Sternum (thorax)

5 Sternum (thorax)

Orientation and general presentation (Figs 5.1 & 5.2)

The sternum is a flat bone located in the anterior part of the thorax (1). It articulates with the seven (sometimes six) first pairs of ribs through the costal cartilages (2, second costal cartilage) and the two clavicles (3, right clavicle). The sternum shows three parts: the manubrium (4), the body or corpus (5) and the xiphoid process (6). Proximally, the manubrium shows laterally two clavicular surfaces (SCS) for the sternoclavicular joints, and medially the jugular notch (SJN). The manubrium and the sternal body are separated by the edge (or angle) of the manubriosternal joint (SME) at the level of the second costal cartilage (2). Both sternal body and xiphoid process articulate through the xiphisternal joint (SXS) at the level of the most distal sternocostal joints. The latter usually involves the costal cartilages of the seventh pair of ribs (7, seventh left costal cartilage). The angles between the seventh costal cartilages and the xiphoid process are the xiphicostal angles (in dotted blue).

Figure 5.1 Sternum (3D model, anterolateral view).

A The sternum (arrow) represents the anterior wall of the thorax. B Relationships of the sternum with other adjacent skeletal structures. See text for explanation.

Figure 5.2 Sternum (anatomic specimens).

Isolated bone: A anterior view; B anterolateral view. Dissection of the thorax: C anterior view; D anterolateral view. Note that the xiphoid process (6) is behind the frontal plane of the seventh costal cartilages (7).

Sternum – Jugular Notch (SJN)[M] ISB H|Anim

Landmark SJN

The jugular notch is along the superior edge of the sternum between the two sternoclavicular joints (see Figs 5.1 & 5.2).

The subject is sitting or lying supine.

Place one forefinger on the medial line of the neck.

Glide down to reach the sternum between the clavicles (blue arrow).

SJN is located between the sternal insertions of both sternocleidomastoid muscles (blue lines).

View the proximal aspect of the sternum along a horizontal view. Select the central point of the notch located between both clavicular joint surfaces.

A depression can be palpated just between the two clavicles.

In this depression, orient the index pulp distally, and gently push the finger into the soft tissue to reach the deepest point of the notch, which is the point to locate.

Then rotate the sternum to a frontal view, and check that the selected point is centered correctly in the notch.

Tags: Color Atlas of Skeletal Landmark Definitions Guidelines for Repr

Sep 9, 2016 | Posted by admin in MANUAL THERAPIST | Comments Off

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