Dominic Stone
The scapula, commonly known as the shoulder blade, is a sturdy, flat, triangular bone that sits above the rib cage in the upper back. It connects the clavicle to the humerus, forming the glenohumeral joint. The scapula has a large surface area, providing attachment points for muscles that enable its movement in six directions. These muscles can be classified as intrinsic, extrinsic, or a third group. The intrinsic muscles include the rotator cuff muscles, which stabilise the glenohumeral joint, while the extrinsic muscles affect motion at this joint. The third group includes muscles responsible for rotational movements and stabilisation of the scapula. Understanding the muscles that move the scapula is essential for comprehending shoulder anatomy and its wide range of motion.
| Characteristics | Values |
|---|---|
| Common Name | Shoulder Blade |
| Function | Forms the posterior of the shoulder girdle |
| Shape | Sturdy, flat, triangular |
| Movement | Six directions |
| Attachment | Connects the clavicle to the humerus |
| Muscles | Rotator Cuff, Teres Major, Subscapularis, Teres Minor, Infraspinatus, Triceps, Biceps, Deltoid, Levator Scapulae, Trapezius, Rhomboids, Serratus Anterior |
| Nerves | Dorsal Scapular, Upper and Lower Subscapular, Suprascapular |
| Conditions | Winged Scapula, Shoulder Impingement Syndrome, Snapping Scapula Syndrome |
Explore related products
What You'll Learn
- The scapula, or shoulder blade, is a triangular bone that connects the clavicle to the humerus
- There are 17 muscles attached to the scapula, separated into three groups: intrinsic, extrinsic, and a third group
- The intrinsic muscles include the rotator cuff and assist with the rotation of the glenohumeral joint
- The extrinsic muscles include the triceps, biceps, and deltoid
- The third group includes the levator scapulae, trapezius, rhomboids, and serratus anterior
The scapula, or shoulder blade, is a triangular bone that connects the clavicle to the humerus
The scapula, or shoulder blade, is a sturdy, flat, triangular bone that connects the clavicle to the humerus. It forms the posterior of the shoulder girdle and creates the shoulder joint where it meets the head of the humerus, the upper arm bone. The scapula has a large surface area, providing a point of attachment for numerous muscles that make up the arm and shoulder. These muscles also allow the scapula to move in six directions.
The intrinsic muscles of the scapula include the rotator cuff muscles (subscapularis, teres major, infraspinatus, and teres minor), which attach to the scapular surface and assist with the movement of the glenohumeral joint. The extrinsic muscles include the triceps, biceps, and deltoid. The third group of muscles includes the levator scapulae, trapezius, rhomboids, and serratus anterior, which are responsible for rotational movements and stabilization of the scapula.
The scapula can smoothly glide over the chest wall, or scapulothoracic joint, due to the muscles that lie between the ribs and the scapula. This allows the arm to move with the scapula, providing a wide range of movement and mobility for the upper limb. The serratus anterior, pectoralis major, and pectoralis minor muscles accomplish protraction, while retraction is achieved by the trapezius, rhomboids, and latissimus dorsi muscles. Elevation is the result of the trapezius, levator scapulae, and rhomboid muscles, and depression is caused by gravity and the actions of the latissimus dorsi, serratus anterior, pectoralis major and minor, and trapezius muscles.
The scapula is susceptible to various conditions that affect its function and morphology. For example, winging of the scapula can be caused by fascioscapulohumeral dystrophy, impacting several muscles related to the scapula. Additionally, snapping scapula syndrome is characterised by abnormal articulation at the scapulothoracic joint, often due to lesions or inflammation of the bursae.
Ultrasound Therapy: Muscle Healing Power?
You may want to see also
Explore related products
There are 17 muscles attached to the scapula, separated into three groups: intrinsic, extrinsic, and a third group
The scapula, or shoulder blade, is a sturdy, flat, triangular bone that connects the humerus (upper arm bone) with the clavicle (collar bone). The scapula forms the posterior of the shoulder girdle. It has a large surface area, providing a point of attachment for 17 muscles that make up the arm and shoulder. These muscles are divided into three groups: intrinsic, extrinsic, and a third group.
