Upper Limb Anatomy

Name structure #1

Answer explanation

The acromial end of the left clavicle has the following key anatomical features:

• Location: It is located at the lateral end of the clavicle, where it articulates with the acromion process of the scapula.

• Articulations: The acromial end forms the acromioclavicular joint (AC joint) with the acromion of the scapula, providing stability and allowing movement of the shoulder complex.

• Arteries: Blood supply typically comes from branches of the subclavian artery, ensuring adequate circulation for bone health.

• Nerves: Innervation involves branches from the supraclavicular nerves, which provide sensory information to the skin overlying the clavicle.

• Muscle Attachments: Muscles attaching to the clavicle include the deltoid and trapezius muscles, which play significant roles in shoulder movement and stability.

• Function: The acromial end of the clavicle acts as a strut, supporting the shoulder and arm movements while also transmitting forces from the upper limb to the axial skeleton.

• Common Issues: Issues with the AC joint, such as sprains or separations, can cause pain, limited shoulder mobility, and tenderness over the acromial end of the clavicle. Fractures of the clavicle near the acromial end are common, often due to direct trauma or falls onto the shoulder.

Understanding the anatomy of the acromial end of the clavicle is crucial for diagnosing and treating shoulder injuries and conditions affecting this area.

Name structure #2

Answer explanation

The sternal end of the clavicle has the following key anatomical features:

• Location: It is located medially and articulates with the manubrium of the sternum at the sternoclavicular joint (SC joint).

• Articulations: The sternal end forms the sternoclavicular joint (SC joint) with the manubrium of the sternum, providing stability and allowing movement of the shoulder complex.

• Arteries: Blood supply typically comes from branches of the subclavian artery, ensuring adequate circulation for bone health.

• Nerves: Innervation involves branches from the supraclavicular nerves, which provide sensory information to the skin overlying the clavicle.

• Muscle Attachments: Muscles attaching to the clavicle include the sternocleidomastoid and subclavius muscles, which help stabilize the clavicle during shoulder movements.

• Function: The sternal end of the clavicle serves as an anchor point for various muscles and ligaments involved in shoulder movement and stability.

• Common Issues: Issues with the SC joint, such as dislocations or arthritis, can cause pain, swelling, and limited shoulder mobility. Fractures of the clavicle near the sternal end are also common, often due to direct trauma or falls.

Understanding the anatomy of the sternal end of the clavicle is essential for diagnosing and treating shoulder injuries and conditions affecting this area.

Name structure #1

Answer explanation

The superior angle of the scapula has the following key anatomical features:

• Location: It is located at the superior-most point of the scapula, where the medial (vertebral) border and superior border meet.

• Muscle Attachments: Muscles attaching to the superior angle include the levator scapulae and the rhomboid muscles (both major and minor). These muscles play a crucial role in stabilizing and moving the scapula.

• Arteries: Blood supply to the scapula comes primarily from branches of the subscapular artery, ensuring adequate circulation for bone health and muscle function.

• Nerves: Innervation involves branches from the dorsal scapular nerve (C5), which innervates the rhomboid muscles, providing motor control.

• Function: The superior angle contributes to the formation of the superior border of the scapula, providing attachment points for muscles involved in scapular movement and shoulder stability.

• Common Issues: Issues with the superior angle of the scapula can include strains or injuries to the muscles attaching to it, such as levator scapulae or rhomboids, resulting in pain or limited range of motion. Fractures of the scapula near the superior angle can occur due to trauma, leading to pain and difficulty moving the shoulder.

Understanding the anatomy of the superior angle of the scapula is important for diagnosing and treating shoulder and scapular-related injuries effectively.

Name structure #1

Answer explanation

The superior angle of the scapula has the following key anatomical features:

• Location: It is located at the superior-most point of the scapula, where the medial (vertebral) border and superior border meet.

• Muscle Attachments: Muscles attaching to the superior angle include the levator scapulae and the rhomboid muscles (both major and minor). These muscles play a crucial role in stabilizing and moving the scapula.

• Arteries: Blood supply to the scapula comes primarily from branches of the subscapular artery, ensuring adequate circulation for bone health and muscle function.

• Nerves: Innervation involves branches from the dorsal scapular nerve (C5), which innervates the rhomboid muscles, providing motor control.

• Function: The superior angle contributes to the formation of the superior border of the scapula, providing attachment points for muscles involved in scapular movement and shoulder stability.

• Common Issues: Issues with the superior angle of the scapula can include strains or injuries to the muscles attaching to it, such as levator scapulae or rhomboids, resulting in pain or limited range of motion. Fractures of the scapula near the superior angle can occur due to trauma, leading to pain and difficulty moving the shoulder.

