Shoulder Joint – Anatomy, Nerve Supply, Functions

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 9 min read
Patient Tools

Read, save, and share this guide

Use these quick tools to make this medical article easier to read, print, save, or share with a family member.

Patient Mode

Understand this article easily

Switch between simple English and easy Bangla patient notes. This is for education and does not replace a doctor consultation.

The shoulder joint, also known as the glenohumeral joint, is a ball and socket joint with the most extensive range of motion in the human body. The muscles of the shoulder have a wide range of functions, including abduction, adduction, flexion, extension, internal and external rotation. [rx] The...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

The shoulder joint, also known as the glenohumeral joint, is a ball and socket joint with the most extensive range of motion in the human body. The muscles of the shoulder have a wide range of functions, including abduction, adduction, flexion, extension, internal and external rotation. [rx] The central bony structure of the shoulder is the scapula, where all of the muscles interact. At the lateral aspect of...

Key Takeaways

  • This article explains Structure of Shoulder Joint in simple medical language.
  • This article explains Blood Supply of Shoulder Joint in simple medical language.
  • This article explains Nerves in simple medical language.
  • This article explains The Major Movements At The Glenohumeral Joint  in simple medical language.
Educational health guideWritten for patient understanding and clinical awareness.
Reviewed content workflowUse writer and reviewer profiles for stronger trust.
Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

Before reading

RX Patient Tools

Use these quick guides before reading the article, or return to them when you need help preparing questions for a doctor.

Start here Choose the right pathway for symptoms, reports, medicines, or urgent warning signs. Disease article roadmap Read this topic step by step: meaning, symptoms, warning signs, diagnosis, treatment, prevention, and follow-up. Treatment planner Prepare questions about treatment choices, benefits, risks, side effects, and follow-up. Family & caregiver guide Organize symptoms, reports, medicines, questions, and follow-up safely. Nutrition & diet guide Prepare food, hydration, supplement, and medicine-timing questions safely. Prevention guide Organize risk factors, protective habits, screening, and warning signs. Recovery guide Prepare a safe plan for activity, rehabilitation, warning signs, and follow-up.
Definition

The shoulder joint, also known as the glenohumeral joint, is a ball and socket joint with the most extensive range of motion in the human body. The muscles of the shoulder have a wide range of functions, including abduction, adduction, flexion, extension, internal and external rotation.  The central bony structure of the shoulder is the scapula, where all of the muscles interact. At the lateral aspect of the scapula is the articular surface of the glenohumeral joint, the glenoid cavity.  The glenoid cavity is peripherally surrounded and reinforced by the glenoid labrum, shoulder joint capsule, supporting ligaments, and the myotendinous attachments of the rotator cuff muscles.  The muscles of the shoulder play a critical role in providing stability to the shoulder joint.  The primary muscle group that supports the shoulder joint is the rotator cuff muscles.  The four rotator cuff muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis. 

Structure of Shoulder Joint

The upper extremity is attached to the axial skeleton by way of the sternoclavicular joint.  The three joints of the pectoral girdle are the sternoclavicular joint, coracoclavicular joint, and the acromioclavicular joint.  The bones of the pectoral girdle are the clavicle, scapula, and humerus.  The clavicle is positioned immediately superior to the first rib.  The distal aspect of the clavicle articulates with the acromial process and coracoid process of the scapula, forming the acromioclavicular joint and coracoclavicular joints, respectively.  The most important structural ligaments of the shoulder joint are the glenohumeral ligaments and the coracoacromial ligament.

The scapula is a flat bone with multiple muscular attachments.  The glenoid fossa serves the articulating function with the humeral head at the lateral angle of the scapula.  The glenohumeral joint is the point of articulation between the humerus and the scapula and thoracic cavity, with the latter occurring through the scapulothoracic articulation.  The scapula connects to the clavicle via the coracoclavicular joint and the acromioclavicular joint.

The coracoclavicular joint is strengthened by the coracoclavicular ligament that unites the undersurface of the clavicle to the coracoid process of the scapula.  The acromioclavicular joint is at the lateral aspect of the clavicle and does not provide much structural support to the shoulder joint.  The coracoid process, the acromion process, and coracoacromial ligament provide peripheral reinforcement for the shoulder joint along with the muscles of the shoulder.  The shoulder muscles and peripheral structures of the shoulder function to increase the structural integrity of the shoulder joint.

