Maximus Gage
The scapula, or shoulder blade, is a sturdy, flat, triangular bone that sits above the rib cage in the upper back. It forms the posterior of the shoulder girdle and creates the shoulder joint where it meets with the head of the humerus, the bone of the upper arm. The scapula can move in six directions, and each movement is produced by specific, primary muscles. The muscles that depress the scapula include the latissimus dorsi, serratus anterior, pectoralis major and minor, and the trapezius muscles. The trapezius muscle is a large, triangular, and thin back muscle that covers the upper back of the shoulders and neck. It is one of the broadest and most superficial muscles of the upper back and trunk.
| Characteristics | Values |
|---|---|
| Muscle that depresses scapula | Trapezius, Latissimus Dorsi, Serratus Anterior, Pectoralis Major and Minor |
| What is the scapula | Commonly referred to as the shoulder blade |
| Location of the scapula | Bone that sits above the rib cage in the upper back |
| Trapezius Muscle | Large, superficial back muscle that resembles a trapezoid |
| Trapezius Muscle Fibre Groups | Upper, Middle, and Lower |
| Trapezius Function | Stabilize and move the scapula |
| Upper Trapezius Fibers Function | Elevate and upwardly rotate the scapula and extend the neck |
| Middle Trapezius Fibers Function | Adduct (medially retract) the scapula |
| Lower Trapezius Fibers Function | Depress and aid the upper fibers in upwardly rotating the scapula |
| Serratus Anterior Muscle | Fan-shaped muscle that originates on the superolateral surfaces of the first to eighth or ninth ribs |
| Serratus Anterior Muscle Location | Lies deep under the scapula and the pectoral muscles |
Explore related products
What You'll Learn
The trapezius muscle
The trapezius is a superficial back muscle, meaning it is close to the skin, and is one of the broadest muscles of the upper back and trunk. It has many attachment points, extending from the skull and vertebral column to the shoulder girdle. The muscle is innervated by the spinal accessory nerve (CN XI) and the anterior rami of the C3 and C4 spinal nerves, which also provide sensory input to the muscle.
The trapezius is susceptible to injury, with overuse, nerve damage, and stress being common causes of trapezius muscle pain. Tearing or straining the trapezius is uncommon and usually occurs in bodybuilders lifting heavy weights or during high-velocity accidents such as car crashes.
Alcohol and Muscle Recovery: Friends or Foes?
You may want to see also
Explore related products
Rhomboid major and minor
The rhomboid major and minor are two functionally similar muscles that make up the rhomboid muscles. They are deep intrinsic shoulder muscles that form the shoulder girdle along with other muscles like the sternocleidomastoid, trapezius, pectoralis muscles, latissimus dorsi, and serratus anterior. The rhomboid minor is a cylindrical muscle that originates at the ligamentum nuchae and C7 and T1 vertebra, while the rhomboid major is a quadrangular muscle located inferior to the rhomboid minor. The rhomboid major is thin and flat and twice as wide as the thicker rhomboid minor, which lies superior to it.
The rhomboid muscles can have a significant impact on upper body posture and shoulder mechanics. They are responsible for scapular retraction and can help relieve pain associated with poor upper body posture. Additionally, they work together with the serratus anterior, trapezius, and sternocleidomastoid muscles to anchor the scapula and prevent winging.
The rhomboid major and minor muscles serve to adduct the scapula and extend the arm at the shoulder. They also assist in depressing the scapula and rotating the arm medially. The dorsal scapular nerve (DSN) controls the motor function of the rhomboid muscles, and they receive arterial blood from the dorsal scapular artery and the deep branch of the transverse cervical artery.
The rhomboid muscles are generally completely separate, but they can be fused in certain individuals. The rhomboid minor partially overlaps the superior portion of the rhomboid major. The exception is a small triangular region over the inferior border of the rhomboid major (triangle of auscultation), which is an important clinical landmark for lung auscultation from the back.
Golden Era Muscle: Legit or Not?
You may want to see also
Explore related products
Serratus anterior
The serratus anterior (SA) is a fan-shaped muscle that originates on the superolateral surfaces of the first to eighth or ninth ribs at the lateral wall of the thorax. It wraps around the ribcage, passing beneath the scapula to insert on the underside of the scapula on its medial border. The serratus anterior is divided into three parts:
- Upper/Superior: The first to second rib → superior angle of scapula.
- Middle/Intermedius: The second to third rib → medial border of scapula.
- Lower/Inferior: The fourth to ninth rib → medial border and inferior angle of scapula.
