Logan Steele
The scapula, or shoulder blade, is a flat, triangular bone that connects the collarbone (clavicle) to the upper arm bone (humerus). It forms part of the shoulder socket and allows for the movement and use of the shoulder. The scapula has three surfaces, three borders, three angles, and three processes. The scapula is also the origin of several muscles, including the supraspinatus, infraspinatus, subscapularis, and teres minor, which are the four rotator cuff muscles. The scapula is a crucial bone as it provides a wide range of movement and mobility for the upper limb.
| Characteristics | Values |
|---|---|
| Common name | Shoulder blade |
| Description | Thick, flat, triangular bone |
| Location | Postero-lateral aspect of the thoracic cage |
| Surfaces | 3 (costal/anterior, lateral, posterior/inferior) |
| Borders | 3 (superior, lateral, medial) |
| Angles | 3 (lateral, superior, inferior) |
| Processes | 3 (coracoid, acromion, spine) |
| Functions | Provides attachment for muscles, tendons, ligaments, nerves, and veins |
| Muscles | Deltoid, Latissimus Dorsi, Trapezius, Serratus Anterior, Biceps Brachii, Coracobrachialis, Pectoralis Minor, Triceps Brachii, Supraspinatus, Infraspinatus, Subscapularis, Teres Major, Teres Minor, Rhomboids, Levator Scapulae, Pectoralis Major |
| Tendons | 12 |
| Ligaments | 6 |
| Nerves | 2 |
| Veins | Axillary vein, suprascapular veins, anastomotic tributaries |
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What You'll Learn
- The scapula is a flat, triangular bone that forms the shoulder blade
- It connects the collarbone to the upper arm bone
- The scapula has three surfaces, three borders, three angles and three processes
- The bone provides an attachment for three groups of muscles: intrinsic, extrinsic, and stabilising and rotating muscles
- The supraspinous fossa is above the spine of the scapula
The scapula is a flat, triangular bone that forms the shoulder blade
The scapula, or shoulder blade, is a flat, triangular bone that forms part of the shoulder joint. It connects the clavicle (collarbone) to the humerus (upper arm bone). The scapula has three surfaces, three borders, three angles, and three processes. The three surfaces are the costal (anterior) surface, the lateral surface, and the posterior (inferior) surface. The three borders are the superior, lateral, and medial borders. The three angles are the superior, lateral, and inferior angles, with the inferior angle pointing downwards. The three processes are the spine, the coracoid, and the acromion.
The scapula provides attachment points for several groups of muscles, including the intrinsic, extrinsic, and stabilizing and rotating muscles. The intrinsic muscles include the rotator cuff muscles, which are the subscapularis, supraspinatus, infraspinatus, and teres minor. These muscles attach to the surface of the scapula and are responsible for internal and external rotation of the shoulder joint, along with humeral abduction. The extrinsic muscles include the triceps, biceps, and deltoid, which attach to the coracoid process and supraglenoid tubercle of the scapula, infraglenoid tubercle of the scapula, and the spine of the scapula. These muscles are responsible for several actions of the glenohumeral joint. The third group of muscles, which is mainly responsible for stabilization and rotation of the scapula, includes the trapezius, serratus anterior, levator scapulae, and rhomboid muscles.
The scapula plays an important role in the function of the shoulder joint, allowing for a wide range of motion and mobility for the upper limb. It is involved in six types of motion: protraction, retraction, elevation, depression, upward rotation, and downward rotation. These movements are accomplished by the actions of various muscles, including the serratus anterior, pectoralis major and minor, trapezius, rhomboids, and latissimus dorsi muscles.
The scapula is also associated with several important anatomical landmarks, such as the glenoid fossa, supraglenoid tubercle, and infraglenoid tubercle. The glenoid fossa is a shallow cavity located on the lateral border of the scapula, which articulates with the head of the humerus to form the glenohumeral joint. The supraglenoid tubercle is a roughening immediately superior to the glenoid fossa and serves as the attachment site for the long head of the biceps brachii muscle. The infraglenoid tubercle, located immediately inferior to the glenoid fossa, is the attachment site for the long head of the triceps brachii muscle.