Understanding the anatomy of the superior angle of the scapula is important for diagnosing and treating shoulder and scapular-related injuries effectively.

Name structure #2

Answer explanation

Key Anatomical Features:

1. Location: The superior border of the scapula is the upper edge of the scapula, extending from the superior angle to the base of the coracoid process.

2. Muscles that Attach:

   • Trapezius muscle: Attaches along the entire length of the superior border, playing a significant role in shoulder movement and stabilization.

   • Levator scapulae muscle: Attaches near the superior angle and helps elevate the scapula.

3. Key Nerves and Arteries:

   • Suprascapular nerve: Runs along the superior border of the scapula, providing motor innervation to the supraspinatus and infraspinatus muscles.

   • Suprascapular artery: Supplies blood to the muscles around the scapula, including those attaching to the superior border.

4. Function: The superior border provides attachment for muscles that assist in scapular movement, particularly elevation, retraction, and stabilization of the shoulder.

5. Distinguishing Symptoms When There's an Issue:

   • Pain or tenderness along the superior border: Could indicate muscle strain, overuse, or nerve impingement.

   • Limited range of motion: Difficulty in raising or rotating the arm due to muscular or nerve-related issues.

   • Muscle weakness: Weakness in shoulder movements, especially elevating or retracting the scapula.

Understanding the anatomy of the superior border of the scapula is crucial for diagnosing and treating shoulder and upper back issues effectively, particularly in cases involving muscle strain, nerve compression, or functional limitations.

Name structure #3

Answer explanation

The acromion is a prominent anatomical feature of the scapula (shoulder blade) with several key associations:

Key Anatomical Features:

1. Location: It forms the highest point of the shoulder and articulates with the clavicle (collarbone) to form the acromioclavicular joint.

2. Muscles that Attach:

   • Deltoid muscle: Attaches to the lateral aspect of the acromion and plays a major role in shoulder abduction.

   • Trapezius muscle: Attaches to the posterior aspect of the acromion and assists in shoulder movement and stabilization.

   • Supraspinatus muscle: Originates from the supraspinous fossa just below the acromion, contributing to shoulder abduction.

3. Key Nerves and Arteries:

   • Suprascapular nerve: Passes underneath the acromion, providing motor innervation to the supraspinatus and infraspinatus muscles.

   • Acromial branch of the thoracoacromial artery: Supplies blood to the acromion and nearby structures.

4. Function: The acromion serves as a point of attachment for muscles involved in shoulder movement and stabilization. It also helps protect the underlying structures of the shoulder joint.

5. Distinguishing Symptoms When There's an Issue:

   • Shoulder impingement syndrome: Pain or discomfort during overhead activities due to compression of tendons (especially the supraspinatus) and bursa under the acromion.

   • Fracture or injury: Pain, swelling, and limited range of motion following trauma to the acromion.

   • Degenerative changes: Bony spurs or osteoarthritis at the acromioclavicular joint can cause pain and reduced mobility.

Understanding the anatomy and function of the acromion is essential for diagnosing and managing conditions affecting the shoulder, including injuries, impingement syndromes, and degenerative changes.

Name structure #4

Answer explanation

The coracoid process is a projection of bone on the scapula (shoulder blade), and here are its key anatomical features:

Key Anatomical Features:

1. Location: It is situated on the anterior (front) aspect of the scapula, projecting anteriorly and slightly inferiorly from the superior border of the scapula.

2. Muscles that Attach:

   • Coracobrachialis muscle: Originates from the coracoid process and assists in flexing and adducting the arm.

   • Short head of the biceps brachii muscle: Also originates from the coracoid process and aids in flexing the arm at the shoulder joint.

   • Pectoralis minor muscle: Attaches to the coracoid process and helps in stabilizing the scapula and in deep inspiration.

3. Key Nerves and Arteries:

   • Musculocutaneous nerve: Provides motor innervation to the coracobrachialis muscle, which originates from the coracoid process.

   • Coracoid branch of the thoracoacromial artery: Supplies blood to the coracoid process and nearby structures.

4. Function: The coracoid process serves as a point of attachment for several muscles involved in shoulder movement and stabilization. It helps stabilize the shoulder joint by providing attachment for muscles that move and support the upper limb.

5. Distinguishing Symptoms When There's an Issue:

   • Fracture: Pain, swelling, and limited shoulder movement following trauma to the coracoid process.

   • Muscular or tendon injury: Pain and weakness in arm movements associated with muscles originating from the coracoid process.

   • Shoulder instability: Instability or decreased shoulder function due to disruption of muscular attachments to the coracoid process.

Understanding the anatomy and function of the coracoid process is crucial for diagnosing and treating shoulder injuries, particularly those involving muscle attachments and stability issues.

