Discuss the layers of the abdominal wall, the superficial inguinal ring, deep inguinal ring, inguinal canal, vaginal process, vaginal tunic, prepubic tendon, and rectus sheath. Discuss the function of the abdominal muscles and effects on breathing and defecation. Discuss the abdominal and inguinal topographic regions. Note: Large animal will be studied in lab weeks 13 and 14. This is an introduction. Describe and discuss the tunica flava abdominis of the large animal abdominal wall and its clinical relevance. Discuss the prepubic tendon and its significance in the horse. Discuss the significance of the accessory ligament of the femoral head in the horse. Describe and discuss the boundaries and importance of the paralumbar fossae.  Topographic regions of the abdomen 91 Ventral view KNI Cranial abdominal – Xiphoid region 2 ofribs cartilage – Hypochondriac below region (right 1 and left 3) Middle abdominal – Umbilical region 5 1 2 3 – Lateral abdominal region (right 4 and left 6) 4 5 6 Caudal abdominal – Pubic region 8 – Inguinal regions 7 8 9 (right 7 and left 9) The term hypochondriasis for a state of disease without real cause reflected the ancient belief that the viscera of the hypochondria were the seat of melancholy and sources of the vapor that caused morbid feelings. Until the early 18th century, the term referred to a "physical disease caused by imbalances in the region that was below your rib cage" Guide to the Dissection of the Dog, 8th ed.; Evans and de Lahunta; Fig. 4-1  Muscles of the abdominal wall B A External abdominal oblique m. removed Superficial view C A. External abdominal oblique m. B. Internal abdominal oblique m. C. Transversus abdominis m. D. Rectus abdominis m. D External and internal abdominal oblique mm. Lateral views of the canine trunk removed Textbook of Veterinary Anatomy, 4th ed.; Dyce, Sack, Wensing; Figs. 2-22 A, 2-23 A & B  External abdominal oblique muscle Large muscle; covers the ventral half of the lateral thoracic wall and the lateral part of the abdominal wall; fibers run caudoventrally Origin: ribs 4-13 and thoracolumbar fascia Insertion: the linea alba by a wide aponeurosis Innervation: Ventral branches of thoracic and lumbar spinal nerves Action: Compression of the abdominal viscera (abdominal press) – aids in expiration, urination, defecation, parturition; flexion of vertebral column; unilateral - lateral bending of the vertebral column handsinpockets caudally ventrally External abdominal oblique m. Color Atlas of Veterinary Anatomy, Vol Superficial inguinal ring 3., 2nd ed.; Done, Goody, Evans, Stickland; Fig. 6.6  Internal abdominal oblique muscle Located medial to the external abdominal oblique muscle; fibers run cranioventrally Origin: Tuber coxae, thoracolumbar fascia and inguinal ligament Insertion: Costal arch, rectus abdominis, linea alba, and prepubic tendon Innervation: Ventral branches of thoracic and lumbar spinal nerves Action: Compression and support of the abdominal viscera Internal abdominal oblique m. deeptoexternalabdominaloblique Inguinal ligament crafinally External abdominal oblique m. removed Color Atlas of Veterinary Anatomy, Vol 3., 2nd ed.; Done, Goody, Evans, Stickland; Fig. 6.7  Transversus abdominis muscle Deepest abdominal muscle; fibers run transversely Origin: Medial surfaces of rib 9-13 and the transverse processes of the lumbar vertebrae Insertion: Linea alba Innervation: Ventral branches of thoracic and lumbar spinal nerves Action: Compression and support of the abdominal viscera Transversus abdominis m. External abdominal oblique m. removed; internal abdominal oblique m. cut and reflected ventrally Color Atlas of Veterinary Anatomy, Vol 3., 2nd ed.; Done, Goody, Evans, Stickland; Fig. 6.10  Rectus abdominis muscle Origin and insertion: first costal cartilage and sternum and pelvis by way of the prepubic tendon Innervation: Ventral branches of thoracic and lumbar spinal nerves Action: Compression and support of the abdominal viscera; bring the pelvis forward, flexion of the back Fibers run longitudinally * * * * * * Color Atlas of Veterinary Anatomy, Vol 3., 2nd ed.; Done, Goody, Evans, Stickland; Figs. 5.12 & 6.7  Rectus abdominis The rectus abdominus m. is more superficial near the cranial abdomen and dives deep as it reaches the more caudal abdomen. cranial middle caudal Guide to the Dissection of the Dog, 8th ed.; Evans and de Lahunta; Fig. 2-78  Layers of the rectus sheath The rectus sheath is formed by aponeuroses of: External abdominal oblique m. Clinical importance: It is Internal abdominal oblique m. the holding layer when Transversus abdominis m. closing the abdomen. Rectus abdominis m. aponeurosis Linea alba  Linea alba Midventral raphe (seam) Ventral view where the aponeuroses of the left and right abdominal muscles meet. Linea alba Guide to the Dissection of the Dog, 8th ed.; Evans and de Lahunta; Fig. 2-77  Inguinal Ligament reaadderformranagra Inguinal Ligament Transversus abdominis IAO Caudal limit of the aponeurosis of the external abdominal oblique muscle Separates the inguinal canal from the vascular lacuna Superficial Inguinal Ring Guide to the Dissection of the Dog p. 89  Prepubic tendon Prepubic tendon is a strong attachment of abdominal muscles to the pelvis. The rectus abdominis muscle definitely contributes, but it varies by species which other abdominal muscles are involved. Miller’s Anatomy of the Dog, 4th ed.; Evans; Fig. 6-38 Veterinary Anatomy of Domestic Animals, 4th ed.; König and Liebich; Fig. 2-16  Deep and superficial inguinal rings Mtfdatdaaaaaao.ae MymkY Deep inguinal ring Passage (gap) between 3 structures: ikm Deep view Superficial view Cranial border - caudal border of the internal External abdominal oblique m. abdominal Medial border - rectus oblique aponeurosis abdominis m. Inguinal lig. Latero-caudal border - inguinal ligament (EAO) Superficial inguinal ring Rectus abdominis muscle opening in the aponeurosis of the external abdominal oblique m. It is indistinct because it is covered by thoracolumbar fascia. Ventral view https://veteriankey.com/abdominal-wall-reconstruction-and-hernias/  Inguinal canal In the region of the groin, it extends between superficial and deep inguinal rings. Contains several structures: Males External pudendal artery and vein and Genitofemoral nerve females Lymphatics Vaginal tunic with spermatic cord (male) Cremaster muscle courses through the superficial inguinal ring (male) Vaginal process (female dog) liningofabdomenvaginaltunic process Inguinal canal: clinical importance Neutering Cryptorchidism (testis not descended into scrotum) Inguinal hernias  Cremaster muscle of it'spart internalabdominaloblique alreadysuperficialas Originates from the caudal border of the internal abdominal oblique m. Pulls the testis closer to the body in response to cold Innervated by genitofemoral nerve Aponeurosis of internal abdominal oblique muscle Cremaster muscle Miller’s Anatomy of the Dog, 4th ed.; Evans; Fig. 9-10  For Thursday’s Lab Read GDD pp. 20-22 on Sterno muscles GDD pp. 84-90 VIDEOS: Cervical Nerves and Associated Structure – 12 minutes Canine Body Wall – 12 minutes