Dominic Stone
The humerus is the upper arm bone, connecting the shoulder to the elbow. It is the longest bone in the upper extremity and is connected to 13 muscles that help the arm move. These muscles include the supraspinatus, infraspinatus, teres minor, subscapularis, deltoid, brachialis, triceps, and pronator teres. The humerus also supports tendons, ligaments, and parts of the circulatory system. The bone itself consists of a shaft (diaphysis) and two extremities (epiphysis). The proximal end of the humerus connects to the shoulder joint, while the distal end forms the elbow joint.
| Characteristics | Values |
|---|---|
| Description | The humerus is the upper arm bone, the longest bone in the upper extremity |
| Parts | Head, anatomical neck, surgical neck, tuberosities, body, shaft, distal and proximal ends |
| Muscles | Deltoid, supraspinatus, infraspinatus, teres minor, subscapularis, coracobrachialis, brachialis, brachioradialis, triceps, teres major, pronator teres, latissimus dorsi, pectoralis major, biceps brachii |
| Nerves | Axillary nerve, radial nerve, median nerve, ulnar nerve, musculocutaneous nerve, posterior cord of the brachial plexus |
| Arteries | Axillary artery, brachial artery, profunda brachii artery, posterior circumflex artery, circumflex humeral artery |
| Ligaments | Coracoacromial, acromioclavicular, transverse ligament, radial collateral ligament, ulnar collateral ligament |
| Joints | Glenohumeral joint, elbow joint |
| Functions | Movement and stability of the upper limb, transmission of forces from shoulder to forearm, support for soft tissues, facilitation of muscle functionality and forearm movements |
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What You'll Learn
- The humerus serves as an attachment for 13 muscles, including the supraspinatus, infraspinatus, and teres minor
- The lateral and medial borders of the distal humerus form the medial and lateral supraepicondylar ridges
- The radial groove is a shallow depression that runs diagonally down the posterior surface of the humerus
- The proximal end of the humerus has a rounded head that articulates with the glenoid fossa of the scapula to form the glenohumeral joint
- The humerus is the only bone in the upper arm, running from the shoulder to the elbow
The humerus serves as an attachment for 13 muscles, including the supraspinatus, infraspinatus, and teres minor
The humerus is a long bone that forms the upper arm. It is the longest bone in the upper extremity. The humerus consists of a shaft (diaphysis) and two extremities (epiphysis). It has a unique structure, including a head, anatomical neck, surgical neck, tuberosities, and body. The humerus serves as an attachment for 13 muscles, which are crucial for the overall movement and stability of the upper limb.
The greater tuberosity is a large, posteriorly placed projection located laterally on the humerus. It has anterior and posterior surfaces and serves as an attachment site for three rotator cuff muscles: the supraspinatus, infraspinatus, and teres minor. These muscles attach to the superior, middle, and inferior facets on the greater tuberosity, respectively. The supraspinatus muscle performs abduction of the arm and pulls the head of the humerus towards the glenoid cavity, preventing it from slipping inferiorly. It also works with the deltoid muscle to perform abduction and is one of the most frequently damaged components of the rotator cuff.
The lesser tuberosity is smaller and more medially located on the bone. It provides attachment for the subscapularis muscle, the last rotator cuff muscle. Separating the greater and lesser tuberosities is the intertubercular sulcus, a deep groove through which the tendon of the long head of the biceps brachii runs. The edges of this groove are called lips, and muscles such as the pectoralis major, teres major, and latissimus dorsi insert onto them.
The shaft of the humerus is also a site of attachment for various muscles. Anteriorly, muscles such as the coracobrachialis, deltoid, brachialis, and brachioradialis attach to the humerus shaft. Posteriorly, the medial and lateral heads of the triceps attach, with their origins demarcated by the spiral groove. The deltoid muscle attaches to a roughened surface on the lateral side of the humeral shaft, known as the deltoid tuberosity.
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The lateral and medial borders of the distal humerus form the medial and lateral supraepicondylar ridges
The humerus is the longest bone in the upper extremity, consisting of a shaft and two extremities. It is a cornerstone in the realm of physiotherapy, as understanding its intricacies is paramount for physiotherapists seeking to optimise patient care and rehabilitation. The lateral and medial borders of the distal humerus form the medial and lateral supraepicondylar ridges, which play a crucial role in the movement and stability of the upper limb.
