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The armpit, or axilla, is a complex anatomical region under the shoulder joint where the arm connects to the torso. The axilla is a cone-shaped area bordered by four walls formed of bones, muscles, and fascia. The axilla includes the axillary space, an anatomical space within the shoulder girdle between the arm and the thoracic cage. The axilla contains a variety of neurovascular structures, including the axillary artery, axillary vein, brachial plexus, and lymph nodes. The axilla is also associated with various muscles, such as the subscapularis, latissimus dorsi, and pectoralis major, which can be strained or injured, causing armpit pain.
| Characteristics | Values |
|---|---|
| Area | Under the shoulder joint |
| Shape | Cone-shaped or pyramid-shaped |
| Borders | Muscles, bones, fascia |
| Walls | Serratus anterior muscle, first four ribs, humerus, coracobrachialis, short head of the biceps, pectoralis major and minor muscles, clavicle, scapula, teres major, subscapularis, latissimus dorsi muscles |
| Vessels and Nerves | Axillary artery, axillary vein, brachial plexus, axillary lymph vessels and nodes, subscapular artery, anterior and posterior humeral circumflex arteries, suprascapular artery, musculocutaneous nerve |
| Functions | Serves as a space for neurovascular and lymphatic structures to travel through to the upper extremity from the neck, supplies muscles of the shoulder girdle and chest, provides sensation to certain areas of the upper extremity |
| Clinical Significance | Axillary intertrigo, swollen lymph nodes, armpit pain, tenderness, weight training, myofascial release treatment, lymphatic vessels for breast cancer, brachial plexus injury, thoracic outlet syndrome |
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What You'll Learn
- The subscapularis muscle is one of the four rotator cuff muscles of the shoulder
- The axilla is an anatomical region under the shoulder joint
- The axilla contains the axillary artery, axillary vein, brachial plexus, and lymph nodes
- The axilla is a complex area of the body, bordered by four walls formed of bones, muscles, and fascia
- Armpit pain can be caused by muscle strain, or by swollen lymph nodes
The subscapularis muscle is one of the four rotator cuff muscles of the shoulder
The armpit, or axilla, is an area of great complexity and clinical significance. It includes several muscles, including the subscapularis muscle, which is one of the four rotator cuff muscles of the shoulder. The rotator cuff is a group of muscles and tendons that surround the shoulder joint and hold the bones together. These four muscles arise from the scapula and insert into the humerus, forming a cuff around the glenohumeral joint. The subscapularis muscle specifically attaches to the middle of the scapula and stretches to the lower part of the humeral head, allowing you to hold your arm outstretched, away from your body.
The primary biomechanical role of the rotator cuff is to stabilise the glenohumeral joint by compressing the humeral head against the glenoid. The rotator cuff muscles also help in the mobility of the shoulder joint by facilitating abduction, medial rotation, and lateral rotation. The rotator cuff provides strength and stability during motion to the shoulder complex, and balanced strength and flexibility in each of the four muscles are vital to maintain the functioning of the entire shoulder girdle.
The rotator cuff tendons blend with the joint capsule and form a musculotendinous collar that surrounds the posterior, superior, and anterior aspects of the joint, leaving the inferior aspect unprotected. This arrangement is important as most shoulder luxations occur when the humerus slides inferiorly through the unprotected part of the joint. During arm movements, the rotator muscles contract and prevent the sliding of the head of the humerus, allowing a full range of motion and providing stability.
Rotator cuff injuries are common, especially among athletes who play contact sports or engage in repetitive overhead activities. These injuries can cause shoulder pain, impaired functional capacities, and a reduced quality of life. Chronic computer use or being placed in a sling for an extended period can also cause the subscapularis muscle to shorten, leading to issues with the external rotation of the humerus and potentially resulting in bursitis, tendonitis, or rotator cuff tears.
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The axilla is an anatomical region under the shoulder joint
The axilla, or armpit, is an anatomical region under the shoulder joint where the arm connects to the shoulder. It is a complex and clinically significant area, housing important structures such as nerves, blood vessels, and lymph nodes. The axilla is bordered by four walls formed of bones, muscles, and fascia at the junction between the arm and torso. It extends from the base of the neck to the rib cage, the top of the arm, and down to the skin of the armpit.
The axilla has five anatomic borders: the superior, anterior, posterior, lateral, and medial walls. The superior wall is formed by the clavicle, scapula, and first rib. The anterior wall is made up of the pectoralis major and minor muscles, while the subclavius muscle lies underneath. The medial wall is the serratus anterior and the first four ribs. The lateral wall is formed by the humerus, coracobrachialis, and the short head of the biceps. The posterior wall is composed of the teres major, subscapularis, and latissimus dorsi muscles.
The axilla serves as a passageway for neurovascular and muscular structures to enter and leave the upper limb. It contains the axillary artery, the main artery supplying the upper limb, and its branches. The axillary vein, the main vein draining the upper limb, and its tributaries, such as the cephalic and basilic veins, are also found in the axilla. Additionally, the axilla includes the brachial plexus, a network of nerves, and lymph nodes, which play a crucial role in the immune system.
The axilla is of significant clinical interest. For example, in the case of breast cancer, axillary lymph node removal, known as axillary clearance, may be necessary to prevent cancer spread. However, this procedure carries a risk of damaging the long thoracic nerve, which can result in winged scapula. Furthermore, understanding the anatomy of the axilla is essential for surgeons to prevent iatrogenic injuries during surgical procedures in this region, such as axillary lymph node biopsies.
