OSTEOLOGIA DE MIEMBRO INFERIOR 1 Diagnostico X

Introduction to the Pelvis and Coxal Bone

Overview of the Topic

• The speaker addresses the audience, particularly students from Universidad Libre in Cali, Colombia, who requested information on the pelvis.

• The focus will be on osteology related to the lower limb, specifically discussing the coxal bone and its components.

Structure of the Pelvis

• The pelvis is formed by two coxal bones (right and left), along with the sacrum and coccyx. This structure is essential for understanding human anatomy.

• The coxal bone is a unique flat bone resulting from the fusion of three separate bones: ilium, pubis, and ischium. These bones converge at a cavity known as the acetabulum.

Detailed Anatomy of the Coxal Bone

Components of the Coxal Bone

• The ilium has a wing-like shape and features an anterior border, superior border, posterior border, external surface (fossa iliaca externa), and an internal surface (fossa iliaca interna).

• Key anatomical landmarks include:

• Anterior superior iliac spine (ASIS) where muscles such as sartorius attach.

• Anterior inferior iliac spine (AIIS) which serves as an attachment point for rectus femoris muscle.

Muscle Attachments

• The ASIS is crucial for abdominal topography; it provides insertion points for muscles like sartorius and tensor fasciae latae. Additionally, ligaments such as iliopubic tract attach here.

• At AIIS, rectus femoris attaches via its direct tendon; this muscle plays a significant role in knee extension. Two tendons are involved: one direct at AIIS and another reflected above acetabulum through supracetabular canal.

Borders and Insertions on Ilium

Iliac Borders

• The superior border forms the iliac crest which serves as an attachment site for abdominal wall muscles including external oblique, internal oblique, transversus abdominis, and latissimus dorsi at its posterior aspect.

• Posteriorly located spines include:

• Posterior superior iliac spine (PSIS)

• Posterior inferior iliac spine (PIIS), both lacking significant detail or function compared to other structures mentioned earlier.

Sciatic Notch Importance

• The greater sciatic notch allows passage for important structures including piriformis muscle above it; below are gluteal vessels/nerves while inside lies internal pudendal artery returning to perineum after exiting through lesser sciatic notch.

Muscle Insertion Points on External Ilium

Gluteal Muscles Attachment Zones

• On fossa iliaca externa's surface are three distinct areas where gluteal muscles insert:

• Anterior area for gluteus minimus,

• Middle area for gluteus medius,

• Posterior area for gluteus maximus which connects to femur's greater trochanter region via lines aspra leading into four branches further down leg anatomy discussion later on in video content .

Internal View of Coxal Bone

Articular Structures

• Internally viewed coxal bone reveals auricular surface resembling an ear that articulates with sacrum forming sacroiliac joint critical in pelvic stability during movement .

Muscle Insertions in the Abdominal Wall

Overview of Muscle Groups

• The upper part of the iliac fossa is where two muscles from the anterior group of the posterior abdominal wall insert: the psoas major and quadratus lumborum.

• The psoas major has portions that attach to the lumbar vertebrae (five lumbar vertebrae and intervertebral discs) and also at the coxal level, known as iliopsoas.

• A lesser-known muscle, referred to as psoas minor, consists of fibers that insert lower on the iliac crest and share a common tendon with iliacus, terminating at the lesser trochanter of the femur.

Key Muscle Insertions

• The only muscle inserting at the lesser trochanter of the femur is iliopsoas, which is often a key point in examinations.