FULL VIDEO: Main muscles of the upper limb - Human Anatomy | Kenhub

Summary

This tutorial delves into the complex anatomy of the upper limb's muscles, categorizing them into shoulder, arm, forearm, and hand regions. It highlights the deltoid and rotator cuff muscles of the shoulder, emphasizing their role in abduction and rotation. Moving to the arm, it distinguishes between the flexor muscles like biceps brachii and the extensor triceps brachii. The forearm's muscles are detailed, with the anterior compartment's flexors and the posterior's extensors, including the supinator's unique action. The hand's intrinsic muscles are also explored for their role in fine motor skills. The script concludes with insights on rotator cuff injuries, their symptoms, and treatment.

Takeaways

• 💪 The upper limb muscles are crucial for movement and can be divided into regions: shoulder, arm, forearm, and hand.
• 🏋️‍♀️ The shoulder region muscles include the deltoid and the rotator cuff muscles, which are essential for abduction, rotation, and stabilization of the arm.
• 🤲 The arm muscles are divided into anterior (flexors) and posterior (extensors) groups, with the biceps brachii and triceps brachii being key players.
• 🙌 The forearm muscles are complex, with the anterior compartment muscles primarily responsible for flexion and the posterior for extension.
• 🤞 The intrinsic muscles of the hand, including the thenar and hypothenar muscles, are vital for fine motor movements and manipulation.
• 🤕 Rotator cuff injuries are common and can result from overuse or acute trauma, often requiring rest, ice, and sometimes surgery.
• 🏥 Clinically, it's important to maintain muscle balance around the shoulder joint to prevent injuries like rotator cuff strains.
• 🔍 The script provides a detailed anatomical review, highlighting the origins, insertions, and actions of various upper limb muscles.
• 📚 Learning about these muscles helps in understanding human movement and is beneficial for healthcare professionals and fitness enthusiasts.
• 📖 For further study, the script encourages visiting Kenhub.com for articles, quizzes, and anatomical images to deepen knowledge of anatomy.

Q & A

What are the main muscles of the shoulder region?

The main muscles of the shoulder region include the deltoid muscle, which is superficial, and the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) which are deep muscles. The teres major is also a deep muscle of the shoulder but does not contribute to the rotator cuff.

What is the function of the deltoid muscle?

The deltoid muscle is the major abductor of the arm at the shoulder joint, moving the arm away from the midline of the body.

Why are the rotator cuff muscles called 'rotator cuff'?

The term 'rotator' comes from the rotational movement these muscles elicit when they contract, and 'cuff' originates from their positioning as they extend from the scapula and cuff the head of the humerus.

What is the SITS mnemonic for remembering the rotator cuff muscles?

SITS is a mnemonic where S stands for supraspinatus, I for infraspinatus, T for teres minor, and the final S for subscapularis.

Which muscles are primarily responsible for the rotational movements of the arm at the shoulder joint?

The deep muscles of the shoulder, specifically the rotator cuff muscles and the teres major, are responsible for the rotational movements of the arm at the shoulder joint.

What are the main muscles of the anterior compartment of the arm?

The main muscles of the anterior compartment of the arm include the biceps brachii, coracobrachialis, and brachialis muscles.

What is the primary function of the biceps brachii muscle?

The biceps brachii muscle is one of the major muscles of the arm and contributes to movement at both the shoulder and elbow joints.

How does the brachialis muscle differ from the biceps brachii muscle in terms of function?

The brachialis muscle is a large and powerful muscle that acts only on the elbow joint, being the main and most powerful flexor of the forearm at the elbow.

What is the main muscle of the posterior compartment of the arm?

The triceps brachii is the main muscle of the posterior compartment of the arm, acting at both the shoulder and elbow joints.

What are the main actions of the muscles in the anterior compartment of the forearm?

The muscles in the anterior compartment of the forearm are predominantly flexors, with some contributing to other movements such as adduction of the arm and supination of the forearm.

What is the main action of the triceps brachii muscle?

The triceps brachii muscle extends the arm and forearm posteriorly at the shoulder and elbow joints.

Which muscles are considered the main superficial muscles of the anterior forearm?

The main superficial muscles of the anterior forearm include the pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and flexor digitorum superficialis muscles.

What is the unique action performed by the supinator muscle in the posterior forearm?

The supinator muscle produces supination of the forearm and wrist at the radioulnar joints.

How are the muscles of the hand divided?

The muscles of the hand are divided into intrinsic and extrinsic muscles. Intrinsic muscles originate and insert within the hand, while extrinsic muscles originate in the arm or forearm and insert onto the palmar and dorsal surfaces of the hand and digits.

What are the five groups of intrinsic muscles of the hand?

The five groups of intrinsic muscles of the hand are the dorsal interossei, palmar interossei, lumbricals, hypothenar muscles, and thenar muscles.

What is a rotator cuff strain and what are its symptoms?

A rotator cuff strain occurs when the tendons of the rotator cuff muscles become overstretched or torn. Symptoms include pain on lifting or rotating the arm, swelling around the shoulder, and shoulder joint stiffness.