Dominic Stone
The humerus is the upper arm bone that runs from the shoulder to the elbow. It is the only bone in the upper arm and is the longest bone in the body besides the bones in the legs. The humerus is connected to 13 muscles, including the supraspinatus, infraspinatus, and teres minor, which facilitate the coordinated actions of the upper limb. These muscles help to elevate the humerus and perform other functions such as flexion, extension, and rotation of the arm. When the humerus is injured, the muscles and nerves attached to it are also often affected.
| Characteristics | Values |
|---|---|
| Muscle attachments | Supraspinatus, infraspinatus, teres minor, subscapularis, deltoid, coracobrachialis, brachialis, brachioradialis, triceps brachii, anconeus, latissimus dorsi, teres major, and pectoralis major |
| Function | The humerus is the upper arm bone and helps the arm move, flex, and rotate. It also stabilizes the rest of the arm, including the elbow and hand. |
| Length | The humerus is the longest bone in the upper extremity |
| Sections | The humerus consists of three sections: the upper extremity, the body, and the lower extremity |
| Upper extremity | Consists of a rounded head, a narrow neck, and two short processes (tubercles, sometimes called tuberosities) |
| Lower extremity | Consists of two epicondyles, two processes (trochlea and capitulum), and three fossae (radial fossa, coronoid fossa, and olecranon fossa) |
| Fractures | Common issues include fractures, osteoporosis, and damage to nerves or muscles. Fractures can occur during trauma, such as a fall or car accident, or while playing sports. |
| Nerve damage | Axillary nerve damage can result in paralysis of the deltoid and teres minor muscles. Radial nerve damage can lead to wrist drop and sensory loss in parts of the hand and fingers. |
Explore related products
What You'll Learn
The supraspinatus, infraspinatus, and teres minor muscles
These muscles are crucial for shoulder joint stability and upper limb movement. Damage to these muscles or the humerus bone can result in reduced mobility and function of the arm. The humerus serves as an attachment point for 13 muscles, including the supraspinatus, infraspinatus, and teres minor, which contribute to the coordinated actions of the upper limb.
Muscle Milk EBT Eligibility: What You Need to Know
You may want to see also
Explore related products
The subscapularis muscle
The primary function of the subscapularis muscle is the internal rotation of the humerus, which is the upper arm bone. It assists in shoulder adduction and extension in certain positions. The arm's position significantly impacts the actions caused by this muscle. When the arm is raised, the subscapularis pulls the humerus forward and downward. When the humerus is in a fixed position, the insertion of the subscapularis can act as an origin, producing abduction of the inferior border of the scapula.
Muscle Proteins: Building Blocks of Strength
You may want to see also
Explore related products
The deltoid muscle
Deltoid muscles help you move your arms in different directions, and they also protect and stabilise your shoulder joint. They cover the front, side, and back of the joint. Conditions that may affect the deltoid muscles include adhesive capsulitis (when the capsule around the shoulder joint gets thick and stiff, causing shoulder pain, muscle spasms, and stiffness), axillary nerve palsy (compression or damage to the nerve can happen during surgery or due to a traumatic injury), bursitis (inflammation of the bursa, tiny, fluid-filled sacs in the shoulders, which can make it hard to move the shoulder joint), and deltoid fibrosis (repeated shoulder muscle injections can lead to fibrosis, causing the muscle to stop repairing itself, resulting in pain or loss of muscle strength and mobility).
The humerus is the only bone in your upper arm, running from your shoulder to your elbow. It is the longest bone in your body other than the bones in your legs. The humerus serves as an attachment to 13 muscles, including the deltoid, which contribute to the movements of the hand and elbow, and therefore the function of the upper limb.
Understanding Cold Muscles: What, Why, and How?
You may want to see also
Explore related products
The coracobrachialis, brachialis, and brachioradialis muscles
The humerus is the upper arm bone, which runs from the shoulder to the elbow. It is the only bone in the upper arm and is the longest bone in the body outside of the legs. The humerus serves as an attachment point for 13 muscles, which help the arm move, flex, and rotate.
The coracobrachialis muscle is located in the upper medial part of the arm, within the anterior compartment of the arm. It originates from the coracoid process of the scapula and inserts onto the middle of the medial aspect of the body of the humerus. The muscle is innervated by the musculocutaneous nerve (C5-C7), a branch of the lateral cord of the brachial plexus. Its main function is to produce flexion and adduction of the arm at the shoulder joint. The muscle fibres run inferolaterally towards the humerus, inserting onto the anteromedial surface of the humeral shaft, between the brachialis muscle and the medial head of triceps. The coracobrachialis muscle lies posterior to the pectoralis major muscle and anterior to the tendons of subscapularis, latissimus dorsi, teres major, and the medial head of triceps.
The brachialis muscle, along with the biceps brachii muscle, is one of the flexors of the arm. It is located lateral to the coracobrachialis muscle. The brachialis muscle is also innervated by the musculocutaneous nerve.
The brachioradialis muscle is a forearm muscle that attaches to the lateral side of the radius, a bone in the forearm, and runs up to the lateral side of the humerus. It is one of the muscles responsible for forearm movements, such as flexion and extension at the elbow, contributing to the overall dexterity of the upper limb.
Foot Inversion: Muscles That Control This Movement
You may want to see also
Explore related products
The triceps brachii and anconeus muscles
The triceps brachii is a three-headed muscle found in the posterior compartment of the arm. It is the only constituent of the posterior muscle group of the arm, spanning almost the entire length of the humerus. The triceps brachii consists of a long, medial, and lateral head, that originate from their respective attachments on the humerus and scapula. The long head arises from the infraglenoid tubercle of the scapula, which is a rough area at the inferior margin of the glenoid fossa. Its attachment extends slightly above to the adjacent glenoid labrum and blends with the glenohumeral capsule of the shoulder joint, contributing to its stability. The lateral head originates from a narrow, linear ridge on the posterior surface of the humerus, just superior to the radial groove.
The triceps brachii is responsible for the extension of the forearm at the elbow joint. Additionally, its long head contributes to the extension and adduction of the arm at the shoulder joint. The triceps brachii also plays a role in creating anatomical spaces that are traversed by neurovascular structures, making it an important surgical landmark. The triceps muscle can be trained in a variety of ways, including isolation and compound elbow extension movements, as well as static contraction to keep the arm straight against resistance.
The anconeus is a small muscle located at the elbow, attaching the humerus and ulna. It is considered a continuation of the triceps brachii, as they share the same nerve innervation and are often partially or completely blended together. The anconeus permits extension of the forearm and provides support for the dorsal joint capsule and the ulna. It is believed that the anconeus also helps stabilize the ulna during pronation movements of the forearm. The anconeus muscle is supplied by the posterior interosseous recurrent artery and a motor branch of the radial nerve.
Engaging Core Muscles: How to Stand with Strength
You may want to see also
Frequently asked questions
The humerus is the upper arm bone that runs from your shoulder to your elbow.
The humerus serves as an attachment to 13 muscles.
The names of the muscles connected to the humerus include the supraspinatus, infraspinatus, teres minor, subscapularis, deltoid, coracobrachialis, brachialis, and brachioradialis.
The muscles connected to the humerus contribute to the movement and stability of the upper limb, including the hand, elbow, forearm, and shoulder.
Injury to the humerus and its associated muscles and nerves is common in sports, falls, and car accidents. Damage to these muscles can result in reduced mobility, pain, and potential long-term complications.