Blood Supply of Shoulder Joint

The arterial supply to the upper extremity originates from the subclavian artery.  These vessels exist on both sides of the body to provide upper extremity blood supply.  Both arteries receive their blood supply from the arch of the aorta.  On both sides of the body, the subclavian artery branches include the vertebral artery, internal thoracic artery, thyrocervical trunk, and dorsal scapular artery.

The subclavian artery becomes the axillary artery once it reaches the lateral border of the first rib.

There are three parts to the axillary artery, with each portion having arterial branches to supply the muscles of the shoulder.  Multiple arteries branch from the axillary artery including the superior thoracic artery, thoracoacromial artery, circumflex humeral artery, and the lateral thoracic artery.  The subscapular artery is a division of the third part of the axillary artery.  The subscapular artery gives off the circumflex scapular artery and the thoracodorsal artery.  In general, the muscles of the shoulder receive vascular supply by named arteries associated with the muscles that they supply.

Efferent lymphatic vessels arise from the distal upper extremity and pass through the shoulder.  Additionally, axillary lymph nodes contribute to efferent lymphatic vessels in the region of the shoulder and pass proximally through the shoulder.  Deep lymphatic vessels accompany superficial lymphatic vessels.  The deep lymphatic vessels drain lymph from the joint capsule, tendons, and nerves.  The lymphatics of the shoulder and axillary region are drained by the subclavian lymphatic trunk.  On the right, the subclavian trunk drains into the right lymphatic duct.  On the left, the subclavian trunk drains into the thoracic duct.

Nerves

The upper and lower branches of the subscapular nerve innervate the subscapularis muscle.  The suprascapular nerve innervates the supraspinatus and infraspinatus muscles. The posterior branch of the axillary nerve supplies the teres minor.  The axillary nerve also innervates the deltoid muscle.  The nerve supply to the trapezius is by the spinal accessory nerve/11th cranial nerve with some direct branches from cervical plexus.  Innervation to levator scapula is by C3-C5.  The nerve supply to the rhomboids is the dorsal scapular nerve.  The nerve supply to serratus anterior is the long thoracic nerve. The pectoralis major muscle receives its nerve supply via the medial and lateral pectoral nerves.

The Major Movements At The Glenohumeral Joint 

  • Abduction – upward lateral movement of humerus out to the side, away from the body, in the plane of the scapula
  • Adduction – downward movement of humerus medially toward the body from abduction, in the plane of the scapula
  • Flexion – the movement of humerus straight anteriorly
  • Extension – the movement of humerus straight posteriorly
  • External rotation – the movement of humerus laterally around its long axis away from the midline
  • Internal rotation – the movement of humerus medially around its long axis toward the midline
  • Horizontal adduction (transverse flexion) – the movement of the humerus in a horizontal or transverse plane toward and across the chest
  • Horizontal abduction (transverse extension) – the movement of the humerus in a horizontal or transverse plane away from the chest

Muscles Attachment of Shoulder Joint

The intrinsic muscles of the shoulder connect the scapula and/or clavicle to the humerus. These include

Deltoid

  • Function:

    • Anterior aspect is responsible for flexion and medial rotation of the arm
    • Middle aspect is responsible for the abduction of the arm (up to 90 degrees)
    • The posterior aspect is responsible for extension and lateral rotation of the arm
  • Origin: Lateral clavicle, acromion and scapular spine
  • Insertion: Deltoid tuberosity
  • Innervation: Axillary nerve (C5, C6)
Teres major
  • Function: Adduction and medial rotation of the arm
  • Origin: Posterior surface of the scapula at its inferior angle
  • Insertion: Intertubercular groove of the proximal humerus on its medial aspect
  • Innervation: Lower scapular nerve (C5, C6)
Supraspinatus (Rotator Cuff)
  • Function: Initiation of arm abduction (first 15 degrees), stabilize glenohumeral joint
  • Origin: Posterior scapula, superior to the scapular spine/supraspinous fossa
  • Insertion: Top of the greater tubercle of the humerus
  • Innervation: Suprascapular nerve (C5, C6)
Infraspinatus (Rotator Cuff)
  • Function: Lateral rotation of the arm, stabilize glenohumeral joint
  • Origin: Posterior scapula, inferior to the scapular spine/Infraspinous fossa
  • Insertion: Greater tubercle of the humerus, between the supraspinatus and teres minor insertion
  • Innervation: Suprascapular nerve (C5, C6)
Teres minor (Rotator Cuff)
  • Function: Lateral rotation of the arm, stabilize glenohumeral joint
  • Origin: Inferior angle of the scapula
  • Insertion: Inferior aspect of the greater tubercle
  • Innervation: Axillary nerve (C5, C6)
Subscapularis (Rotator Cuff)
  • Function: Adduction and medial rotation of the arm, stabilize glenohumeral joint
  • Origin: Anterior aspect of the scapula
  • Insertion: Lesser tubercle of the humerus
  • Innervation: Subscapular nerves (C5, C6, C7)