The lateral supraepicondylar ridge is more roughened and serves as the common origin site for the forearm extensor muscles. The medial supraepicondylar ridge, on the other hand, is the more curved of the two ridges. These ridges are located at the distal ends of the humerus, with the lateral ridge extending to the lateral epicondyle and the medial ridge extending to the medial epicondyle.
Immediately distal to the supraepicondylar ridges are the lateral and medial epicondyles, which are extracapsular projections of bone. These epicondyles can be palpated at the elbow, with the medial epicondyle being larger and extending more distally. The ulnar nerve passes in a groove on the posterior aspect of the medial epicondyle, contributing to the sensory functions of the hand and fingers.
Distally, the trochlea is located medially on the distal humerus and extends onto the posterior aspect of the bone. It articulates with the ulna, enabling flexion and extension movements of the forearm. Lateral to the trochlea is the capitulum, which articulates with the radius. Additionally, three depressions are located on the distal portion of the humerus: the coronoid, radial, and olecranon fossae. These depressions accommodate the forearm bones during flexion or extension at the elbow, further enhancing the overall dexterity of the upper limb.
The humerus serves as an attachment site for 13 muscles, including the supraspinatus, infraspinatus, and teres minor. These muscles contribute to the coordinated actions and functionality of the upper limb, such as facilitating forearm movements through articulation with the radius and ulna at the elbow joint. The greater and lesser tuberosities of the humerus also play a significant role in muscle functionality, providing attachment sites for the rotator cuff muscles and tendons of other muscles like the teres major.
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The radial groove is a shallow depression that runs diagonally down the posterior surface of the humerus
The humerus is the longest bone in the upper extremity, consisting of a shaft and two extremities. It is a crucial component of the musculoskeletal system, facilitating the overall movement and stability of the upper limb. The radial groove, also known as the spiral groove, is a distinctive feature of the humerus bone. It is a shallow depression that runs diagonally down the posterior surface of the humerus, parallel to the deltoid tuberosity.
The radial groove is located on the lateral edge of the humerus bone, providing a pathway for the radial nerve. The radial nerve is relatively exposed in the radial groove, making it susceptible to injury in cases of trauma or fractures of the humerus. Fractures or dislocations of the humerus can lead to compression or damage to the radial nerve, resulting in symptoms such as weakness, loss of sensation, and pain in the arm and hand. This condition is known as radial nerve palsy, which can cause "'wrist drop'" due to paralysis of the wrist extensors.
The radial nerve is not alone in the radial groove; it shares this space with the profunda brachii artery, also known as the deep brachial artery. Together, they lie in the groove, nestled in the centre of the lateral border of the humerus bone. This artery is at risk during a mid-shaft fracture of the humerus, which can result in radial nerve palsy and "wrist drop."
The radial groove is an important landmark in human anatomy, serving as a reference point for identifying the location of the radial nerve during surgical procedures. Its position is described as beginning at the inferior edge of the deltoid tuberosity and extending downward toward the elbow. The deltoid tuberosity itself is a roughened surface on the lateral side of the humeral shaft where the deltoid muscle attaches. This muscle plays a role in the normal rounded shape of the shoulder.
In summary, the radial groove is a shallow depression that diagonally traverses the posterior surface of the humerus. It houses the radial nerve and the profunda brachii artery, contributing to the overall functionality and anatomical landmarks of the upper limb. Its presence underscores the intricate design of the musculoskeletal system and highlights the importance of understanding humeral anatomy for physiotherapists and medical professionals alike.
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The proximal end of the humerus has a rounded head that articulates with the glenoid fossa of the scapula to form the glenohumeral joint
The humerus is a long bone that forms the upper arm. It is the longest bone in the upper extremity. The proximal end of the humerus has a rounded head that faces medially, upwards, and backwards. This head articulates with the glenoid fossa of the scapula to form the glenohumeral joint, also known as the shoulder joint. The glenoid cavity is a shallow osseous structure deepened by a fibrocartilaginous rim called the glenoid labrum. The labrum is continuous with the tendon of the long head of the biceps brachii. The glenohumeral joint is a ball-and-socket joint that allows for a wide range of movements.