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It connects the collarbone to the upper arm bone
The scapula, commonly known as the shoulder blade, is a flat, triangular bone that forms part of the shoulder joint. It is one of the three bones that make up the shoulder joint, connecting the clavicle (collarbone) to the humerus (upper arm bone). This allows for the movement and use of the shoulder.
The scapula has three surfaces: the costal (anterior) surface, the lateral surface, and the posterior (inferior) surface. The front of the scapula, or the costal surface, faces the rib cage and forms a slightly indented cup called the subscapular fossa. This supports one of the rotator cuff muscles, the subscapularis muscle. The subscapular fossa is characterised by three longitudinal oblique ridges, with another thick ridge adjoining the lateral border. The medial two-thirds of the fossa feature a transverse depression, which gives greater strength to the bone.
The lateral surface of the scapula points towards the humerus and includes the glenoid fossa, an indention that forms the back of the shoulder socket. The glenoid fossa articulates with the head of the humerus to form the glenohumeral (shoulder) joint. The lateral surface also includes the supraglenoid tubercle, where the biceps muscle attaches, and the infraglenoid tubercle, where the triceps muscle attaches.
The posterior (inferior) surface of the scapula is the rear part that faces the back. It includes the spine, which forms the apex or top of the shoulder blade, and the acromion, which moves with the clavicle during shoulder movement. The posterior surface is divided into the supraspinous fossa and the infraspinous fossa by the scapular spine. The supraspinous fossa is concave, smooth, and broader at its vertebral than humeral end, giving origin to the supraspinatus muscle. The infraspinous fossa is larger and features a shallow concavity at its upper part, with a prominent convexity towards the axillary border. The infraspinatus muscle originates from this area.
The scapula is connected to 17 muscles, 12 tendons, six ligaments, and two nerves. These attachments allow the shoulder to move in six directions, more than any other joint in the body. The muscles attached to the scapula include the deltoid, latissimus dorsi, trapezius, serratus anterior, biceps brachii, coracobrachialis, pectoralis minor, triceps, levator scapulae, rhomboids major and minor, and the four rotator cuff muscles (supraspinatus, infraspinatus, subscapularis, and teres minor).
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The scapula has three surfaces, three borders, three angles and three processes
The scapula, or shoulder blade, is a flat, triangular bone that forms part of the shoulder joint. It has three surfaces, three borders, three angles, and three processes.
The three surfaces of the scapula are the costal (anterior) surface, the lateral surface, and the posterior (inferior) surface. The front of the scapula, or the costal surface, has a broad concavity called the subscapular fossa, to which the subscapularis muscle attaches. The subscapular fossa is also known as the anterior surface of the scapula. The medial two-thirds of the fossa have three longitudinal oblique ridges, with another thick ridge adjoining the lateral border. The scapula's lateral surface is its outside edge that points toward the humerus. It includes the glenoid fossa, the Superglenoid tubercle, and the Infraglenoid tubercle. The posterior surface of the scapula is the rear part that faces the back. It includes the spine (apex) and the acromion.
The three borders of the scapula are the superior, medial, and lateral borders. The superior border is the shortest and thinnest, extending from the superior angle to the base of the coracoid process. The medial border is the longest of the three borders, extending from the superior angle to the inferior angle. The axillary or lateral border is the thickest of the three borders. It begins above at the lower margin of the glenoid cavity and inclines obliquely downward and backward to the inferior angle.
The three angles of the scapula are the superior, lateral, and inferior angles. The superior angle is formed by the junction of the superior and medial borders of the scapula. The inferior angle is where the medial and lateral borders meet. The inferior angle of the scapula gives origin to the Teres major muscle.
The three processes of the scapula are the coracoid, acromion, and spine. The coracoid process is a small, hooked bump just under the clavicle that anchors three muscles. The acromion forms the summit of the shoulder and is a large, somewhat triangular or oblong process. The spine of the scapula is a protruding ridge of bone that separates the posterior surface into two divisions: the supraspinous fossa and the infraspinous fossa.