Other muscles that affect movement at the shoulder joint include:

Trapezius

  • Function:

    • Upper fibers elevate the scapula and rotate it during abduction of the arm (90 to 180 degrees)
    • Middle fibers retract the scapula
    • Lower fibers pull the scapula inferiorly.
  • Origin: Skull, nuchal ligament and the spinous processes of C7 to T12
  • Insertion: clavicle, acromion and the scapular spine
  • Innervation: Accessory nerve (C5, C6)
Latissmus dorsi
  • Function: Extends, adducts and medially rotates the upper limb
  • Origin: Spinous processes of T6 to T12, iliac crest, thoracolumbar fascia, and the inferior three ribs
  • Insertion: Intertubercular sulcus of the humerus
  • Innervation: Thoracodorsal nerve (C6, C7, C8)
Levator scapulae
  • Function: Elevates the scapula
  • Origin: Transverse processes of the C1 to C4 vertebrae
  • Insertion: Medial border of the scapula
  • Innervation: Dorsal scapular nerve (C5)
Rhomboid major
  • Function: Retracts and rotates the scapula
  • Origin: Spinous processes of T2 to T5 vertebrae
  • Insertion: Inferomedial border of the scapula
  • Innervation: Dorsal scapular nerve (C5)
Rhomboid minor
  • Function: Retracts and rotates the scapula
  • Origin: Spinous processes of C7 to T1 vertebrae
  • Insertion: Medial border of the scapula
  • Innervation: Dorsal scapular nerve (C5)
Serratus anterior
  • Function: fixes the scapula into the thoracic wall, and aids in rotation and abduction of the arm (90 to 180 degrees)
  • Origin: Surface of the upper eight ribs at the side of the chest
  • Insertion: Along the entire anterior length of the medial border of the scapula
  • Innervation: Long thoracic nerve (C5, C6, C7)
Pectoralis major

  • Function:

    • Clavicular head flexes and adducts arm
    • Sternal head adducts and medially rotates the arm
    • Accessory for inspiration

  • Origin:

    • Clavicular head: medial half clavicle
    • Sternocostal head: Lateral manubrium and sternum, six upper costal cartilages and external oblique aponeurosis
  • Insertion: Intertubercular groove of the proximal humerus on its lateral aspect
  • Innervation: Medial and lateral pectoral nerves (C6, C7, C8)
Pectoralis minor
  • Function: Depression of the shoulder, protraction of the scapula
  • Origin: Third, fourth, fifth ribs close to their respective costal cartilages
  • Insertion: Coracoid process
  • Innervation: Medial pectoral nerve (C8, T1)
Subclavius
  • Function: Depression and stabilization of the clavicle
  • Origin: First rib medially
  • Insertion: Middle of the clavicle, inferiorly
  • Innervation: Nerve to subclavius (C5, C6)
Coracobrachialis
  • Function: Flexion and adduction of the arm
  • Origin: Coracoid process
  • Insertion: Middle of the humerus, on its medial aspect
  • Innervation: Musculocutaneous nerve (C5, C6, C7)
Biceps brachii
  • Function: Resists dislocation of the shoulder, flexion of the forearm, supination of the forearm

  • Origin:

    • Short head: coracoid process
    • Long head: supraglenoid tubercle of the scapula and superior labrum
  • Insertion: Radial tuberosity of radius and forearm fascia (as bicipital aponeurosis)
  • Innervation: Musculocutaneous nerve (C5, C6)
Triceps brachii
  • Function: Resists dislocation of the shoulder, major extensor of the forearm

  • Origin:

    • Lateral head: above the radial groove of the humerus,
    • Medial head: below the radial groove of the humerus
    • Long head: infraglenoid tubercle of the scapula
  • Insertion: Olecranon process of ulna and forearm fascia
  • Innervation: Radial nerve (C6, C7, C8)

References

Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Orthopedic doctor, rheumatologist, or physiotherapist depending on cause.

