Orientation and general presentation (Figs 8.1 & 8.2)

The scapula or shoulder blade (1) is a triangular bone located on the lateroposterior aspect of the thorax and on the posterior aspect of the shoulder girdle (Figs 8.1 & 8.2). This bone presents three edges, medial or vertebral (2), lateral or axillary (3) and superior (4), and two angles, one inferior (SIA) and one superior (SSA).

Figure 8.1 Scapula (3D model).

A General position. B Posterior view. C Anterior view. D Superior view.

Figure 8.2 Scapula (anatomic specimen).

Isolated bone: A posterior view; B lateral view; C superior view.

The posterior aspect of the scapula is divided into two parts by the spine (6), which runs from the medial aspect (i.e. the spine root or SRS) to the lateral aspect of the bone. The most lateral part of the spine is called the acromion (7), which articulates with the clavicle (8) through the acromioclavicular joint (SAJ). The angle located between the spine and the acromion is called the acromial angle (SAA). The most anterior part of the acromion is the acromial tip (SAT). The acromial edge (SAE) runs between both SAA and SAT. Note that the center of the glenoid cavity is approximatively below the acromion.

The coracoid process (9) originates from the superior edge, and points forwards and laterally below the clavicle. The summit of the coracoid process is called the coracoid tip (SCT).

Scapula – Inferior Angle (SIA)[R,L] ISB

Landmark SIA

Both lateral and medial edges of the scapula merge into a sharp inferior angle (see Figs 8.1 & 8.2).

The subject is standing or lying prone. The palpator stands behind the subject.

With one forefinger, glide down the medial edge of the scapula, while your thumb follows the lateral edge (blue arrows).

Forefinger and thumb meet at the apex of the inferior angle.

Select the angle apex (SIA) by orienting the forefinger pulp upwards.

NOTE

With the upper arm in neutral position, SIA is on approximately the same horizontal plane (blue line) as TV7 (in blue; see p. 31).

Observe the posterior face of the scapula. Select the most distal point of the inferior angle.

Then observe the bone from an inferior view. Check that the point has been located correctly at the center of the angle.

Scapula – Root of Spine (SRS)[R,L] ISB

Landmark SRS

The root of the scapula spine is located next to the medial edge of the scapula. Keep in mind that the spine root has a triangular shape, the lateral apex of which indicates the true end of the scapula spine.

The subject is standing or lying prone with the shoulder in abduction. The palpator stands next to the subject.

First find the scapula spine in the center of the shoulder region.

Then glide along the scapula spine (blue arrow) with the pulps of all your fingers until the middle finger finds the medial edge (red line).

SRS is under your forefinger, at the intersection of the scapula spine (blue line) and the medial edge (red line), slightly lateral to this edge.

Manual palpation tip

• This landmark can be difficult to palpate when the rhomboid muscles are contracted.

• Placing the subject’s arm along the body may help to relax the shoulder muscles and facilitate the palpation.

Observe the posterior face from a posterior (slightly medial) view. First locate the scapula spine and the triangular shape of its root (blue dotted line).

Select the apex of the root triangle, which is closest to the scapula spine.

Scapula – Superior Angle (SSA)[R,L]

Landmark CAS

Both superior and medial edges of the scapula merge into the superior angle (see Figs 8.1 & 8.2)

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