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The axilla contains the axillary artery, axillary vein, brachial plexus, and lymph nodes
The axilla, or armpit, is a complex anatomical region under the shoulder joint where the arm connects to the shoulder. It is a cone-shaped area bordered by four walls formed of bones, muscles, and fascia at the junction between the arm and torso. The axilla contains the axillary artery, a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla (armpit), and the upper limb. The axillary artery is accompanied by the axillary vein, which lies medial to the artery along its length.
The axilla also contains the brachial plexus, a network of nerves originating from the C5-T1 spinal roots. The brachial plexus is the principal nervous structure in the axillary area and extends from the neck into the axilla. The axilla is an important region for the emission of body odour and contains many hair and sweat glands. It also houses other important structures such as nerves, blood vessels, and lymph nodes.
The axillary lymph nodes are oval or bean-shaped bodies located along the lymphatic system. They play a crucial role in the diagnosis and treatment of breast cancer, as cancer often spreads to these nodes via lymphatic vessels. Axillary lymph node biopsies are important in the detection and management of breast cancer. The axilla also includes the serratus anterior muscle, the teres major muscle, the subscapularis muscle, and the latissimus dorsi muscle. These muscles form the posterior wall of the axilla.
The axilla is a clinically significant area of the body, with its complex anatomy of nerves, blood vessels, and lymph nodes. It serves as a landmark for surgeons during operations to prevent damage to the neurovascular structures within the axilla. Understanding the anatomy of the axilla is crucial in ensuring safe surgical procedures and providing effective treatment for various conditions affecting this region.
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The axilla is a complex area of the body, bordered by four walls formed of bones, muscles, and fascia
The axilla, or armpit, is an area of great complexity and clinical significance. It is a cone-shaped region located between the shoulder girdle and thorax, serving as a space for neurovascular and lymphatic structures to travel through to the upper extremity from the neck. The axilla is bordered by four walls formed of bones, muscles, and fascia at the junction between the arm and torso. It houses important structures such as nerves, blood vessels, and lymph nodes.
The four walls of the axilla are composed of different muscles and bones. The medial wall, also known as the serratus anterior, is formed by the serratus anterior muscle and the first four ribs. This muscle has a function in the anteversion and protraction of the scapula. The lateral wall is made up of the coracobrachialis and the short head of the biceps muscles. These muscles play a role in the flexion and adduction of the elbow joint, as well as flexion and supination of the elbow joint. The anterior wall, or the front of the axilla, is formed by the pectoralis major and minor muscles, which receive innervation from the medial and lateral pectoral nerves.
The posterior wall of the axilla is composed of the teres major, subscapularis, and latissimus dorsi muscles. The subscapularis is one of the four rotator cuff muscles of the shoulder and can be felt by reaching into the opposite armpit and pushing on the front of the scapula. The latissimus dorsi muscle, located on the back or side, attaches to the humerus and assists in moving the shoulder and arm during reaching or pulling movements. It is also connected to the ribs and plays a role in breathing.
The axilla contains a variety of neurovascular structures, including the axillary artery, axillary vein, brachial plexus, and lymph nodes. The axillary artery is the primary blood supply to the axilla and is a major blood supplier to the shoulder and upper arm. The axillary vein, located medial to the axillary artery, receives deoxygenated blood from the cephalic vein, basilic vein, and other tributaries. The brachial plexus is the principal nervous structure in the axillary area, innervating the muscles around the axilla, shoulder, and upper limbs. The axilla also contains more than 20 lymph nodes, which are part of the body's lymphatic system and help fight infections.
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Armpit pain can be caused by muscle strain, or by swollen lymph nodes
The armpit, or axilla, is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm and the thoracic cage. The armpit is home to several muscles, nerves, blood vessels, and lymph nodes.
Armpit pain can be caused by muscle strain, often due to physical stress or overuse of the muscles. This can occur through sports and activities involving lifting, pulling, or throwing, or by overdoing things like lifting something heavy or with repeated movements. Treatment for muscle strain includes resting the muscles, applying ice to the area, and taking over-the-counter pain medications.
Armpit pain can also be caused by swollen lymph nodes, which are small lumps of tissue that are part of the body's lymphatic system and help fight infection. Lymph nodes can become swollen when the body is fighting an illness or infection, and they can be painful and tender to the touch. Many viruses and bacteria can cause swollen lymph nodes, including infectious mononucleosis (mono), influenza, and bacterial infections such as cellulitis. Swollen lymph nodes can also be caused by autoimmune conditions such as rheumatoid arthritis and lupus, or, in some cases, cancer. Treatment for swollen lymph nodes includes applying warm compresses to the area and taking over-the-counter pain medications. If swelling lasts for more than a few weeks, it is recommended to consult a doctor.
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Frequently asked questions
The armpit, or axilla, is an area of great complexity and clinical significance. The axilla is a cone-shaped area bordered by four walls formed of bones, muscles, and fascia at the junction between your arm and torso. The axilla includes the axillary space, an anatomical space within the shoulder girdle between the arm and the thoracic cage. The walls of the axilla include the serratus anterior muscle, the teres major, subscapularis, latissimus dorsi muscle, and the pectoralis major and minor muscles.
The axilla includes the short head of the biceps brachii muscle, coracobrachialis muscle, and fascia and adipose tissue. The subscapularis is one of the four rotator cuff muscles of your shoulder and is considered an armpit muscle.
The latissimus dorsi muscle, which is located in the armpit, helps move your shoulder and arm, particularly when reaching or pulling up. The subscapularis is necessary to get your arm completely overhead without pinching your other rotator cuff tendons in the shoulder joint.
Tightness in the armpit muscles can be caused by activities such as weight training or ballroom dancing. To loosen these areas, you can try using balls on your chest and the chest doorway stretch. Myofascial release treatment in and around the armpit area can also help to reduce symptoms of tightness.