Name structure #5

Answer explanation

The glenoid fossa, also known as the glenoid cavity or glenoid, is a shallow, concave depression on the lateral angle of the scapula that articulates with the head of the humerus to form the glenohumeral (shoulder) joint. Here are its key anatomical features:

Key Anatomical Features:

1. Location: It is located on the lateral aspect of the scapula, specifically on the lateral angle called the glenoid cavity.

2. Structure: The glenoid fossa is relatively shallow and oval-shaped, covered with articular cartilage that helps reduce friction and absorb shock during shoulder movements.

3. Articulation: It articulates with the head of the humerus to form the glenohumeral joint, which is a highly mobile ball-and-socket joint allowing a wide range of motion.

4. Muscles that Attach:

   • Rotator cuff muscles (Supraspinatus, Infraspinatus, Teres Minor, Subscapularis): These muscles stabilize the shoulder joint and provide rotational movement of the arm. They attach around the glenoid fossa and the head of the humerus.

5. Key Nerves and Arteries:

   • Axillary nerve: Innervates the deltoid and teres minor muscles, which attach near the glenoid fossa.

   • Circumflex scapular artery: Supplies blood to the muscles surrounding the scapula, including those attaching to the glenoid fossa.

6. Function: The glenoid fossa provides a stable yet mobile articulation for the head of the humerus, facilitating arm movements in multiple planes (flexion, extension, abduction, adduction, and rotation).

7. Distinguishing Symptoms When There's an Issue:

   • Glenoid labrum tear: Pain, clicking or catching sensation, and instability in the shoulder joint.

   • Shoulder dislocation: Severe pain and loss of shoulder function following trauma, often due to the humeral head slipping out of the glenoid fossa.

   • Osteoarthritis: Gradual onset of pain, stiffness, and decreased range of motion due to degenerative changes in the glenohumeral joint.

Understanding the anatomy and function of the glenoid fossa is essential for diagnosing and treating shoulder injuries, instability, and degenerative conditions affecting the shoulder joint.

Name structure #9

Answer explanation

The inferior angle of the scapula is the lowest part of the scapula, located at the medial (inner) border where the medial and lateral borders meet. Here are the key anatomical features associated with it:

Key Anatomical Features:

• Location: It is situated at the bottom-most point of the scapula, forming the medial border of the scapula.

• Muscles: Several important muscles attach near the inferior angle, including the teres major muscle and the latissimus dorsi muscle. The teres major attaches to the inferior angle itself, while the latissimus dorsi attaches along the medial border of the scapula, extending toward the inferior angle.

• Function: The inferior angle, along with its associated muscles, plays a role in shoulder movement and stability. It helps in pulling the scapula downward and rotating it medially.

• Nerves: The teres major muscle is innervated by the lower subscapular nerve, a branch of the brachial plexus (C5-C6).

Distinguishing Symptoms When There's an Issue:

• Pain or tenderness at the inferior angle of the scapula, often aggravated by movement.

• Limited range of motion in the shoulder joint, especially during activities that involve pulling or reaching overhead.

• Weakness in shoulder movements, particularly those involving pulling or downward movements.

Issues:

• Strains or tears of the teres major or latissimus dorsi muscles can occur due to overuse or trauma, leading to pain and reduced function.

• Inflammation or tendinopathy of the muscles attaching near the inferior angle can cause localized pain and discomfort.

Understanding the anatomy and function of the inferior angle of the scapula and its associated muscles is essential for diagnosing and managing shoulder-related conditions effectively.

Name structure #6

Answer explanation

The subscapular fossa is a concave depression on the anterior surface of the scapula. Here are the key anatomical features associated with it:

Key Anatomical Features:

• Location: It is located on the anterior (front) surface of the scapula, specifically on its costal (rib-cage) aspect.

• Muscles: The subscapular fossa provides attachment for the subscapularis muscle, which covers most of the fossa.

• Function: The subscapular fossa, along with the subscapularis muscle, helps in the internal rotation of the shoulder joint.

• Nerves: The subscapularis muscle is innervated by the upper and lower subscapular nerves, branches of the brachial plexus (C5-C6).

Distinguishing Symptoms When There's an Issue:

• Pain in the anterior shoulder or deep in the shoulder joint.

• Weakness in internal rotation of the shoulder.

• Restricted range of motion, especially during activities involving internal rotation.

Issues:

• Strains or tears of the subscapularis muscle can occur due to trauma or overuse, leading to pain and reduced function.

• Inflammation or tendinopathy of the subscapularis tendon can cause pain and limitation in shoulder movement.

Understanding the anatomy and function of the subscapular fossa and its associated structures is crucial for diagnosing and treating shoulder-related issues effectively.