The intrinsic muscles of the scapula include the rotator cuff muscles: supraspinatus, infraspinatus, subscapularis, and teres minor. These muscles attach directly to the surface of the bone and act to stabilise the glenohumeral joint. They assist with abduction and external and internal rotation of the joint. The supraspinatus muscle, for example, is responsible for abduction at the shoulder joint.
The extrinsic muscles of the scapula include the triceps, biceps, and deltoid. These muscles attach to the processes of the scapula and affect motion at the glenohumeral joint. They resist dislocation of the shoulder and contribute to forearm flexion and supination. The deltoid muscle, in particular, plays a role in flexion, medial rotation, abduction, extension, and lateral rotation at the shoulder joint.
The third group of muscles includes the levator scapulae, trapezius, rhomboids, and serratus anterior. These muscles are responsible for rotational movements and stabilization of the scapula. The trapezius and levator scapulae muscles, along with the rhomboids, contribute to the elevation of the scapula. Meanwhile, depression is achieved through gravity and the actions of muscles like the latissimus dorsi, serratus anterior, and trapezius.
The scapula can move in six directions, thanks to these 17 muscles. These movements include protraction, retraction, elevation, depression, upward rotation, and downward rotation. Through these motions, the scapula enables the full function of the shoulder joint, one of the most mobile and versatile joints in the body.
Acupuncture: Muscle Penetration and Treatment Techniques
You may want to see also
Explore related products
The intrinsic muscles include the rotator cuff and assist with the rotation of the glenohumeral joint
The scapula, or shoulder blade, is a sturdy, flat, triangular bone that connects the clavicle to the humerus. It forms the posterior of the shoulder girdle and the glenohumeral (shoulder) joint. The scapula has a large surface area, providing a point of attachment for 17 muscles that make up the arm and shoulder. These muscles are divided into three groups: intrinsic, extrinsic, and a third group of muscles that includes levator scapulae, trapezius, rhomboids, and serratus anterior.
The intrinsic muscles of the scapula include the rotator cuff muscles: supraspinatus, infraspinatus, subscapularis, and teres minor. These muscles attach directly to the scapular surface and assist with abduction, external rotation, and internal rotation of the glenohumeral joint. The rotator cuff muscles also act to stabilise the glenohumeral joint, resisting dislocation of the shoulder.
The extrinsic muscles of the scapula include the triceps, biceps, and deltoid. These muscles attach to the processes of the scapula and affect motion at the glenohumeral joint. The deltoid muscle, for example, is responsible for flexion, medial rotation, abduction, extension, and lateral rotation at the shoulder joint.
The third group of muscles, including levator scapulae, trapezius, rhomboids, and serratus anterior, are responsible for rotational movements and stabilization of the scapula. For example, upward rotation is accomplished by the trapezius and serratus anterior muscles, while downward rotation is accomplished by the latissimus dorsi, levator scapulae, rhomboids, and pectoralis major and minor muscles.
The scapula plays a crucial role in shoulder function and stability. Its smooth gliding over the chest wall, or scapulothoracic joint, is facilitated by muscles and bursae, which cushion the tissue and decrease friction. The scapulothoracic rhythm, or scapulohumeral rhythm, refers to the coordinated movement between the scapula and humerus, which is essential for efficient arm movement and glenohumeral alignment. Any disturbance in this rhythm can lead to decreased scapulothoracic movement and issues such as fatigue, impingement, and instability.
Muscles' Glycogen Preference: Energy Source Advantage
You may want to see also
Explore related products
The extrinsic muscles include the triceps, biceps, and deltoid
The scapula, or shoulder blade, is a sturdy, flat, triangular bone that sits above the rib cage in the upper back. It connects the clavicle to the humerus and forms the posterior of the shoulder girdle. The scapula provides attachment points for several groups of muscles, including the intrinsic and extrinsic muscles.
