The scapula is located between the second and seventh ribs and is one of two bones that make up the pectoral girdle, the other being the clavicle or collarbone. It consists of the spine, coracoid, acromion process and glenoid cavity.

Table of Contents:

[Scapula Bone Anatomy](#Scapula Bone-Anatomy)

[Scaplua - Functions and Disorders](#Scaplua - Functions and Disorders)

Frequently Asked Questions

Scapula Bone - Anatomy

What is a scapula? - The scapula, or shoulder blade, is a triangular-shaped bone located in the upper back. It is connected to the humerus (upper arm bone) and provides a surface for muscle attachment.

The Scapula, also known as the shoulder blade, is a part of the pectoral girdle. It provides an attachment site to the head of the humerus, as well as many muscles of the shoulder and arms.

The scapula is a triangular bone that lays the foundation to the posterior of the shoulder girdle, connecting the humerus and the clavicle. This bone supports a group of muscles that help with internal and external rotation of the joint and in abduction. The acromioclavicular joint is where the acromion (part of the scapula) and the clavicle meet at the tip.

Characteristics of the Scapula - Features

The main characteristics of the scapula are:

It is a triangular bone.

A pair of scapula bones are present in the pectoral girdle, which connects the upper limbs to the axial skeleton.

It forms the back part of the shoulder girdle and is located behind the ribs, covering the second to seventh ribs.

The dorsal surface of the scapula is convex and there is an elevated ridge, known as the spine of the scapula, which divides the bone into an upper smaller portion (supraspinous fossa) and a lower larger portion (infraspinous fossa).

The acromion process projects laterally from the spine of the scapula, and it articulates with the clavicle by the acromioclavicular joint.

The subscapular fossa is located on the ventral surface and is concave in shape.

The glenoid cavity, located laterally on the scapula bone, is a depression where the head of the humerus articulates with the scapula bone by way of the glenohumeral joint.

The coracoid process is a hook-like projection present below the clavicle and above the glenoid cavity. It is attached to the clavicle by ligaments.

Both scapula bones are not attached directly to the axial skeleton. Rather, they are connected to the vertebral column and thorax through muscles, allowing for a greater range of motion.

There are various types of muscles attached to the scapula that enable the different movements of the shoulder.

The muscles that originate from the scapula region include: biceps, triceps, deltoid, teres minor and major, supra and infraspinatus, etc.

The muscles responsible for the rotation and stabilization of the scapula include the trapezius, levator scapulae, serratus anterior, and rhomboid muscles, among others.

Parts of the Scapula

The main areas of the shoulder are:

• Bones and Joints
• Muscles
• Tendons and Ligaments
• Nerves
• Bursae
• Blood Vessels

Shoulder Bones

There are three main bones of the shoulder:

• Clavicle
• Scapula
• Humerus

Scapula - Shoulder blade

Humerus - Upper arm bone

Clavicle - Collar bone

The acromion - part of the scapula - gives form to the ceiling of the shoulder.

Shoulder Joints

Shoulder is formed by four joints:

The Glenohumeral joint consists of a ball of the humerus sitting into a socket (glenoid) on the scapula.

The Sternoclavicular joint assists in connecting the arms and shoulders to the main skeleton on the front of the chest.

Acromioclavicular Joint - Where the Clavicle Meets the Acromion

The Scapulothoracic joint (False joint) forms where the scapula slides against the thorax.

Muscles of the Shoulder

The rotator cuff muscles, located immediately outside the shoulder joint, are associated with the rotator cuff tendons. These muscles aid in the rotation of the arm in different directions, as well as raising the arm sideways and other activities commonly performed on a daily basis.

The rotator cuff muscles and tendons help to maintain the shoulder joint in a stable position by firmly holding the head of the humerus and the glenoid socket together. The deltoid muscle forms the outer layer of the shoulder, giving it its round shape over the glenohumeral joint. This muscle is the strongest and largest muscle of the shoulder.

Learn more about Muscles Attached to the Scapula

Spine of the Scapula

The spine of scapula is a ridge of the bone, a shelf-like projection distinguishing the posterior surface of the scapula. The posterior side of the scapula is divided into two parts: the supraspinous fossa above and the larger infraspinous fossa below by a transverse spine. This spine and the two fossae provide attachments for muscles which enable the arm to rotate.

