HUMAN ANATOMY ATLAS - G.L. Bilich - 2014

THE LOCOMOTOR SYSTEM

SKELETAL SYSTEM

BONES OF THE LOWER LIMB

Bones of the Pelvic Girdle

The hip bone (os coxae) consists of three separate bones until the age of 13–16 (the ilium, pubis, and ischium) joined by Cartilage within the acetabulum, which later fuse into a single pelvic bone (Figs. 99, 100, 101). The acetabulum serves as the articular socket for the HEAD of the Femur in the hip joint formed by these bones. The elevated margins of the acetabulum are interrupted medially by the acetabular notch (incisura acetabuli), which is bridged by the transverse ligament. Only the smooth lunate surface (facies semilunata) located along the periphery of the socket articulates with the femoral head, while its recessed bottom—the acetabular fossa (fossa acetabuli)—is uneven.

The ilium (os ilium) features a thickened body of the ilium (corpus ossis ilii) inferiorly, which contributes to The formation of the acetabulum, and the iliac ala (ala ossis ilii), which expands superiorly. The upper part of the ala is curved and forms a thickened margin—the iliac crest (crista iliaca)—which exhibits three rough lines for the attachment of the broad Abdominal Muscles: the outer lip (labium externum), inner lip (labium internum), and intermediate line (linea intermedia). The iliac crest terminates anteriorly and posteriorly in bony prominences. The anterior prominence is the anterior superior iliac spine (spina iliaca anterior superior), which is easily palpable through the Skin. Slightly inferior to it lies the anterior inferior iliac spine (spina iliaca anterior inferior). The posterior end of the iliac crest forms the posterior superior iliac spine (spina iliaca posterior superior), below which the posterior inferior iliac spine (spina iliaca posterior inferior) is visible.

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Fig. 99. Right hip bone. Individual bones are highlighted in color:

1 — Ischial tuberosity; 2— Ischium, ramus; 3— Ischial spine; 4 — Bodyofischium; 5 — Ilium; 6 — Ala ofilium; Wingofilium; 7— Iliae crest; 8 — Acetabulum; 9 — Pubis, body; 10— Superior pubic ramus; 11— Inferior pubic ramus; 12 — Obturator foramen

Fig. 100. Right hip bone, lateral view:

1 — Ischial tuberosity; 2 — Lesser sciatic notch; 3 — Ischial spine; 4 — Greater sciatic notch; 5 — Posterior inferior iliac spine; 6 —- Posterior superior iliac spine: 7 — Gluteal surface; 8 — Posterior glutcal line; 9 — Anterior gluteal line; 10 — Iliac crest; 11 — Inferior gluteal line; 12 — Anterior superior iliac spine; 13 — Anterior inferior iliac spine; 14 — Acetabular margin; 15 — Lunate surface; 16 — Acetabular fossa; 17— Acetabular notch; 18= 14 + 15 + 16 + 17 — Acetabulum; 19 — Pubie tubercle; 20 — Obturator foramen

On the external surface of the iliac ala, where the gluteal muscles originate, there are three faintly discernible, arched, rough lines. The longest, the anterior gluteal line (linea glutea anterior), extends from the anterior superior iliac spine to the greater sciatic notch of the ischium. The posterior gluteal line (linea glutea posterior) runs almost vertically along the posterior aspect of the preceding line. The inferior gluteal line (linea glutea inferior) originates between the anterior superior and anterior inferior iliac spines and is located above the acetabulum.

On the internal surface of the iliac ala lies a shallow depression—the iliac fossa (fossa iliaca)—whose lower boundary is formed by the arcuate line (linea arcuata — Douglas' line, named after James Douglas [1675–1742], an English physician and anatomist). Posteriorly, this line approaches the anterior margin of the auricular surface (facies auricularis), which, together with the corresponding surface of the sacrum, forms the sacroiliac joint. Above the auricular surface lies the iliac tuberosity (tuberositas iliaca), to which the interosseous ligaments attach. Anteriorly, the arcuate line transitions into the iliopubic eminence (eminentia iliopubica).

The pubis (os pubis) features a thickened body of the pubis (corpus ossis pubis), which participates in forming the anterior portion of the acetabulum. Projecting forward from the body is the superior pubic ramus (ramus superior ossis pubis), bearing the iliopubic eminence. The steeply curved anterior part of the superior ramus forms the inferior pubic ramus (ramus inferior ossis pubis). The medial side of the transition from the superior to the inferior ramus forms the oval-shaped symphysial surface (facies symphysialis) for articulation with the pubic bone of the opposite side, thereby forming the Pubic Symphysis. Near the medial end of the superior pubic ramus lies the pubic tubercle (tuberculum pubicum), from which the pubic crest (crista pubica) extends toward the iliopubic eminence. On the Inferior surface of the superior pubic ramus, the obturator groove (sulcus obturatorius) runs posteroanteriorly and medially, accommodating the obturator vessels and nerve.

Fig. 101. Right hip bone (A — medial view, B — anterior view):

1 — Obturator foramen; 2 — Inferior pu- bic ramus; 3 — Symphysial surface; 4 — Pu- bic tubercle; 5 — Pecten pubis; Pectinea! line; 6 — Superior pubic ramus; 7— Iliopubiceminen- ce; 8 - Arcuate line; 9 — Anterior inferior iliac spine; 10 — Anterior superior iliac spine; 11 — Iliac fossa; 12 — Iliac tubcrosity; 13 — Iliac crest; 14 —- Posterior superior iliac spine; 15 — Ilium, auricular surface; 16— Bodyof ilium; 17 — Ischial spine; 18 — Bodyof ischium; 19 — Obturator groove; 20 — Ischial tuber; 21 — Acetabulum;

22 — Acetabular margin

Fig. 102. Radiograph of the pelvic bones, anteroposterior projection:

1 — teardrop figure; 2 — half-moon figure; 3 — head of femur; 4 — joint space of the hip joint; 5 — neck of femur; 6 — greater trochanter; 7— lesser trochanter; 8 — obturator foramen; 9 — supraacetabular groove of ilium; 10 — cleft of pubic symphysis; 11 — anterior inferior iliac spine; 12 — ischial tuberosity; 13 — anterior superior iliac spine; 14— iliac crest; 15— posterior superior iliac spine; 16 — posterior inferior iliac spine; 17— joint space of the sacroiliac articulation; 18 — sacrum [sacral vertebrae SI–SV]; 19 — lumbar vertebra [LV]; 20— ala of ilium; 21 — superior pubic ramus; 22— inferior pubic ramus; 23 — ramus of ischium; 24 — coccyx [coccygeal vertebrae CoI–CoIV] (after A.Yu. Vasilyev)

The ischium (os ischii) has a thickened body (corpus ossis ischii) that contributes to the inferior part of the acetabulum. From the lower part of the body, the ramus of the ischium (ramus ossis ischii) extends steeply forward and fuses with the inferior pubic ramus, thereby forming the obturator foramen (foramen obturatum). The junction where the body of the ischium transitions into its ramus becomes thickened, forming the ischial tuberosity (tuber ischiadicum). Superior to it, projecting from the posterior margin of the body, is the ischial spine (spina ischiadica), which separates two notches. The inferior, lesser sciatic notch (incisura ischiadica minor) lies between this spine and the ischial tuberosity. The broader greater sciatic notch (incisura ischiadica major) is bounded superiorly by the posterior part of the iliac ala.

Fig. 102 shows a radiograph of the pelvis and hip joints.