The extrinsic muscles of the scapula attach to the processes of the scapula and affect motion at the glenohumeral joint. These include the triceps, biceps, and deltoid muscles.
The triceps brachii is a large muscle that consists of three parts: the medial, lateral, and long head. All three heads cross the elbow joint, while the long head also crosses the shoulder joint. The triceps muscle contracts when the elbow is straightened and expands when the elbow is bent. The long head of the triceps arises from the infraglenoid tubercle of the scapula and contributes to the stability of the shoulder joint. It helps to hold the head of the humerus in the glenoid cavity and prevents its inferior displacement. The triceps can be targeted through isolation or compound elbow extension movements, such as cable push-downs, lying triceps extensions, and arm extensions behind the back.
The biceps brachii is a flexor muscle that opposes the action of the triceps. During passive extension of the forearm, the extensor action of the triceps is replaced by gravity, and the movement is controlled by the active lengthening or eccentric contraction of the biceps brachii. The biceps brachii also plays a role in stabilising the elbow joint during fine movements of the forearm and hand.
The deltoid muscle originates along the scapula spine to the acromion and the lateral third of the clavicle. It is involved in flexion, medial rotation, abduction, extension, and lateral rotation at the shoulder joint. The deltoids can be targeted through static contraction movements such as pullovers, straight-arm pull-downs, and bent-over lateral raises.
IT Band Muscles: Understanding Your Body's Superpower
You may want to see also
Explore related products
The third group includes the levator scapulae, trapezius, rhomboids, and serratus anterior
The scapula, or shoulder blade, is moved by several muscle groups in the back and neck. The third group of muscles that move the scapula includes the levator scapulae, trapezius, rhomboids, and serratus anterior.
The levator scapulae is a posterior axio-appendicular muscle that connects the upper limb to the vertebral column. It originates on the posterior tubercle of the transverse process of cervical vertebrae one to four and inserts onto the vertebral margin of the scapula. This muscle functions to elevate the scapula and tilt the glenoid cavity by rotating the scapula downward. If the scapula is fixed, contraction of the levator scapulae leads to the lateral flexion of the cervical vertebral column to the side and stabilizes the vertebral column during rotation.
The trapezius muscles are two large muscles that start at the base of the neck and extend across the shoulders to the middle of the back. They have three sections: upper, middle, and lower. These muscles help maintain and adjust posture, including standing up straight or bending the upper back forward. They also enable various motions, such as turning the head, twisting the torso, shrugging the shoulders, and moving the shoulders during arm movements.
The rhomboid muscles consist of the rhomboid minor and rhomboid major. The rhomboid minor is a cylindrical muscle that originates at the ligamentum nuchae and C7 and T1 vertebra, inserting at the scapula's medial border near the base of the spine of the scapula. The rhomboid major is located inferior to the rhomboid minor and originates from the spinous processes of the T2-T5 vertebra, inserting just inferior to the rhomboid minor. The motor function of these muscles is controlled by the dorsal scapular nerve.
The serratus anterior is a fan-shaped muscle that originates on the superolateral surfaces of the first to eighth or ninth ribs and inserts along the superior angle, medial border, and inferior angle of the scapula. It acts as a key scapular stabiliser, keeping the shoulder blades against the rib cage during rest and movement. This muscle is also known as the "boxer's muscle" due to its role in protraction of the scapula during punching motions.
Speeding Muscle Healing: Tips for Quick Recovery
You may want to see also
Frequently asked questions
The scapula, commonly referred to as the shoulder blade, is the bone that sits above the rib cage in the upper back. It connects the clavicle to the humerus and forms the posterior of the shoulder girdle.
There are 17 muscles attached to the scapula, which fix the scapula to the thoracic wall and allow it to move. These muscles are separated into three groups: intrinsic, extrinsic, and a third group that includes the levator scapulae, trapezius, rhomboids, and serratus anterior.
The muscles attached to the scapula facilitate six movements: protraction, retraction, elevation, depression, upward rotation, and downward rotation. These movements allow for the full function of the shoulder joint, one of the most mobile and versatile joints in the human body.