The serratus anterior is a key scapular stabiliser, keeping the shoulder blades against the ribcage at rest and during movement. It is also a prime mover in scapular protraction and scapular upward rotation, which is the pulling of the scapula forward and around the rib cage. This movement is particularly important in throwing a punch, leading to the serratus anterior being nicknamed the "boxer's muscle".
The serratus anterior acts in concert with the upper and lower fibres of the trapezius muscle to sustain upward rotation of the scapula, which allows for overhead lifting. It is also involved in respiration, assisting in lifting the ribs when the shoulder girdle is fixed.
The serratus anterior is vulnerable to injury during certain types of surgery, such as during lymph node clearance from the axilla for breast cancer. Damage to the long thoracic nerve that supplies the serratus anterior muscle is the most common cause of winged scapula.
Plankton's Muscular Mystery: Unveiling Their Unseen Strength
You may want to see also
Explore related products
Latissimus dorsi
The latissimus dorsi is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius. The name "latissimus dorsi" comes from Latin and means "broadest [muscle] of the back". The pair of muscles are often referred to as "lats", especially in bodybuilding contexts. The latissimus dorsi is the widest muscle in the human body. It is relatively thin and covers almost all back muscles at the posterior trunk, except the trapezius.
The latissimus dorsi is innervated by the sixth, seventh, and eighth cervical nerves through the thoracodorsal nerve. The thoracodorsal nerve, a branch of the posterior cord of the brachial plexus, provides innervation to the latissimus dorsi. The nerve travels in the neurovascular bundle with the thoracodorsal artery and its associated veins. The latissimus dorsi is supplied predominantly by the thoracodorsal artery, a continuation of the subscapular artery, which is a branch of the third part of the axillary artery.
The latissimus dorsi is responsible for extension, adduction, transverse extension, flexion from an extended position, and internal rotation of the shoulder joint. It also has a synergistic role in extension and lateral flexion of the lumbar spine. The latissimus dorsi assists in depression of the arm with the teres major and pectoralis major. It adducts, extends, and internally rotates the shoulder. When the arms are in a fixed overhead position, the latissimus dorsi pulls the trunk upward and forward.
The latissimus dorsi crosses the inferior angle of the scapula. A study found that, of 100 cadavers dissected, 43% had "a substantial amount" of fibres in the latissimus dorsi originating from the scapula. 36% had few or no muscular fibres, but a "soft fibrous link" between the scapula and the latissimus dorsi. 21% had little or no connecting tissue between the two structures.
What's the Vulva Made Of? Exploring Its Anatomy
You may want to see also
Explore related products
Levator scapulae
The levator scapulae is a posterior axio-appendicular muscle that connects the upper limb to the vertebral column. It is located in the posterior triangle of the neck, with its superior aspect covered by the sternocleidomastoid muscle and its inferior aspect by the trapezius muscle. The levator scapulae is innervated by the cervical nerve (C3-C4) and the dorsal scapular nerve (C5), and it receives its blood supply from the dorsal scapular artery.
The levator scapulae muscle originates on the posterior tubercle of the transverse process of cervical vertebrae 1 to 4. It then inserts onto the vertebral margin of the scapula, between the superior angle and the root of the spine. The fibres of the levator scapulae pass inferiorly from the transverse processes of the upper cervical vertebrae to the superomedial border of the scapula.
The primary function of the levator scapulae is to elevate the scapula and tilt the glenoid cavity inferiorly by rotating the scapula downward. When the scapula is fixed, contraction of the levator scapulae leads to lateral flexion of the cervical vertebral column to the same side. Additionally, it helps to stabilise the vertebral column during rotation. When the cervical spine is fixed, contraction of the levator scapulae elevates and rotates the scapula, with the lateral angle moving inferiorly.
The levator scapulae is frequently implicated in levator scapulae syndrome, which causes tenderness over the upper medial angle of the scapula. This condition often goes unrecognized, and movements that stretch the muscle can exacerbate symptoms. Treatment options include physical therapy and local corticosteroid injections.
The Intriguing History of Muscle Nomenclature
You may want to see also
Frequently asked questions
The trapezius, latissimus dorsi, serratus anterior, pectoralis major and minor muscles, and the force of gravity all work together to depress the scapula.
The scapula, also known as the shoulder blade, is a triangular bone that connects the clavicle to the humerus, forming the posterior of the shoulder girdle.
The trapezius muscle is a large, triangular, and thin muscle that covers the upper back and neck. It is responsible for stabilizing and moving the scapula, as well as assisting in posture by supporting the spinal column to remain erect.
Injuries to the scapula can include winging of the scapula, which is caused by injury to the long thoracic or spinal accessory nerves. Dysfunctional movements of the scapula can lead to dyskinesis and abnormal motion of the shoulder.