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The bone provides an attachment for three groups of muscles: intrinsic, extrinsic, and stabilising and rotating muscles
The scapula, commonly known as the shoulder blade, is a thick, flat bone lying on the thoracic wall. It has two surfaces, three borders, three angles, and three processes. The scapula provides an attachment for three groups of muscles: intrinsic, extrinsic, and stabilising and rotating muscles.
The intrinsic muscles of the scapula include the muscles of the rotator cuff (subscapularis, supraspinatus, infraspinatus, and teres minor). These muscles attach to the surface of the scapula and are responsible for the internal and external rotation of the shoulder joint, along with humeral abduction. The supraspinatus muscle originates in the supraspinous fossa, which is concave, smooth, and broader at its vertebral end. The infraspinatus muscle originates in the infraspinous fossa, which is directly below the spine and is larger than the supraspinous fossa. The subscapularis muscle attaches to the subscapular fossa, a broad concavity on the front of the scapula. The teres minor attaches to the scapula at the upper two-thirds of the surface between the ridge and the axillary border.
The extrinsic muscles include the biceps, triceps, and deltoid muscles. These muscles attach to the coracoid process, supraglenoid tubercle, infraglenoid tubercle, and spine of the scapula. They are responsible for several actions of the glenohumeral joint. The biceps brachii muscle attaches to the supraglenoid tubercle, while the triceps muscle attaches to the infraglenoid tubercle. The deltoid muscle arises from the lower border of the spine of the scapula.
The third group of muscles is mainly responsible for stabilising and rotating the scapula. These include the trapezius, serratus anterior, levator scapulae, and rhomboid muscles. The levator scapulae attaches to the superior angle of the scapula, while the rhomboids major and minor attach to the medial border. The serratus anterior attaches to the medial margin of the scapula, with one digitation originating from the costal surface superior of the scapula. The trapezius is inserted into the upper border of the spine of the scapula.
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The supraspinous fossa is above the spine of the scapula
The scapula, commonly known as the shoulder blade, is a flat, triangular bone that forms part of the shoulder joint. It is connected to more than a dozen muscles, tendons, and ligaments, and its stability is dependent on the surrounding musculature.
The supraspinous fossa is a depression located on the posterior surface of the scapula, above the spine of the scapula. It is concave, smooth, and broader at its vertebral end than at its humeral end. The supraspinous fossa is the origin point for the supraspinatus muscle, which is one of the four rotator cuff muscles. These muscles form a musculotendinous cuff around the glenohumeral joint and provide muscular support to the joint.
The supraspinous fossa is smaller than the infraspinous fossa, which is located directly below the spine of the scapula. The infraspinatus muscle originates from the infraspinous fossa, which is broader and more indented than the supraspinous fossa.
The supraspinatus and infraspinatus muscles are intrinsic muscles of the scapula and are responsible for the internal and external rotation of the shoulder joint, along with humeral abduction. The extrinsic muscles of the scapula include the biceps, triceps, and deltoid muscles, which attach to different parts of the scapula and are responsible for several actions of the glenohumeral joint.
The scapula has two surfaces, three borders, three angles, and three processes. The front of the scapula, known as the costal or ventral surface, has a broad concavity called the subscapular fossa, to which the subscapularis muscle attaches. The medial two-thirds of the fossa have three longitudinal oblique ridges, providing attachment to the tendinous insertions, while the lateral third is smooth and covered by the fibers of the subscapularis muscle.
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Frequently asked questions
The scapula is a thick, flat bone that forms the posterior of the shoulder girdle. It is commonly known as the shoulder blade.
The scapula is located on the postero-lateral aspect of the thoracic cage. It is behind the clavicle near the back.
The scapula is connected to 17 muscles, including the serratus anterior, pectoralis major, pectoralis minor, levator scapulae, and trapezius.
The scapula provides attachment points for muscles that make up the arm and shoulder. It also allows for a wide range of movement and mobility for the upper limb.