The humerus serves as an attachment point for several muscles, including the supraspinatus, infraspinatus, and teres minor. These muscles attach to the greater tuberosity, which is located laterally on the humerus. The greater tuberosity has anterior and posterior surfaces. The lesser tuberosity, which is smaller and more medially located, provides attachment for the subscapularis muscle. The two tuberosities are separated by a deep groove called the intertubercular sulcus, through which the tendon of the long head of the biceps brachii passes.
The humerus plays a crucial role in transmitting forces generated by the muscles to the shoulder and forearm. It also provides support for various soft tissues, including tendons and ligaments, contributing to the stability of the shoulder joint. The anatomical neck, surgical neck, and tuberosities of the humerus provide this support. The surgical neck is a common site of fracture, usually caused by a direct blow or a fall on an outstretched hand.
The shaft of the humerus is circular proximally and flattened distally. It serves as the attachment site for various muscles, including the deltoid, coracobrachialis, brachialis, and brachioradialis anteriorly, and the medial and lateral heads of the triceps posteriorly. The radial nerve and profunda brachii artery lie in a shallow depression called the radial groove, which runs diagonally down the posterior surface of the humerus.
The distal end of the humerus articulates with the radius and ulna to form the elbow joint. The capitulum of the humerus articulates with the head of the radius, while the trochlea of the humerus articulates with the trochlear notch of the ulna. The lower extremity of the humerus consists of two epicondyles, two processes (trochlea and capitulum), and three fossae (radial fossa, coronoid fossa, and olecranon fossa).
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The humerus is the only bone in the upper arm, running from the shoulder to the elbow
The humerus is the only long bone in the upper arm, running from the shoulder to the elbow. It is a crucial component of the musculoskeletal system, facilitating movement and stability in the upper limb. The humerus provides structural support and serves as an attachment site for numerous muscles, tendons, and ligaments, which are essential for the intricate dance of the upper limb's movements.
The bone consists of a shaft (diaphysis) and two extremities (epiphysis). The proximal humerus, closest to the shoulder joint, is prone to fracture due to its proximity to the shoulder. The distal humerus, on the other hand, articulates at the elbow, connecting with the radius and ulna in the forearm. This articulation enables flexion and extension movements of the forearm, contributing to the overall dexterity of the upper limb.
The humerus has a unique structure, including a head, anatomical neck, surgical neck, tuberosities, and body. The greater tuberosity, located laterally, serves as an attachment site for three rotator cuff muscles: supraspinatus, infraspinatus, and teres minor. The lesser tuberosity, smaller and more medially located, provides an attachment site for the subscapularis muscle. The anatomical neck, surgical neck, and tuberosities provide support for soft tissues, including tendons and ligaments, ensuring the stability of the shoulder joint.
The humerus also facilitates muscle functionality. The greater and lesser tuberosities, for example, enable the functionality of muscles like the supraspinatus, infraspinatus, and teres minor. Additionally, the humerus plays a role in transmitting forces generated by the muscles. Acting as a bridge between the shoulder and the forearm, it helps transmit these forces, contributing to the overall movement and stability of the upper limb.
The humerus serves as an attachment site for several muscles that provide motion for the arm and upper body. These include the deltoids, brachioradialis, coracobrachialis, pronator teres, teres major, brachialis, and common flexor and extensor tendons. The rotator cuff muscles at the shoulder also connect to the humerus, stabilising the highly movable but unstable glenohumeral joint.
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Frequently asked questions
The humerus is the upper arm bone. It is the only bone in the upper arm and is the longest bone in the upper extremity.
The humerus serves as an attachment for 13 muscles, including the supraspinatus, infraspinatus, teres minor, and subscapularis.
The humerus plays a crucial role in the overall movement and stability of the upper limb. It helps transmit forces generated by the muscles and facilitates forearm movements.
The most common issues affecting the humerus include fractures, osteoporosis, and damage to nerves or muscles attached to it. Fractures can occur due to trauma, falls, or sports injuries.
Treatment options for a fractured humerus may include surgery to repair the bone and physical therapy to regain strength and movement in the arm.