What to tell the doctor

  • Write which joints hurt, swelling, morning stiffness duration, fever, injury, and walking difficulty.
  • Bring X-ray, uric acid, ESR/CRP, rheumatoid factor, or previous reports if available.

Questions to ask

  • Is this injury, osteoarthritis, rheumatoid arthritis, gout, infection, or another cause?
  • Which exercises, supports, or lifestyle changes are safe?
  • Do I need blood tests or X-ray?

Tests to discuss

  • Joint examination and range of motion
  • X-ray when chronic arthritis or injury is suspected
  • ESR/CRP, uric acid, rheumatoid tests when inflammatory arthritis is suspected

Avoid these mistakes

  • Do not ignore hot swollen joint with fever.
  • Avoid repeated steroid injections/tablets without a clear diagnosis and follow-up.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
  • Use comfortable posture and gentle movement as tolerated.
  • Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
  • Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Orthopedic / spine specialist, physical medicine doctor, or qualified clinician
Tests to discuss with doctor
  • Neurological examination for leg power, sensation, reflexes, and straight leg raise
  • X-ray only if injury, deformity, long-lasting pain, or doctor suspects bone problem
  • MRI discussion if severe nerve symptoms, weakness, bladder/bowel problem, or persistent symptoms
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?
  • Is physiotherapy, posture correction, or activity modification needed?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Shoulder Joint – Anatomy, Nerve Supply, Functions

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

RX Patient Help

Ask a health question safely

Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area from the RX Article Professional Blocks panel.

More from this topic
  1. How to Reset Your Body from Chronic Stress?

    Chronic? stress isn’t something that arrives very loudly. It builds very slowly — and tight shoulders, having poor sleep, feeling constantly fatigue?, feeling irritable, or just...

    April 7, 2026 • Top Global News
  2. Undescended Shoulder Disease

    DefinitionUndescended shoulder disease is not the usual medical name. Doctors usually call this condition Sprengel deformity, Sprengel shoulder, congenital? high scapula, or congenital? elevation of the...

    April 3, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  3. Sprengel Deformity

    DefinitionSprengel deformity is a birth condition in which one shoulder blade, called the scapula, stays higher than normal because it does not move down to its...

    April 2, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  4. High Shoulder Blade

    DefinitionA high shoulder blade usually means one shoulder blade sits higher than normal from birth. The medical name is Sprengel deformity or congenital? high scapula. “Scapula”...

    April 2, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  5. High Scapula

    DefinitionHigh scapula is a condition where one shoulder blade sits higher than normal on the back from birth. Doctors usually call it Sprengel deformity, congenital? high...

    April 2, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  6. Upward Displacement of the Scapula

    DefinitionUpward displacement of the scapula usually means congenital? elevation of the scapula, which is most often called Sprengel deformity or Sprengel shoulder. In this condition, one...

    April 2, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  7. Congenital Elevation of Scapula

    DefinitionCongenital? elevation of scapula means a baby is born with one shoulder blade sitting higher than normal. The shoulder blade is called the scapula. In this...

    April 2, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  8. Congenital Elbow Dislocation

    DefinitionCongenital? elbow dislocation usually means a baby is born with abnormal alignment around the elbow joint, most often a congenital? radial head dislocation. It is rare,...

    April 2, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)
  9. Congenital Contractural Arachnodactyly

    DefinitionCongenital? contractural arachnodactyly is a rare genetic connective tissue disorder that mainly affects the bones, joints, muscles, ears, and body shape. “Congenital?” means it is present...

    March 30, 2026 • Rx Autoimmune, Genetic and Rare Diseases (A - Z)
  10. Humero-Radio-Ulnar Intercalary Transverse Meromelia

    DefinitionHumero-radio-ulnar intercalary transverse meromelia is a rare birth defect of the arm. In this condition the upper arm bone (humerus) and the two forearm bones (radius...

    March 5, 2026 • Degenerative Bones, Joints, and Spine Care (A - Z)