🥇 HUESO COXAL - HUESO ILÍACO, Anatomía. Fácil y Sencillo

Anatomy of the Coxal Bone

Introduction to the Coxal Bone

• Dr. Juan José Sánchez introduces himself from Venezuela and welcomes viewers to a complex discussion on the anatomy of the coxal bone, also known as the ilium.

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Structure and Importance of the Coxal Bone

• The coxal bone consists of two parts: left and right, articulating at the pubis through the pubic symphysis in front and with the sacrum at the back via sacroiliac joints.

• It connects lower limbs to the body, distributing weight from the spine downwards while providing protection for pelvic structures in both males and females.

Anatomical Features of the Coxal Bone

• The lateral view reveals an important feature called acetabulum, indicating where it articulates with the femur; confusion often arises between coxal bone and coccyx (the tailbone).

• The coxal bone is composed of three fused parts during embryonic development: ilium (upper), ischium (posterior-inferior), and pubis (anterior-inferior).

Detailed Examination of Ilium

• The ilium is identified as the largest part, consisting of a body (smaller section) that connects with ischium and pubis through specific elevations like iliopubic eminence.

• The connection points include a line termed arcuate line or terminal line, which forms part of pelvic structure when viewed from above.

Key Anatomical Landmarks

• The iliac crest runs along its upper edge, starting from anterior superior iliac spine to posterior superior iliac spine; this crest serves as an important landmark for anatomical orientation.

Anatomical Structures of the Iliac Crest

Overview of the Iliac Crest

• The iliac crest consists of two lips: the external lip facing outward and the medial lip facing inward, with a rough area in between known as the interstice.

• A significant structure located 5 cm behind the posterior superior iliac spine is called the tubercle of the iliac crest, which is part of the external lip.

Borders and Faces of the Ilium

Borders of the Ilium

• The wing (ala) of the ilium has three borders: anterior, posterior, and medial. The anterior border starts at the anterior superior iliac spine and extends downward to meet with the pubis at the iliopectineal eminence.

• The posterior border begins at the posterior superior iliac spine and descends to where it connects with ischium; it includes structures like both superior and inferior posterior spines.

• After passing through various structures, including a greater sciatic notch, this border concludes at its junction with ischium.

Medial Border Details

• The medial or internal border starts from the iliac crest downwards through a rough area known as tuberosity iliaca before reaching an unnamed line that ends at iliopectineal eminence.

Faces of the Ilium

External Face (Fossa Ilíaca Externa)

• This face is also referred to as gluteal surface due to its association with gluteal muscle origins. It features three semicircular lines starting from posterior to anterior.

• The most posterior line originates from near the iliac crest and terminates at greater sciatic notch; it's known as gluteal or semicircular line.

Anatomy of the Ilium and Ischium

Semicircular Lines and Pelvic Surfaces

• The anterior semicircular line ends at the greater sciatic notch, while the inferior gluteal line is less pronounced but also terminates at this notch.

• The external surface between the posterior and anterior borders is referred to as the gluteal or external iliac fossa. The internal iliac fossa is smooth and extends from the anterior to medial border.

• The sacropelvic surface articulates with the sacrum, featuring two key anatomical structures: the iliac tuberosity and auricular surface, which resembles an ear shape. This area forms the sacroiliac joint.

Preauricular Groove Significance

• A unique feature called the preauricular groove exists on the anterior-inferior part of the auricular surface; it is only found in females, making it significant for forensic medicine in sex determination of pelvic bones.

Understanding Ischium Structure

• The ischium may be referred to as "ischiatic" or "sciatic," indicating its relation to this bone structure; it consists of a body and an ascending ramus.

• The body of the ischium has two parts: an upper extremity that articulates with both pubis and ilium through acetabulum, and a lower extremity that connects with its ascending ramus. It features a notable anatomical landmark known as the ischial tuberosity, crucial for weight-bearing when seated.

Anatomical Faces and Borders of Ischium

• The body of the ischium presents three distinct faces: femoral (external), posterior, and pelvic (internal). Each face has specific borders separating them: lateral (external), posterior, and anterior borders corresponding to different anatomical orientations.

• These borders help delineate areas such as where they meet at obturator foramen; notably, there are important landmarks like greater sciatic notch formed by these structures including spinae (ischial spine) which projects medially beneath it leading to lesser sciatic notch below it.

Functional Importance of Ischial Tuberosity

Anatomy of the Ischium and Pubis

Overview of the Ischium

• The anterior border defines the limits of the obturator foramen, continuing with the pubis at the ischiopubic notch.

• The ascending ramus connects to the pubis, forming a sharp upper edge that delineates two surfaces: an external (lateral or femoral) face and an internal (medial or pelvic) face.

• Key anatomical landmarks include the greater sciatic notch, lesser sciatic notch, and ischial tuberosity, which are crucial for understanding pelvic structure.

Anatomy of the Pubis

• The pubis consists of three parts: a body, a horizontal branch, and a descending branch. It is also referred to as "pecten" in some contexts.

• The body of the pubis has three faces: an internal (or symphyseal), a femoral face directed towards the femur, and a pelvic face where the urinary bladder rests.

Important Features of Pubic Structure

• Notable structures on the body include:

• Crest Pectinea: An important elevation at its superior part.

• Crest Obturatriz: A ridge leading towards the obturator foramen located inferiorly.

• Crest del Pubis: The most anterior part featuring an external prominence known as tubercle or spine of pubis.

Articulations and Connections

• The body articulates with another pubic bone at its medial side forming the pubic symphysis.

• The horizontal branch connects with other coxal bones through iliopectineal eminence at acetabulum level; it features both pectineal crest above and obturator groove below.

Understanding the Structure of the Pubis

Anatomy of the Horizontal Ramus of the Pubis

• The horizontal ramus of the pubis is complex, featuring three borders and three faces. The anterior border is defined by the pectineal line, marked in black in diagrams.

• The inferior border corresponds to the obturator crest, while the posterior border faces towards the obturator foramen. These borders delineate three distinct surfaces: pectineal, pelvic, and obturator.

Description of Key Surfaces

• The pectineal surface extends from the anterior to inferior border (from pectineal crest to obturator crest) and forms part of the acetabulum. This surface is crucial for understanding hip joint anatomy.

• The pelvic surface runs from the anterior to posterior border and connects with similar surfaces on adjacent bones (ischium and ilium). It plays a role in pelvic cavity structure.

• The obturator surface looks inward towards the obturator canal, extending from the inferior to posterior borders; it contains structures related to nerve and blood supply through this canal.

Descending Ramus and Acetabulum Overview

• The descending ramus connects with the ascending ramus of ischium, forming what is known as the ischiopubic junction or ramus ischiopubica; it primarily closes off the obturator foramen without significant structural importance itself.

• Discussion shifts to the acetabulum, which articulates with femur; it's formed by contributions from all three pelvic bones: ischium (over two-fifths), pubis (two-fifths), and ilium (slightly less than two-fifths). Understanding these proportions aids in comprehending hip joint mechanics.

Acetabular Features

• At its base, there’s an incomplete circle at the ischiopubic notch formed by both pubis and ischium; this area includes what’s referred to as acetabular fossa or cotyloid fossa—important for joint stability during movement.

• Surrounding this fossa are key anatomical features:

• Lunar surface encircles it.