Root of Spine of Scapula: It is the triangular area located at the base of the spine of the scapula.

Check out this link for more information on Parts of Scapula.

Scapula: Functions and Disorders

The Scapula region plays an important role in the body, as it aids in the rotation, elevation, retraction and protraction movements of various muscles. Furthermore, after a certain age, the membranous bones such as the sternum, vertebra, scapula, ribs, iliac bones and skull bones, as well as the ends of long bones, produce RBCs. Typically, fractures or deformities of the scapula are rare due to its protective placement.

Scapula bone function: The scapula, or shoulder blade, is a flat bone located on the posterior side of the thoracic cage. Its primary function is to provide attachment points for the muscles of the shoulder and arm, allowing for a wide range of motion of the shoulder and arm.

The scapula bone provides the main structural support

The scapula bone is attached to muscles such as pectoralis minor, trapezius, deltoid, etc.

The scapula is capable of performing six distinct muscle actions, allowing for a full range of upper extremity movement, including elevation, retraction, protraction, depression, downward and upward rotation.

*Scapula enables the elevation of the upper trapezius and depression of the lower trapezius, as well as downward rotation of the pectoralis minor and upward rotation of the trapezius.

When the scapula does not elevate the acromion process during a serving or throwing motion, it can lead to shoulder impingement due to abnormal functioning of the scapula.

Winging of the scapula is a bone deformity caused by the excessive prominence of the medial border of the scapula, resulting in a loss of pushing and punching actions. When attempting to push, winging of the scapula can occur, causing the arm to not be able to be raised beyond 90°.

The scapula and clavicle form the pectoral girdle, which connects the upper limb to the axial skeleton.

Further Reading: Human Skeletal System

Frequently Asked Questions

The Scapula

The scapula, also known as the shoulder blade, is a flat triangular bone located in the upper back. It connects the humerus (upper arm bone) to the clavicle (collarbone) and functions as a site for muscle attachment. It also provides stability for the shoulder joint and helps to protect the nerves and blood vessels that pass through the shoulder area.

The scapula region is located in the upper part of the back, between the neck and the shoulder.

The scapula is located on the posterior side of the thorax, between the second and seventh ribs.

The scapula or the shoulder blade is a triangular-shaped, flat bone. It is seen at the back of the trunk, residing on the posterior surface of the ribs 2 to 7. In other words, it is seen in the upper thoracic area on the dorsal surface of the rib cage.What are the connecting points of the scapula?

The scapula bone functions to link the humerus at the glenohumeral joint and the clavicle at the acromioclavicular joint, resulting in the formation of the shoulder joint.

Scapula bone function:

• Supports the shoulder joint
• Acts as an attachment point for shoulder muscles
• Helps to stabilize the shoulder joint during movement

The scapula bone provides the main structural support

The scapula bone is attached to muscles such as pectoralis minor, trapezius, deltoid, etc.

The scapula is capable of performing six different muscle actions that enable full-functional upper extremity movement, such as elevation, retraction, protraction, depression, downward rotation, and upward rotation.

The scapula allows for the elevation of the upper trapezius and depression of the lower trapezius, as well as downward rotation of the pectoralis minor and upward rotation of the trapezius.

The Clavicle and Scapula Joint

The clavicle and scapula joint is a joint in the shoulder that connects the clavicle (collarbone) to the scapula (shoulder blade). This joint allows for a wide range of movement in the shoulder, including abduction and adduction, flexion and extension, and rotation.

The spine of scapula is a ridge that runs along the medial side of the scapula, separating the supraspinatous and infraspinatous fossae. It is the highest point of the scapula, and meets the clavicle at the acromioclavicular joint.

The spine of scapula is located on the posterior side of the scapula.

The spine of scapula shows two borders, dividing the infraspinatous fossa from the supraspinous fossa.

The inferior border forms a part of the infraspinatous fossa and is concave. The anterior border is associated with the dorsal surface of the bone, while the posterior border is broader and offers two lips along with an interval.