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Introduction to Scapula Bone:

The scapula or shoulder blade is a flat, triangular-shaped bone that lies adjacent to the posterior surface of ribs 2-7.

The posterior view of skeleton showing the left scapula and humerus

Markings of the Scapula Bone:

  1. It has three borders (superior, lateral, medial), three angles (superior, lateral, medial) and two surfaces (costal, dorsal). A prominent ridge or spine divides the dorsal surface into two, unequal parts called the supraspinous fossa and infraspinous fossa.
  1. A shallow depression at the lateral angle called the glenoid cavity accepts the head of the humerus to form the shoulder or gleno-humeral joint.
The posterior view of skeleton showing the left scapula and humerus with right scapula
3.The scapula also articulates with the clavicle to form the shoulder girdle or pectoral girdle, which supports movements of the humerus.
View of the scapula and humerus on posterior view
4.Seventeen muscles attach to the borders, angles, ridges, bumps, processes, and fossae found on the surface of the scapula.
View of the scapula on posterior view
5.The muscles that insert on the scapula (intrinsic muscles) connect it to the axial skeleton. When these muscles contract, the scapula is elevated, depressed, rotated, protracted, retracted, or stabilized when the humerus is moved.
6.The muscles that originate on the scapula (extrinsic muscles) insert on the humerus, radius, and ulna. They cause the humerus to rotate, abduct, adduct, flex or extend.


Anterior Scapula Bone:

Bone Markings:
  1. Superior border or margin (Margo superior) is the upper edge of the scapula that runs next to the clavicle. The omohyoid muscle attaches along this surface.
Illustration of anterior scapula
2.Medial border or margin (Margo medialis) is the medial edge of the scapula and is also called the vetebral border. This area is an attachment point for the rhomboid major, rhomboid minor and serratus anterior muscles.
Illustration of anterior scapula
  1. Lateral border or margin (Margo lateralis) is the lateral edge of the scapula. The teres minor muscle attaches along this surface, which is also called the axillary border.
Illustration of anterior scapula
4.Superior angle (Angulus superior) is a sharp curvature at the junction of the superior and medial borders. This area is an attachment point for levator scapula muscle.
Illustration of anterior scapula
5.Lateral angle (Angulus lateralis) is the junction of the superior and lateral borders. Its slightly concave lateral edge articulates with the head of the humerus. 
Illustration of anterior scapula
6.Inferior angle (Angulus inferior) is a sharp curvature formed at the junction of the medial and lateral margins. It is an area of attachment for the teres major muscle.
Illustration of anterior scapula
7.Coracoid process (Processus coracoi-deus) is a curved, hook-like anterolateral projection located above the lateral angle. 
  • The term coracoid refers to the marking’s resemblance to a crow’s beak (Gr., korax, crow’s). The biceps brachii, coracobrachialis, and pectoralis minor muscles attach along the surface of this process.
Illustration of anterior scapula
8.Suprascapular (scapular) notch (Incisura scapulae) is a small groove located medial to the coracoid process. It forms a passageway for the suprascapular nerve.
Illustration of anterior scapula
9.Glenoid cavity or fossa (Cavitas glen-oidalis) is a slight concavity at the lateral angle. It forms a shallow socket for the articulation of the head of the humerus. 
Illustration of anterior scapula
10.Infraglenoid tubercle (Tuberculum infra-glenoidale) is a small prominence on the inferior margin of the glenoid fossa. It serves as an attachment point for the long head of the triceps brachii muscle. 
Illustration of anterior scapula
11.Subscapular fossa  (Fossa subscapularis) is a large, slightly depressed region in the middle of scapula’s anterior surface. The subscapularis muscle attaches to this region of the bone.


Illustration of anterior scapula

Posterior Scapula Bone Anatomy

Bone Markings:
  1. Superior border or margin (Margo superior) is the upper edge of the scapula that runs next to the clavicle. The omohyoid muscle attaches along this surface. 
Illustration of posterior scapula
2.Medial border or margin (Margo medialis) is the medial edge of the scapula and is also called the vetebral border. This area is an attachment point for the rhomboid major, rhomboid minor and serratus anterior muscles.
Illustration of posterior scapula
3.Lateral border or margin (Margo lateralis) is the lateral edge of the scapula. The teres minor muscle attaches along this surface, which is also called the axillary border. 
Illustration of posterior scapula
4.Superior angle (Angulus superior) is a sharp curvature at the junction of the superior and medial borders. This area is an attachment point for levator scapula muscle. 
Illustration of posterior scapula
5.Lateral angle (Angulus lateralis) is the junction of the superior and lateral borders. Its slightly concave lateral edge articulates with the head of the humerus. 
Illustration of posterior scapula
6.Inferior angle (Angulus inferior) is a sharp curvature formed at the junction of the medial and lateral margins. It is an area of attachment for the teres major muscle.
Illustration of posterior scapula
7.Scapular spine (Spina scapulae) is a long ridge that runs diagonally across the upper posterior surface of the bone. The trapezius and posterior deltoid muscles attach to the surface of this prominent elevation.
Illustration of posterior scapula
8.Acromion (Acromion scapulae) is a lat-eral, fan-like extension of the spine. It also is an attachment point for the trapezius and posterior deltoid muscles.
Illustration of posterior scapula
9.Supraspinous fossa (Fossa supraspinata) is a slightly depressed area located superior to the spine. The supraspinatus muscle attaches to this region of the scapula. 
Illustration of posterior scapula
10.Infraspinous fossa (Fossa infrspinata) is a large, slightly depressed area located inferior to the spine. It serves as an attachment point for the infraspinatus muscle
Illustration of posterior scapula
11.Glenoid cavity or fossa  (Cavitas glenoidalis) is a slight concavity at the lateral angle. It forms a shallow socket for the articulation of the head of the humerus.
Illustration of posterior scapula
12.Infraglenoid tubercle  (Fossa subscapularis) (Tuberculum infra-glenoidale) is a small prominence on the inferior margin of the glenoid fossa. The long head of the triceps brachii muscle attaches to this knob-like ridge.
Posterior scapula with labeled inferior angle
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